ui/src/frontend/slice_track.ts - third_party/perfetto - Git at Google

 // Copyright (C) 2023 The Android Open Source Project
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 import {duration, Span, Time, time} from '../base/time';
 import {Actions} from '../common/actions';
 import {cropText, drawIncompleteSlice} from '../common/canvas_utils';
 import {getColorForSlice} from '../common/colorizer';
 import {HighPrecisionTime} from '../common/high_precision_time';
 import {TrackData} from '../common/track_data';
 import {TrackHelperLEGACY} from '../common/track_helper';
 import {SliceRect} from '../public';

 import {CROP_INCOMPLETE_SLICE_FLAG} from './base_slice_track';
 import {checkerboardExcept} from './checkerboard';
 import {globals} from './globals';
 import {PxSpan, TimeScale} from './time_scale';

 export const SLICE_TRACK_KIND = 'ChromeSliceTrack';
 const SLICE_HEIGHT = 18;
 const TRACK_PADDING = 2;
 const CHEVRON_WIDTH_PX = 10;
 const HALF_CHEVRON_WIDTH_PX = CHEVRON_WIDTH_PX / 2;
 const INCOMPLETE_SLICE_WIDTH_PX = 20;

 export interface SliceData extends TrackData {
   // Slices are stored in a columnar fashion.
   strings: string[];
   sliceIds: Float64Array;
   starts: BigInt64Array;
   ends: BigInt64Array;
   depths: Uint16Array;
   titles: Uint16Array;   // Index into strings.
   colors?: Uint16Array;  // Index into strings.
   isInstant: Uint16Array;
   isIncomplete: Uint16Array;
   cpuTimeRatio?: Float64Array;
 }

 // Track base class which handles rendering slices in a generic way.
 // This is the old way of rendering slices - i.e. "track v1" format  - and
 // exists as a patch to allow old tracks to be converted to controller-less
 // tracks before they are ported to v2.
 // Slice tracks should extend this class and implement the abstract methods,
 // notably onBoundsChange().
 // Note: This class is deprecated and should not be used for new tracks. Use
 // |BaseSliceTrack| instead.
 export abstract class SliceTrackLEGACY extends TrackHelperLEGACY<SliceData> {
   constructor(
       private maxDepth: number, protected trackKey: string,
       private tableName: string, private namespace?: string) {
     super();
   }

   protected namespaceTable(tableName: string = this.tableName): string {
     if (this.namespace) {
       return this.namespace + '_' + tableName;
     } else {
       return tableName;
     }
   }

   private hoveredTitleId = -1;

   // Font used to render the slice name on the current track.
   protected getFont() {
     return '12px Roboto Condensed';
   }

   renderCanvas(ctx: CanvasRenderingContext2D): void {
     // TODO: fonts and colors should come from the CSS and not hardcoded here.
     const data = this.data;
     if (data === undefined) return;  // Can't possibly draw anything.

     const {visibleTimeSpan, visibleWindowTime, visibleTimeScale, windowSpan} =
         globals.frontendLocalState;

     // If the cached trace slices don't fully cover the visible time range,
     // show a gray rectangle with a "Loading..." label.
     checkerboardExcept(
         ctx,
         this.getHeight(),
         visibleTimeScale.hpTimeToPx(visibleWindowTime.start),
         visibleTimeScale.hpTimeToPx(visibleWindowTime.end),
         visibleTimeScale.timeToPx(data.start),
         visibleTimeScale.timeToPx(data.end),
     );

     ctx.textAlign = 'center';

     // measuretext is expensive so we only use it once.
     const charWidth = ctx.measureText('ACBDLqsdfg').width / 10;

     // The draw of the rect on the selected slice must happen after the other
     // drawings, otherwise it would result under another rect.
     let drawRectOnSelected = () => {};


     for (let i = 0; i < data.starts.length; i++) {
       const tStart = Time.fromRaw(data.starts[i]);
       let tEnd = Time.fromRaw(data.ends[i]);
       const depth = data.depths[i];
       const titleId = data.titles[i];
       const sliceId = data.sliceIds[i];
       const isInstant = data.isInstant[i];
       const isIncomplete = data.isIncomplete[i];
       const title = data.strings[titleId];
       const colorOverride = data.colors && data.strings[data.colors[i]];
       if (isIncomplete) {  // incomplete slice
         // TODO(stevegolton): This isn't exactly equivalent, ideally we should
         // choose tEnd once we've converted to screen space coords.
         tEnd = this.getEndTimeIfInComplete(tStart);
       }

