Merge branch 'main' of github.com:SigNoz/signoz into feat/trace-flamegraph

frontend/src/components/TimelineV3/TimelineV3.styles.scss

@@ -0,0 +1,4 @@
+.timeline-v3-container {
+	// flex: 1;
+	overflow: visible;
+}

frontend/src/components/TimelineV3/TimelineV3.tsx

@@ -0,0 +1,87 @@
+import { useEffect, useState } from 'react';
+import { useMeasure } from 'react-use';
+import { useIsDarkMode } from 'hooks/useDarkMode';
+
+import {
+	getIntervals,
+	getMinimumIntervalsBasedOnWidth,
+	Interval,
+} from './utils';
+
+import './TimelineV3.styles.scss';
+
+interface ITimelineV3Props {
+	startTimestamp: number;
+	endTimestamp: number;
+	timelineHeight: number;
+	offsetTimestamp: number;
+}
+
+function TimelineV3(props: ITimelineV3Props): JSX.Element {
+	const {
+		startTimestamp,
+		endTimestamp,
+		timelineHeight,
+		offsetTimestamp,
+	} = props;
+	const [intervals, setIntervals] = useState<Interval[]>([]);
+	const [ref, { width }] = useMeasure<HTMLDivElement>();
+	const isDarkMode = useIsDarkMode();
+
+	useEffect(() => {
+		const spread = endTimestamp - startTimestamp;
+		if (spread < 0) {
+			return;
+		}
+
+		const minIntervals = getMinimumIntervalsBasedOnWidth(width);
+		const intervalisedSpread = (spread / minIntervals) * 1.0;
+		const intervals = getIntervals(intervalisedSpread, spread, offsetTimestamp);
+
+		setIntervals(intervals);
+	}, [startTimestamp, endTimestamp, width, offsetTimestamp]);
+
+	if (endTimestamp < startTimestamp) {
+		console.error(
+			'endTimestamp cannot be less than startTimestamp',
+			startTimestamp,
+			endTimestamp,
+		);
+		return <div />;
+	}
+
+	const strokeColor = isDarkMode ? ' rgb(192,193,195,0.8)' : 'black';
+
+	return (
+		<div ref={ref as never} className="timeline-v3-container">
+			<svg
+				width={width}
+				height={timelineHeight * 2.5}
+				xmlns="http://www.w3.org/2000/svg"
+				overflow="visible"
+			>
+				{intervals &&
+					intervals.length > 0 &&
+					intervals.map((interval, index) => (
+						<g
+							transform={`translate(${(interval.percentage * width) / 100},0)`}
+							key={`${interval.percentage + interval.label + index}`}
+							textAnchor="middle"
+							fontSize="0.6rem"
+						>
+							<text
+								x={index === intervals.length - 1 ? -10 : 0}
+								y={timelineHeight * 2}
+								fill={strokeColor}
+							>
+								{interval.label}
+							</text>
+							<line y1={0} y2={timelineHeight} stroke={strokeColor} strokeWidth="1" />
+						</g>
+					))}
+			</svg>
+		</div>
+	);
+}
+
+export default TimelineV3;

frontend/src/components/TimelineV3/utils.ts

@@ -0,0 +1,93 @@
+import {
+	IIntervalUnit,
+	Interval,
+	INTERVAL_UNITS,
+	resolveTimeFromInterval,
+} from 'components/TimelineV2/utils';
+import { toFixed } from 'utils/toFixed';
+
+export type { Interval };
+
+/** Fewer intervals than TimelineV2 for a cleaner flamegraph ruler. */
+export function getMinimumIntervalsBasedOnWidth(width: number): number {
+	if (width < 640) {
+		return 3;
+	}
+	if (width < 768) {
+		return 4;
+	}
+	if (width < 1024) {
+		return 5;
+	}
+	return 6;
+}
+
+/**
+ * Computes timeline intervals with offset-aware labels.
+ * Labels reflect absolute time from trace start (offsetTimestamp + elapsed),
+ * so when zoomed into a window, the first tick shows e.g. "50ms" not "0ms".
+ */
+export function getIntervals(
+	intervalSpread: number,
+	baseSpread: number,
+	offsetTimestamp: number,
+): Interval[] {
+	const integerPartString = intervalSpread.toString().split('.')[0];
+	const integerPartLength = integerPartString.length;
+
+	const intervalSpreadNormalized =
+		intervalSpread < 1.0
+			? intervalSpread
+			: Math.floor(Number(integerPartString) / 10 ** (integerPartLength - 1)) *
+			  10 ** (integerPartLength - 1);
+
+	// Unit must suit both: (1) tick granularity (intervalSpread) and (2) label magnitude
+	// (offsetTimestamp). When zoomed deep into a trace, labels show offsetTimestamp + elapsed,
+	// so we must pick a unit where that value is readable (e.g. "500.00s" not "500000.00ms").
+	const valueForUnitSelection = Math.max(offsetTimestamp, intervalSpread);
+	let intervalUnit: IIntervalUnit = INTERVAL_UNITS[0];
+	for (let idx = INTERVAL_UNITS.length - 1; idx >= 0; idx -= 1) {
+		const standardInterval = INTERVAL_UNITS[idx];
+		if (valueForUnitSelection * standardInterval.multiplier >= 1) {
+			intervalUnit = INTERVAL_UNITS[idx];
+			break;
+		}
+	}
+
+	const intervals: Interval[] = [
+		{
+			label: `${toFixed(
+				resolveTimeFromInterval(offsetTimestamp, intervalUnit),
+				2,
+			)}${intervalUnit.name}`,
+			percentage: 0,
+		},
+	];
+
+	let tempBaseSpread = baseSpread;
+	let elapsedIntervals = 0;
+
+	while (tempBaseSpread && intervals.length < 20) {
+		let intervalTime: number;
+
+		if (tempBaseSpread <= 1.5 * intervalSpreadNormalized) {
+			intervalTime = elapsedIntervals + tempBaseSpread;
+			tempBaseSpread = 0;
+		} else {
+			intervalTime = elapsedIntervals + intervalSpreadNormalized;
+			tempBaseSpread -= intervalSpreadNormalized;
+		}
+
+		elapsedIntervals = intervalTime;
+		const labelTime = offsetTimestamp + intervalTime;
+
+		intervals.push({
+			label: `${toFixed(resolveTimeFromInterval(labelTime, intervalUnit), 2)}${
+				intervalUnit.name
+			}`,
+			percentage: (intervalTime / baseSpread) * 100,
+		});
+	}
+
+	return intervals;
+}

frontend/src/constants/theme.ts

@@ -33,6 +33,125 @@ const themeColors = {
 		purple: '#800080',
 		cyan: '#00FFFF',
 	},
+	traceDetailColorsV3: {
+		// Blues
+		dodgerBlue: '#2F80ED',
+		royalBlue: '#3366E6',
+		steelBlue: '#4682B4',
+
+		// Teals / Cyans
+		turquoise: '#00CEC9',
+		lagoon: '#1ABC9C',
+		cyanBright: '#22A6F2',
+
+		// Greens
+		emeraldGreen: '#27AE60',
+		mediumSeaGreen: '#3CB371',
+		limeGreen: '#A3E635',
+
+		// Yellows / Golds
+		festivalYellow: '#F2C94C',
+		sunflower: '#FFD93D',
+		warmAmber: '#FFCA28',
+
+		// Purples / Violets
+		mediumPurple: '#BB6BD9',
+		royalPurple: '#9B51E0',
+		orchid: '#DA77F2',
+
+		// Accent
+		neonViolet: '#C77DFF',
+		electricPurple: '#6C5CE7',
+		arcticBlue: '#48DBFB',
+
+		// Blues extended
+		blue1: '#1F63E0',
+		blue2: '#3A7AED',
+		blue3: '#5A9DF5',
+		blue4: '#2874A6',
+		blue5: '#2E86C1',
+		blue6: '#3498DB',
+
+		// Cyans
+		cyan1: '#00B0AA',
+		cyan2: '#33D6C2',
+		cyan3: '#66E9DA',
+
+		// Greens extended
+		green1: '#1E8449',
+		green2: '#2ECC71',
+		green3: '#58D68D',
+		green4: '#229954',
+		green5: '#27AE60',
+		green6: '#52BE80',
+
+		// Forest
+		forest1: '#27AE60',
+		forest2: '#2ECC71',
+		forest3: '#58D68D',
+
+		// Lime
+		lime1: '#A3E635',
+		lime2: '#B9F18D',
+		lime3: '#D4FFB0',
+
+		// Teals
+		teal1: '#009688',
+		teal2: '#1ABC9C',
+		teal3: '#48C9B0',
+		teal4: '#1ABC9C',
+		teal5: '#48C9B0',
+		teal6: '#76D7C4',
+
+		// Yellows
+		yellow1: '#F1C40F',
+		yellow2: '#F7DC6F',
+		yellow3: '#F9E79F',
+
+		// Gold
+		gold1: '#F39C12',
+		gold2: '#F1C40F',
+		gold3: '#F7DC6F',
+		gold4: '#B7950B',
+		gold5: '#F1C40F',
+		gold6: '#F4D03F',
+
+		// Mustard
+		mustard1: '#F1C40F',
+		mustard2: '#F7DC6F',
+		mustard3: '#F9E79F',
+
+		// Aqua
+		aqua1: '#00BFFF',
+		aqua2: '#1E90FF',
+		aqua3: '#63B8FF',
+
+		// Purple extended
+		purple1: '#8E44AD',
+		purple2: '#9B59B6',
+		purple3: '#BB8FCE',
+
+		violet1: '#8E44AD',
+		violet2: '#9B59B6',
+		violet3: '#BB8FCE',
+		violet4: '#7D3C98',
+		violet5: '#8E44AD',
+		violet6: '#9B59B6',
+
+		// Lavender
+		lavender1: '#9B59B6',
+		lavender2: '#AF7AC5',
+		lavender3: '#C39BD3',
+
+		// Oranges (safe ones, not red-ish)
+		orange4: '#D35400',
+		orange5: '#E67E22',
+		orange6: '#EB984E',
+
+		coral1: '#E67E22',
+		coral2: '#F39C12',
+		coral3: '#F5B041',
+	},
 	chartcolors: {
 		// Blues (3)
 		dodgerBlue: '#2F80ED',

frontend/src/pages/TraceDetailV2/index.tsx

@@ -4,19 +4,11 @@ import ROUTES from 'constants/routes';
 import history from 'lib/history';
 import { Compass, Cone, TowerControl } from 'lucide-react';
 
-import TraceDetailsV2 from './TraceDetailV2';
+import TraceDetailsV3 from '../TraceDetailsV3';
 
 import './TraceDetailV2.styles.scss';
 
-interface INewTraceDetailProps {
+function NewTraceDetail(props: any): JSX.Element {
-	items: {
-		label: JSX.Element;
-		key: string;
-		children: JSX.Element;
-	}[];
-}
-
-function NewTraceDetail(props: INewTraceDetailProps): JSX.Element {
 	const { items } = props;
 	return (
 		<div className="traces-module-container">
@@ -50,7 +42,7 @@ export default function TraceDetailsPage(): JSX.Element {
 				</div>
 			),
 			key: 'trace-details',
-			children: <TraceDetailsV2 />,
+			children: <TraceDetailsV3 />,
 		},
 		{
 			label: (

frontend/src/pages/TraceDetailsV3/TraceDetailsHeader/TraceDetailsHeader.styles.scss

@@ -0,0 +1,91 @@
+.trace-details-header {
+	display: flex;
+	align-items: center;
+	padding: 0px 16px;
+
+	.previous-btn {
+		display: flex;
+		height: 30px;
+		padding: 6px 8px;
+		align-items: center;
+		gap: 4px;
+		border: 1px solid var(--bg-slate-300);
+		background: var(--bg-slate-500);
+		border-radius: 4px;
+		box-shadow: none;
+	}
+
+	.trace-name {
+		display: flex;
+		padding: 6px 8px;
+		margin-left: 6px;
+		align-items: center;
+		gap: 4px;
+		border: 1px solid var(--bg-slate-300);
+		border-radius: 4px 0px 0px 4px;
+		background: var(--bg-slate-500);
+
+		.drafting {
+			color: white;
+		}
+
+		.trace-id {
+			color: #fff;
+			font-family: Inter;
+			font-size: 13px;
+			font-style: normal;
+			font-weight: 400;
+			line-height: 18px;
+			letter-spacing: -0.07px;
+		}
+	}
+
+	.trace-id-value {
+		display: flex;
+		padding: 6px 8px;
+		justify-content: center;
+		align-items: center;
+		gap: 10px;
+		background: var(--bg-slate-400);
+		color: var(--Vanilla-400, #c0c1c3);
+		font-family: Inter;
+		font-size: 13px;
+		font-style: normal;
+		font-weight: 400;
+		line-height: 18px;
+		letter-spacing: -0.07px;
+		border: 1px solid var(--bg-slate-300);
+		border-left: unset;
+		border-radius: 0px 4px 4px 0px;
+	}
+}
+
+.lightMode {
+	.trace-details-header {
+		.previous-btn {
+			border: 1px solid var(--bg-vanilla-300);
+			background: var(--bg-vanilla-200);
+		}
+
+		.trace-name {
+			border: 1px solid var(--bg-vanilla-300);
+			background: var(--bg-vanilla-200);
+			border-right: none;
+
+			.drafting {
+				color: var(--bg-ink-100);
+			}
+
+			.trace-id {
+				color: var(--bg-ink-100);
+			}
+		}
+
+		.trace-id-value {
+			background: var(--bg-vanilla-300);
+			color: var(--bg-ink-400);
+			border: 1px solid var(--bg-vanilla-300);
+		}
+	}
+}
+// TODO: move to new css module name system

frontend/src/pages/TraceDetailsV3/TraceDetailsHeader/TraceDetailsHeader.tsx

@@ -0,0 +1,38 @@
+import { useCallback } from 'react';
+import { useParams } from 'react-router-dom';
+import { Button, Typography } from 'antd';
+import ROUTES from 'constants/routes';
+import history from 'lib/history';
+import { ArrowLeft } from 'lucide-react';
+import { TraceDetailV2URLProps } from 'types/api/trace/getTraceV2';
+
+import './TraceDetailsHeader.styles.scss';
+
+function TraceDetailsHeader(): JSX.Element {
+	const { id: traceID } = useParams<TraceDetailV2URLProps>();
+
+	const handlePreviousBtnClick = useCallback((): void => {
+		const isSpaNavigate =
+			document.referrer &&
+			new URL(document.referrer).origin === window.location.origin;
+		if (isSpaNavigate) {
+			history.goBack();
+		} else {
+			history.push(ROUTES.TRACES_EXPLORER);
+		}
+	}, []);
+
+	return (
+		<div className="trace-details-header">
+			<Button className="previous-btn" onClick={handlePreviousBtnClick}>
+				<ArrowLeft size={14} />
+			</Button>
+			<div className="trace-name">
+				<Typography.Text className="trace-id">Trace ID</Typography.Text>
+			</div>
+			<Typography.Text className="trace-id-value">{traceID}</Typography.Text>
+		</div>
+	);
+}
+
+export default TraceDetailsHeader;

