Viewing github.com/facebook/react/packages/react-devtools-timeline/src/content-views/UserTimingMarksView.js

```
/**
```

 * Copyright (c) Meta Platforms, Inc. and affiliates.

```
 *
```

 * This source code is licensed under the MIT license found in the

 * LICENSE file in the root directory of this source tree.

```
 *
```
```
 * @flow
```
```
 */
```

import type {UserTimingMark} from '../types';

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import type {
```
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  Interaction,
```
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  MouseMoveInteraction,
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  Rect,
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  Size,
```
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  ViewRefs,
```
```
} from '../view-base';
```
```
import {
```
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  positioningScaleFactor,
```
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  timestampToPosition,
```
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  positionToTimestamp,
```
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  widthToDuration,
```
```
} from './utils/positioning';
```
```
import {
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  View,
```
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  Surface,
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  rectContainsPoint,
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  rectIntersectsRect,
```
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  intersectionOfRects,
```
```
} from '../view-base';
```
```
import {
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  COLORS,
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  TOP_ROW_PADDING,
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  USER_TIMING_MARK_SIZE,
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  BORDER_SIZE,
```
```
} from './constants';
```
```
const ROW_HEIGHT_FIXED =
```

  TOP_ROW_PADDING + USER_TIMING_MARK_SIZE + TOP_ROW_PADDING;

export class UserTimingMarksView extends View {

```
  _marks: UserTimingMark[];
```
```
  _intrinsicSize: Size;
```

  _hoveredMark: UserTimingMark | null = null;

  onHover: ((mark: UserTimingMark | null) => void) | null = null;

```
  constructor(
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```
    surface: Surface,
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    frame: Rect,
```
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    marks: UserTimingMark[],
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    duration: number,
```
```
  ) {
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    super(surface, frame);
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    this._marks = marks;
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    this._intrinsicSize = {
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      width: duration,
```
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      height: ROW_HEIGHT_FIXED,
```
```
    };
```
```
  }
```
```
  desiredSize(): Size {
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    return this._intrinsicSize;
```
```
  }
```

  setHoveredMark(hoveredMark: UserTimingMark | null) {

    if (this._hoveredMark === hoveredMark) {

```
      return;
```
```
    }
```
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    this._hoveredMark = hoveredMark;
```
```
    this.setNeedsDisplay();
```
```
  }
```
```
  /**
```

   * Draw a single `UserTimingMark` as a circle in the canvas.

```
   */
```
```
  _drawSingleMark(
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    context: CanvasRenderingContext2D,
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    rect: Rect,
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    mark: UserTimingMark,
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    baseY: number,
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    scaleFactor: number,
```
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    showHoverHighlight: boolean,
```
```
  ) {
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    const {frame} = this;
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    const {timestamp} = mark;
```

    const x = timestampToPosition(timestamp, scaleFactor, frame);

    const size = USER_TIMING_MARK_SIZE;

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    const halfSize = size / 2;
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```
    const markRect: Rect = {
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      origin: {
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        x: x - halfSize,
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        y: baseY,
```
```
      },
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      size: {width: size, height: size},

```
    };
```

    if (!rectIntersectsRect(markRect, rect)) {

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      return; // Not in view
```
```
    }
```

    const fillStyle = showHoverHighlight

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      ? COLORS.USER_TIMING_HOVER
```
```
      : COLORS.USER_TIMING;
```
```
    if (fillStyle !== null) {
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```
      const y = baseY + halfSize;
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```
      context.beginPath();
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      context.fillStyle = fillStyle;
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      context.moveTo(x, y - halfSize);
```
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      context.lineTo(x + halfSize, y);
```
```
      context.lineTo(x, y + halfSize);
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      context.lineTo(x - halfSize, y);
```
```
      context.fill();
```
```
    }
```
```
  }
```

  draw(context: CanvasRenderingContext2D) {

    const {frame, _marks, _hoveredMark, visibleArea} = this;

    context.fillStyle = COLORS.BACKGROUND;

