C++ SkPackARGB32函数代码示例

static void unit_test() {
    for (unsigned a = 0; a <= 255; a++) {
        for (unsigned c = 0; c <= a; c++) {
            SkPMColor pm = SkPackARGB32(a, c, c, c);
            for (unsigned aa = 0; aa <= 255; aa++) {
                for (unsigned cc = 0; cc <= aa; cc++) {
                    SkPMColor pm2 = SkPackARGB32(aa, cc, cc, cc);
                    
                    const size_t N = SK_ARRAY_COUNT(gProcCoeffs);
                    for (size_t i = 0; i < N; i++) {
                        gProcCoeffs[i].fProc(pm, pm2);
                    }
                }
            }
        }
    }            
}

bool SkPNGImageDecoder::getBitmapConfig(png_structp png_ptr, png_infop info_ptr,
        SkBitmap::Config *configp, bool *hasAlphap, bool *doDitherp,
        SkPMColor *theTranspColorp) {
    png_uint_32 origWidth, origHeight;
    int bit_depth, color_type, interlace_type;
    png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bit_depth,
            &color_type, &interlace_type, int_p_NULL, int_p_NULL);

    // check for sBIT chunk data, in case we should disable dithering because
    // our data is not truely 8bits per component
    if (*doDitherp) {
#if 0
        SkDebugf("----- sBIT %d %d %d %d\n", info_ptr->sig_bit.red,
                 info_ptr->sig_bit.green, info_ptr->sig_bit.blue,
                 info_ptr->sig_bit.alpha);
#endif
        // 0 seems to indicate no information available
        if (pos_le(info_ptr->sig_bit.red, SK_R16_BITS) &&
                pos_le(info_ptr->sig_bit.green, SK_G16_BITS) &&
                pos_le(info_ptr->sig_bit.blue, SK_B16_BITS)) {
            *doDitherp = false;
        }
    }

    if (color_type == PNG_COLOR_TYPE_PALETTE) {
        bool paletteHasAlpha = hasTransparencyInPalette(png_ptr, info_ptr);
        *configp = this->getPrefConfig(kIndex_SrcDepth, paletteHasAlpha);
        // now see if we can upscale to their requested config
        if (!canUpscalePaletteToConfig(*configp, paletteHasAlpha)) {
            *configp = SkBitmap::kIndex8_Config;
        }
    } else {
        png_color_16p   transpColor = NULL;
        int             numTransp = 0;

        png_get_tRNS(png_ptr, info_ptr, NULL, &numTransp, &transpColor);

        bool valid = png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS);

        if (valid && numTransp == 1 && transpColor != NULL) {
            /*  Compute our transparent color, which we'll match against later.
                We don't really handle 16bit components properly here, since we
                do our compare *after* the values have been knocked down to 8bit
                which means we will find more matches than we should. The real
                fix seems to be to see the actual 16bit components, do the
                compare, and then knock it down to 8bits ourselves.
            */
            if (color_type & PNG_COLOR_MASK_COLOR) {
                if (16 == bit_depth) {
                    *theTranspColorp = SkPackARGB32(0xFF, transpColor->red >> 8,
                              transpColor->green >> 8, transpColor->blue >> 8);
                } else {
                    *theTranspColorp = SkPackARGB32(0xFF, transpColor->red,
                                      transpColor->green, transpColor->blue);
                }
            } else {    // gray
                if (16 == bit_depth) {

static SkPMColor multiply_modeproc(SkPMColor src, SkPMColor dst) {
    int sa = SkGetPackedA32(src);
    int da = SkGetPackedA32(dst);
    int a = srcover_byte(sa, da);
    int r = blendfunc_multiply_byte(SkGetPackedR32(src), SkGetPackedR32(dst), sa, da);
    int g = blendfunc_multiply_byte(SkGetPackedG32(src), SkGetPackedG32(dst), sa, da);
    int b = blendfunc_multiply_byte(SkGetPackedB32(src), SkGetPackedB32(dst), sa, da);
    return SkPackARGB32(a, r, g, b);
}

