diff options
Diffstat (limited to 'src/images/SkImageDecoder_wbmp.cpp')
-rw-r--r-- | src/images/SkImageDecoder_wbmp.cpp | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/src/images/SkImageDecoder_wbmp.cpp b/src/images/SkImageDecoder_wbmp.cpp new file mode 100644 index 0000000000..9d188f6016 --- /dev/null +++ b/src/images/SkImageDecoder_wbmp.cpp @@ -0,0 +1,167 @@ +/** +** Copyright 2006, The Android Open Source Project +** +** Licensed under the Apache License, Version 2.0 (the "License"); +** you may not use this file except in compliance with the License. +** You may obtain a copy of the License at +** +** http://www.apache.org/licenses/LICENSE-2.0 +** +** Unless required by applicable law or agreed to in writing, software +** distributed under the License is distributed on an "AS IS" BASIS, +** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +** See the License for the specific language governing permissions and +** limitations under the License. +*/ + +#include "SkImageDecoder.h" +#include "SkColor.h" +#include "SkColorPriv.h" +#include "SkMath.h" +#include "SkStream.h" +#include "SkTemplates.h" +#include "SkUtils.h" + +class SkWBMPImageDecoder : public SkImageDecoder { +public: + virtual Format getFormat() const { + return kWBMP_Format; + } + +protected: + virtual bool onDecode(SkStream* stream, SkBitmap* bm, + SkBitmap::Config pref, Mode); +}; + +static bool read_byte(SkStream* stream, uint8_t* data) +{ + return stream->read(data, 1) == 1; +} + +static bool read_mbf(SkStream* stream, int* value) +{ + int n = 0; + uint8_t data; + do { + if (!read_byte(stream, &data)) { + return false; + } + n = (n << 7) | (data & 0x7F); + } while (data & 0x80); + + *value = n; + return true; +} + +struct wbmp_head { + int fWidth; + int fHeight; + + bool init(SkStream* stream) + { + uint8_t data; + + if (!read_byte(stream, &data) || data != 0) { // unknown type + return false; + } + if (!read_byte(stream, &data) || (data & 0x9F)) { // skip fixed header + return false; + } + if (!read_mbf(stream, &fWidth) || (unsigned)fWidth > 0xFFFF) { + return false; + } + if (!read_mbf(stream, &fHeight) || (unsigned)fHeight > 0xFFFF) { + return false; + } + return fWidth != 0 && fHeight != 0; + } +}; + +SkImageDecoder* SkImageDecoder_WBMP_Factory(SkStream* stream) +{ + wbmp_head head; + + if (head.init(stream)) { + return SkNEW(SkWBMPImageDecoder); + } + return NULL; +} + +static void expand_bits_to_bytes(uint8_t dst[], const uint8_t src[], int bits) +{ + int bytes = bits >> 3; + + for (int i = 0; i < bytes; i++) { + unsigned mask = *src++; + dst[0] = (mask >> 7) & 1; + dst[1] = (mask >> 6) & 1; + dst[2] = (mask >> 5) & 1; + dst[3] = (mask >> 4) & 1; + dst[4] = (mask >> 3) & 1; + dst[5] = (mask >> 2) & 1; + dst[6] = (mask >> 1) & 1; + dst[7] = (mask >> 0) & 1; + dst += 8; + } + + bits &= 7; + if (bits > 0) { + unsigned mask = *src; + do { + *dst++ = (mask >> 7) & 1;; + mask <<= 1; + } while (--bits != 0); + } +} + +#define SkAlign8(x) (((x) + 7) & ~7) + +bool SkWBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* decodedBitmap, + SkBitmap::Config prefConfig, Mode mode) +{ + wbmp_head head; + + if (!head.init(stream)) { + return false; + } + + int width = head.fWidth; + int height = head.fHeight; + + // assign these directly, in case we return kDimensions_Result + decodedBitmap->setConfig(SkBitmap::kIndex8_Config, width, height); + decodedBitmap->setIsOpaque(true); + + if (SkImageDecoder::kDecodeBounds_Mode == mode) + return true; + + const SkPMColor colors[] = { SK_ColorBLACK, SK_ColorWHITE }; + SkColorTable* ct = SkNEW_ARGS(SkColorTable, (colors, 2)); + SkAutoUnref aur(ct); + + if (!this->allocPixelRef(decodedBitmap, ct)) { + return false; + } + + SkAutoLockPixels alp(*decodedBitmap); + + uint8_t* dst = decodedBitmap->getAddr8(0, 0); + // store the 1-bit valuess at the end of our pixels, so we won't stomp + // on them before we're read them. Just trying to avoid a temp allocation + size_t srcRB = SkAlign8(width) >> 3; + size_t srcSize = height * srcRB; + uint8_t* src = dst + decodedBitmap->getSize() - srcSize; + if (stream->read(src, srcSize) != srcSize) { + return false; + } + + for (int y = 0; y < height; y++) + { + expand_bits_to_bytes(dst, src, width); + dst += decodedBitmap->rowBytes(); + src += srcRB; + } + + return true; +} + |