```
    context.fillRect(
```
```
      visibleArea.origin.x,
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      visibleArea.origin.y,
```
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      visibleArea.size.width,
```
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      visibleArea.size.height,
```
```
    );
```
```
    // Draw marks
```

    const baseY = frame.origin.y + TOP_ROW_PADDING;

    const scaleFactor = positioningScaleFactor(

```
      this._intrinsicSize.width,
```
```
      frame,
```
```
    );
```
```
    _marks.forEach(mark => {
```
```
      if (mark === _hoveredMark) {
```
```
        return;
```
```
      }
```
```
      this._drawSingleMark(
```
```
        context,
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        visibleArea,
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        mark,
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        baseY,
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        scaleFactor,
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        false,
```
```
      );
```
```
    });
```

    // Draw the hovered and/or selected items on top so they stand out.

    // This is helpful if there are multiple (overlapping) items close to each other.

```
    if (_hoveredMark !== null) {
```
```
      this._drawSingleMark(
```
```
        context,
```
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        visibleArea,
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        _hoveredMark,
```
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        baseY,
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        scaleFactor,
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        true,
```
```
      );
```
```
    }
```
```
    // Render bottom border.
```

    // Propose border rect, check if intersects with `rect`, draw intersection.

```
    const borderFrame: Rect = {
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```
      origin: {
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        x: frame.origin.x,
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        y: frame.origin.y + ROW_HEIGHT_FIXED - BORDER_SIZE,

```
      },
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      size: {
```
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        width: frame.size.width,
```
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        height: BORDER_SIZE,
```
```
      },
```
```
    };
```

    if (rectIntersectsRect(borderFrame, visibleArea)) {

      const borderDrawableRect = intersectionOfRects(borderFrame, visibleArea);

      context.fillStyle = COLORS.PRIORITY_BORDER;

```
      context.fillRect(
```
```
        borderDrawableRect.origin.x,
```
```
        borderDrawableRect.origin.y,
```
```
        borderDrawableRect.size.width,
```

        borderDrawableRect.size.height,

```
      );
```
```
    }
```
```
  }
```
```
  /**
```
```
   * @private
```
```
   */
```

  _handleMouseMove(interaction: MouseMoveInteraction, viewRefs: ViewRefs) {

    const {frame, onHover, visibleArea} = this;

```
    if (!onHover) {
```
```
      return;
```
```
    }
```

    const {location} = interaction.payload;

    if (!rectContainsPoint(location, visibleArea)) {

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      onHover(null);
```
```
      return;
```
```
    }
```
```
    const {_marks} = this;
```

    const scaleFactor = positioningScaleFactor(

```
      this._intrinsicSize.width,
```
```
      frame,
```
```
    );
```

    const hoverTimestamp = positionToTimestamp(location.x, scaleFactor, frame);

    const timestampAllowance = widthToDuration(

```
      USER_TIMING_MARK_SIZE / 2,
```
```
      scaleFactor,
```
```
    );
```

    // Because data ranges may overlap, we want to find the last intersecting item.

    // This will always be the one on "top" (the one the user is hovering over).

    for (let index = _marks.length - 1; index >= 0; index--) {

```
      const mark = _marks[index];
```
```
      const {timestamp} = mark;
```
```
      if (
```

        timestamp - timestampAllowance <= hoverTimestamp &&

        hoverTimestamp <= timestamp + timestampAllowance

```
      ) {
```
```
        viewRefs.hoveredView = this;
```
```
        onHover(mark);
```
```
        return;
```
```
      }
```
```
    }
```
```
    onHover(null);
```
```
  }
```

  handleInteraction(interaction: Interaction, viewRefs: ViewRefs) {

```
    switch (interaction.type) {
```
```
      case 'mousemove':
```

        this._handleMouseMove(interaction, viewRefs);

```
        break;
```
```
    }
```
```
  }
```
```
}
```

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