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1 // Copyright (c) 2011 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 PPAPI_CPP_IMAGE_DATA_H_
6 #define PPAPI_CPP_IMAGE_DATA_H_
7 
8 #include "ppapi/c/ppb_image_data.h"
9 #include "ppapi/cpp/point.h"
10 #include "ppapi/cpp/size.h"
11 #include "ppapi/cpp/resource.h"
12 
13 /// @file
14 /// This file defines the APIs for determining how a browser
15 /// handles image data.
16 namespace pp {
17 
18 class InstanceHandle;
19 
20 class ImageData : public Resource {
21  public:
22   /// Default constructor for creating an is_null() <code>ImageData</code>
23   /// object.
24   ImageData();
25 
26   /// A constructor used when you have received a <code>PP_Resource</code> as a
27   /// return value that has already been reference counted.
28   ///
29   /// @param[in] resource A PP_Resource corresponding to image data.
30   ImageData(PassRef, PP_Resource resource);
31 
32   /// The copy constructor for <code>ImageData</code>. This constructor
33   /// produces an <code>ImageData</code> object that shares the underlying
34   /// <code>Image</code> resource with <code>other</code>.
35   ///
36   /// @param[in] other A pointer to an image data.
37   ImageData(const ImageData& other);
38 
39   /// A constructor that allocates a new <code>ImageData</code> in the browser
40   /// with the provided parameters. The resulting object will be is_null() if
41   /// the allocation failed.
42   ///
43   /// @param[in] instance The instance with which this resource will be
44   /// associated.
45   ///
46   /// @param[in] format A PP_ImageDataFormat containing desired image format.
47   /// PP_ImageDataFormat is an enumeration of the different types of
48   /// image data formats. Refer to
49   /// <a href="../c/ppb__image__data_8h.html">
50   /// <code>ppb_image_data.h</code></a> for further information.
51   ///
52   /// @param[in] size A pointer to a <code>Size</code> containing the image
53   /// size.
54   ///
55   /// @param[in] init_to_zero A bool used to determine transparency at
56   /// creation. Set the <code>init_to_zero</code> flag if you want the bitmap
57   /// initialized to transparent during the creation process. If this flag is
58   /// not set, the current contents of the bitmap will be undefined, and the
59   /// module should be sure to set all the pixels.
60   ImageData(const InstanceHandle& instance,
61             PP_ImageDataFormat format,
62             const Size& size,
63             bool init_to_zero);
64 
65   /// This function decrements the reference count of this
66   /// <code>ImageData</code> and increments the reference count of the
67   /// <code>other</code> <code>ImageData</code>. This <code>ImageData</code>
68   /// shares the underlying image resource with <code>other</code>.
69   ///
70   /// @param[in] other An other image data.
71   ///
72   /// @return A new image data context.
73   ImageData& operator=(const ImageData& other);
74 
75   /// IsImageDataFormatSupported() returns <code>true</code> if the supplied
76   /// format is supported by the browser. Note:
77   /// <code>PP_IMAGEDATAFORMAT_BGRA_PREMUL</code> and
78   /// <code>PP_IMAGEDATAFORMAT_RGBA_PREMUL</code> formats are always supported.
79   /// Other image formats do not make this guarantee, and should be checked
80   /// first with IsImageDataFormatSupported() before using.
81   ///
82   /// @param[in] format Image data format.
83   ///
84   /// @return <code>true</code> if the format is supported by the browser.
85   static bool IsImageDataFormatSupported(PP_ImageDataFormat format);
86 
87   /// GetNativeImageDataFormat() determines the browser's preferred format for
88   /// images. Using this format guarantees no extra conversions will occur when
89   /// painting.
90   ///
91   /// @return <code>PP_ImageDataFormat</code> containing the preferred format.
92   static PP_ImageDataFormat GetNativeImageDataFormat();
93 
94   /// A getter function for returning the current format for images.
95   ///
96   /// @return <code>PP_ImageDataFormat</code> containing the preferred format.
format()97   PP_ImageDataFormat format() const { return desc_.format; }
98 
99   /// A getter function for returning the image size.
100   ///
101   /// @return The image size in pixels.
size()102   pp::Size size() const { return desc_.size; }
103 
104   /// A getter function for returning the row width in bytes.
105   ///
106   /// @return The row width in bytes.
stride()107   int32_t stride() const { return desc_.stride; }
108 
109   /// A getter function for returning a raw pointer to the image pixels.
110   ///
111   /// @return A raw pointer to the image pixels.
data()112   void* data() const { return data_; }
113 
114   /// This function is used retrieve the address of the given pixel for 32-bit
115   /// pixel formats.
116   ///
117   /// @param[in] coord A <code>Point</code> representing the x and y
118   /// coordinates for a specific pixel.
119   ///
120   /// @return The address for the pixel.
121   const uint32_t* GetAddr32(const Point& coord) const;
122 
123   /// This function is used retrieve the address of the given pixel for 32-bit
124   /// pixel formats.
125   ///
126   /// @param[in] coord A <code>Point</code> representing the x and y
127   /// coordinates for a specific pixel.
128   ///
129   /// @return The address for the pixel.
130   uint32_t* GetAddr32(const Point& coord);
131 
132  private:
133   void InitData();
134 
135   PP_ImageDataDesc desc_;
136   void* data_;
137 };
138 
139 }  // namespace pp
140 
141 #endif  // PPAPI_CPP_IMAGE_DATA_H_
142