Method getSlidedAxisExpandWindow

src/coord/parallel/Parallel.ts:415–475

* @return {Object} {axisExpandWindow, delta, behavior: 'jump' | 'slide' | 'none'}.

(point: number[])

     * @return {Object} {axisExpandWindow, delta, behavior: 'jump' | 'slide' | 'none'}.
     */
    getSlidedAxisExpandWindow(point: number[]): {
        axisExpandWindow: number[],
        behavior: SlidedAxisExpandBehavior
    } {
        const layoutInfo = this._makeLayoutInfo();
        const pixelDimIndex = layoutInfo.pixelDimIndex;
        let axisExpandWindow = layoutInfo.axisExpandWindow.slice();
        const winSize = axisExpandWindow[1] - axisExpandWindow[0];
        const extent = [0, layoutInfo.axisExpandWidth * (layoutInfo.axisCount - 1)];

        // Out of the area of coordinate system.
        if (!this.containPoint(point)) {
            return {behavior: 'none', axisExpandWindow: axisExpandWindow};
        }

        // Convert the point from global to expand coordinates.
        const pointCoord = point[pixelDimIndex] - layoutInfo.layoutBase - layoutInfo.axisExpandWindow0Pos;

        // For dragging operation convenience, the window should not be
        // slided when mouse is the center area of the window.
        let delta;
        let behavior: SlidedAxisExpandBehavior = 'slide';
        const axisCollapseWidth = layoutInfo.axisCollapseWidth;
        const triggerArea = this._model.get('axisExpandSlideTriggerArea');
        // But consider touch device, jump is necessary.
        const useJump = triggerArea[0] != null;

        if (axisCollapseWidth) {
            if (useJump && axisCollapseWidth && pointCoord < winSize * triggerArea[0]) {
                behavior = 'jump';
                delta = pointCoord - winSize * triggerArea[2];
            }
            else if (useJump && axisCollapseWidth && pointCoord > winSize * (1 - triggerArea[0])) {
                behavior = 'jump';
                delta = pointCoord - winSize * (1 - triggerArea[2]);
            }
            else {
                (delta = pointCoord - winSize * triggerArea[1]) >= 0
                    && (delta = pointCoord - winSize * (1 - triggerArea[1])) <= 0
                    && (delta = 0);
            }
            delta *= layoutInfo.axisExpandWidth / axisCollapseWidth;
            delta
                ? sliderMove(delta, axisExpandWindow, extent, 'all')
                // Avoid nonsense triger on mousemove.
                : (behavior = 'none');
        }
        // When screen is too narrow, make it visible and slidable, although it is hard to interact.
        else {
            const winSize2 = axisExpandWindow[1] - axisExpandWindow[0];
            const pos = extent[1] * pointCoord / winSize2;
            axisExpandWindow = [mathMax(0, pos - winSize2 / 2)];
            axisExpandWindow[1] = mathMin(extent[1], axisExpandWindow[0] + winSize2);
            axisExpandWindow[0] = axisExpandWindow[1] - winSize2;
        }

        return {
            axisExpandWindow: axisExpandWindow,