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
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443 | 1
1
1
12
12
1
6
4
1
1
1
1
1
1
2
1
388
1
46
46
46
1
1
1
93
1
93
1
93
93
93
1
6
6
1
1
1
5
1
1
5
5
5
27
27
3
2
1
49
3
3
49
49
49
49
49
49
99
99
49
50
49
50
49
1
9
9
9
1
10
10
10
1
240
240
240
1
239
239
239
239
239
239
239
239
192
47
14
14
33
33
33
33
33
33
47
93
93
93
62
62
62
62
31
93
14
93
93
47
1
10
10
10
10
10
10
8
2
10
10
35
35
35
30
30
5
35
25
10
4
4
4
6
10
1
33
33
1
32
4
4
32
1
24
20
1
1
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
20
3
4
4
4
2
2
2
2
3
17
17
17
17
17
17
17
1
2
2
2
1
1
1
1
2
1
16
16
16
1
6
6
6
6
6
6
6
3
6
6
1
54
1
48
1
4
4
4
4
4
4
1
21
21
21
21
21
21
21
21
1
1
1
| (function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
typeof define === 'function' && define.amd ? define(['exports'], factory) :
factory((global.Bin = {}));
}(this, function (exports) { 'use strict';
// I don't think this should have args
function Bin(content, width) {
this.width = width || 0;
this.content = content;
}
function mustImplement(name) {
return function() {
throw new TypeError("MustImplement: " + name );
};
}
// abstract
Bin.prototype.objectAt = function (collection, index) {
return collection[index];
};
// abstract: return coordinates of element at index.
//
// @param index: index of the element in content
// @param width: viewport width.
// @returns {x, y} coordinates of element at index.
//
// May reset cached viewport width.
Bin.prototype.position = mustImplement('position');
// abstract: reset internal state to be anchored at index.
// @param index: index of the element in content
Bin.prototype.flush = mustImplement('flush');
// abstract: return total content height given viewport width.
// @param width: viewport width
//
// May reset cached viewport width.
Bin.prototype.height = mustImplement('height');
// abstract: true if layout places more than one object on a line.
Bin.prototype.isGrid = mustImplement('isGrid');
function _rangeError(length, index) {
throw new RangeError("Parameter must be within: [" + 0 + " and " + length + ") but was: " + index);
}
// abstract: returns number of elements in content.
Bin.prototype.length = function () {
return this.content.length;
};
// maximum offset of content wrt to viewport
// The amount by which content (after being layed out) is taller than
// the viewport.
Bin.prototype.maxContentOffset = function Bin_maxContentOffset(width, height) {
var contentHeight = this.height(width);
var maxOffset = Math.max(contentHeight - height, 0);
return maxOffset;
}
// abstract: returns index of first visible item.
// @param topOffset: scroll position
// @param width: width of viewport
// @param height: height of viewport
//
Bin.prototype.visibleStartingIndex = mustImplement('visibleStartingIndex');
// abstract: returns number of items visible in viewport.
