DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (d8847129d134)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286
/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "SkData.h"
#include "SkDecodingImageGenerator.h"
#include "SkImageDecoder.h"
#include "SkImageInfo.h"
#include "SkImageGenerator.h"
#include "SkImagePriv.h"
#include "SkStream.h"
#include "SkUtils.h"

namespace {
bool equal_modulo_alpha(const SkImageInfo& a, const SkImageInfo& b) {
    return a.width() == b.width() && a.height() == b.height() &&
           a.colorType() == b.colorType();
}

class DecodingImageGenerator : public SkImageGenerator {
public:
    virtual ~DecodingImageGenerator();

    SkData*                fData;
    SkStreamRewindable*    fStream;
    const SkImageInfo      fInfo;
    const int              fSampleSize;
    const bool             fDitherImage;

    DecodingImageGenerator(SkData* data,
                           SkStreamRewindable* stream,
                           const SkImageInfo& info,
                           int sampleSize,
                           bool ditherImage);

protected:
    virtual SkData* onRefEncodedData() SK_OVERRIDE;
    virtual bool onGetInfo(SkImageInfo* info) SK_OVERRIDE {
        *info = fInfo;
        return true;
    }
    virtual bool onGetPixels(const SkImageInfo& info,
                             void* pixels, size_t rowBytes,
                             SkPMColor ctable[], int* ctableCount) SK_OVERRIDE;

private:
    typedef SkImageGenerator INHERITED;
};

/**
 *  Special allocator used by getPixels(). Uses preallocated memory
 *  provided if possible, else fall-back on the default allocator
 */
class TargetAllocator : public SkBitmap::Allocator {
public:
    TargetAllocator(const SkImageInfo& info,
                    void* target,
                    size_t rowBytes)
        : fInfo(info)
        , fTarget(target)
        , fRowBytes(rowBytes)
    {}

    bool isReady() { return (fTarget != NULL); }

    virtual bool allocPixelRef(SkBitmap* bm, SkColorTable* ct) {
        if (NULL == fTarget || !equal_modulo_alpha(fInfo, bm->info())) {
            // Call default allocator.
            return bm->allocPixels(NULL, ct);
        }

        // TODO(halcanary): verify that all callers of this function
        // will respect new RowBytes.  Will be moot once rowbytes belongs
        // to PixelRef.
        bm->installPixels(fInfo, fTarget, fRowBytes, ct, NULL, NULL);

        fTarget = NULL;  // never alloc same pixels twice!
        return true;
    }

private:
    const SkImageInfo fInfo;
    void* fTarget;  // Block of memory to be supplied as pixel memory
                    // in allocPixelRef.  Must be large enough to hold
                    // a bitmap described by fInfo and fRowBytes
    const size_t fRowBytes;  // rowbytes for the destination bitmap

    typedef SkBitmap::Allocator INHERITED;
};

// TODO(halcanary): Give this macro a better name and move it into SkTypes.h
#ifdef SK_DEBUG
    #define SkCheckResult(expr, value)  SkASSERT((value) == (expr))
#else
    #define SkCheckResult(expr, value)  (void)(expr)
#endif

#ifdef SK_DEBUG
inline bool check_alpha(SkAlphaType reported, SkAlphaType actual) {
    return ((reported == actual)
            || ((reported == kPremul_SkAlphaType)
                && (actual == kOpaque_SkAlphaType)));
}
#endif  // SK_DEBUG

////////////////////////////////////////////////////////////////////////////////

DecodingImageGenerator::DecodingImageGenerator(
        SkData* data,
        SkStreamRewindable* stream,
        const SkImageInfo& info,
        int sampleSize,
        bool ditherImage)
    : fData(data)
    , fStream(stream)
    , fInfo(info)
    , fSampleSize(sampleSize)
    , fDitherImage(ditherImage)
{
    SkASSERT(stream != NULL);
    SkSafeRef(fData);  // may be NULL.
}

DecodingImageGenerator::~DecodingImageGenerator() {
    SkSafeUnref(fData);
    fStream->unref();
}

SkData* DecodingImageGenerator::onRefEncodedData() {
    // This functionality is used in `gm --serialize`
    // Does not encode options.
    if (fData != NULL) {
        return SkSafeRef(fData);
    }
    // TODO(halcanary): SkStreamRewindable needs a refData() function
    // which returns a cheap copy of the underlying data.
    if (!fStream->rewind()) {
        return NULL;
    }
    size_t length = fStream->getLength();
    if (0 == length) {
        return NULL;
    }
    void* buffer = sk_malloc_flags(length, 0);
    SkCheckResult(fStream->read(buffer, length), length);
    fData = SkData::NewFromMalloc(buffer, length);
    return SkSafeRef(fData);
}

bool DecodingImageGenerator::onGetPixels(const SkImageInfo& info,
                                         void* pixels, size_t rowBytes,
                                         SkPMColor ctableEntries[], int* ctableCount) {
    if (fInfo != info) {
        // The caller has specified a different info.  This is an
        // error for this kind of SkImageGenerator.  Use the Options
        // to change the settings.
        return false;
    }

