OLD | NEW |
| (Empty) |
1 // Copyright 2013 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef UI_GFX_IMAGE_IMAGE_FAMILY_H_ | |
6 #define UI_GFX_IMAGE_IMAGE_FAMILY_H_ | |
7 | |
8 #include <iterator> | |
9 #include <map> | |
10 #include <utility> | |
11 | |
12 #include "ui/gfx/gfx_export.h" | |
13 #include "ui/gfx/image/image.h" | |
14 | |
15 namespace gfx { | |
16 class ImageSkia; | |
17 class Size; | |
18 | |
19 // A collection of images at different sizes. The images should be different | |
20 // representations of the same basic concept (for example, an icon) at various | |
21 // sizes and (optionally) aspect ratios. A method is provided for finding the | |
22 // most appropriate image to fit in a given rectangle. | |
23 // | |
24 // NOTE: This is not appropriate for storing an image at a single logical pixel | |
25 // size, with high-DPI bitmap versions; use an Image or ImageSkia for that. Each | |
26 // image in an ImageFamily should have a different logical size (and may also | |
27 // include high-DPI representations). | |
28 class GFX_EXPORT ImageFamily { | |
29 private: | |
30 // An <aspect ratio, DIP width> pair. | |
31 // A 0x0 image has aspect ratio 1.0. 0xN and Nx0 images are treated as 0x0. | |
32 struct MapKey : std::pair<float, int> { | |
33 MapKey(float aspect, int width) | |
34 : std::pair<float, int>(aspect, width) {} | |
35 | |
36 float aspect() const { return first; } | |
37 | |
38 int width() const { return second; } | |
39 }; | |
40 | |
41 public: | |
42 // Type for iterating over all images in the family, in order. | |
43 // Dereferencing this iterator returns a gfx::Image. | |
44 class GFX_EXPORT const_iterator : | |
45 std::iterator<std::bidirectional_iterator_tag, const gfx::Image> { | |
46 public: | |
47 const_iterator(); | |
48 | |
49 const_iterator(const const_iterator& other); | |
50 | |
51 ~const_iterator(); | |
52 | |
53 const_iterator& operator++() { | |
54 ++map_iterator_; | |
55 return *this; | |
56 } | |
57 | |
58 const_iterator operator++(int /*unused*/) { | |
59 const_iterator result(*this); | |
60 ++(*this); | |
61 return result; | |
62 } | |
63 | |
64 const_iterator& operator--() { | |
65 --map_iterator_; | |
66 return *this; | |
67 } | |
68 | |
69 const_iterator operator--(int /*unused*/) { | |
70 const_iterator result(*this); | |
71 --(*this); | |
72 return result; | |
73 } | |
74 | |
75 bool operator==(const const_iterator& other) const { | |
76 return map_iterator_ == other.map_iterator_; | |
77 } | |
78 | |
79 bool operator!=(const const_iterator& other) const { | |
80 return map_iterator_ != other.map_iterator_; | |
81 } | |
82 | |
83 const gfx::Image& operator*() const { | |
84 return map_iterator_->second; | |
85 } | |
86 | |
87 const gfx::Image* operator->() const { | |
88 return &**this; | |
89 } | |
90 | |
91 private: | |
92 friend class ImageFamily; | |
93 | |
94 explicit const_iterator( | |
95 const std::map<MapKey, gfx::Image>::const_iterator& other); | |
96 | |
97 std::map<MapKey, gfx::Image>::const_iterator map_iterator_; | |
98 }; | |
99 | |
100 ImageFamily(); | |
101 ~ImageFamily(); | |
102 | |
103 // Gets an iterator to the first image. | |
104 const_iterator begin() const { return const_iterator(map_.begin()); } | |
105 // Gets an iterator to one after the last image. | |
106 const_iterator end() const { return const_iterator(map_.end()); } | |
107 | |
108 // Determines whether the image family has no images in it. | |
109 bool empty() const { return map_.empty(); } | |
110 | |
111 // Removes all images from the family. | |
112 void clear() { return map_.clear(); } | |
113 | |
114 // Adds an image to the family. If another image is already present at the | |
115 // same size, it will be overwritten. | |
116 void Add(const gfx::Image& image); | |
117 | |
118 // Adds an image to the family. If another image is already present at the | |
119 // same size, it will be overwritten. | |
120 void Add(const gfx::ImageSkia& image_skia); | |
121 | |
122 // Gets the best image to use in a rectangle of |width|x|height|. | |
123 // Gets an image at the same aspect ratio as |width|:|height|, if possible, or | |
124 // if not, the closest aspect ratio. Among images of that aspect ratio, | |
125 // returns the smallest image with both its width and height bigger or equal | |
126 // to the requested size. If none exists, returns the largest image of that | |
127 // aspect ratio. If there are no images in the family, returns NULL. | |
128 const gfx::Image* GetBest(int width, int height) const; | |
129 | |
130 // Gets the best image to use in a rectangle of |size|. | |
131 // Gets an image at the same aspect ratio as |size.width()|:|size.height()|, | |
132 // if possible, or if not, the closest aspect ratio. Among images of that | |
133 // aspect ratio, returns the smallest image with both its width and height | |
134 // bigger or equal to the requested size. If none exists, returns the largest | |
135 // image of that aspect ratio. If there are no images in the family, returns | |
136 // NULL. | |
137 const gfx::Image* GetBest(const gfx::Size& size) const; | |
138 | |
139 private: | |
140 // Find the closest aspect ratio in the map to |desired_aspect|. | |
141 // Ties are broken by the thinner aspect. | |
142 // |map_| must not be empty. |desired_aspect| must be > 0.0. | |
143 float GetClosestAspect(float desired_aspect) const; | |
144 | |
145 // Gets an image with aspect ratio |aspect|, at the best size for |width|. | |
146 // Returns the smallest image of aspect ratio |aspect| with its width bigger | |
147 // or equal to |width|. If none exists, returns the largest image of aspect | |
148 // ratio |aspect|. Behavior is undefined if there is not at least one image in | |
149 // |map_| of aspect ratio |aspect|. | |
150 const gfx::Image* GetWithExactAspect(float aspect, int width) const; | |
151 | |
152 // Map from (aspect ratio, width) to image. | |
153 std::map<MapKey, gfx::Image> map_; | |
154 }; | |
155 | |
156 } // namespace gfx | |
157 | |
158 #endif // UI_GFX_IMAGE_IMAGE_FAMILY_H_ | |
OLD | NEW |