summaryrefslogtreecommitdiff
path: root/gfx/2d/BaseRect.h
blob: a4e5e4c1d0742864644d3693082af088174d4fc1 (plain)
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
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef MOZILLA_GFX_BASERECT_H_
#define MOZILLA_GFX_BASERECT_H_

#include <algorithm>
#include <cmath>
#include <ostream>
#include <limits>

#include "mozilla/Assertions.h"
#include "mozilla/FloatingPoint.h"
#include "mozilla/TypeTraits.h"
#include "Types.h"

namespace mozilla {
namespace gfx {

/**
 * Rectangles have two interpretations: a set of (zero-size) points,
 * and a rectangular area of the plane. Most rectangle operations behave
 * the same no matter what interpretation is being used, but some operations
 * differ:
 * -- Equality tests behave differently. When a rectangle represents an area,
 * all zero-width and zero-height rectangles are equal to each other since they
 * represent the empty area. But when a rectangle represents a set of
 * mathematical points, zero-width and zero-height rectangles can be unequal.
 * -- The union operation can behave differently. When rectangles represent
 * areas, taking the union of a zero-width or zero-height rectangle with
 * another rectangle can just ignore the empty rectangle. But when rectangles
 * represent sets of mathematical points, we may need to extend the latter
 * rectangle to include the points of a zero-width or zero-height rectangle.
 *
 * To ensure that these interpretations are explicitly disambiguated, we
 * deny access to the == and != operators and require use of IsEqualEdges and
 * IsEqualInterior instead. Similarly we provide separate Union and UnionEdges
 * methods.
 *
 * Do not use this class directly. Subclass it, pass that subclass as the
 * Sub parameter, and only use that subclass.
 */
template <class T, class Sub, class Point, class SizeT, class MarginT>
struct BaseRect {
  T x, y, width, height;

  // Constructors
  BaseRect() : x(0), y(0), width(0), height(0) {}
  BaseRect(const Point& aOrigin, const SizeT &aSize) :
      x(aOrigin.x), y(aOrigin.y), width(aSize.width), height(aSize.height)
  {
  }
  BaseRect(T aX, T aY, T aWidth, T aHeight) :
      x(aX), y(aY), width(aWidth), height(aHeight)
  {
  }

  // Emptiness. An empty rect is one that has no area, i.e. its height or width
  // is <= 0
  bool IsEmpty() const { return height <= 0 || width <= 0; }
  void SetEmpty() { width = height = 0; }

  // "Finite" means not inf and not NaN
  bool IsFinite() const
  {
    typedef typename mozilla::Conditional<mozilla::IsSame<T, float>::value, float, double>::Type FloatType;
    return (mozilla::IsFinite(FloatType(x)) &&
            mozilla::IsFinite(FloatType(y)) &&
            mozilla::IsFinite(FloatType(width)) &&
            mozilla::IsFinite(FloatType(height)));
  }

  // Returns true if this rectangle contains the interior of aRect. Always
  // returns true if aRect is empty, and always returns false is aRect is
  // nonempty but this rect is empty.
  bool Contains(const Sub& aRect) const
  {
    return aRect.IsEmpty() ||
           (x <= aRect.x && aRect.XMost() <= XMost() &&
            y <= aRect.y && aRect.YMost() <= YMost());
  }
  // Returns true if this rectangle contains the point. Points are considered
  // in the rectangle if they are on the left or top edge, but outside if they
  // are on the right or bottom edge.
  bool Contains(T aX, T aY) const
  {
    return x <= aX && aX < XMost() &&
           y <= aY && aY < YMost();
  }
  // Returns true if this rectangle contains the point. Points are considered
  // in the rectangle if they are on the left or top edge, but outside if they
  // are on the right or bottom edge.
  bool Contains(const Point& aPoint) const { return Contains(aPoint.x, aPoint.y); }

