100 lines
No EOL
2.5 KiB
JavaScript
100 lines
No EOL
2.5 KiB
JavaScript
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Elm.Native.Touch = function(elm) {
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'use strict';
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elm.Native = elm.Native || {};
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if (elm.Native.Touch) return elm.Native.Touch;
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var Signal = Elm.Signal(elm);
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var JS = Elm.JavaScript(elm);
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function Dict() {
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this.keys = [];
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this.values = [];
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this.insert = function(key,value) {
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this.keys.push(key);
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this.values.push(value);
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};
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this.lookup = function(key) {
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var i = this.keys.indexOf(key)
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return i >= 0 ? this.values[i] : {x:0,y:0,t:0};
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};
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this.remove = function(key) {
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var i = this.keys.indexOf(key);
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if (i < 0) return;
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var t = this.values[i];
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this.keys.splice(i,1);
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this.values.splice(i,1);
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return t;
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};
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}
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var root = Signal.constant([]),
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tapTime = 500,
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hasTap = false,
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tap = {_:{},x:0,y:0},
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dict = new Dict();
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function touch(t) {
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var r = dict.lookup(t.identifier);
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return {_ : {},
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id: t.identifier,
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x : t.pageX,
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y : t.pageY,
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x0: r.x,
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y0: r.y,
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t0: r.t
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};
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}
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function start(e) {
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dict.insert(e.identifier,{x:e.pageX,y:e.pageY,t:Date.now()});
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}
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function end(e) {
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var t = dict.remove(e.identifier);
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if (Date.now() - t.t < tapTime) {
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hasTap = true;
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tap = {_:{}, x:t.x, y:t.y};
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}
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}
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function listen(name, f) {
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function update(e) {
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for (var i = e.changedTouches.length; i--; ) { f(e.changedTouches[i]); }
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var ts = new Array(e.touches.length);
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for (var i = e.touches.length; i--; ) { ts[i] = touch(e.touches[i]); }
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var hasListener = elm.notify(root.id, ts);
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if (!hasListener) return elm.node.removeEventListener(name, update);
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e.preventDefault();
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}
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elm.node.addEventListener(name, update);
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}
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listen("touchstart", start);
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listen("touchmove", function(_){});
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listen("touchend", end);
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listen("touchcancel", end);
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listen("touchleave", end);
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function dependency(f) {
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var sig = A2( Signal.lift, f, root );
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root.defaultNumberOfKids += 1;
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sig.defaultNumberOfKids = 0;
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return sig;
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}
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var touches = dependency(JS.fromList);
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var taps = function() {
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var sig = dependency(function(_) { return tap; });
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sig.defaultNumberOfKids = 1;
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function pred(_) { var b = hasTap; hasTap = false; return b; }
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var sig2 = A3( Signal.keepIf, pred, {_:{},x:0,y:0}, sig);
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sig2.defaultNumberOfKids = 0;
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return sig2;
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}();
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return elm.Native.Touch = { touches: touches, taps: taps };
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}; |