csswg-drafts/css-transitions/transition-reversing-demo.html at fd9ea134f8050dfc39088f4bbee32ef7ef74ef2c · w3c/csswg-drafts · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
<!DOCTYPE HTML>
<title>Transition reversing demo</title>
<!-- L. David Baron <dbaron@dbaron.org>, 2013-06-07 -->
<style>
#demo {
    background: blue;
    width: 200px;
    height: 1em;
    padding: 2px;
}
#transitionable {
    position: relative;
    background: fuchsia;
    width: 100px;
    height: 1em;
    pointer-events: none;
}
p.algRadio { margin: 0 }
</style>
<script>

var gDemo;
var gTransitionable;

function start()
{
    var radios = document.getElementsByName("function");
    for (var idx = 0; idx < radios.length; ++idx) {
        var radio = radios[idx];
        radio.addEventListener("change", refresh_tfs, false);
    }

    document.getElementsByName("x1")[0].addEventListener("change", refresh_tfs, false);
    document.getElementsByName("y1")[0].addEventListener("change", refresh_tfs, false);
    document.getElementsByName("x2")[0].addEventListener("change", refresh_tfs, false);
    document.getElementsByName("y2")[0].addEventListener("change", refresh_tfs, false);

    gDemo = document.getElementById("demo");
    gDemo.addEventListener("mouseover", demo_mouseover, false);
    gDemo.addEventListener("mous
10BC0
eout", demo_mouseout, false);
    gTransitionable = document.getElementById("transitionable");

    refresh_tfs();

    var algs = document.getElementById("algorithms");
    for (var alg in gAlgorithms) {
        var radio = document.createElement("input");
        radio.setAttribute("type", "radio");
        radio.setAttribute("name", "algorithm");
        radio.setAttribute("value", alg);
        radio.addEventListener("change", refresh_algs, false);
        var t = document.createTextNode(alg);
        var label = document.createElement("label");
        label.appendChild(radio);
        label.appendChild(t);
        var p = document.createElement("p");
        p.className = "algRadio";
        p.appendChild(label);
        algs.appendChild(p);
    }

    document.getElementsByName("algorithm")[0].checked = true;
    refresh_algs();

    setInterval(tick, 20);
}

function tick()
{
    var value = gCurrentAlgorithm.tick(Date.now());
    //gTransitionable.style.left = Math.round(value) + "px";
    var trans = "translateX(" + Math.round(value) + "px)";
    gTransitionable.style.webkitTransform = trans;
    gTransitionable.style.MozTransform = trans;
    gTransitionable.style.msTransform = trans;
    gTransitionable.style.OTransform = trans;
    gTransitionable.style.transform = trans;
}

function refresh_algs(event)
{
    var alg = "";

    var radios = document.getElementsByName("algorithm");
    for (var idx = 0; idx < radios.length; ++idx) {
        var radio = radios[idx];
        if (radio.checked) {
            alg = radio.value;
        }
    }

    gCurrentAlgorithm = gAlgorithms[alg];
    gCurrentAlgorithm.construct();
}

var gDuration = 4000; // ms

var gAlgorithmData = null;
var gCurrentAlgorithm;

