_computeLabelItems()

in Hands-on lab/lab-files/starter-project/NorthwindMVC/wwwroot/lib/Chart.js/chart.js [5531:5671]

• 141 lines of code
• 31 McCabe index (conditional complexity)

  _computeLabelItems(chartArea) {
    const me = this;
    const axis = me.axis;
    const options = me.options;
    const {position, ticks: optionTicks} = options;
    const isHorizontal = me.isHorizontal();
    const ticks = me.ticks;
    const {align, crossAlign, padding, mirror} = optionTicks;
    const tl = getTickMarkLength(options.grid);
    const tickAndPadding = tl + padding;
    const hTickAndPadding = mirror ? -padding : tickAndPadding;
    const rotation = -toRadians(me.labelRotation);
    const items = [];
    let i, ilen, tick, label, x, y, textAlign, pixel, font, lineHeight, lineCount, textOffset;
    let textBaseline = 'middle';
    if (position === 'top') {
      y = me.bottom - hTickAndPadding;
      textAlign = me._getXAxisLabelAlignment();
    } else if (position === 'bottom') {
      y = me.top + hTickAndPadding;
      textAlign = me._getXAxisLabelAlignment();
    } else if (position === 'left') {
      const ret = me._getYAxisLabelAlignment(tl);
      textAlign = ret.textAlign;
      x = ret.x;
    } else if (position === 'right') {
      const ret = me._getYAxisLabelAlignment(tl);
      textAlign = ret.textAlign;
      x = ret.x;
    } else if (axis === 'x') {
      if (position === 'center') {
        y = ((chartArea.top + chartArea.bottom) / 2) + tickAndPadding;
      } else if (isObject(position)) {
        const positionAxisID = Object.keys(position)[0];
        const value = position[positionAxisID];
        y = me.chart.scales[positionAxisID].getPixelForValue(value) + tickAndPadding;
      }
      textAlign = me._getXAxisLabelAlignment();
    } else if (axis === 'y') {
      if (position === 'center') {
        x = ((chartArea.left + chartArea.right) / 2) - tickAndPadding;
      } else if (isObject(position)) {
        const positionAxisID = Object.keys(position)[0];
        const value = position[positionAxisID];
        x = me.chart.scales[positionAxisID].getPixelForValue(value);
      }
      textAlign = me._getYAxisLabelAlignment(tl).textAlign;
    }
    if (axis === 'y') {
      if (align === 'start') {
        textBaseline = 'top';
      } else if (align === 'end') {
        textBaseline = 'bottom';
      }
    }
    const labelSizes = me._getLabelSizes();
    for (i = 0, ilen = ticks.length; i < ilen; ++i) {
      tick = ticks[i];
      label = tick.label;
      const optsAtIndex = optionTicks.setContext(me.getContext(i));
      pixel = me.getPixelForTick(i) + optionTicks.labelOffset;
      font = me._resolveTickFontOptions(i);
      lineHeight = font.lineHeight;
      lineCount = isArray(label) ? label.length : 1;
      const halfCount = lineCount / 2;
      const color = optsAtIndex.color;
      const strokeColor = optsAtIndex.textStrokeColor;
      const strokeWidth = optsAtIndex.textStrokeWidth;
      if (isHorizontal) {
        x = pixel;
        if (position === 'top') {
          if (crossAlign === 'near' || rotation !== 0) {
            textOffset = -lineCount * lineHeight + lineHeight / 2;
          } else if (crossAlign === 'center') {
            textOffset = -labelSizes.highest.height / 2 - halfCount * lineHeight + lineHeight;
          } else {
            textOffset = -labelSizes.highest.height + lineHeight / 2;
          }
        } else {
          if (crossAlign === 'near' || rotation !== 0) {
            textOffset = lineHeight / 2;
          } else if (crossAlign === 'center') {
            textOffset = labelSizes.highest.height / 2 - halfCount * lineHeight;
          } else {
            textOffset = labelSizes.highest.height - lineCount * lineHeight;
          }
        }
        if (mirror) {
          textOffset *= -1;
        }
      } else {
        y = pixel;
        textOffset = (1 - lineCount) * lineHeight / 2;
      }
      let backdrop;
      if (optsAtIndex.showLabelBackdrop) {
        const labelPadding = toPadding(optsAtIndex.backdropPadding);
        const height = labelSizes.heights[i];
        const width = labelSizes.widths[i];
        let top = y + textOffset - labelPadding.top;
        let left = x - labelPadding.left;
        switch (textBaseline) {
        case 'middle':
          top -= height / 2;
          break;
        case 'bottom':
          top -= height;
          break;
        }
        switch (textAlign) {
        case 'center':
          left -= width / 2;
          break;
        case 'right':
          left -= width;
          break;
        }
        backdrop = {
          left,
          top,
          width: width + labelPadding.width,
          height: height + labelPadding.height,
          color: optsAtIndex.backdropColor,
        };
      }
      items.push({
        rotation,
        label,
        font,
        color,
        strokeColor,
        strokeWidth,
        textOffset,
        textAlign,
        textBaseline,
        translation: [x, y],
        backdrop,
      });
    }
    return items;
  }