Function computePlotScissorDevicePx

src/core/createRenderCoordinator.ts:639–657

(
  gridArea: GridArea
)

};

const computePlotScissorDevicePx = (
  gridArea: GridArea
): { readonly x: number; readonly y: number; readonly w: number; readonly h: number } => {
  const { canvasWidth, canvasHeight, devicePixelRatio } = gridArea;

  const plotLeftDevice = gridArea.left * devicePixelRatio;
  const plotRightDevice = canvasWidth - gridArea.right * devicePixelRatio;
  const plotTopDevice = gridArea.top * devicePixelRatio;
  const plotBottomDevice = canvasHeight - gridArea.bottom * devicePixelRatio;

  const scissorX = clampInt(Math.floor(plotLeftDevice), 0, Math.max(0, canvasWidth));
  const scissorY = clampInt(Math.floor(plotTopDevice), 0, Math.max(0, canvasHeight));
  const scissorR = clampInt(Math.ceil(plotRightDevice), 0, Math.max(0, canvasWidth));
  const scissorB = clampInt(Math.ceil(plotBottomDevice), 0, Math.max(0, canvasHeight));
  const scissorW = Math.max(0, scissorR - scissorX);
  const scissorH = Math.max(0, scissorB - scissorY);

  return { x: scissorX, y: scissorY, w: scissorW, h: scissorH };
};

const clipXToCanvasCssPx = (xClip: number, canvasCssWidth: number): number => ((xClip + 1) / 2) * canvasCssWidth;
const clipYToCanvasCssPx = (yClip: number, canvasCssHeight: number): number => ((1 - yClip) / 2) * canvasCssHeight;