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/FlamegraphCanvas.tsx

@@ -0,0 +1,237 @@
+import React, { useCallback, useEffect, useRef, useState } from 'react';
+import { createPortal } from 'react-dom';
+import TimelineV3 from 'components/TimelineV3/TimelineV3';
+import { useIsDarkMode } from 'hooks/useDarkMode';
+
+import { DEFAULT_ROW_HEIGHT } from './constants';
+import { useCanvasSetup } from './hooks/useCanvasSetup';
+import { useFlamegraphDrag } from './hooks/useFlamegraphDrag';
+import { useFlamegraphDraw } from './hooks/useFlamegraphDraw';
+import { useFlamegraphHover } from './hooks/useFlamegraphHover';
+import { useFlamegraphZoom } from './hooks/useFlamegraphZoom';
+import { useScrollToSpan } from './hooks/useScrollToSpan';
+import { FlamegraphCanvasProps, SpanRect } from './types';
+import { formatDuration } from './utils';
+
+function FlamegraphCanvas(props: FlamegraphCanvasProps): JSX.Element {
+	const { spans, traceMetadata, firstSpanAtFetchLevel, onSpanClick } = props;
+
+	const isDarkMode = useIsDarkMode(); //TODO: see if can be removed or use a new hook
+	const canvasRef = useRef<HTMLCanvasElement>(null);
+	const containerRef = useRef<HTMLDivElement>(null);
+	const spanRectsRef = useRef<SpanRect[]>([]);
+
+	const [viewStartTs, setViewStartTs] = useState<number>(
+		traceMetadata.startTime,
+	);
+	const [viewEndTs, setViewEndTs] = useState<number>(traceMetadata.endTime);
+	const [scrollTop, setScrollTop] = useState<number>(0);
+	const [rowHeight, setRowHeight] = useState<number>(DEFAULT_ROW_HEIGHT);
+
+	// Mutable refs for zoom and drag hooks to read during rAF / mouse callbacks
+	const viewStartRef = useRef(viewStartTs);
+	const viewEndRef = useRef(viewEndTs);
+	const rowHeightRef = useRef(rowHeight);
+	const scrollTopRef = useRef(scrollTop);
+
+	useEffect(() => {
+		viewStartRef.current = viewStartTs;
+	}, [viewStartTs]);
+
+	useEffect(() => {
+		viewEndRef.current = viewEndTs;
+	}, [viewEndTs]);
+
+	useEffect(() => {
+		rowHeightRef.current = rowHeight;
+	}, [rowHeight]);
+
+	useEffect(() => {
+		scrollTopRef.current = scrollTop;
+	}, [scrollTop]);
+
+	useEffect(() => {
+		//TODO: see if this can be removed as once loaded the view start and end ts will not change
+		setViewStartTs(traceMetadata.startTime);
+		setViewEndTs(traceMetadata.endTime);
+		viewStartRef.current = traceMetadata.startTime;
+		viewEndRef.current = traceMetadata.endTime;
+	}, [traceMetadata.startTime, traceMetadata.endTime]);
+
+	const totalHeight = spans.length * rowHeight;
+
+	const { isOverFlamegraphRef } = useFlamegraphZoom({
+		canvasRef,
+		traceMetadata,
+		viewStartRef,
+		viewEndRef,
+		rowHeightRef,
+		setViewStartTs,
+		setViewEndTs,
+		setRowHeight,
+	});
+
+	const {
+		handleMouseDown,
+		handleMouseMove: handleDragMouseMove,
+		handleMouseUp,
+		handleDragMouseLeave,
+		suppressClickRef,
+		isDraggingRef,
+	} = useFlamegraphDrag({
+		canvasRef,
+		containerRef,
+		traceMetadata,
+		viewStartRef,
+		viewEndRef,
+		setViewStartTs,
+		setViewEndTs,
+		scrollTopRef,
+		setScrollTop,
+		totalHeight,
+	});
+
+	const {
+		hoveredSpanId,
+		handleHoverMouseMove,
+		handleHoverMouseLeave,
+		handleClick,
+		tooltipContent,
+	} = useFlamegraphHover({
+		canvasRef,
+		spanRectsRef,
+		traceMetadata,
+		viewStartTs,
+		viewEndTs,
+		isDraggingRef,
+		suppressClickRef,
+		onSpanClick,
+		isDarkMode,
+	});
+
+	const { drawFlamegraph } = useFlamegraphDraw({
+		canvasRef,
+		containerRef,
+		spans,
+		viewStartTs,
+		viewEndTs,
+		scrollTop,
+		rowHeight,
+		selectedSpanId: firstSpanAtFetchLevel || undefined,
+		hoveredSpanId: hoveredSpanId ?? '',
+		isDarkMode,
+		spanRectsRef,
+	});
+
+	useScrollToSpan({
+		firstSpanAtFetchLevel,
+		spans,
+		traceMetadata,
+		containerRef,
+		viewStartRef,
+		viewEndRef,
+		scrollTopRef,
+		rowHeight,
+		setViewStartTs,
+		setViewEndTs,
+		setScrollTop,
+	});
+
+	useCanvasSetup(canvasRef, containerRef, drawFlamegraph);
+
+	const handleMouseMove = useCallback(
+		(e: React.MouseEvent): void => {
+			handleDragMouseMove(e);
+			handleHoverMouseMove(e);
+		},
+		[handleDragMouseMove, handleHoverMouseMove],
+	);
+
+	const handleMouseLeave = useCallback((): void => {
+		isOverFlamegraphRef.current = false;
+		handleDragMouseLeave();
+		handleHoverMouseLeave();
+	}, [isOverFlamegraphRef, handleDragMouseLeave, handleHoverMouseLeave]);
+
+	// todo: move to a separate component/utils file
+	const tooltipElement = tooltipContent
+		? createPortal(
+				<div
+					style={{
+						position: 'fixed',
+						left: Math.min(tooltipContent.clientX + 15, window.innerWidth - 220),
+						top: Math.min(tooltipContent.clientY + 15, window.innerHeight - 100),
+						zIndex: 1000,
+						backgroundColor: 'rgba(30, 30, 30, 0.95)',
+						color: '#fff',
+						padding: '8px 12px',
+						borderRadius: 4,
+						fontSize: 12,
+						fontFamily: 'Inter, sans-serif',
+						boxShadow: '0 2px 8px rgba(0,0,0,0.3)',
+						pointerEvents: 'none',
+					}}
+				>
+					<div
+						style={{
+							fontWeight: 600,
+							marginBottom: 4,
+							color: tooltipContent.spanColor,
+						}}
+					>
+						{tooltipContent.spanName}
+					</div>
+					<div>Status: {tooltipContent.status}</div>
+					<div>Start: {tooltipContent.startMs.toFixed(2)} ms</div>
+					<div>Duration: {formatDuration(tooltipContent.durationMs * 1e6)}</div>
+				</div>,
+				document.body,
+		  )
+		: null;
+
+	return (
+		<div
+			style={{
+				display: 'flex',
+				flexDirection: 'column',
+				height: '100%',
+				padding: '0 15px',
+			}}
+		>
+			{tooltipElement}
+			<TimelineV3
+				startTimestamp={viewStartTs}
+				endTimestamp={viewEndTs}
+				offsetTimestamp={viewStartTs - traceMetadata.startTime}
+				timelineHeight={10}
+			/>
+			<div
+				ref={containerRef}
+				style={{
+					flex: 1,
+					overflow: 'hidden',
+					position: 'relative',
+				}}
+				onMouseEnter={(): void => {
+					isOverFlamegraphRef.current = true;
+				}}
+				onMouseLeave={handleMouseLeave}
+			>
+				<canvas
+					ref={canvasRef}
+					style={{
+						display: 'block',
+						width: '100%',
+						cursor: 'grab',
+					}}
+					onMouseDown={handleMouseDown}
+					onMouseMove={handleMouseMove}
+					onMouseUp={handleMouseUp}
+					onClick={handleClick}
+				/>
+			</div>
+		</div>
+	);
+}
+
+export default FlamegraphCanvas;

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/TraceFlamegraph.tsx

@@ -0,0 +1,107 @@
+import { useCallback, useEffect, useMemo, useState } from 'react';
+import { useHistory, useLocation, useParams } from 'react-router-dom';
+import useGetTraceFlamegraph from 'hooks/trace/useGetTraceFlamegraph';
+import useUrlQuery from 'hooks/useUrlQuery';
+import { TraceDetailFlamegraphURLProps } from 'types/api/trace/getTraceFlamegraph';
+
+import FlamegraphCanvas from './FlamegraphCanvas';
+
+//TODO: analyse if this is needed or not and move to separate file if needed else delete this enum.
+enum TraceFlamegraphState {
+	LOADING = 'LOADING',
+	SUCCESS = 'SUCCESS',
+	NO_DATA = 'NO_DATA',
+	ERROR = 'ERROR',
+	FETCHING_WITH_OLD_DATA = 'FETCHING_WITH_OLD_DATA',
+}
+
+function TraceFlamegraph(): JSX.Element {
+	const { id: traceId } = useParams<TraceDetailFlamegraphURLProps>();
+	const urlQuery = useUrlQuery();
+	const history = useHistory();
+	const { search } = useLocation();
+	const [firstSpanAtFetchLevel, setFirstSpanAtFetchLevel] = useState<string>(
+		urlQuery.get('spanId') || '',
+	);
+
+	useEffect(() => {
+		setFirstSpanAtFetchLevel(urlQuery.get('spanId') || '');
+	}, [urlQuery]);
+
+	const handleSpanClick = useCallback(
+		(spanId: string): void => {
+			setFirstSpanAtFetchLevel(spanId);
+			const searchParams = new URLSearchParams(search);
+			//tood: use from query params constants
+			if (searchParams.get('spanId') !== spanId) {
+				searchParams.set('spanId', spanId);
+				history.replace({ search: searchParams.toString() });
+			}
+		},
+		[history, search],
+	);
+
+	const { data, isFetching, error } = useGetTraceFlamegraph({
+		traceId,
+		selectedSpanId: firstSpanAtFetchLevel,
+	});
+
+	const flamegraphState = useMemo(() => {
+		if (isFetching) {
+			if (data?.payload?.spans && data.payload.spans.length > 0) {
+				return TraceFlamegraphState.FETCHING_WITH_OLD_DATA;
+			}
+			return TraceFlamegraphState.LOADING;
+		}
+		if (error) {
+			return TraceFlamegraphState.ERROR;
+		}
+		if (data?.payload?.spans && data.payload.spans.length === 0) {
+			return TraceFlamegraphState.NO_DATA;
+		}
+		return TraceFlamegraphState.SUCCESS;
+	}, [error, isFetching, data]);
+
+	const spans = useMemo(() => data?.payload?.spans || [], [
+		data?.payload?.spans,
+	]);
+
+	const content = useMemo(() => {
+		switch (flamegraphState) {
+			case TraceFlamegraphState.LOADING:
+				return <div>Loading...</div>;
+			case TraceFlamegraphState.ERROR:
+				return <div>Error loading flamegraph</div>;
+			case TraceFlamegraphState.NO_DATA:
+				return <div>No data found for trace {traceId}</div>;
+			case TraceFlamegraphState.SUCCESS:
+			case TraceFlamegraphState.FETCHING_WITH_OLD_DATA:
+				return (
+					<FlamegraphCanvas
+						spans={spans}
+						firstSpanAtFetchLevel={firstSpanAtFetchLevel}
+						setFirstSpanAtFetchLevel={setFirstSpanAtFetchLevel}
+						onSpanClick={handleSpanClick}
+						traceMetadata={{
+							startTime: data?.payload?.startTimestampMillis || 0,
+							endTime: data?.payload?.endTimestampMillis || 0,
+						}}
+					/>
+				);
+			default:
+				return <div>Fetching the trace...</div>;
+		}
+	}, [
+		data?.payload?.endTimestampMillis,
+		data?.payload?.startTimestampMillis,
+		firstSpanAtFetchLevel,
+		flamegraphState,
+		spans,
+		traceId,
+		handleSpanClick,
+	]);
+
+	return <>{content}</>;
+}
+
+export default TraceFlamegraph;

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/__tests__/drawUtils.test.ts

