Function checkDragging

test/jasmine/tests/annotations_test.js:1060–1120

(findDragger, autoshiftX, autoshiftY, coordScale)

     *  and for the plot defined above, data-referenced has scale 100
     */
    function checkDragging(findDragger, autoshiftX, autoshiftY, coordScale) {
        var bboxInitial = textBox().getBoundingClientRect();
        // first move it within the same auto-anchor zone
        return dragAndReplot(findDragger(), 30, -30)
        .then(function() {
            var bbox = textBox().getBoundingClientRect();

            // I'm not sure why these calculations aren't exact - they end up
            // being off by a fraction of a pixel, or a full pixel sometimes
            // even though as far as I can see in practice the positioning is
            // exact. In any event, this precision is enough to ensure that
            // anchor: auto is being used.
            expect(bbox.left).toBeWithin(bboxInitial.left + 30, 1);
            expect(bbox.top).toBeWithin(bboxInitial.top - 30, 1);

            var ann = gd.layout.annotations[0];
            expect(ann.x).toBeWithin(0.1 * coordScale, 0.01 * coordScale);
            expect(ann.y).toBeWithin(0.1 * coordScale, 0.01 * coordScale);

            // now move it to the center
            // note that we explicitly offset by half the box size because the
            // auto-anchor will move to the center
            return dragAndReplot(findDragger(), 120 - autoshiftX, -120 + autoshiftY);
        })
        .then(function() {
            var bbox = textBox().getBoundingClientRect();
            expect(bbox.left).toBeWithin(bboxInitial.left + 150 - autoshiftX, 2);
            expect(bbox.top).toBeWithin(bboxInitial.top - 150 + autoshiftY, 2);

            var ann = gd.layout.annotations[0];
            expect(ann.x).toBeWithin(0.5 * coordScale, 0.01 * coordScale);
            expect(ann.y).toBeWithin(0.5 * coordScale, 0.01 * coordScale);

            // next move it near the upper right corner, where the auto-anchor
            // moves to the top right corner
            // we don't move it all the way to the corner, so the annotation will
            // still be entirely on the plot even with an arrow.
            return dragAndReplot(findDragger(), 90 - autoshiftX, -90 + autoshiftY);
        })
        .then(function() {
            var bbox = textBox().getBoundingClientRect();
            expect(bbox.left).toBeWithin(bboxInitial.left + 240 - 2 * autoshiftX, 2);
            expect(bbox.top).toBeWithin(bboxInitial.top - 240 + 2 * autoshiftY, 2);

            var ann = gd.layout.annotations[0];
            expect(ann.x).toBeWithin(0.8 * coordScale, 0.01 * coordScale);
            expect(ann.y).toBeWithin(0.8 * coordScale, 0.01 * coordScale);

            // finally move it back to 0, 0
            return dragAndReplot(findDragger(), -240 + 2 * autoshiftX, 240 - 2 * autoshiftY);
        })
        .then(function() {
            var bbox = textBox().getBoundingClientRect();
            expect(bbox.left).toBeWithin(bboxInitial.left, 2);
            expect(bbox.top).toBeWithin(bboxInitial.top, 2);

            var ann = gd.layout.annotations[0];
            expect(ann.x).toBeWithin(0 * coordScale, 0.01 * coordScale);