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phab/webroot/rsrc/js/core/behavior-gesture.js
a91004ef1ba3feature/better-testing

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behavior-gesture.js
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/**
* @provides javelin-behavior-phabricator-gesture
* @requires javelin-behavior
* javelin-behavior-device
* javelin-stratcom
* javelin-vector
* javelin-dom
* javelin-magical-init
* @javelin
*/
/**
* Basic gesture recognition. Unstable. Only supports swipes.
*/
JX.behavior('phabricator-gesture', function() {
var target = null;
var swiping = false;
var p0;
var p1;
JX.Stratcom.listen(
['touchstart', 'touchcancel', 'mousedown'],
'touchable',
function(e) {
if (JX.Device.getDevice() == 'desktop') {
return;
}
if (JX.Stratcom.pass()) {
return;
}
if (target) {
try {
JX.DOM.invoke(target, 'gesture.swipe.cancel', get_swipe_data());
} finally {
stop_swipe();
}
return;
}
target = e.getNode('touchable');
p0 = JX.Vector.getPos(e);
p1 = JX.Vector.getPos(e);
});
JX.enableDispatch(document.body, 'mousemove');
JX.Stratcom.listen(
['touchmove', 'mousemove'],
null,
function(e) {
if (!target) {
return;
}
p1 = JX.Vector.getPos(e);
if (!swiping) {
// Here, we haven't started the swipe yet. We're waiting for you to
// move your finger far enough to make it clear that you intend to
// swipe or drag, not just tap.
var dx = (p1.x - p0.x);
var dy = (p1.y - p0.y);
var swipe_radius = 20;
if ((dx * dx) + (dy * dy) >= (swipe_radius * swipe_radius)) {
// You've moved your finger far enough away from the origin that
// we're sure you mean to swipe, scroll, or drag, not just tap.
// Decide if you're trying to scroll or swipe. If your finger's
// motion has been primarily vertical, assume this is a scroll. If
// your finger's motion has been primarily horizontal, assume this
// is a swipe.
if (dy * dy >= dx * dx) {
stop_swipe();
return;
}
swiping = true;
JX.DOM.invoke(target, 'gesture.swipe.start', get_swipe_data());
}
}
if (swiping) {
if (!e.getNode('touchable')) {
p1 = JX.$V(p0);
}
JX.DOM.invoke(target, 'gesture.swipe.move', get_swipe_data());
e.prevent();
}
});
JX.Stratcom.listen(
['touchend', 'mouseup'],
null,
function() {
if (!target) {
return;
}
try {
if (swiping) {
JX.DOM.invoke(target, 'gesture.swipe.end', get_swipe_data());
}
} finally {
stop_swipe();
}
});
function get_swipe_data() {
var direction = (p1.x > p0.x) ? 'right' : 'left';
var length = Math.abs(p1.x - p0.x);
return {
p0: p0,
p1: p1,
direction: direction,
length: length
};
}
function stop_swipe() {
target = null;
swiping = false;
}
});
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