    SkAssertResult(fStream->rewind());
    SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(fStream));
    if (NULL == decoder.get()) {
        return false;
    }
    decoder->setDitherImage(fDitherImage);
    decoder->setSampleSize(fSampleSize);
    decoder->setRequireUnpremultipliedColors(
            info.fAlphaType == kUnpremul_SkAlphaType);

    SkBitmap bitmap;
    TargetAllocator allocator(fInfo, pixels, rowBytes);
    decoder->setAllocator(&allocator);
    bool success = decoder->decode(fStream, &bitmap, info.colorType(),
                                   SkImageDecoder::kDecodePixels_Mode);
    decoder->setAllocator(NULL);
    if (!success) {
        return false;
    }
    if (allocator.isReady()) {  // Did not use pixels!
        SkBitmap bm;
        SkASSERT(bitmap.canCopyTo(info.colorType()));
        bool copySuccess = bitmap.copyTo(&bm, info.colorType(), &allocator);
        if (!copySuccess || allocator.isReady()) {
            SkDEBUGFAIL("bitmap.copyTo(requestedConfig) failed.");
            // Earlier we checked canCopyto(); we expect consistency.
            return false;
        }
        SkASSERT(check_alpha(info.alphaType(), bm.alphaType()));
    } else {
        SkASSERT(check_alpha(info.alphaType(), bitmap.alphaType()));
    }

    if (kIndex_8_SkColorType == info.colorType()) {
        if (kIndex_8_SkColorType != bitmap.colorType()) {
            return false;   // they asked for Index8, but we didn't receive that from decoder
        }
        SkColorTable* ctable = bitmap.getColorTable();
        if (NULL == ctable) {
            return false;
        }
        const int count = ctable->count();
        memcpy(ctableEntries, ctable->lockColors(), count * sizeof(SkPMColor));
        ctable->unlockColors();
        *ctableCount = count;
    }
    return true;
}

// A contructor-type function that returns NULL on failure.  This
// prevents the returned SkImageGenerator from ever being in a bad
// state.  Called by both Create() functions
SkImageGenerator* CreateDecodingImageGenerator(
        SkData* data,
        SkStreamRewindable* stream,
        const SkDecodingImageGenerator::Options& opts) {
    SkASSERT(stream);
    SkAutoTUnref<SkStreamRewindable> autoStream(stream);  // always unref this.
    SkAssertResult(autoStream->rewind());
    SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(autoStream));
    if (NULL == decoder.get()) {
        return NULL;
    }
    SkBitmap bitmap;
    decoder->setSampleSize(opts.fSampleSize);
    decoder->setRequireUnpremultipliedColors(opts.fRequireUnpremul);
    if (!decoder->decode(stream, &bitmap, SkImageDecoder::kDecodeBounds_Mode)) {
        return NULL;
    }
    if (kUnknown_SkColorType == bitmap.colorType()) {
        return NULL;
    }

    SkImageInfo info = bitmap.info();

    if (opts.fUseRequestedColorType && (opts.fRequestedColorType != info.colorType())) {
        if (!bitmap.canCopyTo(opts.fRequestedColorType)) {
            SkASSERT(bitmap.colorType() != opts.fRequestedColorType);
            return NULL;  // Can not translate to needed config.
        }
        info.fColorType = opts.fRequestedColorType;
    }

    if (opts.fRequireUnpremul && info.fAlphaType != kOpaque_SkAlphaType) {
        info.fAlphaType = kUnpremul_SkAlphaType;
    }

    if (!SkColorTypeValidateAlphaType(info.fColorType, info.fAlphaType, &info.fAlphaType)) {
        return NULL;
    }

    return SkNEW_ARGS(DecodingImageGenerator,
                      (data, autoStream.detach(), info,
                       opts.fSampleSize, opts.fDitherImage));
}

}  // namespace

////////////////////////////////////////////////////////////////////////////////

SkImageGenerator* SkDecodingImageGenerator::Create(
        SkData* data,
        const SkDecodingImageGenerator::Options& opts) {
    SkASSERT(data != NULL);
    if (NULL == data) {
        return NULL;
    }
    SkStreamRewindable* stream = SkNEW_ARGS(SkMemoryStream, (data));
    SkASSERT(stream != NULL);
    SkASSERT(stream->unique());
    return CreateDecodingImageGenerator(data, stream, opts);
}

SkImageGenerator* SkDecodingImageGenerator::Create(
        SkStreamRewindable* stream,
        const SkDecodingImageGenerator::Options& opts) {
    SkASSERT(stream != NULL);
    SkASSERT(stream->unique());
    if ((stream == NULL) || !stream->unique()) {
        SkSafeUnref(stream);
        return NULL;
    }
    return CreateDecodingImageGenerator(NULL, stream, opts);
}