// @param topOffset: scroll position
// @param width: width of viewport
// @param height: height of viewport
Bin.prototype.numberVisibleWithin = mustImplement('numberVisibleWithin');
Bin.prototype.heightAtIndex = function (index) {
return this.content[index].height;
};
Bin.prototype.widthAtIndex = function (index) {
return this.content[index].width;
};
function Entry(height, width, x, y) {
this.height = height;
this.width = width;
this.position = {x:x, y:y};
}
function ShelfFirst(content, width) {
this._super$constructor(content, width);
this._positionEntries = [];
}
ShelfFirst.prototype = Object.create(Bin.prototype);
ShelfFirst.prototype._super$constructor = Bin;
ShelfFirst.prototype.isGrid = function ShelfFirst_isGrid(width) {
if (width != null && width !== this.width) {
this.flush(0);
this.width = width;
}
var length = this.length();
var entry;
// TODO: cache/memoize
for (var i = 0; i < length; i++) {
entry = this._entryAt(i);
if (entry.position.x > 0) {
return true;
}
}
return false;
};
ShelfFirst.prototype.height = function (width) {
if (width != null && width !== this.width) {
this.flush(0);
this.width = width;
}
var length = this.length();
Iif (length === 0) { return 0; }
// find tallest in last row, add to Y
var tallest = 0;
var currentY = 0;
var entry;
for (var i = length - 1; i >= 0; i--) {
entry = this._entryAt(i);
if (currentY > entry.position.y) {
break; // end of last row
} else if (tallest < entry.height) {
tallest = entry.height;
} else {
// do nothing
}
currentY = entry.position.y;
}
return currentY + tallest;
};
ShelfFirst.prototype.flush = function (position) {
var positionEntries = this._positionEntries;
Eif (positionEntries.length > position) {
positionEntries.length = position;
}
};
ShelfFirst.prototype.numberVisibleWithin = function (topOffset, width, height, withPadding) {
Iif (width !== this.width) {
this.flush(0);
this.width = width;
}
var startingIndex = this.visibleStartingIndex(topOffset, width, height);
return this._numberVisibleWithin(startingIndex, height, withPadding);
};
ShelfFirst.prototype._entryAt = function _entryAt(index) {
var length = this.length();
var width = this.width;
if (index >= length) {
_rangeError(length, index);
}
var entry;
var entries = this._positionEntries;
var entriesLength = entries.length;
var startingIndex;
var y, x, i;
var rowHeight = 0;
var rowWidth = 0;
if (index < entriesLength) {
return this._positionEntries[index];
} else if (entriesLength === 0) {
startingIndex = 0;
y = 0;
} else {
startingIndex = entriesLength - 1;
entry = this._positionEntries[startingIndex];
rowWidth = entry.position.x + entry.width;
rowHeight = entry.height;
y = entry.position.y;
startingIndex++;
}
for (i = startingIndex; i < index + 1; i++) {
var currentHeight = this.heightAtIndex(i);
var currentWidth = this.widthAtIndex(i);
if (entry && (currentWidth + rowWidth) > width) {
// new row
y = entry.position.y + entry.height;
x = 0;
rowWidth = 0;
rowHeight = currentHeight;
} else {
x = rowWidth;
}
if (currentHeight > rowHeight) {
rowHeight = currentHeight;
}
entry = this._positionEntries[i] = new Entry(rowHeight, currentWidth, x, y);
rowWidth = x + currentWidth;
}
return entry;
};
ShelfFirst.prototype._numberVisibleWithin = function (startingIndex, height, withPadding) {
var count = 0;
var length = this.length();
var entry, position;
var currentY = 0;
var yOffset = 0;
if (startingIndex > 0 && startingIndex < length) {
yOffset = this._entryAt(startingIndex).position.y;
} else {
yOffset = 0;
}
var firstRowHeight;
for (var i = startingIndex; i < length; i++) {
entry = this._entryAt(i);
position = entry.position;
if (currentY === position.y) {
// same row
} else {
currentY = position.y - yOffset;
if (withPadding && !firstRowHeight) {
firstRowHeight = entry.height;
}
}
if (currentY < height) {
count++;
} else if (withPadding) {
withPadding = false;
height += Math.max(firstRowHeight, entry.height) + 1;
count++;
} else {
break;
}
}
return count;
};
ShelfFirst.prototype.position = function position(index, width) {
var length = this.length();
if (length === 0 || index > length) {
_rangeError(length, index);
}
if (width !== this.width) {
this.flush(0);
this.width = width;
}
return this._entryAt(index).position;
};
ShelfFirst.prototype.visibleStartingIndex = function (topOffset, width, visibleHeight) {
if (topOffset <= 0 ) { return 0; }
if (width != null && width!== this.width) {
this.flush(0);
this.width = width;
}
topOffset = Math.min(topOffset, this.maxContentOffset(width, visibleHeight));
var height = this.height();
var length = this.length();
// Start searching using the last item in the list
// and the bottom of the list for calculating the average height.