@@ -0,0 +1,525 @@
+import { DASHED_BORDER_LINE_DASH, MIN_WIDTH_FOR_NAME } from '../constants';
+import type { FlamegraphRowMetrics } from '../utils';
+import { getFlamegraphRowMetrics } from '../utils';
+import { drawEventDot, drawSpanBar } from '../utils';
+import { MOCK_SPAN } from './testUtils';
+
+jest.mock('container/TraceDetail/utils', () => ({
+	convertTimeToRelevantUnit: (): { time: number; timeUnitName: string } => ({
+		time: 50,
+		timeUnitName: 'ms',
+	}),
+}));
+
+/** Minimal 2D context for createStripePattern's internal canvas (jsdom getContext often returns null) */
+const mockPatternCanvasCtx = {
+	beginPath: jest.fn(),
+	moveTo: jest.fn(),
+	lineTo: jest.fn(),
+	stroke: jest.fn(),
+	globalAlpha: 1,
+};
+
+const originalCreateElement = document.createElement.bind(document);
+document.createElement = function (
+	tagName: string,
+): ReturnType<typeof originalCreateElement> {
+	const el = originalCreateElement(tagName);
+	if (tagName.toLowerCase() === 'canvas') {
+		(el as HTMLCanvasElement).getContext = (() =>
+			mockPatternCanvasCtx as unknown) as HTMLCanvasElement['getContext'];
+	}
+	return el;
+};
+
+function createMockCtx(): jest.Mocked<CanvasRenderingContext2D> {
+	return ({
+		beginPath: jest.fn(),
+		roundRect: jest.fn(),
+		fill: jest.fn(),
+		stroke: jest.fn(),
+		save: jest.fn(),
+		restore: jest.fn(),
+		translate: jest.fn(),
+		rotate: jest.fn(),
+		fillRect: jest.fn(),
+		strokeRect: jest.fn(),
+		setLineDash: jest.fn(),
+		measureText: jest.fn(
+			(text: string) => ({ width: text.length * 6 } as TextMetrics),
+		),
+		createPattern: jest.fn(() => ({} as CanvasPattern)),
+		clip: jest.fn(),
+		rect: jest.fn(),
+		fillText: jest.fn(),
+		font: '',
+		fillStyle: '',
+		strokeStyle: '',
+		textAlign: '',
+		textBaseline: '',
+		lineWidth: 0,
+		globalAlpha: 1,
+	} as unknown) as jest.Mocked<CanvasRenderingContext2D>;
+}
+
+const METRICS: FlamegraphRowMetrics = getFlamegraphRowMetrics(24);
+
+describe('Canvas Draw Utils', () => {
+	describe('drawSpanBar', () => {
+		it('draws rect + fill for normal span (no selected/hovered)', () => {
+			const ctx = createMockCtx();
+			const spanRectsArray: {
+				span: typeof MOCK_SPAN;
+				x: number;
+				y: number;
+				width: number;
+				height: number;
+				level: number;
+			}[] = [];
+
+			drawSpanBar({
+				ctx,
+				span: { ...MOCK_SPAN, event: [] },
+				x: 10,
+				y: 0,
+				width: 100,
+				levelIndex: 0,
+				spanRectsArray,
+				color: '#1890ff',
+				isDarkMode: false,
+				metrics: METRICS,
+			});
+
+			expect(ctx.beginPath).toHaveBeenCalled();
+			expect(ctx.roundRect).toHaveBeenCalledWith(10, 1, 100, 22, 2);
+			expect(ctx.fill).toHaveBeenCalled();
+			expect(ctx.stroke).not.toHaveBeenCalled();
+			expect(spanRectsArray).toHaveLength(1);
+			expect(spanRectsArray[0]).toMatchObject({
+				x: 10,
+				y: 1,
+				width: 100,
+				height: 22,
+				level: 0,
+			});
+		});
+
+		it('uses stripe pattern + dashed stroke + 2px when selected', () => {
+			const ctx = createMockCtx();
+			const spanRectsArray: {
+				span: typeof MOCK_SPAN;
+				x: number;
+				y: number;
+				width: number;
+				height: number;
+				level: number;
+			}[] = [];
+
+			drawSpanBar({
+				ctx,
+				span: { ...MOCK_SPAN, spanId: 'sel', event: [] },
+				x: 20,
+				y: 0,
+				width: 80,
+				levelIndex: 1,
+				spanRectsArray,
+				color: '#2F80ED',
+				isDarkMode: false,
+				metrics: METRICS,
+				selectedSpanId: 'sel',
+			});
+
+			expect(ctx.createPattern).toHaveBeenCalled();
+			expect(ctx.setLineDash).toHaveBeenCalledWith(DASHED_BORDER_LINE_DASH);
+			expect(ctx.strokeStyle).toBe('#2F80ED');
+			expect(ctx.lineWidth).toBe(2);
+			expect(ctx.stroke).toHaveBeenCalled();
+			expect(ctx.setLineDash).toHaveBeenLastCalledWith([]);
+		});
+
+		it('uses stripe pattern + solid stroke + 1px when hovered (not selected)', () => {
+			const ctx = createMockCtx();
+			const spanRectsArray: {
+				span: typeof MOCK_SPAN;
+				x: number;
+				y: number;
+				width: number;
+				height: number;
+				level: number;
+			}[] = [];
+
+			drawSpanBar({
+				ctx,
+				span: { ...MOCK_SPAN, spanId: 'hov', event: [] },
+				x: 30,
+				y: 0,
+				width: 60,
+				levelIndex: 0,
+				spanRectsArray,
+				color: '#2F80ED',
+				isDarkMode: false,
+				metrics: METRICS,
+				hoveredSpanId: 'hov',
+			});
+
+			expect(ctx.createPattern).toHaveBeenCalled();
+			expect(ctx.setLineDash).not.toHaveBeenCalled();
+			expect(ctx.lineWidth).toBe(1);
+			expect(ctx.stroke).toHaveBeenCalled();
+		});
+
+		it('pushes spanRectsArray with correct dimensions', () => {
+			const ctx = createMockCtx();
+			const spanRectsArray: {
+				span: typeof MOCK_SPAN;
+				x: number;
+				y: number;
+				width: number;
+				height: number;
+				level: number;
+			}[] = [];
+
+			drawSpanBar({
+				ctx,
+				span: { ...MOCK_SPAN, spanId: 'rect-test', event: [] },
+				x: 5,
+				y: 24,
+				width: 200,
+				levelIndex: 2,
+				spanRectsArray,
+				color: '#000',
+				isDarkMode: false,
+				metrics: METRICS,
+			});
+
+			expect(spanRectsArray[0]).toMatchObject({
+				x: 5,
+				y: 25,
+				width: 200,
+				height: 22,
+				level: 2,
+			});
+			expect(spanRectsArray[0].span.spanId).toBe('rect-test');
+		});
+	});
+
+	describe('drawSpanLabel (via drawSpanBar)', () => {
+		it('skips label when width < MIN_WIDTH_FOR_NAME', () => {
+			const ctx = createMockCtx();
+			const spanRectsArray: {
+				span: typeof MOCK_SPAN;
+				x: number;
+				y: number;
+				width: number;
+				height: number;
+				level: number;
+			}[] = [];
+
+			drawSpanBar({
+				ctx,
+				span: { ...MOCK_SPAN, name: 'long-span-name', event: [] },
+				x: 0,
+				y: 0,
+				width: MIN_WIDTH_FOR_NAME - 1,
+				levelIndex: 0,
+				spanRectsArray,
+				color: '#000',
+				isDarkMode: false,
+				metrics: METRICS,
+			});
+
+			expect(ctx.clip).not.toHaveBeenCalled();
+			expect(ctx.fillText).not.toHaveBeenCalled();
+		});
+
+		it('draws name only when width >= MIN_WIDTH_FOR_NAME but < MIN_WIDTH_FOR_NAME_AND_DURATION', () => {
+			const ctx = createMockCtx();
+			ctx.measureText = jest.fn(
+				(t: string) => ({ width: t.length * 6 } as TextMetrics),
+			);
+
+			drawSpanBar({
+				ctx,
+				span: { ...MOCK_SPAN, name: 'foo', event: [] },
+				x: 0,
+				y: 0,
+				width: 50,
+				levelIndex: 0,
+				spanRectsArray: [],
+				color: '#000',
+				isDarkMode: false,
+				metrics: METRICS,
+			});
+
+			expect(ctx.clip).toHaveBeenCalled();
+			expect(ctx.fillText).toHaveBeenCalled();
+			expect(ctx.textAlign).toBe('left');
+		});
+
+		it('draws name + duration when width >= MIN_WIDTH_FOR_NAME_AND_DURATION', () => {
+			const ctx = createMockCtx();
+			ctx.measureText = jest.fn(
+				(t: string) => ({ width: t.length * 6 } as TextMetrics),
+			);
+
+			drawSpanBar({
+				ctx,
+				span: { ...MOCK_SPAN, name: 'my-span', event: [] },
+				x: 0,
+				y: 0,
+				width: 100,
+				levelIndex: 0,
+				spanRectsArray: [],
+				color: '#000',
+				isDarkMode: false,
+				metrics: METRICS,
+			});
+
+			expect(ctx.fillText).toHaveBeenCalledTimes(2);
+			expect(ctx.fillText).toHaveBeenCalledWith(
+				'50ms',
+				expect.any(Number),
+				expect.any(Number),
+			);
+			expect(ctx.fillText).toHaveBeenCalledWith(
+				'my-span',
+				expect.any(Number),
+				expect.any(Number),
+			);
+		});
+	});
+
+	describe('truncateText (via drawSpanBar)', () => {
+		it('uses full text when it fits', () => {
+			const ctx = createMockCtx();
+			ctx.measureText = jest.fn(
+				(t: string) => ({ width: t.length * 4 } as TextMetrics),
+			);
+
+			drawSpanBar({
+				ctx,
+				span: { ...MOCK_SPAN, name: 'short', event: [] },
+				x: 0,
+				y: 0,
+				width: 100,
+				levelIndex: 0,
+				spanRectsArray: [],
+				color: '#000',
+				isDarkMode: false,
+				metrics: METRICS,
+			});
+
+			expect(ctx.fillText).toHaveBeenCalledWith(
+				'short',
+				expect.any(Number),
+				expect.any(Number),
+			);
+		});
+
+		it('truncates text when it exceeds available width', () => {
+			const ctx = createMockCtx();
+			ctx.measureText = jest.fn(
+				(t: string) =>
+					({
+						width: t.includes('...') ? 24 : t.length * 10,
+					} as TextMetrics),
+			);
+
+			drawSpanBar({
+				ctx,
+				span: { ...MOCK_SPAN, name: 'very-long-span-name', event: [] },
+				x: 0,
+				y: 0,
+				width: 50,
+				levelIndex: 0,
+				spanRectsArray: [],
+				color: '#000',
+				isDarkMode: false,
+				metrics: METRICS,
+			});
+
+			const fillTextCalls = (ctx.fillText as jest.Mock).mock.calls;
+			const nameArg = fillTextCalls.find((c) => c[0] !== '50ms')?.[0];
+			expect(nameArg).toBeDefined();
+			expect(nameArg).toMatch(/\.\.\.$/);
+		});
+	});
+
+	describe('drawEventDot', () => {
+		it('uses error styling when isError is true', () => {
+			const ctx = createMockCtx();
+
+			drawEventDot({
+				ctx,
+				x: 50,
+				y: 11,
+				isError: true,
+				isDarkMode: false,
+				eventDotSize: 6,
+			});
+
+			expect(ctx.save).toHaveBeenCalled();
+			expect(ctx.translate).toHaveBeenCalledWith(50, 11);
+			expect(ctx.rotate).toHaveBeenCalledWith(Math.PI / 4);
+			expect(ctx.fillStyle).toBe('rgb(220, 38, 38)');
+			expect(ctx.strokeStyle).toBe('rgb(153, 27, 27)');
+			expect(ctx.fillRect).toHaveBeenCalledWith(-3, -3, 6, 6);
+			expect(ctx.strokeRect).toHaveBeenCalledWith(-3, -3, 6, 6);
+			expect(ctx.restore).toHaveBeenCalled();
+		});
+
+		it('uses normal styling when isError is false', () => {
+			const ctx = createMockCtx();
+
+			drawEventDot({
+				ctx,
+				x: 0,
+				y: 0,
+				isError: false,
+				isDarkMode: false,
+				eventDotSize: 6,
+			});
+
+			expect(ctx.fillStyle).toBe('rgb(6, 182, 212)');
+			expect(ctx.strokeStyle).toBe('rgb(8, 145, 178)');
+		});
+
+		it('uses dark mode colors for error', () => {
+			const ctx = createMockCtx();
+
+			drawEventDot({
+				ctx,
+				x: 0,
+				y: 0,
+				isError: true,
+				isDarkMode: true,
+				eventDotSize: 6,
+			});
+
+			expect(ctx.fillStyle).toBe('rgb(239, 68, 68)');
+			expect(ctx.strokeStyle).toBe('rgb(185, 28, 28)');
+		});
+
+		it('uses dark mode colors for non-error', () => {
+			const ctx = createMockCtx();
+
+			drawEventDot({
+				ctx,
+				x: 0,
+				y: 0,
+				isError: false,
+				isDarkMode: true,
+				eventDotSize: 6,
+			});
+
+			expect(ctx.fillStyle).toBe('rgb(14, 165, 233)');
+			expect(ctx.strokeStyle).toBe('rgb(2, 132, 199)');
+		});
+
+		it('calls save, translate, rotate, restore', () => {
+			const ctx = createMockCtx();
+
+			drawEventDot({
+				ctx,
+				x: 10,
+				y: 20,
+				isError: false,
+				isDarkMode: false,
+				eventDotSize: 4,
+			});
+
+			expect(ctx.save).toHaveBeenCalled();
+			expect(ctx.translate).toHaveBeenCalledWith(10, 20);
+			expect(ctx.rotate).toHaveBeenCalledWith(Math.PI / 4);
+			expect(ctx.restore).toHaveBeenCalled();
+		});
+	});
+
+	describe('createStripePattern (via drawSpanBar)', () => {
+		it('uses pattern when createPattern returns non-null', () => {
+			const ctx = createMockCtx();
+			const mockPattern = {} as CanvasPattern;
+			(ctx.createPattern as jest.Mock).mockReturnValue(mockPattern);
+
+			drawSpanBar({
+				ctx,
+				span: { ...MOCK_SPAN, spanId: 'p', event: [] },
+				x: 0,
+				y: 0,
+				width: MIN_WIDTH_FOR_NAME - 1,
+				levelIndex: 0,
+				spanRectsArray: [],
+				color: '#000',
+				isDarkMode: false,
+				metrics: METRICS,
+				hoveredSpanId: 'p',
+			});
+
+			expect(ctx.createPattern).toHaveBeenCalled();
+			expect(ctx.fillStyle).toBe(mockPattern);
+			expect(ctx.fill).toHaveBeenCalled();
+		});
+
+		it('skips fill when createPattern returns null', () => {
+			const ctx = createMockCtx();
+			(ctx.createPattern as jest.Mock).mockReturnValue(null);
+
+			drawSpanBar({
+				ctx,
+				span: { ...MOCK_SPAN, spanId: 'p', event: [] },
+				x: 0,
+				y: 0,
+				width: MIN_WIDTH_FOR_NAME - 1,
+				levelIndex: 0,
+				spanRectsArray: [],
+				color: '#000',
+				isDarkMode: false,
+				metrics: METRICS,
+				selectedSpanId: 'p',
+			});
+
+			expect(ctx.fill).not.toHaveBeenCalled();
+			expect(ctx.stroke).toHaveBeenCalled();
+		});
+	});
+
+	describe('drawSpanBar with events', () => {
+		it('draws event dots for each span event', () => {
+			const ctx = createMockCtx();
+			const spanWithEvents = {
+				...MOCK_SPAN,
+				event: [
+					{
+						name: 'e1',
+						timeUnixNano: 1_010_000_000,
+						attributeMap: {},
+						isError: false,
+					},
+					{
+						name: 'e2',
+						timeUnixNano: 1_025_000_000,
+						attributeMap: {},
+						isError: true,
+					},
+				],
+			};
+
+			drawSpanBar({
+				ctx,
+				span: spanWithEvents,
+				x: 0,
+				y: 0,
+				width: 100,
+				levelIndex: 0,
+				spanRectsArray: [],
+				color: '#000',
+				isDarkMode: false,
+				metrics: METRICS,
+			});
+
+			expect(ctx.save).toHaveBeenCalledTimes(3);
+			expect(ctx.translate).toHaveBeenCalledTimes(2);
+			expect(ctx.fillRect).toHaveBeenCalledTimes(2);
+		});
+	});
+});

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/__tests__/testUtils.ts

@@ -0,0 +1,54 @@
+import { FlamegraphSpan } from 'types/api/trace/getTraceFlamegraph';
+
+/** Minimal FlamegraphSpan for unit tests */
+export const MOCK_SPAN: FlamegraphSpan = {
+	timestamp: 1000,
+	durationNano: 50_000_000, // 50ms
+	spanId: 'span-1',
+	parentSpanId: '',
+	traceId: 'trace-1',
+	hasError: false,
+	serviceName: 'test-service',
+	name: 'test-span',
+	level: 0,
+	event: [],
+};
+
+/** Nested spans structure for findSpanById tests */
+export const MOCK_SPANS: FlamegraphSpan[][] = [
+	[
+		{
+			...MOCK_SPAN,
+			spanId: 'root',
+			parentSpanId: '',
+			level: 0,
+		},
+	],
+	[
+		{
+			...MOCK_SPAN,
+			spanId: 'child-a',
+			parentSpanId: 'root',
+			level: 1,
+		},
+		{
+			...MOCK_SPAN,
+			spanId: 'child-b',
+			parentSpanId: 'root',
+			level: 1,
+		},
+	],
+	[
+		{
+			...MOCK_SPAN,
+			spanId: 'grandchild',
+			parentSpanId: 'child-a',
+			level: 2,
+		},
+	],
+];
+
+export const MOCK_TRACE_METADATA = {
+	startTime: 0,
+	endTime: 1000,
+};

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/__tests__/useFlamegraphDrag.test.ts

@@ -0,0 +1,196 @@
+import React from 'react';
+import { act, renderHook } from '@testing-library/react';
+
+import { useFlamegraphDrag } from '../hooks/useFlamegraphDrag';
+import { MOCK_TRACE_METADATA } from './testUtils';
+
+function createMockCanvas(): HTMLCanvasElement {
+	const canvas = document.createElement('canvas');
+	canvas.getBoundingClientRect = jest.fn(
+		(): DOMRect =>
+			({
+				left: 0,
+				top: 0,
+				width: 800,
+				height: 400,
+				x: 0,
+				y: 0,
+				bottom: 400,
+				right: 800,
+				toJSON: (): Record<string, unknown> => ({}),
+			} as DOMRect),
+	);
+	return canvas;
+}
+
+function createMockContainer(): HTMLDivElement {
+	const div = document.createElement('div');
+	Object.defineProperty(div, 'clientHeight', { value: 400 });
+	return div;
+}
+
+const defaultArgs = {
+	canvasRef: { current: createMockCanvas() },
+	containerRef: { current: createMockContainer() },
+	traceMetadata: MOCK_TRACE_METADATA,
+	viewStartRef: { current: 0 },
+	viewEndRef: { current: 1000 },
+	setViewStartTs: jest.fn(),
+	setViewEndTs: jest.fn(),
+	scrollTopRef: { current: 0 },
+	setScrollTop: jest.fn(),
+	totalHeight: 1000,
+};
+
+describe('useFlamegraphDrag', () => {
+	beforeEach(() => {
+		jest.clearAllMocks();
+		defaultArgs.viewStartRef.current = 0;
+		defaultArgs.viewEndRef.current = 1000;
+		defaultArgs.scrollTopRef.current = 0;
+	});
+
+	it('starts drag state on mousedown', () => {
+		const { result } = renderHook(() => useFlamegraphDrag(defaultArgs));
+
+		act(() => {
+			result.current.handleMouseDown(({
+				button: 0,
+				clientX: 100,
+				clientY: 50,
+				preventDefault: jest.fn(),
+			} as unknown) as React.MouseEvent);
+		});
+
+		expect(result.current.isDraggingRef.current).toBe(true);
+	});
+
+	it('ignores non-left button mousedown', () => {
+		const { result } = renderHook(() => useFlamegraphDrag(defaultArgs));
+
+		act(() => {
+			result.current.handleMouseDown(({
+				button: 1,
+				clientX: 100,
+				clientY: 50,
+				preventDefault: jest.fn(),
+			} as unknown) as React.MouseEvent);
+		});
+
+		expect(result.current.isDraggingRef.current).toBe(false);
+	});
+
+	it('updates pan/scroll on mousemove', () => {
+		const { result } = renderHook(() => useFlamegraphDrag(defaultArgs));
+
+		act(() => {
+			result.current.handleMouseDown(({
+				button: 0,
+				clientX: 100,
+				clientY: 50,
+				preventDefault: jest.fn(),
+			} as unknown) as React.MouseEvent);
+		});
+
+		act(() => {
+			result.current.handleMouseMove(({
+				clientX: 150,
+				clientY: 100,
+			} as unknown) as React.MouseEvent);
+		});
+
+		expect(defaultArgs.setViewStartTs).toHaveBeenCalled();
+		expect(defaultArgs.setViewEndTs).toHaveBeenCalled();
+		expect(defaultArgs.setScrollTop).toHaveBeenCalled();
+	});
+
+	it('does not set suppressClickRef when movement is below threshold', () => {
+		const { result } = renderHook(() => useFlamegraphDrag(defaultArgs));
+
+		act(() => {
+			result.current.handleMouseDown(({
+				button: 0,
+				clientX: 100,
+				clientY: 50,
+				preventDefault: jest.fn(),
+			} as unknown) as React.MouseEvent);
+		});
+
+		act(() => {
+			result.current.handleMouseMove(({
+				clientX: 102,
+				clientY: 51,
+			} as unknown) as React.MouseEvent);
+		});
+
+		act(() => {
+			result.current.handleMouseUp();
+		});
+
+		expect(result.current.suppressClickRef.current).toBe(false);
+	});
+
+	it('sets suppressClickRef when drag exceeds threshold', () => {
+		const { result } = renderHook(() => useFlamegraphDrag(defaultArgs));
+
+		act(() => {
+			result.current.handleMouseDown(({
+				button: 0,
+				clientX: 100,
+				clientY: 50,
+				preventDefault: jest.fn(),
+			} as unknown) as React.MouseEvent);
+		});
+
+		act(() => {
+			result.current.handleMouseMove(({
+				clientX: 150,
+				clientY: 100,
+			} as unknown) as React.MouseEvent);
+		});
+
+		act(() => {
+			result.current.handleMouseUp();
+		});
+
+		expect(result.current.suppressClickRef.current).toBe(true);
+	});
+
+	it('resets drag state on mouseup', () => {
+		const { result } = renderHook(() => useFlamegraphDrag(defaultArgs));
+
+		act(() => {
+			result.current.handleMouseDown(({
+				button: 0,
+				clientX: 100,
+				clientY: 50,
+				preventDefault: jest.fn(),
+			} as unknown) as React.MouseEvent);
+		});
+
+		act(() => {
+			result.current.handleMouseUp();
+		});
+
+		expect(result.current.isDraggingRef.current).toBe(false);
+	});
+
+	it('cancels drag on mouseleave', () => {
+		const { result } = renderHook(() => useFlamegraphDrag(defaultArgs));
+
+		act(() => {
+			result.current.handleMouseDown(({
+				button: 0,
+				clientX: 100,
+				clientY: 50,
+				preventDefault: jest.fn(),
+			} as unknown) as React.MouseEvent);
+		});
+
+		act(() => {
+			result.current.handleDragMouseLeave();
+		});
+
+		expect(result.current.isDraggingRef.current).toBe(false);
+	});
+});