       if (!visibleTimeSpan.intersects(tStart, tEnd)) {
         continue;
       }

       const rect = this.getSliceRect(
           visibleTimeScale, visibleTimeSpan, windowSpan, tStart, tEnd, depth);
       if (!rect || !rect.visible) {
         continue;
       }

       const currentSelection = globals.state.currentSelection;
       const isSelected = currentSelection &&
           currentSelection.kind === 'CHROME_SLICE' &&
           currentSelection.id !== undefined && currentSelection.id === sliceId;

       const highlighted = titleId === this.hoveredTitleId ||
           globals.state.highlightedSliceId === sliceId;

       const hasFocus = highlighted || isSelected;
       const colorScheme = getColorForSlice(title);
       const colorObj = hasFocus ? colorScheme.variant : colorScheme.base;
       const textColor =
           hasFocus ? colorScheme.textVariant : colorScheme.textBase;

       let color: string;
       if (colorOverride === undefined) {
         color = colorObj.cssString;
       } else {
         color = colorOverride;
       }
       ctx.fillStyle = color;

       // We draw instant events as upward facing chevrons starting at A:
       //     A
       //    ###
       //   ##C##
       //  ##   ##
       // D       B
       // Then B, C, D and back to A:
       if (isInstant) {
         if (isSelected) {
           drawRectOnSelected = () => {
             ctx.save();
             ctx.translate(rect.left, rect.top);

             // Draw a rectangle around the selected slice
             ctx.strokeStyle = colorObj.setHSL({s: 100, l: 10}).cssString;
             ctx.beginPath();
             ctx.lineWidth = 3;
             ctx.strokeRect(
                 -HALF_CHEVRON_WIDTH_PX, 0, CHEVRON_WIDTH_PX, SLICE_HEIGHT);
             ctx.closePath();

             // Draw inner chevron as interior
             ctx.fillStyle = color;
             this.drawChevron(ctx);

             ctx.restore();
           };
         } else {
           ctx.save();
           ctx.translate(rect.left, rect.top);
           this.drawChevron(ctx);
           ctx.restore();
         }
         continue;
       }

       if (isIncomplete && rect.width > SLICE_HEIGHT / 4) {
         drawIncompleteSlice(
             ctx,
             rect.left,
             rect.top,
             rect.width,
             SLICE_HEIGHT,
             !CROP_INCOMPLETE_SLICE_FLAG.get());
       } else if (
           data.cpuTimeRatio !== undefined && data.cpuTimeRatio[i] < 1 - 1e-9) {
         // We draw two rectangles, representing the ratio between wall time and
         // time spent on cpu.
         const cpuTimeRatio = data.cpuTimeRatio![i];
         const firstPartWidth = rect.width * cpuTimeRatio;
         const secondPartWidth = rect.width * (1 - cpuTimeRatio);
         ctx.fillRect(rect.left, rect.top, rect.width, SLICE_HEIGHT);
         ctx.fillStyle = '#FFFFFF50';
         ctx.fillRect(
             rect.left + firstPartWidth,
             rect.top,
             secondPartWidth,
             SLICE_HEIGHT);
       } else {
         ctx.fillRect(rect.left, rect.top, rect.width, SLICE_HEIGHT);
       }

       // Selected case
       if (isSelected) {
         drawRectOnSelected = () => {
           ctx.strokeStyle = colorObj.setHSL({s: 100, l: 10}).cssString;
           ctx.beginPath();
           ctx.lineWidth = 3;
           ctx.strokeRect(
               rect.left, rect.top - 1.5, rect.width, SLICE_HEIGHT + 3);
           ctx.closePath();
         };
       }

