112 lines
No EOL
3.4 KiB
JavaScript
112 lines
No EOL
3.4 KiB
JavaScript
/*! Time
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Library for working with time. Type `Time` represents some number of
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milliseconds.
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!*/
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Elm.Time = function() {
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/*[Times]*/
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/** hour, minute, second, ms : Time
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Units of time, making it easier to specify things like a
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half-second `(second / 2)`.
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**/
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function timeNow() { return (new window.Date).getTime(); }
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/*[Tickers]*/
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/** fps : Number -> Signal Time
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Takes desired number of frames per second (fps). The resulting signal
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gives a sequence of time deltas as quickly as possible until it reaches
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the desired FPS. A time delta is the time between the last frame and the
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current frame.
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**/
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/** fpsWhen : Number -> Signal Bool -> Signal Time
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Same as the fps function, but you can turn it on and off. Allows you
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to do brief animations based on user input without major ineffeciencies.
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The first time delta after a pause is always zero, no matter how long
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the pause was. This way summing the deltas will actually give the amount
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of time that the output signal has been running.
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**/
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function fpsWhen(desiredFPS) { return function (isOn) {
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var msPerFrame = 1000 / desiredFPS;
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var prev = timeNow(), curr = prev, diff = 0, wasOn = true;
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var ticker = Elm.Signal.constant(diff);
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function tick(zero) { return function() {
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curr = timeNow();
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diff = zero ? 0 : curr - prev;
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prev = curr;
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Dispatcher.notify(ticker.id, diff);
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};
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}
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var timeoutID = 0;
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function f(isOn) { return function(t) {
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if (isOn) {
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timeoutID = setTimeout(tick(!wasOn && isOn), msPerFrame);
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} else if (wasOn) {
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clearTimeout(timeoutID);
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}
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wasOn = isOn;
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return t;
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};
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}
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return Elm.Signal.lift2(f)(isOn)(ticker);
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};
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}
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/** every : Time -> Signal Time
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Takes a time interval t. The resulting signal is the current time,
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updated every t.
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**/
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function everyWhen(isOn) { return function(t) {
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var clock = Elm.Signal.constant(timeNow());
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function tellTime() { Dispatcher.notify(clock.id, timeNow()); }
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setInterval(tellTime, t);
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return clock;
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};
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}
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function since(t) { return function(s) {
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function cmp(a) { return function(b) { return !Value.eq(a,b); }; }
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var dcount = Elm.Signal.count(Elm.Signal.delay(t)(s));
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return Elm.Signal.lift2(cmp)(Elm.Signal.count(s))(dcount);
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};
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}
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function after(t) {
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t *= 1000;
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var thread = Elm.Signal.constant(false);
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setTimeout(function() { Dispatcher.notify(thread.id, true); }, t);
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return thread;
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}
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function before(t) {
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t *= 1000;
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var thread = Elm.Signal.constant(true);
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setTimeout(function() { Dispatcher.notify(thread.id, false); }, t);
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return thread;
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}
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function read(s) {
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var t = window.Date.parse(s);
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return isNaN(t) ? ["Nothing"] : ["Just",t];
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}
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return {fpsWhen : fpsWhen,
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fps : function(t) { return fpsWhen(t)(Elm.Signal.constant(true)); },
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every : everyWhen(Elm.Signal.constant(true)),
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delay : Elm.Signal.delay,
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since : since,
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after : after,
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before : before,
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hour : 3600000,
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minute : 60000,
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second : 1000,
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ms : 1,
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inHours : function(t) { return t / 3600000; },
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inMinutes : function(t) { return t / 60000; },
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inSeconds : function(t) { return t / 1000; },
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inMss : function(t) { return t; },
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toDate : function(t) { return new window.Date(t); },
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read : read
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};
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}(); |