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comparison: image/decoders/nsBMPDecoder.h
image/decoders/nsBMPDecoder.h
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| 1 /* vim:set tw=80 expandtab softtabstop=4 ts=4 sw=4: */ | |
| 2 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 3 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 5 | |
| 6 | |
| 7 #ifndef _nsBMPDecoder_h | |
| 8 #define _nsBMPDecoder_h | |
| 9 | |
| 10 #include "nsAutoPtr.h" | |
| 11 #include "gfxColor.h" | |
| 12 #include "Decoder.h" | |
| 13 #include "BMPFileHeaders.h" | |
| 14 | |
| 15 namespace mozilla { | |
| 16 namespace image { | |
| 17 | |
| 18 class RasterImage; | |
| 19 | |
| 20 /** | |
| 21 * Decoder for BMP-Files, as used by Windows and OS/2 | |
| 22 */ | |
| 23 class nsBMPDecoder : public Decoder | |
| 24 { | |
| 25 public: | |
| 26 | |
| 27 nsBMPDecoder(RasterImage &aImage); | |
| 28 ~nsBMPDecoder(); | |
| 29 | |
| 30 // Specifies whether or not the BMP file will contain alpha data | |
| 31 // If set to true and the BMP is 32BPP, the alpha data will be | |
| 32 // retrieved from the 4th byte of image data per pixel | |
| 33 void SetUseAlphaData(bool useAlphaData); | |
| 34 // Obtains the bits per pixel from the internal BIH header | |
| 35 int32_t GetBitsPerPixel() const; | |
| 36 // Obtains the width from the internal BIH header | |
| 37 int32_t GetWidth() const; | |
| 38 // Obtains the abs-value of the height from the internal BIH header | |
| 39 int32_t GetHeight() const; | |
| 40 // Obtains the internal output image buffer | |
| 41 uint32_t* GetImageData(); | |
| 42 // Obtains the size of the compressed image resource | |
| 43 int32_t GetCompressedImageSize() const; | |
| 44 // Obtains whether or not a BMP file had alpha data in its 4th byte | |
| 45 // for 32BPP bitmaps. Only use after the bitmap has been processed. | |
| 46 bool HasAlphaData() const; | |
| 47 | |
| 48 virtual void WriteInternal(const char* aBuffer, uint32_t aCount, DecodeStrategy aStrategy); | |
| 49 virtual void FinishInternal(); | |
| 50 | |
| 51 private: | |
| 52 | |
| 53 /** Calculates the red-, green- and blueshift in mBitFields using | |
| 54 * the bitmasks from mBitFields */ | |
| 55 NS_METHOD CalcBitShift(); | |
| 56 | |
| 57 uint32_t mPos; | |
| 58 | |
| 59 BMPFILEHEADER mBFH; | |
| 60 BITMAPV5HEADER mBIH; | |
| 61 char mRawBuf[WIN_V3_INTERNAL_BIH_LENGTH]; | |
| 62 | |
| 63 uint32_t mLOH; ///< Length of the header | |
| 64 | |
| 65 uint32_t mNumColors; ///< The number of used colors, i.e. the number of entries in mColors | |
| 66 colorTable *mColors; | |
| 67 | |
| 68 bitFields mBitFields; | |
| 69 | |
| 70 uint8_t *mRow; ///< Holds one raw line of the image | |
| 71 uint32_t mRowBytes; ///< How many bytes of the row were already received | |
| 72 int32_t mCurLine; ///< Index of the line of the image that's currently being decoded: [height,1] | |
| 73 int32_t mOldLine; ///< Previous index of the line | |
| 74 int32_t mCurPos; ///< Index in the current line of the image | |
| 75 | |
| 76 ERLEState mState; ///< Maintains the current state of the RLE decoding | |
| 77 uint32_t mStateData;///< Decoding information that is needed depending on mState | |
| 78 | |
| 79 /** Set mBFH from the raw data in mRawBuf, converting from little-endian | |
| 80 * data to native data as necessary */ | |
| 81 void ProcessFileHeader(); | |
| 82 /** Set mBIH from the raw data in mRawBuf, converting from little-endian | |
| 83 * data to native data as necessary */ | |
| 84 void ProcessInfoHeader(); | |
| 85 | |
| 86 // Stores whether the image data may store alpha data, or if | |
| 87 // the alpha data is unspecified and filled with a padding byte of 0. | |
| 88 // When a 32BPP bitmap is stored in an ICO or CUR file, its 4th byte | |
| 89 // is used for alpha transparency. When it is stored in a BMP, its | |
| 90 // 4th byte is reserved and is always 0. | |
| 91 // Reference: | |
| 92 // http://en.wikipedia.org/wiki/ICO_(file_format)#cite_note-9 | |
| 93 // Bitmaps where the alpha bytes are all 0 should be fully visible. | |
| 94 bool mUseAlphaData; | |
| 95 // Whether the 4th byte alpha data was found to be non zero and hence used. | |
| 96 bool mHaveAlphaData; | |
| 97 }; | |
| 98 | |
| 99 /** Sets the pixel data in aDecoded to the given values. | |
| 100 * @param aDecoded pointer to pixel to be set, will be incremented to point to the next pixel. | |
| 101 */ | |
| 102 static inline void SetPixel(uint32_t*& aDecoded, uint8_t aRed, uint8_t aGreen, uint8_t aBlue, uint8_t aAlpha = 0xFF) | |
| 103 { | |
| 104 *aDecoded++ = gfxPackedPixel(aAlpha, aRed, aGreen, aBlue); | |
| 105 } | |
| 106 | |
| 107 static inline void SetPixel(uint32_t*& aDecoded, uint8_t idx, colorTable* aColors) | |
| 108 { | |
| 109 SetPixel(aDecoded, aColors[idx].red, aColors[idx].green, aColors[idx].blue); | |
| 110 } | |
| 111 | |
| 112 /** Sets two (or one if aCount = 1) pixels | |
| 113 * @param aDecoded where the data is stored. Will be moved 4 resp 8 bytes | |
| 114 * depending on whether one or two pixels are written. | |
| 115 * @param aData The values for the two pixels | |
| 116 * @param aCount Current count. Is decremented by one or two. | |
| 117 */ | |
| 118 inline void Set4BitPixel(uint32_t*& aDecoded, uint8_t aData, | |
| 119 uint32_t& aCount, colorTable* aColors) | |
| 120 { | |
| 121 uint8_t idx = aData >> 4; | |
| 122 SetPixel(aDecoded, idx, aColors); | |
| 123 if (--aCount > 0) { | |
| 124 idx = aData & 0xF; | |
| 125 SetPixel(aDecoded, idx, aColors); | |
| 126 --aCount; | |
| 127 } | |
| 128 } | |
| 129 | |
| 130 } // namespace image | |
| 131 } // namespace mozilla | |
| 132 | |
| 133 | |
| 134 #endif | |
| 135 |