       // Don't render text when we have less than 5px to play with.
       if (rect.width >= 5) {
         ctx.fillStyle = textColor.cssString;
         const displayText = cropText(title, charWidth, rect.width);
         const rectXCenter = rect.left + rect.width / 2;
         ctx.textBaseline = 'middle';
         ctx.font = this.getFont();
         ctx.fillText(displayText, rectXCenter, rect.top + SLICE_HEIGHT / 2);
       }
     }
     drawRectOnSelected();
   }

   drawChevron(ctx: CanvasRenderingContext2D) {
     // Draw a chevron at a fixed location and size. Should be used with
     // ctx.translate and ctx.scale to alter location and size.
     ctx.beginPath();
     ctx.moveTo(0, 0);
     ctx.lineTo(HALF_CHEVRON_WIDTH_PX, SLICE_HEIGHT);
     ctx.lineTo(0, SLICE_HEIGHT - HALF_CHEVRON_WIDTH_PX);
     ctx.lineTo(-HALF_CHEVRON_WIDTH_PX, SLICE_HEIGHT);
     ctx.lineTo(0, 0);
     ctx.fill();
   }

   getSliceIndex({x, y}: {x: number, y: number}): number|void {
     const data = this.data;
     if (data === undefined) return;
     const {
       visibleTimeScale: timeScale,
     } = globals.frontendLocalState;
     if (y < TRACK_PADDING) return;
     const instantWidthTime = timeScale.pxDeltaToDuration(HALF_CHEVRON_WIDTH_PX);
     const t = timeScale.pxToHpTime(x);
     const depth = Math.floor((y - TRACK_PADDING) / SLICE_HEIGHT);

     for (let i = 0; i < data.starts.length; i++) {
       if (depth !== data.depths[i]) {
         continue;
       }
       const start = Time.fromRaw(data.starts[i]);
       const tStart = HighPrecisionTime.fromTime(start);
       if (data.isInstant[i]) {
         if (tStart.sub(t).abs().lt(instantWidthTime)) {
           return i;
         }
       } else {
         const end = Time.fromRaw(data.ends[i]);
         let tEnd = HighPrecisionTime.fromTime(end);
         if (data.isIncomplete[i]) {
           const endTime = this.getEndTimeIfInComplete(start);
           tEnd = HighPrecisionTime.fromTime(endTime);
         }
         if (tStart.lte(t) && t.lte(tEnd)) {
           return i;
         }
       }
     }
   }

   getEndTimeIfInComplete(start: time): time {
     const {visibleTimeScale, visibleWindowTime} = globals.frontendLocalState;

     let end = visibleWindowTime.end.toTime('ceil');
     if (CROP_INCOMPLETE_SLICE_FLAG.get()) {
       const widthTime =
           visibleTimeScale.pxDeltaToDuration(INCOMPLETE_SLICE_WIDTH_PX)
               .toTime();
       end = Time.add(start, widthTime);
     }

     return end;
   }

   onMouseMove({x, y}: {x: number, y: number}) {
     this.hoveredTitleId = -1;
     globals.dispatch(Actions.setHighlightedSliceId({sliceId: -1}));
     const sliceIndex = this.getSliceIndex({x, y});
     if (sliceIndex === undefined) return;
     const data = this.data;
     if (data === undefined) return;
     this.hoveredTitleId = data.titles[sliceIndex];
     const sliceId = data.sliceIds[sliceIndex];
     globals.dispatch(Actions.setHighlightedSliceId({sliceId}));
   }

   onMouseOut() {
     this.hoveredTitleId = -1;
     globals.dispatch(Actions.setHighlightedSliceId({sliceId: -1}));
   }

   onMouseClick({x, y}: {x: number, y: number}): boolean {
     const sliceIndex = this.getSliceIndex({x, y});
     if (sliceIndex === undefined) return false;
     const data = this.data;
     if (data === undefined) return false;
     const sliceId = data.sliceIds[sliceIndex];
     if (sliceId !== undefined && sliceId !== -1) {
       globals.makeSelection(Actions.selectChromeSlice({
         id: sliceId,
         trackKey: this.trackKey,
         table: this.namespace,
       }));
       return true;
     }
     return false;
   }

   getHeight() {
     return SLICE_HEIGHT * (this.maxDepth + 1) + 2 * TRACK_PADDING;
   }

   getSliceRect(
       visibleTimeScale: TimeScale, visibleWindow: Span<time, duration>,
       windowSpan: PxSpan, tStart: time, tEnd: time, depth: number): SliceRect
       |undefined {
     const pxEnd = windowSpan.end;
     const left = Math.max(visibleTimeScale.timeToPx(tStart), 0);
     const right = Math.min(visibleTimeScale.timeToPx(tEnd), pxEnd);

     const visible = visibleWindow.intersects(tStart, tEnd);

