src/image/SkImage.cpp

#include "SkImage.h"

#include "SkBitmap.h"

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

class SkImage_Base : public SkImage {
public:
    SkImage_Base(int width, int height) : INHERITED(width, height) {}

    virtual const SkBitmap* asABitmap() { return NULL; }

private:    
    typedef SkImage INHERITED;
};

static SkImage_Base* asIB(SkImage* image) {
    return static_cast<SkImage_Base*>(image);
}

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

static SkBitmap::Config InfoToConfig(const SkImage::Info& info, bool* isOpaque) {
    switch (info.fColorType) {
        case SkImage::kAlpha_8_ColorType:
            switch (info.fAlphaType) {
                case SkImage::kIgnore_AlphaType:
                    // makes no sense
                    return SkBitmap::kNo_Config;

                case SkImage::kOpaque_AlphaType:
                    *isOpaque = true;
                    return SkBitmap::kA8_Config;

                case SkImage::kPremul_AlphaType:
                case SkImage::kUnpremul_AlphaType:
                    *isOpaque = false;
                    return SkBitmap::kA8_Config;
            }
            break;

        case SkImage::kRGB_565_ColorType:
            // we ignore fAlpahType, though some would not make sense
            *isOpaque = true;
            return SkBitmap::kRGB_565_Config;

        case SkImage::kRGBA_8888_ColorType:
        case SkImage::kBGRA_8888_ColorType:
            // not supported yet
            return SkBitmap::kNo_Config;

        case SkImage::kPMColor_ColorType:
            switch (info.fAlphaType) {
                case SkImage::kIgnore_AlphaType:
                case SkImage::kUnpremul_AlphaType:
                    // not supported yet
                    return SkBitmap::kNo_Config;
                case SkImage::kOpaque_AlphaType:
                    *isOpaque = true;
                    return SkBitmap::kARGB_8888_Config;
                case SkImage::kPremul_AlphaType:
                    *isOpaque = false;
                    return SkBitmap::kARGB_8888_Config;
            }
            break;
    }
    SkASSERT(!"how did we get here");
    return SkBitmap::kNo_Config;
}

static int BytesPerPixel(SkImage::ColorType ct) {
    static const uint8_t gColorTypeBytesPerPixel[] = {
        1,  // kAlpha_8_ColorType
        2,  // kRGB_565_ColorType
        4,  // kRGBA_8888_ColorType
        4,  // kBGRA_8888_ColorType
        4,  // kPMColor_ColorType
    };

    SkASSERT((size_t)ct < SK_ARRAY_COUNT(gColorTypeBytesPerPixel));
    return gColorTypeBytesPerPixel[ct];
}

static size_t ComputeMinRowBytes(const SkImage::Info& info) {
    return info.fWidth * BytesPerPixel(info.fColorType);
}

class SkImage_Raster : public SkImage_Base {
public:
    static bool ValidArgs(const Info& info, SkColorSpace* cs, size_t rowBytes) {
        const int maxDimension = SK_MaxS32 >> 2;
        const size_t kMaxPixelByteSize = SK_MaxS32;

        if (info.fWidth < 0 || info.fHeight < 0) {
            return false;
        }
        if (info.fWidth > maxDimension || info.fHeight > maxDimension) {
            return false;
        }
        if ((unsigned)info.fColorType > (unsigned)kLastEnum_ColorType) {
            return false;
        }
        if ((unsigned)info.fAlphaType > (unsigned)kLastEnum_AlphaType) {
            return false;
        }

        bool isOpaque;
        if (InfoToConfig(info, &isOpaque) == SkBitmap::kNo_Config) {
            return false;
        }
            
        // TODO: check colorspace
        
        if (rowBytes < ComputeMinRowBytes(info)) {
            return false;
        }
        
        int64_t size = (int64_t)info.fHeight * rowBytes;
        if (size > kMaxPixelByteSize) {
            return false;
        }
        return true;
    }

    static SkImage* NewEmpty();

    SkImage_Raster(const SkImage::Info&, SkColorSpace*, SkData*, size_t rb);
    virtual ~SkImage_Raster();

    virtual const SkBitmap* asABitmap() SK_OVERRIDE;

private:
    SkImage_Raster() : INHERITED(0, 0) {}

    SkBitmap    fBitmap;

    typedef SkImage_Base INHERITED;
};

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

#include "SkData.h"
#include "SkDataPixelRef.h"

SkImage* SkImage_Raster::NewEmpty() {
    // Returns lazily created singleton
    static SkImage* gEmpty;
    if (NULL == gEmpty) {
        gEmpty = SkNEW(SkImage_Raster);
    }
    gEmpty->ref();
    return gEmpty;
}

SkImage_Raster::SkImage_Raster(const Info& info, SkColorSpace* cs,
                               SkData* data, size_t rowBytes)
        : INHERITED(info.fWidth, info.fHeight) {
    bool isOpaque;
    SkBitmap::Config config = InfoToConfig(info, &isOpaque);

    fBitmap.setConfig(config, info.fWidth, info.fHeight, rowBytes);
    fBitmap.setPixelRef(SkNEW_ARGS(SkDataPixelRef, (data)))->unref();
    fBitmap.setIsOpaque(isOpaque);
    fBitmap.setImmutable();   // Yea baby!
}

SkImage_Raster::~SkImage_Raster() {}

const SkBitmap* SkImage_Raster::asABitmap() {
    return &fBitmap;
}

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

SkImage* SkImage::NewRasterCopy(const SkImage::Info& info, SkColorSpace* cs,
                                const void* pixels, size_t rowBytes) {
    if (!SkImage_Raster::ValidArgs(info, cs, rowBytes)) {
        return NULL;
    }
    if (0 == info.fWidth && 0 == info.fHeight) {
        return SkImage_Raster::NewEmpty();
    }
    // check this after empty-check
    if (NULL == pixels) {
        return NULL;
    }
    
    // Here we actually make a copy of the caller's pixel data
    SkAutoDataUnref data(SkData::NewWithCopy(pixels, info.fHeight * rowBytes));
    return SkNEW_ARGS(SkImage_Raster, (info, cs, data, rowBytes));
}


SkImage* SkImage::NewRasterData(const SkImage::Info& info, SkColorSpace* cs,
                                SkData* pixelData, size_t rowBytes) {
    if (!SkImage_Raster::ValidArgs(info, cs, rowBytes)) {
        return NULL;
    }
    if (0 == info.fWidth && 0 == info.fHeight) {
        return SkImage_Raster::NewEmpty();
    }
    // check this after empty-check
    if (NULL == pixelData) {
        return NULL;
    }
    
    // did they give us enough data?
    size_t size = info.fHeight * rowBytes;
    if (pixelData->size() < size) {
        return NULL;
    }
    
    SkAutoDataUnref data(pixelData);
    return SkNEW_ARGS(SkImage_Raster, (info, cs, data, rowBytes));
}

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

#include "SkCanvas.h"

uint32_t SkImage::NextUniqueID() {
    static int32_t gUniqueID;

    // never return 0;
    uint32_t id;
    do {
        id = sk_atomic_inc(&gUniqueID) + 1;
    } while (0 == id);
    return id;
}

void SkImage::draw(SkCanvas* canvas, SkScalar x, SkScalar y,
                   const SkPaint* paint) {
    const SkBitmap* bitmap = asIB(this)->asABitmap();
    if (bitmap) {
        canvas->drawBitmap(*bitmap, x, y, paint);
    }
}