1 2/* 3 * Copyright 2007 The Android Open Source Project 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10#include "bmpdecoderhelper.h" 11#include "SkImageDecoder.h" 12#include "SkScaledBitmapSampler.h" 13#include "SkStream.h" 14#include "SkColorPriv.h" 15#include "SkTDArray.h" 16#include "SkTRegistry.h" 17 18class SkBMPImageDecoder : public SkImageDecoder { 19public: 20 SkBMPImageDecoder() {} 21 22 virtual Format getFormat() const SK_OVERRIDE { 23 return kBMP_Format; 24 } 25 26protected: 27 virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode mode) SK_OVERRIDE; 28 29private: 30 typedef SkImageDecoder INHERITED; 31}; 32 33/////////////////////////////////////////////////////////////////////////////// 34DEFINE_DECODER_CREATOR(BMPImageDecoder); 35/////////////////////////////////////////////////////////////////////////////// 36 37static bool is_bmp(SkStream* stream) { 38 static const char kBmpMagic[] = { 'B', 'M' }; 39 40 41 char buffer[sizeof(kBmpMagic)]; 42 43 return stream->read(buffer, sizeof(kBmpMagic)) == sizeof(kBmpMagic) && 44 !memcmp(buffer, kBmpMagic, sizeof(kBmpMagic)); 45} 46 47static SkImageDecoder* sk_libbmp_dfactory(SkStream* stream) { 48 if (is_bmp(stream)) { 49 return SkNEW(SkBMPImageDecoder); 50 } 51 return NULL; 52} 53 54static SkTRegistry<SkImageDecoder*, SkStream*> gReg(sk_libbmp_dfactory); 55 56static SkImageDecoder::Format get_format_bmp(SkStream* stream) { 57 if (is_bmp(stream)) { 58 return SkImageDecoder::kBMP_Format; 59 } 60 return SkImageDecoder::kUnknown_Format; 61} 62 63static SkTRegistry<SkImageDecoder::Format, SkStream*> gFormatReg(get_format_bmp); 64 65/////////////////////////////////////////////////////////////////////////////// 66 67class SkBmpDecoderCallback : public image_codec::BmpDecoderCallback { 68public: 69 // we don't copy the bitmap, just remember the pointer 70 SkBmpDecoderCallback(bool justBounds) : fJustBounds(justBounds) {} 71 72 // override from BmpDecoderCallback 73 virtual uint8* SetSize(int width, int height) { 74 fWidth = width; 75 fHeight = height; 76 if (fJustBounds) { 77 return NULL; 78 } 79 80 fRGB.setCount(width * height * 3); // 3 == r, g, b 81 return fRGB.begin(); 82 } 83 84 int width() const { return fWidth; } 85 int height() const { return fHeight; } 86 const uint8_t* rgb() const { return fRGB.begin(); } 87 88private: 89 SkTDArray<uint8_t> fRGB; 90 int fWidth; 91 int fHeight; 92 bool fJustBounds; 93}; 94 95bool SkBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) { 96 97 size_t length = stream->getLength(); 98 SkAutoMalloc storage(length); 99 100 if (stream->read(storage.get(), length) != length) { 101 return false; 102 } 103 104 const bool justBounds = SkImageDecoder::kDecodeBounds_Mode == mode; 105 SkBmpDecoderCallback callback(justBounds); 106 107 // Now decode the BMP into callback's rgb() array [r,g,b, r,g,b, ...] 108 { 109 image_codec::BmpDecoderHelper helper; 110 const int max_pixels = 16383*16383; // max width*height 111 if (!helper.DecodeImage((const char*)storage.get(), length, 112 max_pixels, &callback)) { 113 return false; 114 } 115 } 116 117 // we don't need this anymore, so free it now (before we try to allocate 118 // the bitmap's pixels) rather than waiting for its destructor 119 storage.free(); 120 121 int width = callback.width(); 122 int height = callback.height(); 123 SkBitmap::Config config = this->getPrefConfig(k32Bit_SrcDepth, false); 124 125 // only accept prefConfig if it makes sense for us 126 if (SkBitmap::kARGB_4444_Config != config && 127 SkBitmap::kRGB_565_Config != config) { 128 config = SkBitmap::kARGB_8888_Config; 129 } 130 131 SkScaledBitmapSampler sampler(width, height, getSampleSize()); 132 133 bm->setConfig(config, sampler.scaledWidth(), sampler.scaledHeight()); 134 bm->setIsOpaque(true); 135 136 if (justBounds) { 137 return true; 138 } 139 140 if (!this->allocPixelRef(bm, NULL)) { 141 return false; 142 } 143 144 SkAutoLockPixels alp(*bm); 145 146 if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, getDitherImage())) { 147 return false; 148 } 149 150 const int srcRowBytes = width * 3; 151 const int dstHeight = sampler.scaledHeight(); 152 const uint8_t* srcRow = callback.rgb(); 153 154 srcRow += sampler.srcY0() * srcRowBytes; 155 for (int y = 0; y < dstHeight; y++) { 156 sampler.next(srcRow); 157 srcRow += sampler.srcDY() * srcRowBytes; 158 } 159 return true; 160} 161