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/__tests__/useFlamegraphHover.test.ts

@@ -0,0 +1,174 @@
+import type React from 'react';
+import { act, renderHook } from '@testing-library/react';
+
+import { useFlamegraphHover } from '../hooks/useFlamegraphHover';
+import type { SpanRect } from '../types';
+import { MOCK_SPAN, MOCK_TRACE_METADATA } from './testUtils';
+
+function createMockCanvas(): HTMLCanvasElement {
+	const canvas = document.createElement('canvas');
+	canvas.width = 800;
+	canvas.height = 400;
+	canvas.getBoundingClientRect = jest.fn(
+		(): DOMRect =>
+			({
+				left: 0,
+				top: 0,
+				width: 800,
+				height: 400,
+				x: 0,
+				y: 0,
+				bottom: 400,
+				right: 800,
+				toJSON: (): Record<string, unknown> => ({}),
+			} as DOMRect),
+	);
+	return canvas;
+}
+
+const spanRect: SpanRect = {
+	span: { ...MOCK_SPAN, spanId: 'hover-span', name: 'test-span' },
+	x: 100,
+	y: 50,
+	width: 200,
+	height: 22,
+	level: 0,
+};
+
+const defaultArgs = {
+	canvasRef: { current: createMockCanvas() },
+	spanRectsRef: { current: [spanRect] },
+	traceMetadata: MOCK_TRACE_METADATA,
+	viewStartTs: MOCK_TRACE_METADATA.startTime,
+	viewEndTs: MOCK_TRACE_METADATA.endTime,
+	isDraggingRef: { current: false },
+	suppressClickRef: { current: false },
+	onSpanClick: jest.fn(),
+	isDarkMode: false,
+};
+
+describe('useFlamegraphHover', () => {
+	beforeEach(() => {
+		Object.defineProperty(window, 'devicePixelRatio', {
+			configurable: true,
+			value: 1,
+		});
+		jest.clearAllMocks();
+		defaultArgs.spanRectsRef.current = [spanRect];
+		defaultArgs.isDraggingRef.current = false;
+		defaultArgs.suppressClickRef.current = false;
+	});
+
+	it('sets hoveredSpanId and tooltipContent when hovering on span', () => {
+		const { result } = renderHook(() => useFlamegraphHover(defaultArgs));
+
+		act(() => {
+			result.current.handleHoverMouseMove({
+				clientX: 150,
+				clientY: 61,
+			} as React.MouseEvent);
+		});
+
+		expect(result.current.hoveredSpanId).toBe('hover-span');
+		expect(result.current.tooltipContent).not.toBeNull();
+		expect(result.current.tooltipContent?.spanName).toBe('test-span');
+		expect(result.current.tooltipContent?.clientX).toBe(150);
+		expect(result.current.tooltipContent?.clientY).toBe(61);
+	});
+
+	it('clears hover when moving to empty area', () => {
+		const { result } = renderHook(() => useFlamegraphHover(defaultArgs));
+
+		act(() => {
+			result.current.handleHoverMouseMove({
+				clientX: 150,
+				clientY: 61,
+			} as React.MouseEvent);
+		});
+
+		expect(result.current.hoveredSpanId).toBe('hover-span');
+
+		act(() => {
+			result.current.handleHoverMouseMove({
+				clientX: 10,
+				clientY: 10,
+			} as React.MouseEvent);
+		});
+
+		expect(result.current.hoveredSpanId).toBeNull();
+		expect(result.current.tooltipContent).toBeNull();
+	});
+
+	it('clears hover on mouse leave', () => {
+		const { result } = renderHook(() => useFlamegraphHover(defaultArgs));
+
+		act(() => {
+			result.current.handleHoverMouseMove({
+				clientX: 150,
+				clientY: 61,
+			} as React.MouseEvent);
+		});
+
+		act(() => {
+			result.current.handleHoverMouseLeave();
+		});
+
+		expect(result.current.hoveredSpanId).toBeNull();
+		expect(result.current.tooltipContent).toBeNull();
+	});
+
+	it('suppresses click when suppressClickRef is set', () => {
+		const { result } = renderHook(() => useFlamegraphHover(defaultArgs));
+		defaultArgs.suppressClickRef.current = true;
+
+		act(() => {
+			result.current.handleClick({
+				clientX: 150,
+				clientY: 61,
+			} as React.MouseEvent);
+		});
+
+		expect(defaultArgs.onSpanClick).not.toHaveBeenCalled();
+	});
+
+	it('calls onSpanClick when clicking on span', () => {
+		const { result } = renderHook(() => useFlamegraphHover(defaultArgs));
+
+		act(() => {
+			result.current.handleClick({
+				clientX: 150,
+				clientY: 61,
+			} as React.MouseEvent);
+		});
+
+		expect(defaultArgs.onSpanClick).toHaveBeenCalledWith('hover-span');
+	});
+
+	it('uses clientX/clientY for tooltip positioning', () => {
+		const { result } = renderHook(() => useFlamegraphHover(defaultArgs));
+
+		act(() => {
+			result.current.handleHoverMouseMove({
+				clientX: 200,
+				clientY: 60,
+			} as React.MouseEvent);
+		});
+
+		expect(result.current.tooltipContent?.clientX).toBe(200);
+		expect(result.current.tooltipContent?.clientY).toBe(60);
+	});
+
+	it('does not update hover during drag', () => {
+		const { result } = renderHook(() => useFlamegraphHover(defaultArgs));
+		defaultArgs.isDraggingRef.current = true;
+
+		act(() => {
+			result.current.handleHoverMouseMove({
+				clientX: 150,
+				clientY: 61,
+			} as React.MouseEvent);
+		});
+
+		expect(result.current.hoveredSpanId).toBeNull();
+	});
+});

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/__tests__/useFlamegraphZoom.test.ts

@@ -0,0 +1,279 @@
+import { act, renderHook } from '@testing-library/react';
+
+import { DEFAULT_ROW_HEIGHT, MIN_VISIBLE_SPAN_MS } from '../constants';
+import { useFlamegraphZoom } from '../hooks/useFlamegraphZoom';
+import { MOCK_TRACE_METADATA } from './testUtils';
+
+function createMockCanvas(): HTMLCanvasElement {
+	const canvas = document.createElement('canvas');
+	canvas.width = 800;
+	canvas.height = 400;
+	canvas.getBoundingClientRect = jest.fn(
+		(): DOMRect =>
+			({
+				left: 0,
+				top: 0,
+				width: 800,
+				height: 400,
+				x: 0,
+				y: 0,
+				bottom: 400,
+				right: 800,
+				toJSON: (): Record<string, unknown> => ({}),
+			} as DOMRect),
+	);
+	return canvas;
+}
+
+describe('useFlamegraphZoom', () => {
+	const traceMetadata = { ...MOCK_TRACE_METADATA };
+
+	beforeEach(() => {
+		Object.defineProperty(window, 'devicePixelRatio', {
+			configurable: true,
+			value: 1,
+		});
+	});
+
+	it('handleResetZoom restores traceMetadata.startTime/endTime', () => {
+		const setViewStartTs = jest.fn();
+		const setViewEndTs = jest.fn();
+		const setRowHeight = jest.fn();
+		const viewStartRef = { current: 100 };
+		const viewEndRef = { current: 500 };
+		const rowHeightRef = { current: 30 };
+		const canvasRef = { current: createMockCanvas() };
+
+		const { result } = renderHook(() =>
+			useFlamegraphZoom({
+				canvasRef,
+				traceMetadata,
+				viewStartRef,
+				viewEndRef,
+				rowHeightRef,
+				setViewStartTs,
+				setViewEndTs,
+				setRowHeight,
+			}),
+		);
+
+		act(() => {
+			result.current.handleResetZoom();
+		});
+
+		expect(setViewStartTs).toHaveBeenCalledWith(traceMetadata.startTime);
+		expect(setViewEndTs).toHaveBeenCalledWith(traceMetadata.endTime);
+		expect(setRowHeight).toHaveBeenCalledWith(DEFAULT_ROW_HEIGHT);
+		expect(viewStartRef.current).toBe(traceMetadata.startTime);
+		expect(viewEndRef.current).toBe(traceMetadata.endTime);
+		expect(rowHeightRef.current).toBe(DEFAULT_ROW_HEIGHT);
+	});
+
+	it('wheel zoom in decreases visible time range', async () => {
+		const setViewStartTs = jest.fn();
+		const setViewEndTs = jest.fn();
+		const setRowHeight = jest.fn();
+		const viewStartRef = { current: traceMetadata.startTime };
+		const viewEndRef = { current: traceMetadata.endTime };
+		const rowHeightRef = { current: DEFAULT_ROW_HEIGHT };
+		const canvas = createMockCanvas();
+		const canvasRef = { current: canvas };
+
+		renderHook(() =>
+			useFlamegraphZoom({
+				canvasRef,
+				traceMetadata,
+				viewStartRef,
+				viewEndRef,
+				rowHeightRef,
+				setViewStartTs,
+				setViewEndTs,
+				setRowHeight,
+			}),
+		);
+
+		const initialSpan = viewEndRef.current - viewStartRef.current;
+
+		await act(async () => {
+			canvas.dispatchEvent(
+				new WheelEvent('wheel', {
+					clientX: 400,
+					deltaY: -100,
+					bubbles: true,
+				}),
+			);
+		});
+
+		await act(async () => {
+			await new Promise((r) => requestAnimationFrame(r));
+		});
+
+		expect(setViewStartTs).toHaveBeenCalled();
+		expect(setViewEndTs).toHaveBeenCalled();
+		const [newStart] = setViewStartTs.mock.calls[0] ?? [];
+		const [newEnd] = setViewEndTs.mock.calls[0] ?? [];
+		if (newStart != null && newEnd != null) {
+			const newSpan = newEnd - newStart;
+			expect(newSpan).toBeLessThan(initialSpan);
+		}
+	});
+
+	it('wheel zoom out increases visible time range', async () => {
+		const setViewStartTs = jest.fn();
+		const setViewEndTs = jest.fn();
+		const setRowHeight = jest.fn();
+		const halfSpan = (traceMetadata.endTime - traceMetadata.startTime) / 2;
+		const viewStartRef = { current: traceMetadata.startTime + halfSpan * 0.25 };
+		const viewEndRef = { current: traceMetadata.startTime + halfSpan * 0.75 };
+		const rowHeightRef = { current: DEFAULT_ROW_HEIGHT };
+		const canvas = createMockCanvas();
+		const canvasRef = { current: canvas };
+
+		renderHook(() =>
+			useFlamegraphZoom({
+				canvasRef,
+				traceMetadata,
+				viewStartRef,
+				viewEndRef,
+				rowHeightRef,
+				setViewStartTs,
+				setViewEndTs,
+				setRowHeight,
+			}),
+		);
+
+		const initialSpan = viewEndRef.current - viewStartRef.current;
+
+		await act(async () => {
+			canvas.dispatchEvent(
+				new WheelEvent('wheel', {
+					clientX: 400,
+					deltaY: 100,
+					bubbles: true,
+				}),
+			);
+		});
+
+		await act(async () => {
+			await new Promise((r) => requestAnimationFrame(r));
+		});
+
+		expect(setViewStartTs).toHaveBeenCalled();
+		expect(setViewEndTs).toHaveBeenCalled();
+		const [newStart] = setViewStartTs.mock.calls[0] ?? [];
+		const [newEnd] = setViewEndTs.mock.calls[0] ?? [];
+		if (newStart != null && newEnd != null) {
+			const newSpan = newEnd - newStart;
+			expect(newSpan).toBeGreaterThanOrEqual(initialSpan);
+		}
+	});
+
+	it('clamps zoom to MIN_VISIBLE_SPAN_MS', async () => {
+		const setViewStartTs = jest.fn();
+		const setViewEndTs = jest.fn();
+		const setRowHeight = jest.fn();
+		const viewStartRef = { current: traceMetadata.startTime };
+		const viewEndRef = { current: traceMetadata.startTime + 100 };
+		const rowHeightRef = { current: DEFAULT_ROW_HEIGHT };
+		const canvas = createMockCanvas();
+		const canvasRef = { current: canvas };
+
+		renderHook(() =>
+			useFlamegraphZoom({
+				canvasRef,
+				traceMetadata,
+				viewStartRef,
+				viewEndRef,
+				rowHeightRef,
+				setViewStartTs,
+				setViewEndTs,
+				setRowHeight,
+			}),
+		);
+
+		await act(async () => {
+			canvas.dispatchEvent(
+				new WheelEvent('wheel', {
+					clientX: 400,
+					deltaY: 10000,
+					bubbles: true,
+				}),
+			);
+		});
+
+		await act(async () => {
+			await new Promise((r) => requestAnimationFrame(r));
+		});
+
+		const [newStart] = setViewStartTs.mock.calls[0] ?? [];
+		const [newEnd] = setViewEndTs.mock.calls[0] ?? [];
+		if (newStart != null && newEnd != null) {
+			const newSpan = newEnd - newStart;
+			expect(newSpan).toBeGreaterThanOrEqual(MIN_VISIBLE_SPAN_MS);
+		}
+	});
+
+	it('clamps viewStart/viewEnd to trace bounds', async () => {
+		const setViewStartTs = jest.fn();
+		const setViewEndTs = jest.fn();
+		const setRowHeight = jest.fn();
+		const viewStartRef = { current: traceMetadata.startTime };
+		const viewEndRef = { current: traceMetadata.endTime };
+		const rowHeightRef = { current: DEFAULT_ROW_HEIGHT };
+		const canvas = createMockCanvas();
+		const canvasRef = { current: canvas };
+
+		renderHook(() =>
+			useFlamegraphZoom({
+				canvasRef,
+				traceMetadata,
+				viewStartRef,
+				viewEndRef,
+				rowHeightRef,
+				setViewStartTs,
+				setViewEndTs,
+				setRowHeight,
+			}),
+		);
+
+		await act(async () => {
+			canvas.dispatchEvent(
+				new WheelEvent('wheel', {
+					clientX: 400,
+					deltaY: -5000,
+					bubbles: true,
+				}),
+			);
+		});
+
+		await act(async () => {
+			await new Promise((r) => requestAnimationFrame(r));
+		});
+
+		const [newStart] = setViewStartTs.mock.calls[0] ?? [];
+		const [newEnd] = setViewEndTs.mock.calls[0] ?? [];
+		if (newStart != null && newEnd != null) {
+			expect(newStart).toBeGreaterThanOrEqual(traceMetadata.startTime);
+			expect(newEnd).toBeLessThanOrEqual(traceMetadata.endTime);
+		}
+	});
+
+	it('returns isOverFlamegraphRef', () => {
+		const canvasRef = { current: createMockCanvas() };
+		const { result } = renderHook(() =>
+			useFlamegraphZoom({
+				canvasRef,
+				traceMetadata,
+				viewStartRef: { current: 0 },
+				viewEndRef: { current: 1000 },
+				rowHeightRef: { current: 24 },
+				setViewStartTs: jest.fn(),
+				setViewEndTs: jest.fn(),
+				setRowHeight: jest.fn(),
+			}),
+		);
+
+		expect(result.current.isOverFlamegraphRef).toBeDefined();
+		expect(result.current.isOverFlamegraphRef.current).toBe(false);
+	});
+});

