export function rotate()

in src/axis/labelLayoutStrategy.ts [139:211]
63 lines of code
12 McCabe index (conditional complexity)

export function rotate(
    labelSelection: Selection<any, any, any, any>,
    maxBottomMargin: number,
    textTruncator: (properties: TextProperties, maxWidth: number) => string,
    textProperties: TextProperties,
    needRotate: boolean,
    needEllipsis: boolean,
    axisProperties: IAxisProperties,
    margin: IMargin,
    scrollbarVisible: boolean) {

    let rotatedLength;
    let defaultRotation: any;
    let tickSize = axisProperties.axis.tickSize();

    if (scrollbarVisible) {
        if (!tickSize) // zero or undefined
            defaultRotation = DefaultRotationWithScrollbarTickSizeZero;
        else
            defaultRotation = DefaultRotationWithScrollbar;
    }
    else {
        defaultRotation = DefaultRotation;
    }

    if (needRotate) {
        rotatedLength = maxBottomMargin / defaultRotation.sine;
    }

    labelSelection.each(function (datum) {
        let axisLabel = select(this);
        let labelText = axisLabel.text();
        textProperties.text = labelText;
        if (needRotate) {
            let textContentIndex = axisProperties.values.indexOf(this.textContent);
            let allowedLengthProjectedOnXAxis =
                // Left margin is the width of Y axis.
                margin.left
                // There could be a padding before the first category.
                + axisProperties.outerPadding
                // Align the rotated text's top right corner to the middle of the corresponding category first.
                + axisProperties.categoryThickness * (textContentIndex + 0.5);

            // Subtracting the left padding space from the allowed length.
            if (!scrollbarVisible)
                allowedLengthProjectedOnXAxis -= LeftPadding;

            // Truncate if scrollbar is visible or rotatedLength exceeds allowedLength
            let allowedLength = allowedLengthProjectedOnXAxis / defaultRotation.cosine;
            if (scrollbarVisible || needEllipsis || (allowedLength < rotatedLength)) {
                labelText = textTruncator(textProperties, Math.min(allowedLength, rotatedLength));
                axisLabel.text(labelText);
            }

            // NOTE: see note above - rotation only lines up with default d3 tickSize(6,0)
            // TODO don't do these rotations if we already did them
            axisLabel.style("text-anchor", "end")
                .attr("dx", "-0.5em")
                .attr("dy", defaultRotation.dy)
                .attr("transform", defaultRotation.transform);
        } else {
            let maxLabelWidth = !arrayIsEmpty(axisProperties.xLabelMaxWidths) ? axisProperties.xLabelMaxWidths[datum] : axisProperties.xLabelMaxWidth;
            let newLabelText = textTruncator(textProperties, maxLabelWidth);
            if (newLabelText !== labelText)
                axisLabel.text(newLabelText);
            // TODO don't do these rotations if we already did them
            axisLabel.style("text-anchor", "middle")
                .attr("dx", "0em")
                .attr("dy", "1em")
                .attr("transform", "rotate(0)");
        }
    });
}