  // Intersection. Returns TRUE if the receiver's area has non-empty
  // intersection with aRect's area, and FALSE otherwise.
  // Always returns false if aRect is empty or 'this' is empty.
  bool Intersects(const Sub& aRect) const
  {
    return !IsEmpty() && !aRect.IsEmpty() &&
           x < aRect.XMost() && aRect.x < XMost() &&
           y < aRect.YMost() && aRect.y < YMost();
  }
  // Returns the rectangle containing the intersection of the points
  // (including edges) of *this and aRect. If there are no points in that
  // intersection, returns an empty rectangle with x/y set to the std::max of the x/y
  // of *this and aRect.
  //
  // Intersection with an empty Rect may not produce an empty Rect if overflow
  // occurs. e.g. {INT_MIN, 0, 0, 20} Intersect { 5000, 0, 500, 20 } gives:
  // the non-emtpy {5000, 0, 500, 20 } instead of {5000, 0, 0, 0}
  MOZ_MUST_USE Sub Intersect(const Sub& aRect) const
  {
    Sub result;
    result.x = std::max<T>(x, aRect.x);
    result.y = std::max<T>(y, aRect.y);
    result.width = std::min<T>(x - result.x + width, aRect.x - result.x + aRect.width);
    result.height = std::min<T>(y - result.y + height, aRect.y - result.y + aRect.height);
    if (result.width < 0 || result.height < 0) {
      result.SizeTo(0, 0);
    }
    return result;
  }
  // Gives the same results as Intersect() but handles integer overflow
  // better. This comes at a tiny cost in performance.
  // e.g. {INT_MIN, 0, 0, 20} Intersect { 5000, 0, 500, 20 } gives:
  // {5000, 0, 0, 0}
  MOZ_MUST_USE Sub SafeIntersect(const Sub& aRect) const
  {
    Sub result;
    result.x = std::max<T>(x, aRect.x);
    result.y = std::max<T>(y, aRect.y);
    T right = std::min<T>(x + width, aRect.x + aRect.width);
    T bottom = std::min<T>(y + height, aRect.y + aRect.height);
    if (right < result.x || bottom < result.y) {
      result.width = 0;
      result.height = 0;
    } else {
      result.width = right - result.x;
      result.height = bottom - result.y;
    }
    return result;
  }
  // Sets *this to be the rectangle containing the intersection of the points
  // (including edges) of *this and aRect. If there are no points in that
  // intersection, sets *this to be an empty rectangle with x/y set to the std::max
  // of the x/y of *this and aRect.
  //
  // 'this' can be the same object as either aRect1 or aRect2
  bool IntersectRect(const Sub& aRect1, const Sub& aRect2)
  {
    *static_cast<Sub*>(this) = aRect1.Intersect(aRect2);
    return !IsEmpty();
  }

  // Returns the smallest rectangle that contains both the area of both
  // this and aRect2.
  // Thus, empty input rectangles are ignored.
  // If both rectangles are empty, returns this.
  // WARNING! This is not safe against overflow, prefer using SafeUnion instead
  // when dealing with int-based rects.
  MOZ_MUST_USE Sub Union(const Sub& aRect) const
  {
    if (IsEmpty()) {
      return aRect;
    } else if (aRect.IsEmpty()) {
      return *static_cast<const Sub*>(this);
    } else {
      return UnionEdges(aRect);
    }
  }
  // Returns the smallest rectangle that contains both the points (including
  // edges) of both aRect1 and aRect2.
  // Thus, empty input rectangles are allowed to affect the result.
  // WARNING! This is not safe against overflow, prefer using SafeUnionEdges
  // instead when dealing with int-based rects.
  MOZ_MUST_USE Sub UnionEdges(const Sub& aRect) const
  {
    Sub result;
    result.x = std::min(x, aRect.x);
    result.y = std::min(y, aRect.y);
    result.width = std::max(XMost(), aRect.XMost()) - result.x;
    result.height = std::max(YMost(), aRect.YMost()) - result.y;
    return result;
  }
  // Computes the smallest rectangle that contains both the area of both
  // aRect1 and aRect2, and fills 'this' with the result.
  // Thus, empty input rectangles are ignored.
  // If both rectangles are empty, sets 'this' to aRect2.
  //
  // 'this' can be the same object as either aRect1 or aRect2
  void UnionRect(const Sub& aRect1, const Sub& aRect2)
  {
    *static_cast<Sub*>(this) = aRect1.Union(aRect2);
  }

  // Computes the smallest rectangle that contains both the points (including
  // edges) of both aRect1 and aRect2.
  // Thus, empty input rectangles are allowed to affect the result.
  //
  // 'this' can be the same object as either aRect1 or aRect2
  void UnionRectEdges(const Sub& aRect1, const Sub& aRect2)
  {
    *static_cast<Sub*>(this) = aRect1.UnionEdges(aRect2);
  }