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/__tests__/useScrollToSpan.test.tsx

@@ -0,0 +1,212 @@
+import type { Dispatch, SetStateAction } from 'react';
+import { useRef } from 'react';
+import { act, render, waitFor } from '@testing-library/react';
+
+import { useScrollToSpan } from '../hooks/useScrollToSpan';
+import { MOCK_SPANS, MOCK_TRACE_METADATA } from './testUtils';
+
+function TestWrapper({
+	firstSpanAtFetchLevel,
+	spans,
+	traceMetadata,
+	setViewStartTs,
+	setViewEndTs,
+	setScrollTop,
+}: {
+	firstSpanAtFetchLevel: string;
+	spans: typeof MOCK_SPANS;
+	traceMetadata: typeof MOCK_TRACE_METADATA;
+	setViewStartTs: Dispatch<SetStateAction<number>>;
+	setViewEndTs: Dispatch<SetStateAction<number>>;
+	setScrollTop: Dispatch<SetStateAction<number>>;
+}): JSX.Element {
+	const containerRef = useRef<HTMLDivElement>(null);
+	const viewStartRef = useRef(traceMetadata.startTime);
+	const viewEndRef = useRef(traceMetadata.endTime);
+	const scrollTopRef = useRef(0);
+
+	useScrollToSpan({
+		firstSpanAtFetchLevel,
+		spans,
+		traceMetadata,
+		containerRef,
+		viewStartRef,
+		viewEndRef,
+		scrollTopRef,
+		rowHeight: 24,
+		setViewStartTs,
+		setViewEndTs,
+		setScrollTop,
+	});
+
+	return <div ref={containerRef} data-testid="container" />;
+}
+
+describe('useScrollToSpan', () => {
+	beforeEach(() => {
+		Object.defineProperty(HTMLElement.prototype, 'clientHeight', {
+			configurable: true,
+			value: 400,
+		});
+	});
+
+	it('does not update when firstSpanAtFetchLevel is empty', async () => {
+		const setViewStartTs = jest.fn();
+		const setViewEndTs = jest.fn();
+		const setScrollTop = jest.fn();
+
+		render(
+			<TestWrapper
+				firstSpanAtFetchLevel=""
+				spans={MOCK_SPANS}
+				traceMetadata={MOCK_TRACE_METADATA}
+				setViewStartTs={setViewStartTs}
+				setViewEndTs={setViewEndTs}
+				setScrollTop={setScrollTop}
+			/>,
+		);
+
+		await waitFor(() => {
+			expect(setViewStartTs).not.toHaveBeenCalled();
+			expect(setViewEndTs).not.toHaveBeenCalled();
+			expect(setScrollTop).not.toHaveBeenCalled();
+		});
+	});
+
+	it('does not update when spans are empty', async () => {
+		const setViewStartTs = jest.fn();
+		const setViewEndTs = jest.fn();
+		const setScrollTop = jest.fn();
+
+		render(
+			<TestWrapper
+				firstSpanAtFetchLevel="root"
+				spans={[]}
+				traceMetadata={MOCK_TRACE_METADATA}
+				setViewStartTs={setViewStartTs}
+				setViewEndTs={setViewEndTs}
+				setScrollTop={setScrollTop}
+			/>,
+		);
+
+		await waitFor(() => {
+			expect(setViewStartTs).not.toHaveBeenCalled();
+			expect(setViewEndTs).not.toHaveBeenCalled();
+			expect(setScrollTop).not.toHaveBeenCalled();
+		});
+	});
+
+	it('does not update when target span not found', async () => {
+		const setViewStartTs = jest.fn();
+		const setViewEndTs = jest.fn();
+		const setScrollTop = jest.fn();
+
+		render(
+			<TestWrapper
+				firstSpanAtFetchLevel="nonexistent"
+				spans={MOCK_SPANS}
+				traceMetadata={MOCK_TRACE_METADATA}
+				setViewStartTs={setViewStartTs}
+				setViewEndTs={setViewEndTs}
+				setScrollTop={setScrollTop}
+			/>,
+		);
+
+		await waitFor(() => {
+			expect(setViewStartTs).not.toHaveBeenCalled();
+			expect(setViewEndTs).not.toHaveBeenCalled();
+			expect(setScrollTop).not.toHaveBeenCalled();
+		});
+	});
+
+	it('calls setters when target span found', async () => {
+		const setViewStartTs = jest.fn();
+		const setViewEndTs = jest.fn();
+		const setScrollTop = jest.fn();
+
+		const { getByTestId } = render(
+			<TestWrapper
+				firstSpanAtFetchLevel="grandchild"
+				spans={MOCK_SPANS}
+				traceMetadata={MOCK_TRACE_METADATA}
+				setViewStartTs={setViewStartTs}
+				setViewEndTs={setViewEndTs}
+				setScrollTop={setScrollTop}
+			/>,
+		);
+
+		expect(getByTestId('container')).toBeInTheDocument();
+
+		await waitFor(() => {
+			expect(setViewStartTs).toHaveBeenCalled();
+			expect(setViewEndTs).toHaveBeenCalled();
+			expect(setScrollTop).toHaveBeenCalled();
+		});
+
+		const [viewStart] = setViewStartTs.mock.calls[0];
+		const [viewEnd] = setViewEndTs.mock.calls[0];
+		const [scrollTop] = setScrollTop.mock.calls[0];
+
+		expect(viewEnd - viewStart).toBeGreaterThan(0);
+		expect(viewStart).toBeGreaterThanOrEqual(MOCK_TRACE_METADATA.startTime);
+		expect(viewEnd).toBeLessThanOrEqual(MOCK_TRACE_METADATA.endTime);
+		expect(scrollTop).toBeGreaterThanOrEqual(0);
+	});
+
+	it('centers span vertically (scrollTop centers span row)', async () => {
+		const setScrollTop = jest.fn();
+
+		await act(async () => {
+			render(
+				<TestWrapper
+					firstSpanAtFetchLevel="grandchild"
+					spans={MOCK_SPANS}
+					traceMetadata={MOCK_TRACE_METADATA}
+					setViewStartTs={jest.fn()}
+					setViewEndTs={jest.fn()}
+					setScrollTop={setScrollTop}
+				/>,
+			);
+		});
+
+		await waitFor(() => expect(setScrollTop).toHaveBeenCalled());
+
+		const [scrollTop] = setScrollTop.mock.calls[0];
+		const levelIndex = 2;
+		const rowHeight = 24;
+		const viewportHeight = 400;
+		const expectedCenter =
+			levelIndex * rowHeight - viewportHeight / 2 + rowHeight / 2;
+		expect(scrollTop).toBeCloseTo(Math.max(0, expectedCenter), -1);
+	});
+
+	it('zooms horizontally to span with 2x duration padding', async () => {
+		const setViewStartTs = jest.fn();
+		const setViewEndTs = jest.fn();
+
+		await act(async () => {
+			render(
+				<TestWrapper
+					firstSpanAtFetchLevel="root"
+					spans={MOCK_SPANS}
+					traceMetadata={MOCK_TRACE_METADATA}
+					setViewStartTs={setViewStartTs}
+					setViewEndTs={setViewEndTs}
+					setScrollTop={jest.fn()}
+				/>,
+			);
+		});
+
+		await waitFor(() => {
+			expect(setViewStartTs).toHaveBeenCalled();
+			expect(setViewEndTs).toHaveBeenCalled();
+		});
+
+		const [viewStart] = setViewStartTs.mock.calls[0];
+		const [viewEnd] = setViewEndTs.mock.calls[0];
+		const visibleWindow = viewEnd - viewStart;
+		const rootSpan = MOCK_SPANS[0][0];
+		const spanDurationMs = rootSpan.durationNano / 1e6;
+		expect(visibleWindow).toBeGreaterThanOrEqual(Math.max(spanDurationMs * 2, 5));
+	});
+});

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/__tests__/utils.math.test.ts

@@ -0,0 +1,135 @@
+import {
+	clamp,
+	findSpanById,
+	formatDuration,
+	getFlamegraphRowMetrics,
+} from '../utils';
+import { MOCK_SPANS } from './testUtils';
+
+jest.mock('container/TraceDetail/utils', () => ({
+	convertTimeToRelevantUnit: (
+		valueMs: number,
+	): { time: number; timeUnitName: string } => {
+		if (valueMs === 0) {
+			return { time: 0, timeUnitName: 'ms' };
+		}
+		if (valueMs < 1) {
+			return { time: valueMs, timeUnitName: 'ms' };
+		}
+		if (valueMs < 1000) {
+			return { time: valueMs, timeUnitName: 'ms' };
+		}
+		if (valueMs < 60_000) {
+			return { time: valueMs / 1000, timeUnitName: 's' };
+		}
+		if (valueMs < 3_600_000) {
+			return { time: valueMs / 60_000, timeUnitName: 'm' };
+		}
+		return { time: valueMs / 3_600_000, timeUnitName: 'hr' };
+	},
+}));
+
+describe('Pure Math and Data Utils', () => {
+	describe('clamp', () => {
+		it('returns value when within range', () => {
+			expect(clamp(5, 0, 10)).toBe(5);
+			expect(clamp(-3, -5, 5)).toBe(-3);
+		});
+
+		it('returns min when value is below min', () => {
+			expect(clamp(-1, 0, 10)).toBe(0);
+			expect(clamp(2, 5, 10)).toBe(5);
+		});
+
+		it('returns max when value is above max', () => {
+			expect(clamp(11, 0, 10)).toBe(10);
+			expect(clamp(100, 0, 50)).toBe(50);
+		});
+
+		it('handles min === max', () => {
+			expect(clamp(5, 7, 7)).toBe(7);
+			expect(clamp(7, 7, 7)).toBe(7);
+		});
+	});
+
+	describe('findSpanById', () => {
+		it('finds span in first level', () => {
+			const result = findSpanById(MOCK_SPANS, 'root');
+			expect(result).not.toBeNull();
+			expect(result?.span.spanId).toBe('root');
+			expect(result?.levelIndex).toBe(0);
+		});
+
+		it('finds span in nested level', () => {
+			const result = findSpanById(MOCK_SPANS, 'grandchild');
+			expect(result).not.toBeNull();
+			expect(result?.span.spanId).toBe('grandchild');
+			expect(result?.levelIndex).toBe(2);
+		});
+
+		it('returns null when span not found', () => {
+			expect(findSpanById(MOCK_SPANS, 'nonexistent')).toBeNull();
+		});
+
+		it('handles empty spans', () => {
+			expect(findSpanById([], 'root')).toBeNull();
+			expect(findSpanById([[], []], 'root')).toBeNull();
+		});
+	});
+
+	describe('getFlamegraphRowMetrics', () => {
+		it('computes normal row height metrics (24px)', () => {
+			const m = getFlamegraphRowMetrics(24);
+			expect(m.ROW_HEIGHT).toBe(24);
+			expect(m.SPAN_BAR_HEIGHT).toBe(22);
+			expect(m.SPAN_BAR_Y_OFFSET).toBe(1);
+			expect(m.EVENT_DOT_SIZE).toBe(6);
+		});
+
+		it('clamps span bar height to max for large row heights', () => {
+			const m = getFlamegraphRowMetrics(100);
+			expect(m.SPAN_BAR_HEIGHT).toBe(22);
+			expect(m.SPAN_BAR_Y_OFFSET).toBe(39);
+		});
+
+		it('clamps span bar height to min for small row heights', () => {
+			const m = getFlamegraphRowMetrics(6);
+			expect(m.SPAN_BAR_HEIGHT).toBe(8);
+			// spanBarYOffset = floor((6-8)/2) = -1 when bar exceeds row height
+			expect(m.SPAN_BAR_Y_OFFSET).toBe(-1);
+		});
+
+		it('clamps event dot size within min/max', () => {
+			const mSmall = getFlamegraphRowMetrics(6);
+			expect(mSmall.EVENT_DOT_SIZE).toBe(4);
+
+			const mLarge = getFlamegraphRowMetrics(24);
+			expect(mLarge.EVENT_DOT_SIZE).toBe(6);
+		});
+	});
+
+	describe('formatDuration', () => {
+		it('formats nanos as ms', () => {
+			// 1e6 nanos = 1ms
+			expect(formatDuration(1_000_000)).toBe('1ms');
+		});
+
+		it('formats larger durations as s/m/hr', () => {
+			// 2e9 nanos = 2000ms = 2s
+			expect(formatDuration(2_000_000_000)).toBe('2s');
+		});
+
+		it('formats zero duration', () => {
+			expect(formatDuration(0)).toBe('0ms');
+		});
+
+		it('formats very small values', () => {
+			// 1000 nanos = 0.001ms → mock returns { time: 0.001, timeUnitName: 'ms' }
+			expect(formatDuration(1000)).toBe('0ms');
+		});
+
+		it('formats decimal seconds correctly', () => {
+			expect(formatDuration(1_500_000_000)).toBe('1.5s');
+		});
+	});
+});

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/__tests__/utils.presentation.test.ts

@@ -0,0 +1,67 @@
+import { getSpanColor } from '../utils';
+import { MOCK_SPAN } from './testUtils';
+
+const mockGenerateColor = jest.fn();
+
+jest.mock('lib/uPlotLib/utils/generateColor', () => ({
+	generateColor: (key: string, colorMap: Record<string, string>): string =>
+		mockGenerateColor(key, colorMap),
+}));
+
+describe('Presentation / Styling Utils', () => {
+	beforeEach(() => {
+		jest.clearAllMocks();
+		mockGenerateColor.mockReturnValue('#2F80ED');
+	});
+
+	describe('getSpanColor', () => {
+		it('uses generated service color for normal span', () => {
+			mockGenerateColor.mockReturnValue('#1890ff');
+
+			const color = getSpanColor({
+				span: { ...MOCK_SPAN, hasError: false },
+				isDarkMode: false,
+			});
+
+			expect(mockGenerateColor).toHaveBeenCalledWith(
+				MOCK_SPAN.serviceName,
+				expect.any(Object),
+			);
+			expect(color).toBe('#1890ff');
+		});
+
+		it('overrides with error color in light mode when span has error', () => {
+			mockGenerateColor.mockReturnValue('#1890ff');
+
+			const color = getSpanColor({
+				span: { ...MOCK_SPAN, hasError: true },
+				isDarkMode: false,
+			});
+
+			expect(color).toBe('rgb(220, 38, 38)');
+		});
+
+		it('overrides with error color in dark mode when span has error', () => {
+			mockGenerateColor.mockReturnValue('#1890ff');
+
+			const color = getSpanColor({
+				span: { ...MOCK_SPAN, hasError: true },
+				isDarkMode: true,
+			});
+
+			expect(color).toBe('rgb(239, 68, 68)');
+		});
+
+		it('passes serviceName to generateColor', () => {
+			getSpanColor({
+				span: { ...MOCK_SPAN, serviceName: 'my-service' },
+				isDarkMode: false,
+			});
+
+			expect(mockGenerateColor).toHaveBeenCalledWith(
+				'my-service',
+				expect.any(Object),
+			);
+		});
+	});
+});

