elm/libraries/Native/Touch.js

99 lines
No EOL
2.4 KiB
JavaScript

/*
import Signal
import JavaScript
*/
(function() {
'use strict';
function Dict() {
this.keys = [];
this.values = [];
this.insert = function(key,value) {
this.keys.push(key);
this.values.push(value);
};
this.lookup = function(key) {
var i = this.keys.indexOf(key)
return i >= 0 ? this.values[i] : {x:0,y:0,t:0};
};
this.remove = function(key) {
var i = this.keys.indexOf(key);
if (i < 0) return;
var t = this.values[i];
this.keys.splice(i,1);
this.values.splice(i,1);
return t;
};
}
var root = Elm.Signal.constant([]),
tapTime = 500,
hasTap = false,
tap = {_:{},x:0,y:0},
dict = new Dict();
function touch(t) {
var r = dict.lookup(t.identifier);
return {_ : {},
id: t.identifier,
x : t.pageX,
y : t.pageY,
x0: r.x,
y0: r.y,
t0: r.t
};
}
function start(e) {
dict.insert(e.identifier,{x:e.pageX,y:e.pageY,t:Date.now()});
}
function end(e) {
var t = dict.remove(e.identifier);
if (Date.now() - t.t < tapTime) {
hasTap = true;
tap = {_:{}, x:t.x, y:t.y};
}
}
function listen(name, f) {
function update(e) {
for (var i = e.changedTouches.length; i--; ) { f(e.changedTouches[i]); }
var ts = new Array(e.touches.length);
for (var i = e.touches.length; i--; ) { ts[i] = touch(e.touches[i]); }
var hasListener = Dispatcher.notify(root.id, ts);
if (!hasListener) return document.removeEventListener(name, update);
e.preventDefault();
}
Value.addListener(document, name, update);
}
listen("touchstart", start);
listen("touchmove", function(_){});
listen("touchend", end);
listen("touchcancel", end);
listen("touchleave", end);
function dependency(f) {
var sig = Elm.Signal.lift(f)(root);
root.defaultNumberOfKids += 1;
sig.defaultNumberOfKids = 0;
return sig;
}
var touches = dependency(function(ts) {
return Elm.JavaScript.castJSArrayToList(ts);
});
var taps = function() {
var sig = dependency(function(_) { return tap; });
sig.defaultNumberOfKids = 1;
function pred(_) { var b = hasTap; hasTap = false; return b; }
var sig2 = Elm.Signal.keepIf(pred)({_:{},x:0,y:0})(sig);
sig2.defaultNumberOfKids = 0;
return sig2;
}();
Elm.Native.Touch = { touches: touches, taps: taps };
}());