interface/rawbmp.h

   1
   2 /**
   3     @class wxPixelData
   4     @wxheader{rawbmp.h}
   5
   6     A class template with ready to use implementations for getting
   7     direct and efficient access to wxBitmap's internal data and
   8     wxImage's internal data through a standard interface. It is
   9     possible to extend this class (interface) to other types of
  10     image content.
  11
  12     Implemented on Windows, GTK+ and OS X:
  13        @li wxNativePixelData: Class to access to wxBitmap's internal data without alpha channel (RGB).
  14        @li wxAlphaPixelData: Class to access to wxBitmap's internal data with alpha channel (RGBA).
  15
  16     Implemented everywhere:
  17        @li wxImagePixelData: Class to access to wxImage's internal data with alpha channel (RGBA).
  18
  19     @code
  20     wxBitmap bmp;
  21     wxNativePixelData data(bmp);
  22     if ( !data )
  23     {
  24         // ... raw access to bitmap data unavailable, do something else ...
  25         return;
  26     }
  27
  28     if ( data.GetWidth() < 20 || data.GetHeight() < 20 )
  29     {
  30         // ... complain: the bitmap it too small ...
  31         return;
  32     }
  33
  34     wxNativePixelData::Iterator p(data);
  35
  36     // we draw a (10, 10)-(20, 20) rect manually using the given r, g, b
  37     p.Offset(data, 10, 10);
  38
  39     for ( int y = 0; y < 10; ++y )
  40     {
  41         wxNativePixelData::Iterator rowStart = p;
  42
  43         for ( int x = 0; x < 10; ++x, ++p )
  44         {
  45             p.Red() = r;
  46             p.Green() = g;
  47             p.Blue() = b;
  48         }
  49
  50         p = rowStart;
  51         p.OffsetY(data, 1);
  52     }
  53     @endcode
  54
  55     @library{wxcore}
  56     @category{gdi}
  57
  58     @see wxBitmap, wxImage
  59 */
  60 template <class Image, class PixelFormat = wxPixelFormatFor<Image> >
  61 class wxPixelData :
  62     public wxPixelDataOut<Image>::template wxPixelDataIn<PixelFormat>
  63 {
  64 public:
  65     /**
  66         the type of the class we're working with
  67     */
  68     typedef Image ImageType;
  69
  70     /**
  71         Create pixel data object representing the entire image
  72     */
  73     wxPixelData(Image& image);
  74
  75
  76     /**
  77         Create pixel data object representing the area
  78         of the image defined by @e rect.
  79     */
  80     wxPixelData(Image& i, const wxRect& rect);
  81
  82     /**
  83         Create pixel data object representing the area
  84         of the image defined by @e pt and @e sz.
  85     */
  86     wxPixelData(Image& i, const wxPoint& pt, const wxSize& sz)
  87
  88     /**
  89         Return true of if we could get access to bitmap data
  90         successfully
  91     */
  92     operator bool() const:
  93
  94     /**
  95        Return the iterator pointing to the origin of the image
  96     */
  97     Iterator GetPixels() const;
  98
  99     /**
 100         Returns origin of the rectangular region we represent
 101     */
 102     wxPoint GetOrigin() const;
 103
 104     /**
 105          Return width of the region we represent
 106     */
 107     int GetWidth() const;
 108
 109     /**
 110          Return height of the region we represent
 111     */
 112     int GetHeight() const;
 113
 114     /*
 115         Return area which this class represents in the image
 116     */
 117     wxSize GetSize() const;
 118
 119     /**
 120        Return the distance between two rows
 121     */
 122     int GetRowStride() const;
 123
 124
 125     /**
 126         Iterator
 127     */
 128         class Iterator
 129         {
 130         public:
 131             /**
 132                go back to (0, 0)
 133             */
 134             void Reset(const PixelData& data);
 135
 136             /**
 137                Initializes the iterator to point to the origin of the given
 138                pixel data
 139             */
 140             Iterator(PixelData& data);
 141
 142             /**
 143                Initializes the iterator to point to the origin of the given
 144                Bitmap
 145             */
 146             Iterator(wxBitmap& bmp, PixelData& data);
 147
 148             /**
 149                Default constructor
 150             */
 151             Iterator();
 152
 153             /**
 154                Return true if this iterator is valid
 155             */
 156             bool IsOk() const;
 157
 158             /**
 159                Advance the iterator to the next pixel, prefix version
 160             */
 161             Iterator& operator++();
 162
 163             /**
 164                Postfix (hence less efficient -- don't use it unless you
 165                absolutely must) version
 166             */
 167             Iterator operator++(int);
 168
 169             /**
 170                Move x pixels to the right and y down
 171                note that the rows don't wrap!
 172             */
 173             void Offset(const PixelData& data, int x, int y);
 174
 175             /**
 176                Move x pixels to the right (again, no row wrapping)
 177             */
 178             void OffsetX(const PixelData&data, int x);
 179
 180             /**
 181                Move y rows to the bottom
 182             */
 183             void OffsetY(const PixelData& data, int y);
 184
 185             /**
 186                Go to the given position
 187             */
 188             void MoveTo(const PixelData& data, int x, int y);
 189
 190     //@{
 191             /**
 192                Data access: gives access to invidividual colour components.
 193             */
 194             ChannelType& Red();
 195             ChannelType& Green();
 196             ChannelType& Blue();
 197             ChannelType& Alpha();
 198     //@}
 199         };
 200 };
 201