1 /* 2 * Copyright 2007, The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "bmpdecoderhelper.h" 18 #include "SkImageDecoder.h" 19 #include "SkScaledBitmapSampler.h" 20 #include "SkStream.h" 21 #include "SkColorPriv.h" 22 #include "SkTDArray.h" 23 #include "SkTRegistry.h" 24 25 class SkBMPImageDecoder : public SkImageDecoder { 26 public: 27 SkBMPImageDecoder() {} 28 29 virtual Format getFormat() const { 30 return kBMP_Format; 31 } 32 33 protected: 34 virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode mode); 35 }; 36 37 static SkImageDecoder* Factory(SkStream* stream) { 38 static const char kBmpMagic[] = { 'B', 'M' }; 39 40 size_t len = stream->getLength(); 41 char buffer[sizeof(kBmpMagic)]; 42 43 if (len > sizeof(kBmpMagic) && 44 stream->read(buffer, sizeof(kBmpMagic)) == sizeof(kBmpMagic) && 45 !memcmp(buffer, kBmpMagic, sizeof(kBmpMagic))) { 46 return SkNEW(SkBMPImageDecoder); 47 } 48 return NULL; 49 } 50 51 static SkTRegistry<SkImageDecoder*, SkStream*> gReg(Factory); 52 53 /////////////////////////////////////////////////////////////////////////////// 54 55 class SkBmpDecoderCallback : public image_codec::BmpDecoderCallback { 56 public: 57 // we don't copy the bitmap, just remember the pointer 58 SkBmpDecoderCallback(bool justBounds) : fJustBounds(justBounds) {} 59 60 // override from BmpDecoderCallback 61 virtual uint8* SetSize(int width, int height) { 62 fWidth = width; 63 fHeight = height; 64 if (fJustBounds) { 65 return NULL; 66 } 67 68 fRGB.setCount(width * height * 3); // 3 == r, g, b 69 return fRGB.begin(); 70 } 71 72 int width() const { return fWidth; } 73 int height() const { return fHeight; } 74 uint8_t* rgb() const { return fRGB.begin(); } 75 76 private: 77 SkTDArray<uint8_t> fRGB; 78 int fWidth; 79 int fHeight; 80 bool fJustBounds; 81 }; 82 83 bool SkBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) { 84 85 size_t length = stream->getLength(); 86 SkAutoMalloc storage(length); 87 88 if (stream->read(storage.get(), length) != length) { 89 return false; 90 } 91 92 const bool justBounds = SkImageDecoder::kDecodeBounds_Mode == mode; 93 SkBmpDecoderCallback callback(justBounds); 94 95 // Now decode the BMP into callback's rgb() array [r,g,b, r,g,b, ...] 96 { 97 image_codec::BmpDecoderHelper helper; 98 const int max_pixels = 16383*16383; // max width*height 99 if (!helper.DecodeImage((const char*)storage.get(), length, 100 max_pixels, &callback)) { 101 return false; 102 } 103 } 104 105 // we don't need this anymore, so free it now (before we try to allocate 106 // the bitmap's pixels) rather than waiting for its destructor 107 storage.free(); 108 109 int width = callback.width(); 110 int height = callback.height(); 111 SkBitmap::Config config = this->getPrefConfig(k32Bit_SrcDepth, false); 112 113 // only accept prefConfig if it makes sense for us 114 if (SkBitmap::kARGB_4444_Config != config && 115 SkBitmap::kRGB_565_Config != config) { 116 config = SkBitmap::kARGB_8888_Config; 117 } 118 119 SkScaledBitmapSampler sampler(width, height, getSampleSize()); 120 121 bm->setConfig(config, sampler.scaledWidth(), sampler.scaledHeight()); 122 bm->setIsOpaque(true); 123 if (justBounds) { 124 return true; 125 } 126 127 if (!this->allocPixelRef(bm, NULL)) { 128 return false; 129 } 130 131 SkAutoLockPixels alp(*bm); 132 133 if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, getDitherImage())) { 134 return false; 135 } 136 137 const int srcRowBytes = width * 3; 138 const int dstHeight = sampler.scaledHeight(); 139 const uint8_t* srcRow = callback.rgb(); 140 141 srcRow += sampler.srcY0() * srcRowBytes; 142 for (int y = 0; y < dstHeight; y++) { 143 sampler.next(srcRow); 144 srcRow += sampler.srcDY() * srcRowBytes; 145 } 146 return true; 147 } 148