  // Expands the rect to include the point
  void ExpandToEnclose(const Point& aPoint)
  {
    if (aPoint.x < x) {
      width = XMost() - aPoint.x;
      x = aPoint.x;
    } else if (aPoint.x > XMost()) {
      width = aPoint.x - x;
    }
    if (aPoint.y < y) {
      height = YMost() - aPoint.y;
      y = aPoint.y;
    } else if (aPoint.y > YMost()) {
      height = aPoint.y - y;
    }
  }

  void SetRect(T aX, T aY, T aWidth, T aHeight)
  {
    x = aX; y = aY; width = aWidth; height = aHeight;
  }
  void SetRect(const Point& aPt, const SizeT& aSize)
  {
    SetRect(aPt.x, aPt.y, aSize.width, aSize.height);
  }
  void MoveTo(T aX, T aY) { x = aX; y = aY; }
  void MoveTo(const Point& aPoint) { x = aPoint.x; y = aPoint.y; }
  void MoveBy(T aDx, T aDy) { x += aDx; y += aDy; }
  void MoveBy(const Point& aPoint) { x += aPoint.x; y += aPoint.y; }

  // Variant of MoveBy that ensures that even after translation by a point that
  // the rectangle coordinates will still fit within numeric limits. The origin
  // and size will be clipped within numeric limits to ensure this.
  void SafeMoveByX(T aDx) {
    T x2 = XMost();
    if (aDx >= T(0)) {
      T limit = std::numeric_limits<T>::max();
      x = limit - aDx < x ? limit : x + aDx;
      width = (limit - aDx < x2 ? limit : x2 + aDx) - x;
    } else {
      T limit = std::numeric_limits<T>::min();
      x = limit - aDx > x ? limit : x + aDx;
      width = (limit - aDx > x2 ? limit : x2 + aDx) - x;
    }
  }
  void SafeMoveByY(T aDy) {
    T y2 = YMost();
    if (aDy >= T(0)) {
      T limit = std::numeric_limits<T>::max();
      y = limit - aDy < y ? limit : y + aDy;
      height = (limit - aDy < y2 ? limit : y2 + aDy) - y;
    } else {
      T limit = std::numeric_limits<T>::min();
      y = limit - aDy > y ? limit : y + aDy;
      height = (limit - aDy > y2 ? limit : y2 + aDy) - y;
    }
  }
  void SafeMoveBy(T aDx, T aDy) {
    SafeMoveByX(aDx);
    SafeMoveByY(aDy);
  }
  void SafeMoveBy(const Point& aPoint) { SafeMoveBy(aPoint.x, aPoint.y); }

  void SizeTo(T aWidth, T aHeight) { width = aWidth; height = aHeight; }
  void SizeTo(const SizeT& aSize) { width = aSize.width; height = aSize.height; }

  void Inflate(T aD) { Inflate(aD, aD); }
  void Inflate(T aDx, T aDy)
  {
    x -= aDx;
    y -= aDy;
    width += 2 * aDx;
    height += 2 * aDy;
  }
  void Inflate(const MarginT& aMargin)
  {
    x -= aMargin.left;
    y -= aMargin.top;
    width += aMargin.LeftRight();
    height += aMargin.TopBottom();
  }
  void Inflate(const SizeT& aSize) { Inflate(aSize.width, aSize.height); }

  void Deflate(T aD) { Deflate(aD, aD); }
  void Deflate(T aDx, T aDy)
  {
    x += aDx;
    y += aDy;
    width = std::max(T(0), width - 2 * aDx);
    height = std::max(T(0), height - 2 * aDy);
  }
  void Deflate(const MarginT& aMargin)
  {
    x += aMargin.left;
    y += aMargin.top;
    width = std::max(T(0), width - aMargin.LeftRight());
    height = std::max(T(0), height - aMargin.TopBottom());
  }
  void Deflate(const SizeT& aSize) { Deflate(aSize.width, aSize.height); }