     return {
       left,
       width: Math.max(right - left, 1),
       top: TRACK_PADDING + depth * SLICE_HEIGHT,
       height: SLICE_HEIGHT,
       visible,
     };
   }
 }
	// Copyright (C) 2023 The Android Open Source Project
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	import {duration, Span, Time, time} from '../base/time';
	import {Actions} from '../common/actions';
	import {cropText, drawIncompleteSlice} from '../common/canvas_utils';
	import {getColorForSlice} from '../common/colorizer';
	import {HighPrecisionTime} from '../common/high_precision_time';
	import {TrackData} from '../common/track_data';
	import {TrackHelperLEGACY} from '../common/track_helper';
	import {SliceRect} from '../public';

	import {CROP_INCOMPLETE_SLICE_FLAG} from './base_slice_track';
	import {checkerboardExcept} from './checkerboard';
	import {globals} from './globals';
	import {PxSpan, TimeScale} from './time_scale';

	export const SLICE_TRACK_KIND = 'ChromeSliceTrack';
	const SLICE_HEIGHT = 18;
	const TRACK_PADDING = 2;
	const CHEVRON_WIDTH_PX = 10;
	const HALF_CHEVRON_WIDTH_PX = CHEVRON_WIDTH_PX / 2;
	const INCOMPLETE_SLICE_WIDTH_PX = 20;

	export interface SliceData extends TrackData {
	// Slices are stored in a columnar fashion.
	strings: string[];
	sliceIds: Float64Array;
	starts: BigInt64Array;
	ends: BigInt64Array;
	depths: Uint16Array;
	titles: Uint16Array; // Index into strings.
	colors?: Uint16Array; // Index into strings.
	isInstant: Uint16Array;
	isIncomplete: Uint16Array;
	cpuTimeRatio?: Float64Array;
	}

	// Track base class which handles rendering slices in a generic way.
	// This is the old way of rendering slices - i.e. "track v1" format - and
	// exists as a patch to allow old tracks to be converted to controller-less
	// tracks before they are ported to v2.
	// Slice tracks should extend this class and implement the abstract methods,
	// notably onBoundsChange().
	// Note: This class is deprecated and should not be used for new tracks. Use
	// \|BaseSliceTrack\| instead.
	export abstract class SliceTrackLEGACY extends TrackHelperLEGACY<SliceData> {
	constructor(
	private maxDepth: number, protected trackKey: string,
	private tableName: string, private namespace?: string) {
	super();
	}

	protected namespaceTable(tableName: string = this.tableName): string {
	if (this.namespace) {
	return this.namespace + '_' + tableName;
	} else {
	return tableName;
	}
	}

	private hoveredTitleId = -1;

	// Font used to render the slice name on the current track.
	protected getFont() {
	return '12px Roboto Condensed';
	}

	renderCanvas(ctx: CanvasRenderingContext2D): void {
	// TODO: fonts and colors should come from the CSS and not hardcoded here.
	const data = this.data;
	if (data === undefined) return; // Can't possibly draw anything.

	const {visibleTimeSpan, visibleWindowTime, visibleTimeScale, windowSpan} =
	globals.frontendLocalState;

	// If the cached trace slices don't fully cover the visible time range,
	// show a gray rectangle with a "Loading..." label.
	checkerboardExcept(
	ctx,
	this.getHeight(),
	visibleTimeScale.hpTimeToPx(visibleWindowTime.start),
	visibleTimeScale.hpTimeToPx(visibleWindowTime.end),
	visibleTimeScale.timeToPx(data.start),
	visibleTimeScale.timeToPx(data.end),
	);

	ctx.textAlign = 'center';

	// measuretext is expensive so we only use it once.
	const charWidth = ctx.measureText('ACBDLqsdfg').width / 10;

	// The draw of the rect on the selected slice must happen after the other
	// drawings, otherwise it would result under another rect.
	let drawRectOnSelected = () => {};


	for (let i = 0; i < data.starts.length; i++) {
	const tStart = Time.fromRaw(data.starts[i]);
	let tEnd = Time.fromRaw(data.ends[i]);
	const depth = data.depths[i];
	const titleId = data.titles[i];
	const sliceId = data.sliceIds[i];
	const isInstant = data.isInstant[i];
	const isIncomplete = data.isIncomplete[i];
	const title = data.strings[titleId];
	const colorOverride = data.colors && data.strings[data.colors[i]];
	if (isIncomplete) { // incomplete slice
	// TODO(stevegolton): This isn't exactly equivalent, ideally we should
	// choose tEnd once we've converted to screen space coords.
	tEnd = this.getEndTimeIfInComplete(tStart);
	}

