1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/image/decoders/nsBMPDecoder.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,135 @@
1.4 +/* vim:set tw=80 expandtab softtabstop=4 ts=4 sw=4: */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +
1.10 +#ifndef _nsBMPDecoder_h
1.11 +#define _nsBMPDecoder_h
1.12 +
1.13 +#include "nsAutoPtr.h"
1.14 +#include "gfxColor.h"
1.15 +#include "Decoder.h"
1.16 +#include "BMPFileHeaders.h"
1.17 +
1.18 +namespace mozilla {
1.19 +namespace image {
1.20 +
1.21 +class RasterImage;
1.22 +
1.23 +/**
1.24 + * Decoder for BMP-Files, as used by Windows and OS/2
1.25 + */
1.26 +class nsBMPDecoder : public Decoder
1.27 +{
1.28 +public:
1.29 +
1.30 + nsBMPDecoder(RasterImage &aImage);
1.31 + ~nsBMPDecoder();
1.32 +
1.33 + // Specifies whether or not the BMP file will contain alpha data
1.34 + // If set to true and the BMP is 32BPP, the alpha data will be
1.35 + // retrieved from the 4th byte of image data per pixel
1.36 + void SetUseAlphaData(bool useAlphaData);
1.37 + // Obtains the bits per pixel from the internal BIH header
1.38 + int32_t GetBitsPerPixel() const;
1.39 + // Obtains the width from the internal BIH header
1.40 + int32_t GetWidth() const;
1.41 + // Obtains the abs-value of the height from the internal BIH header
1.42 + int32_t GetHeight() const;
1.43 + // Obtains the internal output image buffer
1.44 + uint32_t* GetImageData();
1.45 + // Obtains the size of the compressed image resource
1.46 + int32_t GetCompressedImageSize() const;
1.47 + // Obtains whether or not a BMP file had alpha data in its 4th byte
1.48 + // for 32BPP bitmaps. Only use after the bitmap has been processed.
1.49 + bool HasAlphaData() const;
1.50 +
1.51 + virtual void WriteInternal(const char* aBuffer, uint32_t aCount, DecodeStrategy aStrategy);
1.52 + virtual void FinishInternal();
1.53 +
1.54 +private:
1.55 +
1.56 + /** Calculates the red-, green- and blueshift in mBitFields using
1.57 + * the bitmasks from mBitFields */
1.58 + NS_METHOD CalcBitShift();
1.59 +
1.60 + uint32_t mPos;
1.61 +
1.62 + BMPFILEHEADER mBFH;
1.63 + BITMAPV5HEADER mBIH;
1.64 + char mRawBuf[WIN_V3_INTERNAL_BIH_LENGTH];
1.65 +
1.66 + uint32_t mLOH; ///< Length of the header
1.67 +
1.68 + uint32_t mNumColors; ///< The number of used colors, i.e. the number of entries in mColors
1.69 + colorTable *mColors;
1.70 +
1.71 + bitFields mBitFields;
1.72 +
1.73 + uint8_t *mRow; ///< Holds one raw line of the image
1.74 + uint32_t mRowBytes; ///< How many bytes of the row were already received
1.75 + int32_t mCurLine; ///< Index of the line of the image that's currently being decoded: [height,1]
1.76 + int32_t mOldLine; ///< Previous index of the line
1.77 + int32_t mCurPos; ///< Index in the current line of the image
1.78 +
1.79 + ERLEState mState; ///< Maintains the current state of the RLE decoding
1.80 + uint32_t mStateData;///< Decoding information that is needed depending on mState
1.81 +
1.82 + /** Set mBFH from the raw data in mRawBuf, converting from little-endian
1.83 + * data to native data as necessary */
1.84 + void ProcessFileHeader();
1.85 + /** Set mBIH from the raw data in mRawBuf, converting from little-endian
1.86 + * data to native data as necessary */
1.87 + void ProcessInfoHeader();
1.88 +
1.89 + // Stores whether the image data may store alpha data, or if
1.90 + // the alpha data is unspecified and filled with a padding byte of 0.
1.91 + // When a 32BPP bitmap is stored in an ICO or CUR file, its 4th byte
1.92 + // is used for alpha transparency. When it is stored in a BMP, its
1.93 + // 4th byte is reserved and is always 0.
1.94 + // Reference:
1.95 + // http://en.wikipedia.org/wiki/ICO_(file_format)#cite_note-9
1.96 + // Bitmaps where the alpha bytes are all 0 should be fully visible.
1.97 + bool mUseAlphaData;
1.98 + // Whether the 4th byte alpha data was found to be non zero and hence used.
1.99 + bool mHaveAlphaData;
1.100 +};
1.101 +
1.102 +/** Sets the pixel data in aDecoded to the given values.
1.103 + * @param aDecoded pointer to pixel to be set, will be incremented to point to the next pixel.
1.104 + */
1.105 +static inline void SetPixel(uint32_t*& aDecoded, uint8_t aRed, uint8_t aGreen, uint8_t aBlue, uint8_t aAlpha = 0xFF)
1.106 +{
1.107 + *aDecoded++ = gfxPackedPixel(aAlpha, aRed, aGreen, aBlue);
1.108 +}
1.109 +
1.110 +static inline void SetPixel(uint32_t*& aDecoded, uint8_t idx, colorTable* aColors)
1.111 +{
1.112 + SetPixel(aDecoded, aColors[idx].red, aColors[idx].green, aColors[idx].blue);
1.113 +}
1.114 +
1.115 +/** Sets two (or one if aCount = 1) pixels
1.116 + * @param aDecoded where the data is stored. Will be moved 4 resp 8 bytes
1.117 + * depending on whether one or two pixels are written.
1.118 + * @param aData The values for the two pixels
1.119 + * @param aCount Current count. Is decremented by one or two.
1.120 + */
1.121 +inline void Set4BitPixel(uint32_t*& aDecoded, uint8_t aData,
1.122 + uint32_t& aCount, colorTable* aColors)
1.123 +{
1.124 + uint8_t idx = aData >> 4;
1.125 + SetPixel(aDecoded, idx, aColors);
1.126 + if (--aCount > 0) {
1.127 + idx = aData & 0xF;
1.128 + SetPixel(aDecoded, idx, aColors);
1.129 + --aCount;
1.130 + }
1.131 +}
1.132 +
1.133 +} // namespace image
1.134 +} // namespace mozilla
1.135 +
1.136 +
1.137 +#endif
1.138 +
