1/* 2 * Copyright 2014 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8#include "SkColorPriv.h" 9#include "SkImageDecoder.h" 10#include "SkScaledBitmapSampler.h" 11#include "SkStream.h" 12#include "SkStreamPriv.h" 13#include "SkTextureCompressor.h" 14#include "SkTypes.h" 15 16#include "etc1.h" 17 18class SkPKMImageDecoder : public SkImageDecoder { 19public: 20 SkPKMImageDecoder() { } 21 22 virtual Format getFormat() const SK_OVERRIDE { 23 return kPKM_Format; 24 } 25 26protected: 27 virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode) SK_OVERRIDE; 28 29private: 30 typedef SkImageDecoder INHERITED; 31}; 32 33///////////////////////////////////////////////////////////////////////////////////////// 34 35bool SkPKMImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) { 36 SkAutoMalloc autoMal; 37 const size_t length = SkCopyStreamToStorage(&autoMal, stream); 38 if (0 == length) { 39 return false; 40 } 41 42 unsigned char* buf = (unsigned char*)autoMal.get(); 43 44 // Make sure original PKM header is there... 45 SkASSERT(etc1_pkm_is_valid(buf)); 46 47 const unsigned short width = etc1_pkm_get_width(buf); 48 const unsigned short height = etc1_pkm_get_height(buf); 49 50#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER 51 // should we allow the Chooser (if present) to pick a config for us??? 52 if (!this->chooseFromOneChoice(kN32_SkColorType, width, height)) { 53 return false; 54 } 55#endif 56 57 // Setup the sampler... 58 SkScaledBitmapSampler sampler(width, height, this->getSampleSize()); 59 60 // Set the config... 61 bm->setInfo(SkImageInfo::MakeN32(sampler.scaledWidth(), sampler.scaledHeight(), 62 kOpaque_SkAlphaType)); 63 if (SkImageDecoder::kDecodeBounds_Mode == mode) { 64 return true; 65 } 66 67 if (!this->allocPixelRef(bm, NULL)) { 68 return false; 69 } 70 71 // Lock the pixels, since we're about to write to them... 72 SkAutoLockPixels alp(*bm); 73 74 if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, *this)) { 75 return false; 76 } 77 78 // Advance buffer past the header 79 buf += ETC_PKM_HEADER_SIZE; 80 81 // ETC1 Data is encoded as RGB pixels, so we should extract it as such 82 int nPixels = width * height; 83 SkAutoMalloc outRGBData(nPixels * 3); 84 uint8_t *outRGBDataPtr = reinterpret_cast<uint8_t *>(outRGBData.get()); 85 86 // Decode ETC1 87 if (!SkTextureCompressor::DecompressBufferFromFormat( 88 outRGBDataPtr, width*3, buf, width, height, SkTextureCompressor::kETC1_Format)) { 89 return false; 90 } 91 92 // Set each of the pixels... 93 const int srcRowBytes = width * 3; 94 const int dstHeight = sampler.scaledHeight(); 95 const uint8_t *srcRow = reinterpret_cast<uint8_t *>(outRGBDataPtr); 96 srcRow += sampler.srcY0() * srcRowBytes; 97 for (int y = 0; y < dstHeight; ++y) { 98 sampler.next(srcRow); 99 srcRow += sampler.srcDY() * srcRowBytes; 100 } 101 102 return true; 103} 104 105///////////////////////////////////////////////////////////////////////////////////////// 106DEFINE_DECODER_CREATOR(PKMImageDecoder); 107///////////////////////////////////////////////////////////////////////////////////////// 108 109static bool is_pkm(SkStreamRewindable* stream) { 110 // Read the PKM header and make sure it's valid. 111 unsigned char buf[ETC_PKM_HEADER_SIZE]; 112 if (stream->read((void*)buf, ETC_PKM_HEADER_SIZE) != ETC_PKM_HEADER_SIZE) { 113 return false; 114 } 115 116 return SkToBool(etc1_pkm_is_valid(buf)); 117} 118 119static SkImageDecoder* sk_libpkm_dfactory(SkStreamRewindable* stream) { 120 if (is_pkm(stream)) { 121 return SkNEW(SkPKMImageDecoder); 122 } 123 return NULL; 124} 125 126static SkImageDecoder_DecodeReg gReg(sk_libpkm_dfactory); 127 128static SkImageDecoder::Format get_format_pkm(SkStreamRewindable* stream) { 129 if (is_pkm(stream)) { 130 return SkImageDecoder::kPKM_Format; 131 } 132 return SkImageDecoder::kUnknown_Format; 133} 134 135static SkImageDecoder_FormatReg gFormatReg(get_format_pkm); 136