	if (!visibleTimeSpan.intersects(tStart, tEnd)) {
	continue;
	}

	const rect = this.getSliceRect(
	visibleTimeScale, visibleTimeSpan, windowSpan, tStart, tEnd, depth);
	if (!rect \|\| !rect.visible) {
	continue;
	}

	const currentSelection = globals.state.currentSelection;
	const isSelected = currentSelection &&
	currentSelection.kind === 'CHROME_SLICE' &&
	currentSelection.id !== undefined && currentSelection.id === sliceId;

	const highlighted = titleId === this.hoveredTitleId \|\|
	globals.state.highlightedSliceId === sliceId;

	const hasFocus = highlighted \|\| isSelected;
	const colorScheme = getColorForSlice(title);
	const colorObj = hasFocus ? colorScheme.variant : colorScheme.base;
	const textColor =
	hasFocus ? colorScheme.textVariant : colorScheme.textBase;

	let color: string;
	if (colorOverride === undefined) {
	color = colorObj.cssString;
	} else {
	color = colorOverride;
	}
	ctx.fillStyle = color;

	// We draw instant events as upward facing chevrons starting at A:
	// A
	// ###
	// ##C##
	// ## ##
	// D B
	// Then B, C, D and back to A:
	if (isInstant) {
	if (isSelected) {
	drawRectOnSelected = () => {
	ctx.save();
	ctx.translate(rect.left, rect.top);

	// Draw a rectangle around the selected slice
	ctx.strokeStyle = colorObj.setHSL({s: 100, l: 10}).cssString;
	ctx.beginPath();
	ctx.lineWidth = 3;
	ctx.strokeRect(
	-HALF_CHEVRON_WIDTH_PX, 0, CHEVRON_WIDTH_PX, SLICE_HEIGHT);
	ctx.closePath();

	// Draw inner chevron as interior
	ctx.fillStyle = color;
	this.drawChevron(ctx);

	ctx.restore();
	};
	} else {
	ctx.save();
	ctx.translate(rect.left, rect.top);
	this.drawChevron(ctx);
	ctx.restore();
	}
	continue;
	}

	if (isIncomplete && rect.width > SLICE_HEIGHT / 4) {
	drawIncompleteSlice(
	ctx,
	rect.left,
	rect.top,
	rect.width,
	SLICE_HEIGHT,
	!CROP_INCOMPLETE_SLICE_FLAG.get());
	} else if (
	data.cpuTimeRatio !== undefined && data.cpuTimeRatio[i] < 1 - 1e-9) {
	// We draw two rectangles, representing the ratio between wall time and
	// time spent on cpu.
	const cpuTimeRatio = data.cpuTimeRatio![i];
	const firstPartWidth = rect.width * cpuTimeRatio;
	const secondPartWidth = rect.width * (1 - cpuTimeRatio);
	ctx.fillRect(rect.left, rect.top, rect.width, SLICE_HEIGHT);
	ctx.fillStyle = '#FFFFFF50';
	ctx.fillRect(
	rect.left + firstPartWidth,
	rect.top,
	secondPartWidth,
	SLICE_HEIGHT);
	} else {
	ctx.fillRect(rect.left, rect.top, rect.width, SLICE_HEIGHT);
	}

	// Selected case
	if (isSelected) {
	drawRectOnSelected = () => {
	ctx.strokeStyle = colorObj.setHSL({s: 100, l: 10}).cssString;
	ctx.beginPath();
	ctx.lineWidth = 3;
	ctx.strokeRect(
	rect.left, rect.top - 1.5, rect.width, SLICE_HEIGHT + 3);
	ctx.closePath();
	};
	}

