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Summary: Ref T2700. Allow JS to listen for swipes on devices. There are a bunch of tricky cases here and I probably didn't get them all totally right, but this interaction broadly looks like this: - We implement gesture recognition for the mouse in device modes (narrow browser), and for touch events from an actual device. - The sigil `touchable` indicates that a node wants to react to touch events. - When the user touches a `touchable` node, we start listening for moves. They might be tapping/clicking (in which case we don't care), but they might also be gesturing. - Once the user moves their finger/pointer far enough away from the tap origin, we recognize it as a gesture. I hardcoded this at 20px; I wasn't able to find any "official" Apple value, but 20px seems like a common default. - At this point, we look at where their finger has moved. - If they moved it mostly up/down, we interpret the gesture as "scroll" and just stop listening. The device does its own thing. - However, if they moved it mostly left/right, we interpret it as a "swipe". We start killing the moves so the device doesn't scroll. - Once we've recognized that a gesture is underway, we send a "gesture.swipe.start" event and then "gesture.swipe.move" events for every move. - When the user ends the gesture, we send "gesture.swipe.end". - If the user cancels the gesture (currently, only by tapping with a second finger), we send "gesture.swipe.cancel". - Gesture events have raw position data and some convenience fields. Test Plan: Wrote UI example and used it from the Desktop, iPhone simulator, and a real iphone. - The code always seems to get "scroll" vs "swipe" correct (i.e., consistent with my intentions). - The threshold feels pretty good to me. - Tapping with a second finger cancels the action. Reviewers: chad, btrahan Reviewed By: chad CC: aran Maniphest Tasks: T2700 Differential Revision: https://secure.phabricator.com/D5308
85 lines
1.7 KiB
JavaScript
85 lines
1.7 KiB
JavaScript
/**
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* @requires javelin-stratcom
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* javelin-behavior
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* javelin-vector
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* javelin-dom
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* @provides javelin-behavior-phabricator-gesture-example
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*/
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JX.behavior('phabricator-gesture-example', function(config) {
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var strokes = [];
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var current = [];
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var root = JX.$(config.rootID);
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var canvas = JX.$N('canvas');
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var d = JX.Vector.getDim(root);
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canvas.width = d.x;
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canvas.height = d.y;
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root.appendChild(canvas);
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var cxt = canvas.getContext('2d');
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JX.Stratcom.listen(
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'gesture.swipe.end',
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null,
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function(e) {
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var stroke = get_stroke(e);
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strokes.push(stroke);
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current = [];
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redraw();
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});
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JX.Stratcom.listen(
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'gesture.swipe.move',
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null,
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function(e) {
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var stroke = get_stroke(e);
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current = [stroke];
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redraw();
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});
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JX.Stratcom.listen(
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'gesture.swipe.cancel',
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null,
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function(e) {
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current = [];
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redraw();
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});
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function get_stroke(e) {
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var data = e.getData();
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var p = JX.$V(root);
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return [
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data.p0.x - p.x,
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data.p0.y - p.y,
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data.p1.x - p.x,
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data.p1.y - p.y
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];
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}
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function redraw() {
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cxt.fillStyle = '#dfdfdf';
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cxt.fillRect(0, 0, d.x, d.y);
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for (var ii = 0; ii < strokes.length; ii++) {
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var s = strokes[ii];
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cxt.strokeStyle = 'rgba(0, 0, 0, 0.50)';
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cxt.beginPath();
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cxt.moveTo(s[0], s[1]);
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cxt.lineTo(s[2], s[3]);
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cxt.stroke();
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}
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for (var ii = 0; ii < current.length; ii++) {
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var s = current[ii];
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cxt.strokeStyle = 'rgba(255, 0, 0, 1)';
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cxt.beginPath();
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cxt.moveTo(s[0], s[1]);
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cxt.lineTo(s[2], s[3]);
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cxt.stroke();
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}
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}
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redraw();
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});
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