var gAlgorithms = {
    "No Reversing Adjustment": {
        construct: function() {
            gAlgorithmData = {
                current:0,
                starttime: Date.now(),
                startpos: 0,
                endpos: 0,
            };
        },
        over: function() {
            var now = Date.now();
            gAlgorithmData.startpos = this.tick(now);
            gAlgorithmData.endpos = 100;
            gAlgorithmData.starttime = now;
        },
        out: function() {
            var now = Date.now();
            gAlgorithmData.startpos = this.tick(now);
            gAlgorithmData.endpos = 0;
            gAlgorithmData.starttime = now;
        },
        tick: function(t) {
            var time_portion = clamp((t - gAlgorithmData.starttime) / gDuration);
            var value_portion = gCurrentTF(time_portion);
            return value_portion * gAlgorithmData.endpos + (1 - value_portion) * gAlgorithmData.startpos;
        },
    },
    "2013-06-07 spec text on reversing (Apple proposal)": {
        construct: function() {
            gAlgorithmData = {
                current:0,
                starttime: Date.now(),
                startpos: 0,
                endpos: 0,
                reverse_tf: false,
            };
        },
        over: function() {
            var now = Date.now();
            var curpos = this.tick(now);
            if (curpos == gAlgorithmData.endpos) {
                gAlgorithmData.reverse_tf = false;
                gAlgorithmData.starttime = now;
            } else {
                gAlgorithmData.reverse_tf = !gAlgorithmData.reverse_tf;
                gAlgorithmData.starttime = now - ((gAlgorithmData.starttime + gDuration) - now);
            }
            gAlgorithmData.startpos = 0;
            gAlgorithmData.endpos = 100;
        },
        out: function() {
            var now = Date.now();
            var curpos = this.tick(now);
            if (curpos == gAlgorithmData.endpos) {
                gAlgorithmData.reverse_tf = false;
                gAlgorithmData.starttime = now;
            } else {
                gAlgorithmData.reverse_tf = !gAlgorithmData.reverse_tf;
                gAlgorithmData.starttime = now - ((gAlgorithmData.starttime + gDuration) - now);
            }
            gAlgorithmData.startpos = 100;
            gAlgorithmData.endpos = 0;
        },
        tick: function(t) {
            var time_portion = clamp((t - gAlgorithmData.starttime) / gDuration);
            if (gAlgorithmData.reverse_tf) {
                time_portion = 1.0 - time_portion;
            }
            var value_portion = gCurrentTF(time_portion);
            if (gAlgorithmData.reverse_tf) {
                value_portion = 1.0 - value_portion;
            }
            return value_portion * gAlgorithmData.endpos + (1 - value_portion) * gAlgorithmData.startpos;
        },
    },
    "dbaron proposal (implemented in Gecko)": {
        construct: function() {
            gAlgorithmData = {
                current:0,
                starttime: Date.now(),
                startpos: 0,
                endpos: 0,
                duration: gDuration,
            };
        },
        over: function() {
            var now = Date.now();
            var curpos = this.tick(now);
            if (curpos == gAlgorithmData.endpos) {
                gAlgorithmData.duration = gDuration;
            } else {
                gAlgorithmData.duration = gDuration * Math.abs(curpos - gAlgorithmData.startpos) / 100;
            }
            gAlgorithmData.startpos = curpos;
            gAlgorithmData.endpos = 100;
            gAlgorithmData.starttime = now;
        },
        out: function() {
            var now = Date.now();
            var curpos = this.tick(now);
            if (curpos == gAlgorithmData.endpos) {
                gAlgorithmData.duration = gDuration;
            } else {
                gAlgorithmData.duration = gDuration * Math.abs(curpos - gAlgorithmData.startpos) / 100;
            }
            gAlgorithmData.startpos = curpos;
            gAlgorithmData.endpos = 0;
            gAlgorithmData.starttime = now;
        },
        tick: function(t) {
            var time_portion = clamp((t - gAlgorithmData.starttime) / gAlgorithmData.duration);
            var value_portion = gCurrentTF(time_portion);
            return value_portion * gAlgorithmData.endpos + (1 - value_portion) * gAlgorithmData.startpos;
        },
    },
    "plinss proposal (jump to current point on reverse curve)": {
        construct: function() {
            gAlgorithmData = {
                current:0,
                starttime: Date.now(),
                startpos: 0,
                endpos: 0,
            };
        },
        over: function() {
            var now = Date.now();
            var curpos = this.tick(now);
            if (curpos == gAlgorithmData.endpos) {
                gAlgorithmData.starttime = now;
            } else {
				var time_portion = gCurrentInverseTF(1.0 - gCurrentTF(this.time_portion(now)))
                gAlgorithmData.starttime = now - time_portion * gDuration;
            }
            gAlgorithmData.startpos = 0;
            gAlgorithmData.endpos = 100;
        },
        out: function() {
            var now = Date.now();
            var curpos = this.tick(now);
            if (curpos == gAlgorithmData.endpos) {
                gAlgorithmData.starttime = now;
            } else {
				var time_portion = gCurrentInverseTF(1.0 - gCurrentTF(this.time_portion(now)))
                gAlgorithmData.starttime = now - time_portion * gDuration;
            }
            gAlgorithmData.startpos = 100;
            gAlgorithmData.endpos = 0;
        },
		time_portion: function(t) {
            return clamp((t - gAlgorithmData.starttime) / gDuration);
		},
        tick: function(t) {
            var value_portion = gCurrentTF(this.time_portion(t));
            return value_portion * gAlgorithmData.endpos + (1 - value_portion) * gAlgorithmData.startpos;
        },
    },
    "vhardy proposal (accumulation) (NOT YET IMPLEMENTED)": {
    },
}

function demo_mouseover(event)
{
    if (event.target != gDemo) {
        return;
    }

    gCurrentAlgorithm.over();
}

function demo_mouseout(event)
{
    if (event.target != gDemo) {
        return;
    }