	// Don't render text when we have less than 5px to play with.
	if (rect.width >= 5) {
	ctx.fillStyle = textColor.cssString;
	const displayText = cropText(title, charWidth, rect.width);
	const rectXCenter = rect.left + rect.width / 2;
	ctx.textBaseline = 'middle';
	ctx.font = this.getFont();
	ctx.fillText(displayText, rectXCenter, rect.top + SLICE_HEIGHT / 2);
	}
	}
	drawRectOnSelected();
	}

	drawChevron(ctx: CanvasRenderingContext2D) {
	// Draw a chevron at a fixed location and size. Should be used with
	// ctx.translate and ctx.scale to alter location and size.
	ctx.beginPath();
	ctx.moveTo(0, 0);
	ctx.lineTo(HALF_CHEVRON_WIDTH_PX, SLICE_HEIGHT);
	ctx.lineTo(0, SLICE_HEIGHT - HALF_CHEVRON_WIDTH_PX);
	ctx.lineTo(-HALF_CHEVRON_WIDTH_PX, SLICE_HEIGHT);
	ctx.lineTo(0, 0);
	ctx.fill();
	}

	getSliceIndex({x, y}: {x: number, y: number}): number\|void {
	const data = this.data;
	if (data === undefined) return;
	const {
	visibleTimeScale: timeScale,
	} = globals.frontendLocalState;
	if (y < TRACK_PADDING) return;
	const instantWidthTime = timeScale.pxDeltaToDuration(HALF_CHEVRON_WIDTH_PX);
	const t = timeScale.pxToHpTime(x);
	const depth = Math.floor((y - TRACK_PADDING) / SLICE_HEIGHT);

	for (let i = 0; i < data.starts.length; i++) {
	if (depth !== data.depths[i]) {
	continue;
	}
	const start = Time.fromRaw(data.starts[i]);
	const tStart = HighPrecisionTime.fromTime(start);
	if (data.isInstant[i]) {
	if (tStart.sub(t).abs().lt(instantWidthTime)) {
	return i;
	}
	} else {
	const end = Time.fromRaw(data.ends[i]);
	let tEnd = HighPrecisionTime.fromTime(end);
	if (data.isIncomplete[i]) {
	const endTime = this.getEndTimeIfInComplete(start);
	tEnd = HighPrecisionTime.fromTime(endTime);
	}
	if (tStart.lte(t) && t.lte(tEnd)) {
	return i;
	}
	}
	}
	}

	getEndTimeIfInComplete(start: time): time {
	const {visibleTimeScale, visibleWindowTime} = globals.frontendLocalState;

	let end = visibleWindowTime.end.toTime('ceil');
	if (CROP_INCOMPLETE_SLICE_FLAG.get()) {
	const widthTime =
	visibleTimeScale.pxDeltaToDuration(INCOMPLETE_SLICE_WIDTH_PX)
	.toTime();
	end = Time.add(start, widthTime);
	}

	return end;
	}

	onMouseMove({x, y}: {x: number, y: number}) {
	this.hoveredTitleId = -1;
	globals.dispatch(Actions.setHighlightedSliceId({sliceId: -1}));
	const sliceIndex = this.getSliceIndex({x, y});
	if (sliceIndex === undefined) return;
	const data = this.data;
	if (data === undefined) return;
	this.hoveredTitleId = data.titles[sliceIndex];
	const sliceId = data.sliceIds[sliceIndex];
	globals.dispatch(Actions.setHighlightedSliceId({sliceId}));
	}

	onMouseOut() {
	this.hoveredTitleId = -1;
	globals.dispatch(Actions.setHighlightedSliceId({sliceId: -1}));
	}

	onMouseClick({x, y}: {x: number, y: number}): boolean {
	const sliceIndex = this.getSliceIndex({x, y});
	if (sliceIndex === undefined) return false;
	const data = this.data;
	if (data === undefined) return false;
	const sliceId = data.sliceIds[sliceIndex];
	if (sliceId !== undefined && sliceId !== -1) {
	globals.makeSelection(Actions.selectChromeSlice({
	id: sliceId,
	trackKey: this.trackKey,
	table: this.namespace,
	}));
	return true;
	}
	return false;
	}

	getHeight() {
	return SLICE_HEIGHT * (this.maxDepth + 1) + 2 * TRACK_PADDING;
	}

	getSliceRect(
	visibleTimeScale: TimeScale, visibleWindow: Span<time, duration>,
	windowSpan: PxSpan, tStart: time, tEnd: time, depth: number): SliceRect
	\|undefined {
	const pxEnd = windowSpan.end;
	const left = Math.max(visibleTimeScale.timeToPx(tStart), 0);
	const right = Math.min(visibleTimeScale.timeToPx(tEnd), pxEnd);

	const visible = visibleWindow.intersects(tStart, tEnd);

	return {
	left,
	width: Math.max(right - left, 1),
	top: TRACK_PADDING + depth * SLICE_HEIGHT,
	height: SLICE_HEIGHT,
	visible,
	};
	}
	}