_computeGridLineItems()

in Hands-on lab/lab-files/starter-project/NorthwindMVC/wwwroot/lib/Chart.js/chart.js [5417:5530]

• 111 lines of code
• 18 McCabe index (conditional complexity)

  _computeGridLineItems(chartArea) {
    const me = this;
    const axis = me.axis;
    const chart = me.chart;
    const options = me.options;
    const {grid, position} = options;
    const offset = grid.offset;
    const isHorizontal = me.isHorizontal();
    const ticks = me.ticks;
    const ticksLength = ticks.length + (offset ? 1 : 0);
    const tl = getTickMarkLength(grid);
    const items = [];
    const borderOpts = grid.setContext(me.getContext());
    const axisWidth = borderOpts.drawBorder ? borderOpts.borderWidth : 0;
    const axisHalfWidth = axisWidth / 2;
    const alignBorderValue = function(pixel) {
      return _alignPixel(chart, pixel, axisWidth);
    };
    let borderValue, i, lineValue, alignedLineValue;
    let tx1, ty1, tx2, ty2, x1, y1, x2, y2;
    if (position === 'top') {
      borderValue = alignBorderValue(me.bottom);
      ty1 = me.bottom - tl;
      ty2 = borderValue - axisHalfWidth;
      y1 = alignBorderValue(chartArea.top) + axisHalfWidth;
      y2 = chartArea.bottom;
    } else if (position === 'bottom') {
      borderValue = alignBorderValue(me.top);
      y1 = chartArea.top;
      y2 = alignBorderValue(chartArea.bottom) - axisHalfWidth;
      ty1 = borderValue + axisHalfWidth;
      ty2 = me.top + tl;
    } else if (position === 'left') {
      borderValue = alignBorderValue(me.right);
      tx1 = me.right - tl;
      tx2 = borderValue - axisHalfWidth;
      x1 = alignBorderValue(chartArea.left) + axisHalfWidth;
      x2 = chartArea.right;
    } else if (position === 'right') {
      borderValue = alignBorderValue(me.left);
      x1 = chartArea.left;
      x2 = alignBorderValue(chartArea.right) - axisHalfWidth;
      tx1 = borderValue + axisHalfWidth;
      tx2 = me.left + tl;
    } else if (axis === 'x') {
      if (position === 'center') {
        borderValue = alignBorderValue((chartArea.top + chartArea.bottom) / 2 + 0.5);
      } else if (isObject(position)) {
        const positionAxisID = Object.keys(position)[0];
        const value = position[positionAxisID];
        borderValue = alignBorderValue(me.chart.scales[positionAxisID].getPixelForValue(value));
      }
      y1 = chartArea.top;
      y2 = chartArea.bottom;
      ty1 = borderValue + axisHalfWidth;
      ty2 = ty1 + tl;
    } else if (axis === 'y') {
      if (position === 'center') {
        borderValue = alignBorderValue((chartArea.left + chartArea.right) / 2);
      } else if (isObject(position)) {
        const positionAxisID = Object.keys(position)[0];
        const value = position[positionAxisID];
        borderValue = alignBorderValue(me.chart.scales[positionAxisID].getPixelForValue(value));
      }
      tx1 = borderValue - axisHalfWidth;
      tx2 = tx1 - tl;
      x1 = chartArea.left;
      x2 = chartArea.right;
    }
    const limit = valueOrDefault(options.ticks.maxTicksLimit, ticksLength);
    const step = Math.max(1, Math.ceil(ticksLength / limit));
    for (i = 0; i < ticksLength; i += step) {
      const optsAtIndex = grid.setContext(me.getContext(i));
      const lineWidth = optsAtIndex.lineWidth;
      const lineColor = optsAtIndex.color;
      const borderDash = grid.borderDash || [];
      const borderDashOffset = optsAtIndex.borderDashOffset;
      const tickWidth = optsAtIndex.tickWidth;
      const tickColor = optsAtIndex.tickColor;
      const tickBorderDash = optsAtIndex.tickBorderDash || [];
      const tickBorderDashOffset = optsAtIndex.tickBorderDashOffset;
      lineValue = getPixelForGridLine(me, i, offset);
      if (lineValue === undefined) {
        continue;
      }
      alignedLineValue = _alignPixel(chart, lineValue, lineWidth);
      if (isHorizontal) {
        tx1 = tx2 = x1 = x2 = alignedLineValue;
      } else {
        ty1 = ty2 = y1 = y2 = alignedLineValue;
      }
      items.push({
        tx1,
        ty1,
        tx2,
        ty2,
        x1,
        y1,
        x2,
        y2,
        width: lineWidth,
        color: lineColor,
        borderDash,
        borderDashOffset,
        tickWidth,
        tickColor,
        tickBorderDash,
        tickBorderDashOffset,
      });
    }
    me._ticksLength = ticksLength;
    me._borderValue = borderValue;
    return items;
  }