    gCurrentAlgorithm.out();
}

function clamp(v)
{
    if (v < 0) return 0;
    if (v > 1) return 1;
    return v;
}

var gCurrentTF;
var gCurrentInverseTF;
var gX1, gY1, gX2, gY2;
var gCurrentInput, gCurrentOutput;

function refresh_tfs()
{
    var func = "";

    var radios = document.getElementsByName("function");
    for (var idx = 0; idx < radios.length; ++idx) {
        var radio = radios[idx];
        if (radio.checked) {
            func = radio.value;
        }
    }

    var x1o = document.getElementById("x1");
    var y1o = document.getElementById("y1");
    var x2o = document.getElementById("x2");
    var y2o = document.getElementById("y2");

    x1o.value = "";
    y1o.value = "";
    x2o.value = "";
    y2o.value = "";

    var x1, y1, x2, y2;
    switch (func) {
        case "ease":
            x1 = 0.25; y1 = 0.10; x2 = 0.25; y2 = 1.00;
            break;
        case "linear":
            x1 = 0.00; y1 = 0.00; x2 = 1.00; y2 = 1.00;
            break;
        case "ease-in":
            x1 = 0.42; y1 = 0.00; x2 = 1.00; y2 = 1.00;
            break;
        case "ease-out":
            x1 = 0.00; y1 = 0.00; x2 = 0.58; y2 = 1.00;
            break;
        case "ease-in-out":
            x1 = 0.42; y1 = 0.00; x2 = 0.58; y2 = 1.00;
            break;
        case "cubic-bezier":
            x1 = clamp(Number(document.getElementsByName("x1")[0].value));
            y1 = Number(document.getElementsByName("y1")[0].value);
            x2 = clamp(Number(document.getElementsByName("x2")[0].value));
            y2 = Number(document.getElementsByName("y2")[0].value);
            break;
        default:
            return;
    }

    x1o.innerHTML = x1.toFixed(2);
    y1o.innerHTML = y1.toFixed(2);
    x2o.innerHTML = x2.toFixed(2);
    y2o.innerHTML = y2.toFixed(2);

    var tf = bezier(x1, y1, x2, y2);
    gX1 = x1; gY1 = y1; gX2 = x2; gY2 = y2;
    gCurrentTF = tf;
    gCurrentInverseTF = bezier(y1, x1, y2, x2);
}

function bezier(x1, y1, x2, y2) {
    // Cubic bezier with control points (0, 0), (x1, y1), (x2, y2), and (1, 1).
    function x_for_t(t) {
        var omt = 1-t;
        return 3 * omt * omt * t * x1 + 3 * omt * t * t * x2 + t * t * t;
    }
    function y_for_t(t) {
        var omt = 1-t;
        return 3 * omt * omt * t * y1 + 3 * omt * t * t * y2 + t * t * t;
    }
    function t_for_x(x) {
        // Binary subdivision.
        var mint = 0, maxt = 1;
        for (var i = 0; i < 30; ++i) {
            var guesst = (mint + maxt) / 2;
            var guessx = x_for_t(guesst);
            if (x < guessx)
                maxt = guesst;
            else
                mint = guesst;
        }
        return (mint + maxt) / 2;
    }
    return function bezier_closure(x) {
        if (x == 0) return 0;
        if (x == 1) return 1;
        return y_for_t(t_for_x(x));
    }
}

</script>

<body onload="start()">

<p>Choose a timing function:<br>
<label><input type="radio" name="function" value="ease" checked>ease</label>
<label><input type="radio" name="function" value="linear">linear</label>
<label><input type="radio" name="function" value="ease-in">ease-in</label>
<label><input type="radio" name="function" value="ease-out">ease-out</label>
<label><input type="radio" name="function" value="ease-in-out">ease-in-out</label>
<label><input type="radio" name="function" value="cubic-bezier" id="cbez">cubic-bezier</label>(<input type="text" size="4" name="x1" value="0.25">, <input type="text" size="4" name="y1" value="0">, <input type="text" size="4" name="x2" value="0.75">, <input type="text" size="4" name="y2" value="1">)
</p>

<p>Cubic bezier curve with control points: (0, 0) &rarr;
(<span id="x1"></span>, <span id="y1"></span>) &rarr;
(<span id="x2"></span>, <span id="y2"></span>) &rarr;
(1, 1).  This function maps time to value.</p>

<div id="algorithms">
</div>

<p>Hover over the outer box:</p>
<div id="demo">
  <div id="transitionable"></div>
</div>