image/ICOFileHeaders.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5
   6 #ifndef mozilla_image_ICOFileHeaders_h
   7 #define mozilla_image_ICOFileHeaders_h
   8
   9 namespace mozilla {
  10 namespace image {
  11
  12 #define ICONFILEHEADERSIZE 6
  13 #define ICODIRENTRYSIZE 16
  14 #define PNGSIGNATURESIZE 8
  15 #define BMPFILEHEADERSIZE 14
  16
  17 /**
  18  * The header that comes right at the start of an icon file. (This
  19  * corresponds to the Windows ICONDIR structure.)
  20  */
  21 struct IconFileHeader
  22 {
  23   /**
  24    * Must be set to 0;
  25    */
  26   uint16_t   mReserved;
  27   /**
  28    * 1 for icon (.ICO) image (or 2 for cursor (.CUR) image (icon with the
  29    * addition of a hotspot), but we don't support cursor).
  30    */
  31   uint16_t   mType;
  32   /**
  33    * The number of BMP/PNG images contained in the icon file.
  34    */
  35   uint16_t   mCount;
  36 };
  37
  38 /**
  39  * For each BMP/PNG image that the icon file contains there must be a
  40  * corresponding icon dir entry. (This corresponds to the Windows
  41  * ICONDIRENTRY structure.) These entries are encoded directly after the
  42  * IconFileHeader.
  43  */
  44 struct IconDirEntry
  45 {
  46   uint8_t   mWidth;
  47   uint8_t   mHeight;
  48   /**
  49    * The number of colors in the color palette of the BMP/PNG that this dir
  50    * entry corresponds to, or 0 if the image does not use a color palette.
  51    */
  52   uint8_t   mColorCount;
  53   /**
  54    * Should be set to 0.
  55    */
  56   uint8_t   mReserved;
  57   union {
  58     uint16_t mPlanes;   // ICO
  59     uint16_t mXHotspot; // CUR
  60   };
  61   union {
  62     uint16_t mBitCount; // ICO (bits per pixel)
  63     uint16_t mYHotspot; // CUR
  64   };
  65   /**
  66    * "bytes in resource" is the length of the encoded BMP/PNG that this dir
  67    * entry corresponds to.
  68    */
  69   uint32_t  mBytesInRes;
  70   /**
  71    * The offset of the start of the encoded BMP/PNG that this dir entry
  72    * corresponds to (from the start of the icon file).
  73    */
  74   uint32_t  mImageOffset;
  75 };
  76
  77
  78 } // namespace image
  79 } // namespace mozilla
  80
  81 #endif // mozilla_image_ICOFileHeaders_h