// This algorithm is necessary for efficiently finding
// the starting index of a list with variable heights
// in less than O(n) time.
// Ideally, the performance will be O(log n).
// The algorithm implemented assumes that the best case
// is a list of items with all equal heights.
// Lists with consistent distributions should arrive
// at results fairly quickly as well.
var index = length;
var bottom = height;
var previousIndex;
for (;;) {
// Try to find an item that straddles the top offset
// or is flush with it
var averageHeight = bottom / index;
// Guess the index based off the average height
index = Math.min(Math.floor(topOffset / averageHeight), length - 1);
Iif (previousIndex === index) {
return index;
}
var entry = this._entryAt(index);
var position = entry.position;
var top = position.y;
bottom = top + entry.height;
previousIndex = index;
if (bottom > topOffset) {
// Walk backwards until we find an item that won't be shown
while (bottom >= topOffset) {
previousIndex = index;
index--;
if (index === -1) {
break;
}
entry = this._entryAt(index);
position = entry.position;
bottom = position.y + entry.height;
}
return previousIndex;
} else Eif (topOffset === bottom) {
// Walk forwards until we find the next one- it should be close
while (bottom <= topOffset) {
index++;
entry = this._entryAt(index);
position = entry.position;
bottom = position.y + entry.height;
}
return index;
}
}
return -1;
};
function FixedGrid(content, elementWidth, elementHeight) {
this._elementWidth = elementWidth;
this._elementHeight = elementHeight;
this._super$constructor(content);
}
FixedGrid.prototype = Object.create(Bin.prototype);
FixedGrid.prototype._super$constructor = Bin;
FixedGrid.prototype.flush = function (/* index, to */) {
};
FixedGrid.prototype.isGrid = function (width) {
return (Math.floor(width / this.widthAtIndex(0)) || 1) > 1;
};
FixedGrid.prototype.visibleStartingIndex = function (topOffset, width, height) {
topOffset = Math.min(topOffset, this.maxContentOffset(width, height));
var columns = Math.floor(width / this.widthAtIndex(0)) || 1;
return Math.floor(topOffset / this.heightAtIndex(0)) * columns;
};
FixedGrid.prototype.numberVisibleWithin = function (topOffset, width, height, withPadding) {
var startingIndex = this.visibleStartingIndex(topOffset, width, height);
var columns = Math.floor(width / this.widthAtIndex(0)) || 1;
var length = this.length();
var rowHeight = this.heightAtIndex(0);
var rows = Math.ceil(height / rowHeight);
var maxNeeded = rows * columns;
if (withPadding) {
maxNeeded += columns;
}
var potentialVisible = length - startingIndex;
return Math.max(Math.min(maxNeeded, potentialVisible), 0);
};
FixedGrid.prototype.widthAtIndex = function (/* index */) {
return this._elementWidth;
};
FixedGrid.prototype.heightAtIndex = function (/* index */) {
return this._elementHeight;
};
FixedGrid.prototype.position = function (index, width) {
var length = this.length();
Iif (length === 0 || index > length) {
rangeError(length, index);
}
var columns = Math.floor(width / this.widthAtIndex(index)) || 1;
var x = index % columns * this.widthAtIndex(index) | 0;
var y = Math.floor(index / columns) * this.heightAtIndex(index);
return {x:x, y:y};
};
FixedGrid.prototype.height = function (visibleWidth) {
Iif (typeof visibleWidth !== 'number') {
throw new TypeError('height depends on the first argument of visibleWidth(number)');
}
var length = this.length();
Iif (length === 0) { return 0; }
var columnCount = Math.max(Math.floor(visibleWidth/this.widthAtIndex(0), 1));
columnCount = columnCount > 0 ? columnCount : 1;
var rows = Math.ceil(length/columnCount);
var totalHeight = rows * this.heightAtIndex(0);
return totalHeight;
};
exports.Bin = Bin;
exports.ShelfFirst = ShelfFirst;
exports.FixedGrid = FixedGrid;
}));
//# sourceMappingURL=layout-bin-packer.js.map |