static SkPMColor hardlight_modeproc(SkPMColor src, SkPMColor dst) {
    int sa = SkGetPackedA32(src);
    int da = SkGetPackedA32(dst);
    int a = srcover_byte(sa, da);
    int r = hardlight_byte(SkGetPackedR32(src), SkGetPackedR32(dst), sa, da);
    int g = hardlight_byte(SkGetPackedG32(src), SkGetPackedG32(dst), sa, da);
    int b = hardlight_byte(SkGetPackedB32(src), SkGetPackedB32(dst), sa, da);
    return SkPackARGB32(a, r, g, b);
}

static SkPMColor SkFourByteInterp(SkPMColor src, SkPMColor dst, unsigned scale)
{
    unsigned a = SkAlphaBlend(SkGetPackedA32(src), SkGetPackedA32(dst), scale);
    unsigned r = SkAlphaBlend(SkGetPackedR32(src), SkGetPackedR32(dst), scale);
    unsigned g = SkAlphaBlend(SkGetPackedG32(src), SkGetPackedG32(dst), scale);
    unsigned b = SkAlphaBlend(SkGetPackedB32(src), SkGetPackedB32(dst), scale);

    return SkPackARGB32(a, r, g, b);
}

static inline SkPMColor rgb2gray(SkPMColor c) {
    unsigned r = SkGetPackedR32(c);
    unsigned g = SkGetPackedG32(c);
    unsigned b = SkGetPackedB32(c);

    unsigned x = (r * 5 + g * 7 + b * 4) >> 4;

    return SkPackARGB32(0, x, x, x) | (c & (SK_A32_MASK << SK_A32_SHIFT));
}

void ImageBuffer::putUnmultipliedImageData(ByteArray* source, const IntSize& sourceSize, const IntRect& sourceRect, const IntPoint& destPoint)
{
    GraphicsContext* gc = this->context();
    if (!gc) {
        return;
    }

    const SkBitmap& dst = imageBufferCanvas(this)->getDevice()->accessBitmap(true);
    SkAutoLockPixels alp(dst);
    if (!dst.getPixels()) {
        return;
    }

    ASSERT(sourceRect.width() > 0);
    ASSERT(sourceRect.height() > 0);

    int originx = sourceRect.x();
    int destx = destPoint.x() + sourceRect.x();
    ASSERT(destx >= 0);
    ASSERT(destx < m_size.width());
    ASSERT(originx >= 0);
    ASSERT(originx <= sourceRect.maxX());

    int endx = destPoint.x() + sourceRect.maxX();
    ASSERT(endx <= m_size.width());

    int numColumns = endx - destx;

    int originy = sourceRect.y();
    int desty = destPoint.y() + sourceRect.y();
    ASSERT(desty >= 0);
    ASSERT(desty < m_size.height());
    ASSERT(originy >= 0);
    ASSERT(originy <= sourceRect.maxY());

    int endy = destPoint.y() + sourceRect.maxY();
    ASSERT(endy <= m_size.height());
    int numRows = endy - desty;

    unsigned srcBytesPerRow = 4 * sourceSize.width();
    unsigned dstPixelsPerRow = dst.rowBytesAsPixels();

    unsigned char* srcRows = source->data() + originy * srcBytesPerRow + originx * 4;
    SkPMColor* dstRows = dst.getAddr32(destx, desty);
    for (int y = 0; y < numRows; ++y) {
        for (int x = 0; x < numColumns; x++) {
            int basex = x * 4;
            dstRows[x] = SkPackARGB32(srcRows[basex + 3],
                                      srcRows[basex + 0],
                                      srcRows[basex + 1],
                                      srcRows[basex + 2]);
        }
        dstRows += dstPixelsPerRow;
        srcRows += srcBytesPerRow;
    }
}

void SkGifCodec::initializeColorTable(const SkImageInfo& dstInfo, SkPMColor* inputColorPtr,
        int* inputColorCount) {
    // Set up our own color table
    const uint32_t maxColors = 256;
    SkPMColor colorPtr[256];
    if (NULL != inputColorCount) {
        // We set the number of colors to maxColors in order to ensure
        // safe memory accesses.  Otherwise, an invalid pixel could
        // access memory outside of our color table array.
        *inputColorCount = maxColors;
    }

