Function touchDrag

test/jasmine/tests/gl2d_plot_interact_test.js:688–695

(target, start, end)

        }

        function touchDrag(target, start, end) {
            return new Promise(function(resolve) {
                touchEvent('touchstart', start[0], start[1], {element: target});
                touchEvent('touchmove', end[0], end[1], {element: target});
                touchEvent('touchend', end[0], end[1], {element: target});
                setTimeout(resolve, 0);
            });
        }

        function assertEvent(e) {
            expect(e.defaultPrevented).toEqual(true);