  // Return true if the rectangles contain the same set of points, including
  // points on the edges.
  // Use when we care about the exact x/y/width/height values being
  // equal (i.e. we care about differences in empty rectangles).
  bool IsEqualEdges(const Sub& aRect) const
  {
    return x == aRect.x && y == aRect.y &&
           width == aRect.width && height == aRect.height;
  }
  // Return true if the rectangles contain the same area of the plane.
  // Use when we do not care about differences in empty rectangles.
  bool IsEqualInterior(const Sub& aRect) const
  {
    return IsEqualEdges(aRect) || (IsEmpty() && aRect.IsEmpty());
  }

  friend Sub operator+(Sub aSub, const Point& aPoint)
  {
    aSub += aPoint;
    return aSub;
  }
  friend Sub operator-(Sub aSub, const Point& aPoint)
  {
    aSub -= aPoint;
    return aSub;
  }
  friend Sub operator+(Sub aSub, const SizeT& aSize)
  {
    aSub += aSize;
    return aSub;
  }
  friend Sub operator-(Sub aSub, const SizeT& aSize)
  {
    aSub -= aSize;
    return aSub;
  }
  Sub& operator+=(const Point& aPoint)
  {
    MoveBy(aPoint);
    return *static_cast<Sub*>(this);
  }
  Sub& operator-=(const Point& aPoint)
  {
    MoveBy(-aPoint);
    return *static_cast<Sub*>(this);
  }
  Sub& operator+=(const SizeT& aSize)
  {
    width += aSize.width;
    height += aSize.height;
    return *static_cast<Sub*>(this);
  }
  Sub& operator-=(const SizeT& aSize)
  {
    width -= aSize.width;
    height -= aSize.height;
    return *static_cast<Sub*>(this);
  }
  // Find difference as a Margin
  MarginT operator-(const Sub& aRect) const
  {
    return MarginT(aRect.y - y,
                   XMost() - aRect.XMost(),
                   YMost() - aRect.YMost(),
                   aRect.x - x);
  }

  // Helpers for accessing the vertices
  Point TopLeft() const { return Point(x, y); }
  Point TopRight() const { return Point(XMost(), y); }
  Point BottomLeft() const { return Point(x, YMost()); }
  Point BottomRight() const { return Point(XMost(), YMost()); }
  Point AtCorner(int aCorner) const {
    switch (aCorner) {
      case RectCorner::TopLeft: return TopLeft();
      case RectCorner::TopRight: return TopRight();
      case RectCorner::BottomRight: return BottomRight();
      case RectCorner::BottomLeft: return BottomLeft();
    }
    MOZ_CRASH("GFX: Incomplete switch");
  }
  Point CCWCorner(mozilla::Side side) const {
    switch (side) {
      case NS_SIDE_TOP: return TopLeft();
      case NS_SIDE_RIGHT: return TopRight();
      case NS_SIDE_BOTTOM: return BottomRight();
      case NS_SIDE_LEFT: return BottomLeft();
    }
    MOZ_CRASH("GFX: Incomplete switch");
  }
  Point CWCorner(mozilla::Side side) const {
    switch (side) {
      case NS_SIDE_TOP: return TopRight();
      case NS_SIDE_RIGHT: return BottomRight();
      case NS_SIDE_BOTTOM: return BottomLeft();
      case NS_SIDE_LEFT: return TopLeft();
    }
    MOZ_CRASH("GFX: Incomplete switch");
  }
  Point Center() const { return Point(x, y) + Point(width, height)/2; }
  SizeT Size() const { return SizeT(width, height); }

  T Area() const { return width * height; }

  // Helper methods for computing the extents
  T X() const { return x; }
  T Y() const { return y; }
  T Width() const { return width; }
  T Height() const { return height; }
  T XMost() const { return x + width; }
  T YMost() const { return y + height; }

  // Get the coordinate of the edge on the given side.
  T Edge(mozilla::Side aSide) const
  {
    switch (aSide) {
      case NS_SIDE_TOP: return Y();
      case NS_SIDE_RIGHT: return XMost();
      case NS_SIDE_BOTTOM: return YMost();
      case NS_SIDE_LEFT: return X();
    }
    MOZ_CRASH("GFX: Incomplete switch");
  }

  // Moves one edge of the rect without moving the opposite edge.
  void SetLeftEdge(T aX) {
    MOZ_ASSERT(aX <= XMost());
    width = XMost() - aX;
    x = aX;
  }
  void SetRightEdge(T aXMost) { 
    MOZ_ASSERT(aXMost >= x);
    width = aXMost - x; 
  }
  void SetTopEdge(T aY) {
    MOZ_ASSERT(aY <= YMost());
    height = YMost() - aY;
    y = aY;
  }
  void SetBottomEdge(T aYMost) { 
    MOZ_ASSERT(aYMost >= y);
    height = aYMost - y; 
  }