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/constants.ts

@@ -0,0 +1,36 @@
+export const ROW_HEIGHT = 24;
+export const SPAN_BAR_HEIGHT = 22;
+export const SPAN_BAR_Y_OFFSET = Math.floor((ROW_HEIGHT - SPAN_BAR_HEIGHT) / 2);
+export const EVENT_DOT_SIZE = 6;
+
+// Span bar sizing relative to row height (used by getFlamegraphRowMetrics)
+export const SPAN_BAR_HEIGHT_RATIO = SPAN_BAR_HEIGHT / ROW_HEIGHT;
+export const MIN_SPAN_BAR_HEIGHT = 8;
+export const MAX_SPAN_BAR_HEIGHT = SPAN_BAR_HEIGHT;
+
+// Event dot sizing relative to span bar height
+export const EVENT_DOT_SIZE_RATIO = EVENT_DOT_SIZE / SPAN_BAR_HEIGHT;
+export const MIN_EVENT_DOT_SIZE = 4;
+export const MAX_EVENT_DOT_SIZE = EVENT_DOT_SIZE;
+
+export const LABEL_FONT = '11px Inter, sans-serif';
+export const LABEL_PADDING_X = 8;
+export const MIN_WIDTH_FOR_NAME = 30;
+export const MIN_WIDTH_FOR_NAME_AND_DURATION = 80;
+
+// Dynamic row height (vertical zoom) -- disabled for now (MIN === MAX)
+export const MIN_ROW_HEIGHT = 24;
+export const MAX_ROW_HEIGHT = 24;
+export const DEFAULT_ROW_HEIGHT = MIN_ROW_HEIGHT;
+
+// Zoom intensity -- how fast zoom reacts to wheel/pinch delta
+export const PINCH_ZOOM_INTENSITY_H = 0.01;
+export const SCROLL_ZOOM_INTENSITY_H = 0.0015;
+export const PINCH_ZOOM_INTENSITY_V = 0.008;
+export const SCROLL_ZOOM_INTENSITY_V = 0.001;
+
+// Minimum visible time span in ms (prevents zooming to sub-pixel)
+export const MIN_VISIBLE_SPAN_MS = 5;
+
+// Selected span style (dashed border)
+export const DASHED_BORDER_LINE_DASH = [4, 2];

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/hooks/useCanvasSetup.ts

@@ -0,0 +1,55 @@
+import { RefObject, useCallback, useEffect } from 'react';
+
+export function useCanvasSetup(
+	canvasRef: RefObject<HTMLCanvasElement>,
+	containerRef: RefObject<HTMLDivElement>,
+	onDraw: () => void,
+): void {
+	const updateCanvasSize = useCallback(() => {
+		const canvas = canvasRef.current;
+		const container = containerRef.current;
+		if (!canvas || !container) {
+			return;
+		}
+
+		const dpr = window.devicePixelRatio || 1;
+		const rect = container.getBoundingClientRect();
+		const viewportHeight = container.clientHeight;
+
+		canvas.style.width = `${rect.width}px`;
+		canvas.style.height = `${viewportHeight}px`;
+
+		const newWidth = Math.floor(rect.width * dpr);
+		const newHeight = Math.floor(viewportHeight * dpr);
+
+		if (canvas.width !== newWidth || canvas.height !== newHeight) {
+			canvas.width = newWidth;
+			canvas.height = newHeight;
+			onDraw();
+		}
+	}, [canvasRef, containerRef, onDraw]);
+
+	useEffect(() => {
+		const container = containerRef.current;
+		if (!container) {
+			return (): void => {};
+		}
+
+		const resizeObserver = new ResizeObserver(updateCanvasSize);
+		resizeObserver.observe(container);
+		updateCanvasSize();
+
+		// when dpr changes, update the canvas size
+		const dprQuery = window.matchMedia('(resolution: 1dppx)');
+		dprQuery.addEventListener('change', updateCanvasSize);
+
+		return (): void => {
+			resizeObserver.disconnect();
+			dprQuery.removeEventListener('change', updateCanvasSize);
+		};
+	}, [containerRef, updateCanvasSize]);
+
+	useEffect(() => {
+		onDraw();
+	}, [onDraw]);
+}

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/hooks/useFlamegraphDrag.ts

@@ -0,0 +1,178 @@
+import {
+	Dispatch,
+	MouseEvent as ReactMouseEvent,
+	MutableRefObject,
+	RefObject,
+	SetStateAction,
+	useCallback,
+	useRef,
+} from 'react';
+
+import { ITraceMetadata } from '../types';
+import { clamp } from '../utils';
+
+interface UseFlamegraphDragArgs {
+	canvasRef: RefObject<HTMLCanvasElement>;
+	containerRef: RefObject<HTMLDivElement>;
+	traceMetadata: ITraceMetadata;
+	viewStartRef: MutableRefObject<number>;
+	viewEndRef: MutableRefObject<number>;
+	setViewStartTs: Dispatch<SetStateAction<number>>;
+	setViewEndTs: Dispatch<SetStateAction<number>>;
+	scrollTopRef: MutableRefObject<number>;
+	setScrollTop: Dispatch<SetStateAction<number>>;
+	totalHeight: number;
+}
+
+interface UseFlamegraphDragResult {
+	handleMouseDown: (e: ReactMouseEvent) => void;
+	handleMouseMove: (e: ReactMouseEvent) => void;
+	handleMouseUp: () => void;
+	handleDragMouseLeave: () => void;
+	suppressClickRef: MutableRefObject<boolean>;
+	isDraggingRef: MutableRefObject<boolean>;
+}
+
+const DRAG_THRESHOLD = 5;
+
+export function useFlamegraphDrag(
+	args: UseFlamegraphDragArgs,
+): UseFlamegraphDragResult {
+	const {
+		canvasRef,
+		containerRef,
+		traceMetadata,
+		viewStartRef,
+		viewEndRef,
+		setViewStartTs,
+		setViewEndTs,
+		scrollTopRef,
+		setScrollTop,
+		totalHeight,
+	} = args;
+
+	const isDraggingRef = useRef(false);
+	const dragStartRef = useRef<{ x: number; y: number } | null>(null);
+	const dragDistanceRef = useRef(0);
+	const suppressClickRef = useRef(false);
+
+	const clampScrollTop = useCallback(
+		(next: number): number => {
+			const container = containerRef.current;
+			if (!container) {
+				return 0;
+			}
+			const viewportHeight = container.clientHeight;
+			const maxScroll = Math.max(0, totalHeight - viewportHeight);
+			return clamp(next, 0, maxScroll);
+		},
+		[containerRef, totalHeight],
+	);
+
+	const handleMouseDown = useCallback(
+		(event: ReactMouseEvent): void => {
+			if (event.button !== 0) {
+				return;
+			}
+			event.preventDefault();
+
+			isDraggingRef.current = true;
+			dragStartRef.current = { x: event.clientX, y: event.clientY };
+			dragDistanceRef.current = 0;
+
+			const canvas = canvasRef.current;
+			if (canvas) {
+				canvas.style.cursor = 'grabbing';
+			}
+		},
+		[canvasRef],
+	);
+
+	const handleMouseMove = useCallback(
+		(event: ReactMouseEvent): void => {
+			if (!isDraggingRef.current || !dragStartRef.current) {
+				return;
+			}
+
+			const canvas = canvasRef.current;
+			if (!canvas) {
+				return;
+			}
+
+			const rect = canvas.getBoundingClientRect();
+			const deltaX = event.clientX - dragStartRef.current.x;
+			const deltaY = event.clientY - dragStartRef.current.y;
+
+			dragDistanceRef.current = Math.sqrt(deltaX * deltaX + deltaY * deltaY);
+
+			// --- Horizontal pan ---
+			const timeSpan = viewEndRef.current - viewStartRef.current;
+			const deltaTime = (deltaX / rect.width) * timeSpan;
+
+			const newStart = viewStartRef.current - deltaTime;
+			const clampedStart = clamp(
+				newStart,
+				traceMetadata.startTime,
+				traceMetadata.endTime - timeSpan,
+			);
+			const clampedEnd = clampedStart + timeSpan;
+
+			viewStartRef.current = clampedStart;
+			viewEndRef.current = clampedEnd;
+			setViewStartTs(clampedStart);
+			setViewEndTs(clampedEnd);
+
+			// --- Vertical scroll pan ---
+			const nextScrollTop = clampScrollTop(scrollTopRef.current - deltaY);
+			scrollTopRef.current = nextScrollTop;
+			setScrollTop(nextScrollTop);
+
+			dragStartRef.current = { x: event.clientX, y: event.clientY };
+		},
+		[
+			canvasRef,
+			traceMetadata,
+			viewStartRef,
+			viewEndRef,
+			setViewStartTs,
+			setViewEndTs,
+			scrollTopRef,
+			setScrollTop,
+			clampScrollTop,
+		],
+	);
+
+	const handleMouseUp = useCallback((): void => {
+		const wasDrag = dragDistanceRef.current > DRAG_THRESHOLD;
+		suppressClickRef.current = wasDrag;
+
+		isDraggingRef.current = false;
+		dragStartRef.current = null;
+		dragDistanceRef.current = 0;
+
+		const canvas = canvasRef.current;
+		if (canvas) {
+			canvas.style.cursor = 'grab';
+		}
+	}, [canvasRef]);
+
+	const handleDragMouseLeave = useCallback((): void => {
+		isDraggingRef.current = false;
+		dragStartRef.current = null;
+		dragDistanceRef.current = 0;
+
+		const canvas = canvasRef.current;
+		if (canvas) {
+			canvas.style.cursor = 'grab';
+		}
+	}, [canvasRef]);
+
+	return {
+		handleMouseDown,
+		handleMouseMove,
+		handleMouseUp,
+		handleDragMouseLeave,
+		suppressClickRef,
+		isDraggingRef,
+	};
+}

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/hooks/useFlamegraphDraw.ts

@@ -0,0 +1,222 @@
+import React, { RefObject, useCallback, useRef } from 'react';
+import { FlamegraphSpan } from 'types/api/trace/getTraceFlamegraph';
+
+import { SpanRect } from '../types';
+import {
+	clamp,
+	drawSpanBar,
+	FlamegraphRowMetrics,
+	getFlamegraphRowMetrics,
+	getSpanColor,
+} from '../utils';
+
+interface UseFlamegraphDrawArgs {
+	canvasRef: RefObject<HTMLCanvasElement>;
+	containerRef: RefObject<HTMLDivElement>;
+	spans: FlamegraphSpan[][];
+	viewStartTs: number;
+	viewEndTs: number;
+	scrollTop: number;
+	rowHeight: number;
+	selectedSpanId: string | undefined;
+	hoveredSpanId: string;
+	isDarkMode: boolean;
+	spanRectsRef?: React.MutableRefObject<SpanRect[]>;
+}
+
+interface UseFlamegraphDrawResult {
+	drawFlamegraph: () => void;
+	spanRectsRef: RefObject<SpanRect[]>;
+}
+
+const OVERSCAN_ROWS = 4;
+
+interface DrawLevelArgs {
+	ctx: CanvasRenderingContext2D;
+	levelSpans: FlamegraphSpan[];
+	levelIndex: number;
+	y: number;
+	viewStartTs: number;
+	timeSpan: number;
+	cssWidth: number;
+	selectedSpanId: string | undefined;
+	hoveredSpanId: string;
+	isDarkMode: boolean;
+	spanRectsArray: SpanRect[];
+	metrics: FlamegraphRowMetrics;
+}
+
+function drawLevel(args: DrawLevelArgs): void {
+	const {
+		ctx,
+		levelSpans,
+		levelIndex,
+		y,
+		viewStartTs,
+		timeSpan,
+		cssWidth,
+		selectedSpanId,
+		hoveredSpanId,
+		isDarkMode,
+		spanRectsArray,
+		metrics,
+	} = args;
+
+	const viewEndTs = viewStartTs + timeSpan;
+
+	for (let i = 0; i < levelSpans.length; i++) {
+		const span = levelSpans[i];
+		const spanStartMs = span.timestamp;
+		const spanEndMs = span.timestamp + span.durationNano / 1e6;
+
+		// Time culling -- skip spans entirely outside the visible time window
+		if (spanEndMs < viewStartTs || spanStartMs > viewEndTs) {
+			continue;
+		}
+
+		const leftOffset = ((spanStartMs - viewStartTs) / timeSpan) * cssWidth;
+		const rightEdge = ((spanEndMs - viewStartTs) / timeSpan) * cssWidth;
+		let width = rightEdge - leftOffset;
+
+		// Clamp to visible x-range
+		if (leftOffset < 0) {
+			width += leftOffset;
+			if (width <= 0) {
+				continue;
+			}
+		}
+		if (rightEdge > cssWidth) {
+			width = cssWidth - Math.max(0, leftOffset);
+			if (width <= 0) {
+				continue;
+			}
+		}
+
+		// Minimum 1px width so tiny spans remain visible
+		width = clamp(width, 1, Infinity);
+
+		const color = getSpanColor({ span, isDarkMode });
+
+		drawSpanBar({
+			ctx,
+			span,
+			x: Math.max(0, leftOffset),
+			y,
+			width,
+			levelIndex,
+			spanRectsArray,
+			color,
+			isDarkMode,
+			metrics,
+			selectedSpanId,
+			hoveredSpanId,
+		});
+	}
+}
+
+export function useFlamegraphDraw(
+	args: UseFlamegraphDrawArgs,
+): UseFlamegraphDrawResult {
+	const {
+		canvasRef,
+		containerRef,
+		spans,
+		viewStartTs,
+		viewEndTs,
+		scrollTop,
+		rowHeight,
+		selectedSpanId,
+		hoveredSpanId,
+		isDarkMode,
+		spanRectsRef: spanRectsRefProp,
+	} = args;
+
+	const spanRectsRefInternal = useRef<SpanRect[]>([]);
+	const spanRectsRef = spanRectsRefProp ?? spanRectsRefInternal;
+
+	const drawFlamegraph = useCallback(() => {
+		const canvas = canvasRef.current;
+		const container = containerRef.current;
+		if (!canvas || !container) {
+			return;
+		}
+
+		const ctx = canvas.getContext('2d');
+		if (!ctx) {
+			return;
+		}
+
+		const dpr = window.devicePixelRatio || 1;
+		ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
+
+		const timeSpan = viewEndTs - viewStartTs;
+		if (timeSpan <= 0) {
+			return;
+		}
+
+		const cssWidth = canvas.width / dpr;
+		const metrics = getFlamegraphRowMetrics(rowHeight);
+
+		// ---- Vertical clipping window ----
+		const viewportHeight = container.clientHeight;
+
+		//starts drawing OVERSCAN_ROWS(4) rows above the visible area.
+		const firstLevel = Math.max(
+			0,
+			Math.floor(scrollTop / metrics.ROW_HEIGHT) - OVERSCAN_ROWS,
+		);
+		// adds 2*OVERSCAN_ROWS extra rows above and below the visible area.
+		const visibleLevelCount =
+			Math.ceil(viewportHeight / metrics.ROW_HEIGHT) + 2 * OVERSCAN_ROWS;
+
+		const lastLevel = Math.min(spans.length - 1, firstLevel + visibleLevelCount);
+
+		ctx.clearRect(0, 0, cssWidth, viewportHeight);
+
+		const spanRectsArray: SpanRect[] = [];
+
+		// ---- Draw only visible levels ----
+		for (let levelIndex = firstLevel; levelIndex <= lastLevel; levelIndex++) {
+			const levelSpans = spans[levelIndex];
+			if (!levelSpans) {
+				continue;
+			}
+
+			drawLevel({
+				ctx,
+				levelSpans,
+				levelIndex,
+				y: levelIndex * metrics.ROW_HEIGHT - scrollTop,
+				viewStartTs,
+				timeSpan,
+				cssWidth,
+				selectedSpanId,
+				hoveredSpanId,
+				isDarkMode,
+				spanRectsArray,
+				metrics,
+			});
+		}
+
+		spanRectsRef.current = spanRectsArray;
+	}, [
+		canvasRef,
+		containerRef,
+		spanRectsRef,
+		spans,
+		viewStartTs,
+		viewEndTs,
+		scrollTop,
+		rowHeight,
+		selectedSpanId,
+		hoveredSpanId,
+		isDarkMode,
+	]);
+
+	// TODO: spanRectsRef is a flat array — hover scans all visible rects O(N).
+	// Upgrade to per-level buckets: spanRects[levelIndex] = [...] so hover can
+	// compute level from mouseY / ROW_HEIGHT and scan only that row.
+	// Further: binary search within a level by x (spans are sorted by start time)
+	// to reduce hover cost from O(N) to O(log N).
+	return { drawFlamegraph, spanRectsRef };
+}