    // Get local color table
    ColorMapObject* colorMap = fGif->Image.ColorMap;
    // If there is no local color table, use the global color table
    if (NULL == colorMap) {
        colorMap = fGif->SColorMap;
    }

    uint32_t colorCount = 0;
    if (NULL != colorMap) {
        colorCount = colorMap->ColorCount;
        // giflib guarantees these properties
        SkASSERT(colorCount == (unsigned) (1 << (colorMap->BitsPerPixel)));
        SkASSERT(colorCount <= 256);
        for (uint32_t i = 0; i < colorCount; i++) {
            colorPtr[i] = SkPackARGB32(0xFF, colorMap->Colors[i].Red,
                    colorMap->Colors[i].Green, colorMap->Colors[i].Blue);
        }
    }

    // Gifs have the option to specify the color at a single index of the color
    // table as transparent.  If the transparent index is greater than the
    // colorCount, we know that there is no valid transparent color in the color
    // table.  If there is not valid transparent index, we will try to use the
    // backgroundIndex as the fill index.  If the backgroundIndex is also not
    // valid, we will let fFillIndex default to 0 (it is set to zero in the
    // constructor).  This behavior is not specified but matches
    // SkImageDecoder_libgif.
    uint32_t backgroundIndex = fGif->SBackGroundColor;
    if (fTransIndex < colorCount) {
        colorPtr[fTransIndex] = SK_ColorTRANSPARENT;
        fFillIndex = fTransIndex;
    } else if (backgroundIndex < colorCount) {
        fFillIndex = backgroundIndex;
    }

    // Fill in the color table for indices greater than color count.
    // This allows for predictable, safe behavior.
    for (uint32_t i = colorCount; i < maxColors; i++) {
        colorPtr[i] = colorPtr[fFillIndex];
    }

    fColorTable.reset(new SkColorTable(colorPtr, maxColors));
    copy_color_table(dstInfo, this->fColorTable, inputColorPtr, inputColorCount);
}

static void copyLine(uint32_t* dst, const unsigned char* src, const ColorMapObject* cmap,
                     int transparent, int width)
{
    for (; width > 0; width--, src++, dst++) {
        if (*src != transparent) {
            const GifColorType& col = cmap->Colors[*src];
            *dst = SkPackARGB32(0xFF, col.Red, col.Green, col.Blue);
        }
    }
}

static sk_sp<SkShader> make_bg_shader() {
    SkBitmap bm;
    bm.allocN32Pixels(2, 2);
    *bm.getAddr32(0, 0) = *bm.getAddr32(1, 1) = 0xFFFFFFFF;
    *bm.getAddr32(1, 0) = *bm.getAddr32(0, 1) = SkPackARGB32(0xFF, 0xCC, 0xCC, 0xCC);

    SkMatrix m;
    m.setScale(SkIntToScalar(6), SkIntToScalar(6));

    return SkShader::MakeBitmapShader(bm, SkShader::kRepeat_TileMode,
                                      SkShader::kRepeat_TileMode, &m);
}