  // Round the rectangle edges to integer coordinates, such that the rounded
  // rectangle has the same set of pixel centers as the original rectangle.
  // Edges at offset 0.5 round up.
  // Suitable for most places where integral device coordinates
  // are needed, but note that any translation should be applied first to
  // avoid pixel rounding errors.
  // Note that this is *not* rounding to nearest integer if the values are negative.
  // They are always rounding as floor(n + 0.5).
  // See https://bugzilla.mozilla.org/show_bug.cgi?id=410748#c14
  // If you need similar method which is using NS_round(), you should create
  // new |RoundAwayFromZero()| method.
  void Round()
  {
    T x0 = static_cast<T>(floor(T(X()) + 0.5));
    T y0 = static_cast<T>(floor(T(Y()) + 0.5));
    T x1 = static_cast<T>(floor(T(XMost()) + 0.5));
    T y1 = static_cast<T>(floor(T(YMost()) + 0.5));

    x = x0;
    y = y0;

    width = x1 - x0;
    height = y1 - y0;
  }

  // Snap the rectangle edges to integer coordinates, such that the
  // original rectangle contains the resulting rectangle.
  void RoundIn()
  {
    T x0 = static_cast<T>(ceil(T(X())));
    T y0 = static_cast<T>(ceil(T(Y())));
    T x1 = static_cast<T>(floor(T(XMost())));
    T y1 = static_cast<T>(floor(T(YMost())));

    x = x0;
    y = y0;

    width = x1 - x0;
    height = y1 - y0;
  }

  // Snap the rectangle edges to integer coordinates, such that the
  // resulting rectangle contains the original rectangle.
  void RoundOut()
  {
    T x0 = static_cast<T>(floor(T(X())));
    T y0 = static_cast<T>(floor(T(Y())));
    T x1 = static_cast<T>(ceil(T(XMost())));
    T y1 = static_cast<T>(ceil(T(YMost())));

    x = x0;
    y = y0;

    width = x1 - x0;
    height = y1 - y0;
  }

  // Scale 'this' by aScale without doing any rounding.
  void Scale(T aScale) { Scale(aScale, aScale); }
  // Scale 'this' by aXScale and aYScale, without doing any rounding.
  void Scale(T aXScale, T aYScale)
  {
    T right = XMost() * aXScale;
    T bottom = YMost() * aYScale;
    x = x * aXScale;
    y = y * aYScale;
    width = right - x;
    height = bottom - y;
  }
  // Scale 'this' by aScale, converting coordinates to integers so that the result is
  // the smallest integer-coordinate rectangle containing the unrounded result.
  // Note: this can turn an empty rectangle into a non-empty rectangle
  void ScaleRoundOut(double aScale) { ScaleRoundOut(aScale, aScale); }
  // Scale 'this' by aXScale and aYScale, converting coordinates to integers so
  // that the result is the smallest integer-coordinate rectangle containing the
  // unrounded result.
  // Note: this can turn an empty rectangle into a non-empty rectangle
  void ScaleRoundOut(double aXScale, double aYScale)
  {
    T right = static_cast<T>(ceil(double(XMost()) * aXScale));
    T bottom = static_cast<T>(ceil(double(YMost()) * aYScale));
    x = static_cast<T>(floor(double(x) * aXScale));
    y = static_cast<T>(floor(double(y) * aYScale));
    width = right - x;
    height = bottom - y;
  }
  // Scale 'this' by aScale, converting coordinates to integers so that the result is
  // the largest integer-coordinate rectangle contained by the unrounded result.
  void ScaleRoundIn(double aScale) { ScaleRoundIn(aScale, aScale); }
  // Scale 'this' by aXScale and aYScale, converting coordinates to integers so
  // that the result is the largest integer-coordinate rectangle contained by the
  // unrounded result.
  void ScaleRoundIn(double aXScale, double aYScale)
  {
    T right = static_cast<T>(floor(double(XMost()) * aXScale));
    T bottom = static_cast<T>(floor(double(YMost()) * aYScale));
    x = static_cast<T>(ceil(double(x) * aXScale));
    y = static_cast<T>(ceil(double(y) * aYScale));
    width = std::max<T>(0, right - x);
    height = std::max<T>(0, bottom - y);
  }
  // Scale 'this' by 1/aScale, converting coordinates to integers so that the result is
  // the smallest integer-coordinate rectangle containing the unrounded result.
  // Note: this can turn an empty rectangle into a non-empty rectangle
  void ScaleInverseRoundOut(double aScale) { ScaleInverseRoundOut(aScale, aScale); }
  // Scale 'this' by 1/aXScale and 1/aYScale, converting coordinates to integers so
  // that the result is the smallest integer-coordinate rectangle containing the
  // unrounded result.
  // Note: this can turn an empty rectangle into a non-empty rectangle
  void ScaleInverseRoundOut(double aXScale, double aYScale)
  {
    T right = static_cast<T>(ceil(double(XMost()) / aXScale));
    T bottom = static_cast<T>(ceil(double(YMost()) / aYScale));
    x = static_cast<T>(floor(double(x) / aXScale));
    y = static_cast<T>(floor(double(y) / aYScale));
    width = right - x;
    height = bottom - y;
  }
  // Scale 'this' by 1/aScale, converting coordinates to integers so that the result is
  // the largest integer-coordinate rectangle contained by the unrounded result.
  void ScaleInverseRoundIn(double aScale) { ScaleInverseRoundIn(aScale, aScale); }
  // Scale 'this' by 1/aXScale and 1/aYScale, converting coordinates to integers so
  // that the result is the largest integer-coordinate rectangle contained by the
  // unrounded result.
  void ScaleInverseRoundIn(double aXScale, double aYScale)
  {
    T right = static_cast<T>(floor(double(XMost()) / aXScale));
    T bottom = static_cast<T>(floor(double(YMost()) / aYScale));
    x = static_cast<T>(ceil(double(x) / aXScale));
    y = static_cast<T>(ceil(double(y) / aYScale));
    width = std::max<T>(0, right - x);
    height = std::max<T>(0, bottom - y);
  }