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/hooks/useFlamegraphHover.ts

@@ -0,0 +1,214 @@
+import {
+	Dispatch,
+	MouseEvent as ReactMouseEvent,
+	MutableRefObject,
+	RefObject,
+	SetStateAction,
+	useCallback,
+	useState,
+} from 'react';
+import { FlamegraphSpan } from 'types/api/trace/getTraceFlamegraph';
+
+import { SpanRect } from '../types';
+import { ITraceMetadata } from '../types';
+import { getSpanColor } from '../utils';
+
+function getCanvasPointer(
+	canvas: HTMLCanvasElement,
+	clientX: number,
+	clientY: number,
+): { cssX: number; cssY: number } | null {
+	const rect = canvas.getBoundingClientRect();
+	const dpr = window.devicePixelRatio || 1;
+	const cssWidth = canvas.width / dpr;
+	const cssHeight = canvas.height / dpr;
+	const cssX = (clientX - rect.left) * (cssWidth / rect.width);
+	const cssY = (clientY - rect.top) * (cssHeight / rect.height);
+	return { cssX, cssY };
+}
+
+function findSpanAtPosition(
+	cssX: number,
+	cssY: number,
+	spanRects: SpanRect[],
+): FlamegraphSpan | null {
+	for (let i = spanRects.length - 1; i >= 0; i--) {
+		const r = spanRects[i];
+		if (
+			cssX >= r.x &&
+			cssX <= r.x + r.width &&
+			cssY >= r.y &&
+			cssY <= r.y + r.height
+		) {
+			return r.span;
+		}
+	}
+	return null;
+}
+
+export interface TooltipContent {
+	spanName: string;
+	status: 'ok' | 'warning' | 'error';
+	startMs: number;
+	durationMs: number;
+	clientX: number;
+	clientY: number;
+	spanColor: string;
+}
+
+interface UseFlamegraphHoverArgs {
+	canvasRef: RefObject<HTMLCanvasElement>;
+	spanRectsRef: MutableRefObject<SpanRect[]>;
+	traceMetadata: ITraceMetadata;
+	viewStartTs: number;
+	viewEndTs: number;
+	isDraggingRef: MutableRefObject<boolean>;
+	suppressClickRef: MutableRefObject<boolean>;
+	onSpanClick: (spanId: string) => void;
+	isDarkMode: boolean;
+}
+
+interface UseFlamegraphHoverResult {
+	hoveredSpanId: string | null;
+	setHoveredSpanId: Dispatch<SetStateAction<string | null>>;
+	handleHoverMouseMove: (e: ReactMouseEvent) => void;
+	handleHoverMouseLeave: () => void;
+	handleClick: (e: ReactMouseEvent) => void;
+	tooltipContent: TooltipContent | null;
+}
+
+export function useFlamegraphHover(
+	args: UseFlamegraphHoverArgs,
+): UseFlamegraphHoverResult {
+	const {
+		canvasRef,
+		spanRectsRef,
+		traceMetadata,
+		viewStartTs,
+		viewEndTs,
+		isDraggingRef,
+		suppressClickRef,
+		onSpanClick,
+		isDarkMode,
+	} = args;
+
+	const [hoveredSpanId, setHoveredSpanId] = useState<string | null>(null);
+	const [tooltipContent, setTooltipContent] = useState<TooltipContent | null>(
+		null,
+	);
+
+	const isZoomed =
+		viewStartTs !== traceMetadata.startTime ||
+		viewEndTs !== traceMetadata.endTime;
+
+	const updateCursor = useCallback(
+		(canvas: HTMLCanvasElement, span: FlamegraphSpan | null): void => {
+			if (span) {
+				canvas.style.cursor = 'pointer';
+			} else if (isZoomed) {
+				canvas.style.cursor = 'grab';
+			} else {
+				canvas.style.cursor = 'default';
+			}
+		},
+		[isZoomed],
+	);
+
+	const handleHoverMouseMove = useCallback(
+		(e: ReactMouseEvent): void => {
+			if (isDraggingRef.current) {
+				return;
+			}
+
+			const canvas = canvasRef.current;
+			if (!canvas) {
+				return;
+			}
+
+			const pointer = getCanvasPointer(canvas, e.clientX, e.clientY);
+			if (!pointer) {
+				return;
+			}
+
+			const span = findSpanAtPosition(
+				pointer.cssX,
+				pointer.cssY,
+				spanRectsRef.current,
+			);
+
+			if (span) {
+				setHoveredSpanId(span.spanId);
+				setTooltipContent({
+					spanName: span.name || 'unknown',
+					status: span.hasError ? 'error' : 'ok',
+					startMs: span.timestamp - traceMetadata.startTime,
+					durationMs: span.durationNano / 1e6,
+					clientX: e.clientX,
+					clientY: e.clientY,
+					spanColor: getSpanColor({ span, isDarkMode }),
+				});
+				updateCursor(canvas, span);
+			} else {
+				setHoveredSpanId(null);
+				setTooltipContent(null);
+				updateCursor(canvas, null);
+			}
+		},
+		[
+			canvasRef,
+			spanRectsRef,
+			traceMetadata.startTime,
+			isDraggingRef,
+			updateCursor,
+			isDarkMode,
+		],
+	);
+
+	const handleHoverMouseLeave = useCallback((): void => {
+		setHoveredSpanId(null);
+		setTooltipContent(null);
+
+		const canvas = canvasRef.current;
+		if (canvas) {
+			updateCursor(canvas, null);
+		}
+	}, [canvasRef, updateCursor]);
+
+	const handleClick = useCallback(
+		(e: ReactMouseEvent): void => {
+			if (suppressClickRef.current) {
+				return;
+			}
+
+			const canvas = canvasRef.current;
+			if (!canvas) {
+				return;
+			}
+
+			const pointer = getCanvasPointer(canvas, e.clientX, e.clientY);
+			if (!pointer) {
+				return;
+			}
+
+			const span = findSpanAtPosition(
+				pointer.cssX,
+				pointer.cssY,
+				spanRectsRef.current,
+			);
+
+			if (span) {
+				onSpanClick(span.spanId);
+			}
+		},
+		[canvasRef, spanRectsRef, suppressClickRef, onSpanClick],
+	);
+
+	return {
+		hoveredSpanId,
+		setHoveredSpanId,
+		handleHoverMouseMove,
+		handleHoverMouseLeave,
+		handleClick,
+		tooltipContent,
+	};
+}

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/hooks/useFlamegraphZoom.ts

@@ -0,0 +1,224 @@
+import {
+	Dispatch,
+	MutableRefObject,
+	RefObject,
+	SetStateAction,
+	useCallback,
+	useEffect,
+	useRef,
+} from 'react';
+
+import {
+	DEFAULT_ROW_HEIGHT,
+	MAX_ROW_HEIGHT,
+	MIN_ROW_HEIGHT,
+	MIN_VISIBLE_SPAN_MS,
+	PINCH_ZOOM_INTENSITY_H,
+	PINCH_ZOOM_INTENSITY_V,
+	SCROLL_ZOOM_INTENSITY_H,
+	SCROLL_ZOOM_INTENSITY_V,
+} from '../constants';
+import { ITraceMetadata } from '../types';
+import { clamp } from '../utils';
+
+interface UseFlamegraphZoomArgs {
+	canvasRef: RefObject<HTMLCanvasElement>;
+	traceMetadata: ITraceMetadata;
+	viewStartRef: MutableRefObject<number>;
+	viewEndRef: MutableRefObject<number>;
+	rowHeightRef: MutableRefObject<number>;
+	setViewStartTs: Dispatch<SetStateAction<number>>;
+	setViewEndTs: Dispatch<SetStateAction<number>>;
+	setRowHeight: Dispatch<SetStateAction<number>>;
+}
+
+interface UseFlamegraphZoomResult {
+	handleResetZoom: () => void;
+	isOverFlamegraphRef: MutableRefObject<boolean>;
+}
+
+function getCanvasPointer(
+	canvasRef: RefObject<HTMLCanvasElement>,
+	clientX: number,
+): { cssX: number; cssWidth: number } | null {
+	const canvas = canvasRef.current;
+	if (!canvas) {
+		return null;
+	}
+
+	const rect = canvas.getBoundingClientRect();
+	const dpr = window.devicePixelRatio || 1;
+	const cssWidth = canvas.width / dpr;
+	const cssX = (clientX - rect.left) * (cssWidth / rect.width);
+
+	return { cssX, cssWidth };
+}
+
+export function useFlamegraphZoom(
+	args: UseFlamegraphZoomArgs,
+): UseFlamegraphZoomResult {
+	const {
+		canvasRef,
+		traceMetadata,
+		viewStartRef,
+		viewEndRef,
+		rowHeightRef,
+		setViewStartTs,
+		setViewEndTs,
+		setRowHeight,
+	} = args;
+
+	const isOverFlamegraphRef = useRef(false);
+	const wheelDeltaRef = useRef(0);
+	const rafRef = useRef<number | null>(null);
+	const lastCursorXRef = useRef(0);
+	const lastCssWidthRef = useRef(1);
+	const lastIsPinchRef = useRef(false);
+	const lastWheelClientXRef = useRef<number | null>(null);
+
+	// Prevent browser zoom when pinching over the flamegraph
+	useEffect(() => {
+		const onWheel = (e: WheelEvent): void => {
+			if (isOverFlamegraphRef.current && e.ctrlKey) {
+				e.preventDefault();
+			}
+		};
+
+		window.addEventListener('wheel', onWheel, { passive: false, capture: true });
+
+		return (): void => {
+			window.removeEventListener('wheel', onWheel, {
+				capture: true,
+			} as EventListenerOptions);
+		};
+	}, []);
+
+	const applyWheelZoom = useCallback(() => {
+		rafRef.current = null;
+
+		const cssWidth = lastCssWidthRef.current || 1;
+		const cursorX = lastCursorXRef.current;
+		const fullSpanMs = traceMetadata.endTime - traceMetadata.startTime;
+
+		const oldStart = viewStartRef.current;
+		const oldEnd = viewEndRef.current;
+		const oldSpan = oldEnd - oldStart;
+
+		const deltaY = wheelDeltaRef.current;
+		wheelDeltaRef.current = 0;
+		if (deltaY === 0) {
+			return;
+		}
+
+		const zoomH = lastIsPinchRef.current
+			? PINCH_ZOOM_INTENSITY_H
+			: SCROLL_ZOOM_INTENSITY_H;
+		const zoomV = lastIsPinchRef.current
+			? PINCH_ZOOM_INTENSITY_V
+			: SCROLL_ZOOM_INTENSITY_V;
+
+		const factorH = Math.exp(deltaY * zoomH);
+		const factorV = Math.exp(deltaY * zoomV);
+
+		// --- Horizontal zoom ---
+		const desiredSpan = oldSpan * factorH;
+		const minSpanMs = Math.max(
+			MIN_VISIBLE_SPAN_MS,
+			oldSpan / Math.max(cssWidth, 1),
+		);
+		const clampedSpan = clamp(desiredSpan, minSpanMs, fullSpanMs);
+
+		const cursorRatio = clamp(cursorX / cssWidth, 0, 1);
+		const anchorTs = oldStart + cursorRatio * oldSpan;
+
+		let nextStart = anchorTs - cursorRatio * clampedSpan;
+		nextStart = clamp(
+			nextStart,
+			traceMetadata.startTime,
+			traceMetadata.endTime - clampedSpan,
+		);
+		const nextEnd = nextStart + clampedSpan;
+
+		// --- Vertical zoom (row height) ---
+		const desiredRow = rowHeightRef.current * (1 / factorV);
+		const nextRow = clamp(desiredRow, MIN_ROW_HEIGHT, MAX_ROW_HEIGHT);
+
+		// Write refs immediately so rapid wheel events read fresh values
+		viewStartRef.current = nextStart;
+		viewEndRef.current = nextEnd;
+		rowHeightRef.current = nextRow;
+
+		setViewStartTs(nextStart);
+		setViewEndTs(nextEnd);
+		setRowHeight(nextRow);
+	}, [
+		traceMetadata,
+		viewStartRef,
+		viewEndRef,
+		rowHeightRef,
+		setViewStartTs,
+		setViewEndTs,
+		setRowHeight,
+	]);
+
+	// Native wheel listener on the canvas (passive: false for reliable preventDefault)
+	useEffect(() => {
+		const canvas = canvasRef.current;
+		if (!canvas) {
+			return (): void => {};
+		}
+
+		const onWheel = (e: WheelEvent): void => {
+			e.preventDefault();
+
+			const pointer = getCanvasPointer(canvasRef, e.clientX);
+			if (!pointer) {
+				return;
+			}
+
+			// Flush accumulated delta if cursor moved significantly
+			if (lastWheelClientXRef.current !== null) {
+				const moved = Math.abs(e.clientX - lastWheelClientXRef.current);
+				if (moved > 6) {
+					wheelDeltaRef.current = 0;
+				}
+			}
+			lastWheelClientXRef.current = e.clientX;
+
+			lastIsPinchRef.current = e.ctrlKey;
+			lastCssWidthRef.current = pointer.cssWidth;
+			lastCursorXRef.current = pointer.cssX;
+			wheelDeltaRef.current += e.deltaY;
+
+			if (rafRef.current == null) {
+				rafRef.current = requestAnimationFrame(applyWheelZoom);
+			}
+		};
+
+		canvas.addEventListener('wheel', onWheel, { passive: false });
+
+		return (): void => {
+			canvas.removeEventListener('wheel', onWheel);
+		};
+	}, [canvasRef, applyWheelZoom]);
+
+	const handleResetZoom = useCallback(() => {
+		viewStartRef.current = traceMetadata.startTime;
+		viewEndRef.current = traceMetadata.endTime;
+		rowHeightRef.current = DEFAULT_ROW_HEIGHT;
+
+		setViewStartTs(traceMetadata.startTime);
+		setViewEndTs(traceMetadata.endTime);
+		setRowHeight(DEFAULT_ROW_HEIGHT);
+	}, [
+		traceMetadata,
+		viewStartRef,
+		viewEndRef,
+		rowHeightRef,
+		setViewStartTs,
+		setViewEndTs,
+		setRowHeight,
+	]);
+
+	return { handleResetZoom, isOverFlamegraphRef };
+}

