109 lines
No EOL
3.1 KiB
JavaScript
109 lines
No EOL
3.1 KiB
JavaScript
/*! Touch
|
|
This is an early version of the touch library. It will likely grow to
|
|
include gestures that would be useful for both games and web-pages.
|
|
!*/
|
|
|
|
Elm.Touch = function() {
|
|
|
|
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 = {_:[true],x:[0],y:[0]},
|
|
dict = new Dict();
|
|
|
|
function touch(t) {
|
|
var r = dict.lookup(t.identifier);
|
|
return {_ : [true], 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 = {_:[true], 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;
|
|
}
|
|
|
|
/*[Touches]*/
|
|
|
|
/** touches : Signal [{ x:Int, y:Int, id:Int, x0:Int, y0:Int, t0:Time }]
|
|
A list of touches. Each ongoing touch is represented by a set of
|
|
coordinates and an identifier id that allows you to distinguish
|
|
between different touches. Each touch also contains the coordinates and
|
|
time of the initial contact (x0, y0, and t0) which helps compute more
|
|
complicated gestures.
|
|
**/
|
|
var touches = dependency(function(ts) {
|
|
return Elm.JavaScript.castJSArrayToList(ts);
|
|
});
|
|
|
|
/*[Gestures]*/
|
|
|
|
/** taps : Signal { x:Int, y:Int }
|
|
The last position that was tapped. Default value is `{x=0,y=0}`.
|
|
Updates whenever the user taps the screen.
|
|
**/
|
|
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)({_:[true],x:[0],y:[0]})(sig);
|
|
sig2.defaultNumberOfKids = 0;
|
|
return sig2;
|
|
}();
|
|
|
|
return { touches: touches, taps: taps };
|
|
}(); |