  /**
   * Clamp aPoint to this rectangle. It is allowed to end up on any
   * edge of the rectangle.
   */
  MOZ_MUST_USE Point ClampPoint(const Point& aPoint) const
  {
    return Point(std::max(x, std::min(XMost(), aPoint.x)),
                 std::max(y, std::min(YMost(), aPoint.y)));
  }

  /**
   * Translate this rectangle to be inside aRect. If it doesn't fit inside
   * aRect then the dimensions that don't fit will be shrunk so that they
   * do fit. The resulting rect is returned.
   */
  MOZ_MUST_USE Sub MoveInsideAndClamp(const Sub& aRect) const
  {
    Sub rect(std::max(aRect.x, x),
             std::max(aRect.y, y),
             std::min(aRect.width, width),
             std::min(aRect.height, height));
    rect.x = std::min(rect.XMost(), aRect.XMost()) - rect.width;
    rect.y = std::min(rect.YMost(), aRect.YMost()) - rect.height;
    return rect;
  }

  // Returns the largest rectangle that can be represented with 32-bit
  // signed integers, centered around a point at 0,0.  As BaseRect's represent
  // the dimensions as a top-left point with a width and height, the width
  // and height will be the largest positive 32-bit value.  The top-left
  // position coordinate is divided by two to center the rectangle around a
  // point at 0,0.
  static Sub MaxIntRect()
  {
    return Sub(
      static_cast<T>(-std::numeric_limits<int32_t>::max() * 0.5),
      static_cast<T>(-std::numeric_limits<int32_t>::max() * 0.5),
      static_cast<T>(std::numeric_limits<int32_t>::max()),
      static_cast<T>(std::numeric_limits<int32_t>::max())
    );
  };

  friend std::ostream& operator<<(std::ostream& stream,
      const BaseRect<T, Sub, Point, SizeT, MarginT>& aRect) {
    return stream << '(' << aRect.x << ',' << aRect.y << ','
                  << aRect.width << ',' << aRect.height << ')';
  }

private:
  // Do not use the default operator== or operator!= !
  // Use IsEqualEdges or IsEqualInterior explicitly.
  bool operator==(const Sub& aRect) const { return false; }
  bool operator!=(const Sub& aRect) const { return false; }
};

} // namespace gfx
} // namespace mozilla

#endif /* MOZILLA_GFX_BASERECT_H_ */