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/hooks/useScrollToSpan.ts

@@ -0,0 +1,118 @@
+import {
+	Dispatch,
+	MutableRefObject,
+	RefObject,
+	SetStateAction,
+	useEffect,
+} from 'react';
+import { FlamegraphSpan } from 'types/api/trace/getTraceFlamegraph';
+
+import { MIN_VISIBLE_SPAN_MS } from '../constants';
+import { ITraceMetadata } from '../types';
+import { clamp, findSpanById, getFlamegraphRowMetrics } from '../utils';
+
+interface UseScrollToSpanArgs {
+	firstSpanAtFetchLevel: string;
+	spans: FlamegraphSpan[][];
+	traceMetadata: ITraceMetadata;
+	containerRef: RefObject<HTMLDivElement>;
+	viewStartRef: MutableRefObject<number>;
+	viewEndRef: MutableRefObject<number>;
+	scrollTopRef: MutableRefObject<number>;
+	rowHeight: number;
+	setViewStartTs: Dispatch<SetStateAction<number>>;
+	setViewEndTs: Dispatch<SetStateAction<number>>;
+	setScrollTop: Dispatch<SetStateAction<number>>;
+}
+
+/**
+ * When firstSpanAtFetchLevel (from URL spanId) changes, scroll and zoom the
+ * flamegraph so the selected span is centered in view.
+ */
+export function useScrollToSpan(args: UseScrollToSpanArgs): void {
+	const {
+		firstSpanAtFetchLevel,
+		spans,
+		traceMetadata,
+		containerRef,
+		viewStartRef,
+		viewEndRef,
+		scrollTopRef,
+		rowHeight,
+		setViewStartTs,
+		setViewEndTs,
+		setScrollTop,
+	} = args;
+
+	useEffect(() => {
+		if (!firstSpanAtFetchLevel || spans.length === 0) {
+			return;
+		}
+
+		const result = findSpanById(spans, firstSpanAtFetchLevel);
+		if (!result) {
+			return;
+		}
+
+		const { span, levelIndex } = result;
+		const container = containerRef.current;
+		if (!container) {
+			return;
+		}
+
+		const metrics = getFlamegraphRowMetrics(rowHeight);
+		const viewportHeight = container.clientHeight;
+		const totalHeight = spans.length * metrics.ROW_HEIGHT;
+		const maxScroll = Math.max(0, totalHeight - viewportHeight);
+
+		// Vertical: center the span's row in the viewport
+		const targetScrollTop = clamp(
+			levelIndex * metrics.ROW_HEIGHT -
+				viewportHeight / 2 +
+				metrics.ROW_HEIGHT / 2,
+			0,
+			maxScroll,
+		);
+
+		// Horizontal: zoom to span with padding (2x span duration), center it
+		const spanStartMs = span.timestamp;
+		const spanEndMs = span.timestamp + span.durationNano / 1e6;
+		const spanDurationMs = spanEndMs - spanStartMs;
+		const spanCenterMs = (spanStartMs + spanEndMs) / 2;
+
+		const visibleWindowMs = Math.max(spanDurationMs * 2, MIN_VISIBLE_SPAN_MS);
+		const fullSpanMs = traceMetadata.endTime - traceMetadata.startTime;
+		const clampedWindow = clamp(visibleWindowMs, MIN_VISIBLE_SPAN_MS, fullSpanMs);
+
+		let targetViewStart = spanCenterMs - clampedWindow / 2;
+		let targetViewEnd = spanCenterMs + clampedWindow / 2;
+
+		targetViewStart = clamp(
+			targetViewStart,
+			traceMetadata.startTime,
+			traceMetadata.endTime - clampedWindow,
+		);
+		targetViewEnd = targetViewStart + clampedWindow;
+
+		// Apply immediately (instant jump)
+		viewStartRef.current = targetViewStart;
+		viewEndRef.current = targetViewEnd;
+		scrollTopRef.current = targetScrollTop;
+
+		setViewStartTs(targetViewStart);
+		setViewEndTs(targetViewEnd);
+		setScrollTop(targetScrollTop);
+	}, [
+		firstSpanAtFetchLevel,
+		spans,
+		traceMetadata,
+		containerRef,
+		viewStartRef,
+		viewEndRef,
+		scrollTopRef,
+		rowHeight,
+		setViewStartTs,
+		setViewEndTs,
+		setScrollTop,
+	]);
+}

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/types.ts

@@ -0,0 +1,24 @@
+import { Dispatch, SetStateAction } from 'react';
+import { FlamegraphSpan } from 'types/api/trace/getTraceFlamegraph';
+
+export interface ITraceMetadata {
+	startTime: number;
+	endTime: number;
+}
+
+export interface FlamegraphCanvasProps {
+	spans: FlamegraphSpan[][];
+	firstSpanAtFetchLevel: string;
+	setFirstSpanAtFetchLevel: Dispatch<SetStateAction<string>>;
+	onSpanClick: (spanId: string) => void;
+	traceMetadata: ITraceMetadata;
+}
+
+export interface SpanRect {
+	span: FlamegraphSpan;
+	x: number;
+	y: number;
+	width: number;
+	height: number;
+	level: number;
+}

frontend/src/pages/TraceDetailsV3/TraceFlamegraph/utils.ts

@@ -0,0 +1,355 @@
+import { themeColors } from 'constants/theme';
+import { convertTimeToRelevantUnit } from 'container/TraceDetail/utils';
+import { generateColor } from 'lib/uPlotLib/utils/generateColor';
+import { FlamegraphSpan } from 'types/api/trace/getTraceFlamegraph';
+
+import {
+	DASHED_BORDER_LINE_DASH,
+	EVENT_DOT_SIZE_RATIO,
+	LABEL_FONT,
+	LABEL_PADDING_X,
+	MAX_EVENT_DOT_SIZE,
+	MAX_SPAN_BAR_HEIGHT,
+	MIN_EVENT_DOT_SIZE,
+	MIN_SPAN_BAR_HEIGHT,
+	MIN_WIDTH_FOR_NAME,
+	MIN_WIDTH_FOR_NAME_AND_DURATION,
+	SPAN_BAR_HEIGHT_RATIO,
+} from './constants';
+import { SpanRect } from './types';
+
+export function clamp(v: number, min: number, max: number): number {
+	return Math.max(min, Math.min(max, v));
+}
+
+/** Create diagonal stripe pattern for selected/hovered span (repeating-linear-gradient -45deg style). */
+function createStripePattern(
+	ctx: CanvasRenderingContext2D,
+	color: string,
+): CanvasPattern | null {
+	const size = 20;
+	const patternCanvas = document.createElement('canvas');
+	patternCanvas.width = size;
+	patternCanvas.height = size;
+	const pCtx = patternCanvas.getContext('2d');
+	if (!pCtx) {
+		return null;
+	}
+
+	// Diagonal stripes at -45deg: 10px transparent, 10px colored (0.04 opacity), repeat
+	pCtx.globalAlpha = 0.04;
+	pCtx.strokeStyle = color;
+	pCtx.lineWidth = 10;
+	pCtx.lineCap = 'butt';
+	for (let i = -size; i < size * 2; i += size) {
+		pCtx.beginPath();
+		pCtx.moveTo(i + size, 0);
+		pCtx.lineTo(i, size);
+		pCtx.stroke();
+	}
+	pCtx.globalAlpha = 1;
+
+	return ctx.createPattern(patternCanvas, 'repeat');
+}
+
+export function findSpanById(
+	spans: FlamegraphSpan[][],
+	spanId: string,
+): { span: FlamegraphSpan; levelIndex: number } | null {
+	for (let levelIndex = 0; levelIndex < spans.length; levelIndex++) {
+		const span = spans[levelIndex]?.find((s) => s.spanId === spanId);
+		if (span) {
+			return { span, levelIndex };
+		}
+	}
+	return null;
+}
+
+export interface FlamegraphRowMetrics {
+	ROW_HEIGHT: number;
+	SPAN_BAR_HEIGHT: number;
+	SPAN_BAR_Y_OFFSET: number;
+	EVENT_DOT_SIZE: number;
+}
+
+export function getFlamegraphRowMetrics(
+	rowHeight: number,
+): FlamegraphRowMetrics {
+	const spanBarHeight = clamp(
+		Math.round(rowHeight * SPAN_BAR_HEIGHT_RATIO),
+		MIN_SPAN_BAR_HEIGHT,
+		MAX_SPAN_BAR_HEIGHT,
+	);
+	const spanBarYOffset = Math.floor((rowHeight - spanBarHeight) / 2);
+	const eventDotSize = clamp(
+		Math.round(spanBarHeight * EVENT_DOT_SIZE_RATIO),
+		MIN_EVENT_DOT_SIZE,
+		MAX_EVENT_DOT_SIZE,
+	);
+
+	return {
+		ROW_HEIGHT: rowHeight,
+		SPAN_BAR_HEIGHT: spanBarHeight,
+		SPAN_BAR_Y_OFFSET: spanBarYOffset,
+		EVENT_DOT_SIZE: eventDotSize,
+	};
+}
+
+interface GetSpanColorArgs {
+	span: FlamegraphSpan;
+	isDarkMode: boolean;
+}
+
+export function getSpanColor(args: GetSpanColorArgs): string {
+	const { span, isDarkMode } = args;
+	let color = generateColor(span.serviceName, themeColors.traceDetailColorsV3);
+
+	if (span.hasError) {
+		color = isDarkMode ? 'rgb(239, 68, 68)' : 'rgb(220, 38, 38)';
+	}
+
+	return color;
+}
+
+interface DrawEventDotArgs {
+	ctx: CanvasRenderingContext2D;
+	x: number;
+	y: number;
+	isError: boolean;
+	isDarkMode: boolean;
+	eventDotSize: number;
+}
+
+export function drawEventDot(args: DrawEventDotArgs): void {
+	const { ctx, x, y, isError, isDarkMode, eventDotSize } = args;
+
+	ctx.save();
+	ctx.translate(x, y);
+	ctx.rotate(Math.PI / 4);
+
+	if (isError) {
+		ctx.fillStyle = isDarkMode ? 'rgb(239, 68, 68)' : 'rgb(220, 38, 38)';
+		ctx.strokeStyle = isDarkMode ? 'rgb(185, 28, 28)' : 'rgb(153, 27, 27)';
+	} else {
+		ctx.fillStyle = isDarkMode ? 'rgb(14, 165, 233)' : 'rgb(6, 182, 212)';
+		ctx.strokeStyle = isDarkMode ? 'rgb(2, 132, 199)' : 'rgb(8, 145, 178)';
+	}
+
+	ctx.lineWidth = 1;
+	const half = eventDotSize / 2;
+	ctx.fillRect(-half, -half, eventDotSize, eventDotSize);
+	ctx.strokeRect(-half, -half, eventDotSize, eventDotSize);
+	ctx.restore();
+}
+
+interface DrawSpanBarArgs {
+	ctx: CanvasRenderingContext2D;
+	span: FlamegraphSpan;
+	x: number;
+	y: number;
+	width: number;
+	levelIndex: number;
+	spanRectsArray: SpanRect[];
+	color: string;
+	isDarkMode: boolean;
+	metrics: FlamegraphRowMetrics;
+	selectedSpanId?: string | null;
+	hoveredSpanId?: string | null;
+}
+
+export function drawSpanBar(args: DrawSpanBarArgs): void {
+	const {
+		ctx,
+		span,
+		x,
+		y,
+		width,
+		levelIndex,
+		spanRectsArray,
+		color,
+		isDarkMode,
+		metrics,
+		selectedSpanId,
+		hoveredSpanId,
+	} = args;
+
+	const spanY = y + metrics.SPAN_BAR_Y_OFFSET;
+	const isSelected = selectedSpanId === span.spanId;
+	const isHovered = hoveredSpanId === span.spanId;
+	const isSelectedOrHovered = isSelected || isHovered;
+
+	ctx.beginPath();
+	ctx.roundRect(x, spanY, width, metrics.SPAN_BAR_HEIGHT, 2);
+
+	if (isSelectedOrHovered) {
+		// Diagonal stripe pattern (repeating-linear-gradient -45deg style) + border in span color
+		const pattern = createStripePattern(ctx, color);
+		if (pattern) {
+			ctx.fillStyle = pattern;
+			ctx.fill();
+		}
+		if (isSelected) {
+			ctx.setLineDash(DASHED_BORDER_LINE_DASH);
+		}
+		ctx.strokeStyle = color;
+		ctx.lineWidth = isSelected ? 2 : 1;
+		ctx.stroke();
+		if (isSelected) {
+			ctx.setLineDash([]);
+		}
+	} else {
+		ctx.fillStyle = color;
+		ctx.fill();
+	}
+
+	spanRectsArray.push({
+		span,
+		x,
+		y: spanY,
+		width,
+		height: metrics.SPAN_BAR_HEIGHT,
+		level: levelIndex,
+	});
+
+	span.event?.forEach((event) => {
+		const spanDurationMs = span.durationNano / 1e6;
+		if (spanDurationMs <= 0) {
+			return;
+		}
+
+		const eventTimeMs = event.timeUnixNano / 1e6;
+		const eventOffsetPercent =
+			((eventTimeMs - span.timestamp) / spanDurationMs) * 100;
+		const clampedOffset = clamp(eventOffsetPercent, 1, 99);
+		const eventX = x + (clampedOffset / 100) * width;
+		const eventY = spanY + metrics.SPAN_BAR_HEIGHT / 2;
+
+		drawEventDot({
+			ctx,
+			x: eventX,
+			y: eventY,
+			isError: event.isError,
+			isDarkMode,
+			eventDotSize: metrics.EVENT_DOT_SIZE,
+		});
+	});
+
+	drawSpanLabel({
+		ctx,
+		span,
+		x,
+		y: spanY,
+		width,
+		color,
+		isSelectedOrHovered,
+		isDarkMode,
+		spanBarHeight: metrics.SPAN_BAR_HEIGHT,
+	});
+}
+
+export function formatDuration(durationNano: number): string {
+	const durationMs = durationNano / 1e6;
+	const { time, timeUnitName } = convertTimeToRelevantUnit(durationMs);
+	return `${parseFloat(time.toFixed(2))}${timeUnitName}`;
+}
+
+interface DrawSpanLabelArgs {
+	ctx: CanvasRenderingContext2D;
+	span: FlamegraphSpan;
+	x: number;
+	y: number;
+	width: number;
+	color: string;
+	isSelectedOrHovered: boolean;
+	isDarkMode: boolean;
+	spanBarHeight: number;
+}
+
+function drawSpanLabel(args: DrawSpanLabelArgs): void {
+	const {
+		ctx,
+		span,
+		x,
+		y,
+		width,
+		color,
+		isSelectedOrHovered,
+		isDarkMode,
+		spanBarHeight,
+	} = args;
+
+	if (width < MIN_WIDTH_FOR_NAME) {
+		return;
+	}
+
+	const name = span.name;
+
+	ctx.save();
+
+	// Clip text to span bar bounds
+	ctx.beginPath();
+	ctx.rect(x, y, width, spanBarHeight);
+	ctx.clip();
+
+	ctx.font = LABEL_FONT;
+	ctx.fillStyle = isSelectedOrHovered
+		? color
+		: isDarkMode
+		? 'rgba(0, 0, 0, 0.9)'
+		: 'rgba(255, 255, 255, 0.9)';
+	ctx.textBaseline = 'middle';
+
+	const textY = y + spanBarHeight / 2;
+	const leftX = x + LABEL_PADDING_X;
+	const rightX = x + width - LABEL_PADDING_X;
+	const availableWidth = width - LABEL_PADDING_X * 2;
+
+	if (width >= MIN_WIDTH_FOR_NAME_AND_DURATION) {
+		const duration = formatDuration(span.durationNano);
+		const durationWidth = ctx.measureText(duration).width;
+		const minGap = 6;
+		const nameSpace = availableWidth - durationWidth - minGap;
+
+		// Duration right-aligned
+		ctx.textAlign = 'right';
+		ctx.fillText(duration, rightX, textY);
+
+		// Name left-aligned, truncated to fit remaining space
+		if (nameSpace > 20) {
+			ctx.textAlign = 'left';
+			ctx.fillText(truncateText(ctx, name, nameSpace), leftX, textY);
+		}
+	} else {
+		// Name only, truncated to fit
+		ctx.textAlign = 'left';
+		ctx.fillText(truncateText(ctx, name, availableWidth), leftX, textY);
+	}
+
+	ctx.restore();
+}
+
+function truncateText(
+	ctx: CanvasRenderingContext2D,
+	text: string,
+	maxWidth: number,
+): string {
+	const ellipsis = '...';
+	const ellipsisWidth = ctx.measureText(ellipsis).width;
+
+	if (ctx.measureText(text).width <= maxWidth) {
+		return text;
+	}
+
+	let lo = 0;
+	let hi = text.length;
+	while (lo < hi) {
+		const mid = Math.ceil((lo + hi) / 2);
+		if (ctx.measureText(text.slice(0, mid)).width + ellipsisWidth <= maxWidth) {
+			lo = mid;
+		} else {
+			hi = mid - 1;
+		}
+	}
+
+	return lo > 0 ? `${text.slice(0, lo)}${ellipsis}` : ellipsis;
+}

frontend/src/pages/TraceDetailsV3/index.tsx

@@ -0,0 +1,37 @@
+import {
+	ResizableHandle,
+	ResizablePanel,
+	ResizablePanelGroup,
+} from '@signozhq/resizable';
+
+import TraceDetailsHeader from './TraceDetailsHeader/TraceDetailsHeader';
+import TraceFlamegraph from './TraceFlamegraph/TraceFlamegraph';
+
+function TraceDetailsV3(): JSX.Element {
+	return (
+		<div
+			style={{
+				height: 'calc(100vh - 90px)',
+				display: 'flex',
+				flexDirection: 'column',
+			}}
+		>
+			<TraceDetailsHeader />
+			<ResizablePanelGroup
+				direction="vertical"
+				autoSaveId="trace-details-v3-layout"
+				style={{ flex: 1 }}
+			>
+				<ResizablePanel defaultSize={40} minSize={20} maxSize={80}>
+					<TraceFlamegraph />
+				</ResizablePanel>
+				<ResizableHandle withHandle />
+				<ResizablePanel defaultSize={60} minSize={20}>
+					<div />
+				</ResizablePanel>
+			</ResizablePanelGroup>
+		</div>
+	);
+}
+
+export default TraceDetailsV3;