Function prepare

src/renderers/createCandlestickRenderer.ts:264–454

(series, data, xScale, yScale, gridArea, backgroundColor)

  };

  const prepare: CandlestickRenderer['prepare'] = (series, data, xScale, yScale, gridArea, backgroundColor) => {
    assertNotDisposed();

    if (data.length === 0) {
      instanceCount = 0;
      hollowInstanceCount = 0;
      return;
    }

    const plotSize = computePlotSizeCssPx(gridArea);
    if (!plotSize) {
      instanceCount = 0;
      hollowInstanceCount = 0;
      return;
    }

    const plotClipRect = computePlotClipRect(gridArea);
    const clipPerCssX = plotSize.plotWidthCss > 0 ? plotClipRect.width / plotSize.plotWidthCss : 0;

    lastCanvasWidth = gridArea.canvasWidth;
    lastCanvasHeight = gridArea.canvasHeight;
    lastScissor = computePlotScissorDevicePx(gridArea);

    // Compute category step and width
    const categoryStep = computeCategoryStep(data);
    const categoryWidthClip = computeCategoryWidthClip(xScale, categoryStep, plotClipRect, data.length);

    // Compute body width in clip space
    let bodyWidthClip = 0;
    const rawBarWidth = series.barWidth;
    if (typeof rawBarWidth === 'number') {
      bodyWidthClip = Math.max(0, rawBarWidth) * clipPerCssX;
    } else if (typeof rawBarWidth === 'string') {
      const p = parsePercent(rawBarWidth);
      bodyWidthClip = p == null ? 0 : categoryWidthClip * clamp01(p);
    }

    // Apply min/max width constraints (CSS pixels converted to clip space)
    const minWidthClip = series.barMinWidth * clipPerCssX;
    const maxWidthClip = series.barMaxWidth * clipPerCssX;
    bodyWidthClip = Math.min(Math.max(bodyWidthClip, minWidthClip), maxWidthClip);

    // Compute wick width in clip space (default 1px CSS)
    const wickWidthCssPx = series.itemStyle.borderWidth ?? DEFAULT_WICK_WIDTH_CSS_PX;
    const wickWidthClip = Math.max(0, wickWidthCssPx) * clipPerCssX;

    // Write VS uniforms (identity transform + wick width)
    vsUniformScratchF32.set([
      1, 0, 0, 0, // col0
      0, 1, 0, 0, // col1
      0, 0, 1, 0, // col2
      0, 0, 0, 1, // col3
      wickWidthClip,
      0,
      0,
      0,
    ]);
    writeUniformBuffer(device, vsUniformBuffer, vsUniformScratchBuffer);