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