SkARGB32_Blitter::SkARGB32_Blitter(const SkBitmap& device, const SkPaint& paint)
        : INHERITED(device) {
    uint32_t color = paint.getColor();

    fSrcA = SkColorGetA(color);
    unsigned scale = SkAlpha255To256(fSrcA);
    fSrcR = SkAlphaMul(SkColorGetR(color), scale);
    fSrcG = SkAlphaMul(SkColorGetG(color), scale);
    fSrcB = SkAlphaMul(SkColorGetB(color), scale);

    fPMColor = SkPackARGB32(fSrcA, fSrcR, fSrcG, fSrcB);
}

static void copy_g8_to_32(void* dst, size_t dstRB, const void* src, size_t srcRB, int w, int h) {
    uint32_t* dst32 = (uint32_t*)dst;
    const uint8_t* src8 = (const uint8_t*)src;
    
    for (int y = 0; y < h; ++y) {
        for (int x = 0; x < w; ++x) {
            dst32[x] = SkPackARGB32(0xFF, src8[x], src8[x], src8[x]);
        }
        dst32 = (uint32_t*)((char*)dst32 + dstRB);
        src8 += srcRB;
    }
}

static sk_sp<SkImage> make_image(GrContext* context, int size, GrSurfaceOrigin origin) {
    if (context) {
        SkImageInfo ii = SkImageInfo::Make(size, size, kN32_SkColorType, kPremul_SkAlphaType);
        sk_sp<SkSurface> surf(SkSurface::MakeRenderTarget(context, SkBudgeted::kYes, ii, 0,
                                                          origin, nullptr));
        if (!surf) {
            return nullptr;
        }

        SkCanvas* canvas = surf->getCanvas();

        canvas->clear(SK_ColorRED);
        const struct {
            SkPoint fPt;
            SkColor fColor;
        } rec[] = {
            { { 1.5f, 1.5f }, SK_ColorGREEN },
            { { 2.5f, 1.5f }, SK_ColorBLUE },
            { { 1.5f, 2.5f }, SK_ColorCYAN },
            { { 2.5f, 2.5f }, SK_ColorGRAY },
        };
        SkPaint paint;
        for (const auto& r : rec) {
            paint.setColor(r.fColor);
            canvas->drawPoints(SkCanvas::kPoints_PointMode, 1, &r.fPt, paint);
        }
        return surf->makeImageSnapshot();
    } else {
        SkBitmap bm;
        bm.allocN32Pixels(size, size);
        bm.eraseColor(SK_ColorRED);
        *bm.getAddr32(1, 1) = SkPackARGB32(0xFF, 0x00, 0xFF, 0x00);
        *bm.getAddr32(2, 1) = SkPackARGB32(0xFF, 0x00, 0x00, 0xFF);
        *bm.getAddr32(1, 2) = SkPackARGB32(0xFF, 0x00, 0xFF, 0xFF);
        *bm.getAddr32(2, 2) = SkPackARGB32(0xFF, 0x88, 0x88, 0x88);

        return SkImage::MakeFromBitmap(bm);
    }
}

 static void apply_gamma(const SkBitmap& bm) {
     return; // below is our experiment for sRGB correction
     bm.lockPixels();
     for (int y = 0; y < bm.height(); ++y) {
         for (int x = 0; x < bm.width(); ++x) {
             SkPMColor c = *bm.getAddr32(x, y);
             unsigned r = gamma(SkGetPackedR32(c));
             unsigned g = gamma(SkGetPackedG32(c));
             unsigned b = gamma(SkGetPackedB32(c));
             *bm.getAddr32(x, y) = SkPackARGB32(0xFF, r, g, b);
         }
     }
 }

//  kDstATop_Mode,  //!< [Sa, Sa * Dc + Sc * (1 - Da)]
static SkPMColor dstatop_modeproc(SkPMColor src, SkPMColor dst) {
    unsigned sa = SkGetPackedA32(src);
    unsigned da = SkGetPackedA32(dst);
    unsigned ida = 255 - da;

    return SkPackARGB32(sa,
                        SkAlphaMulAlpha(ida, SkGetPackedR32(src)) +
                            SkAlphaMulAlpha(sa, SkGetPackedR32(dst)),
                        SkAlphaMulAlpha(ida, SkGetPackedG32(src)) +
                            SkAlphaMulAlpha(sa, SkGetPackedG32(dst)),
                        SkAlphaMulAlpha(ida, SkGetPackedB32(src)) +
                            SkAlphaMulAlpha(sa, SkGetPackedB32(dst)));
}