C++ SkGetPackedA32函数代码示例

static inline bool S32A_D565_Blend_01(SkPMColor sc, uint16_t dc, U8CPU alpha) {
    unsigned dst_scale = 255 - SkMulDiv255Round(SkGetPackedA32(sc), alpha);
    unsigned dr = SkMulS16(SkGetPackedR32(sc), alpha) + SkMulS16(SkGetPackedR16(dc) << 3, dst_scale);
    unsigned dg = SkMulS16(SkGetPackedG32(sc), alpha) + SkMulS16(SkGetPackedG16(dc) << 2, dst_scale);

    unsigned rr = SkDiv255Round(dr) >> 3;
    unsigned rg = SkDiv255Round(dg) >> 2;

    if (rr <= 31 && rg <= 63) {
        return true;
    }
    return false;
}

SkColor SkPMColorToColor(SkPMColor pm)
{
    if (0 == pm)
        return 0;
    
    unsigned a = SkGetPackedA32(pm);
    uint32_t scale = (255 << 16) / a;
    
    return SkColorSetARGB(a,
                          InvScaleByte(SkGetPackedR32(pm), scale),
                          InvScaleByte(SkGetPackedG32(pm), scale),
                          InvScaleByte(SkGetPackedB32(pm), scale));
}

static SkStream* extract_argb8888_data(const SkBitmap& bitmap,
                                       const SkIRect& srcRect,
                                       bool extractAlpha,
                                       bool* isOpaque,
                                       bool* isTransparent) {
    size_t streamSize = extractAlpha ? srcRect.width() * srcRect.height()
                                     : get_uncompressed_size(bitmap, srcRect);
    SkStream* stream = SkNEW_ARGS(SkMemoryStream, (streamSize));
    uint8_t* dst = (uint8_t*)stream->getMemoryBase();

    const SkUnPreMultiply::Scale* scaleTable = SkUnPreMultiply::GetScaleTable();

    for (int y = srcRect.fTop; y < srcRect.fBottom; y++) {
        uint32_t* src = bitmap.getAddr32(0, y);
        for (int x = srcRect.fLeft; x < srcRect.fRight; x++) {
            SkPMColor c = src[x];
            U8CPU alpha = SkGetPackedA32(c);
            if (extractAlpha) {
                *isOpaque &= alpha == SK_AlphaOPAQUE;
                *isTransparent &= alpha == SK_AlphaTRANSPARENT;
                *dst++ = alpha;
            } else {
                if (SK_AlphaTRANSPARENT == alpha) {
                    // It is necessary to average the color component of
                    // transparent pixels with their surrounding neighbors
                    // since the PDF renderer may separately re-sample the
                    // alpha and color channels when the image is not
                    // displayed at its native resolution. Since an alpha of
                    // zero gives no information about the color component,
                    // the pathological case is a white image with sharp
                    // transparency bounds - the color channel goes to black,
                    // and the should-be-transparent pixels are rendered
                    // as grey because of the separate soft mask and color
                    // resizing.
                    c = get_argb8888_neighbor_avg_color(bitmap, x, y);
                    *dst++ = SkGetPackedR32(c);
                    *dst++ = SkGetPackedG32(c);
                    *dst++ = SkGetPackedB32(c);
                } else {
                    SkUnPreMultiply::Scale s = scaleTable[alpha];
                    *dst++ = SkUnPreMultiply::ApplyScale(s, SkGetPackedR32(c));
                    *dst++ = SkUnPreMultiply::ApplyScale(s, SkGetPackedG32(c));
                    *dst++ = SkUnPreMultiply::ApplyScale(s, SkGetPackedB32(c));
                }
            }
        }
    }
    SkASSERT(dst == streamSize + (uint8_t*)stream->getMemoryBase());
    return stream;
}

bool Image::ConvertToRGBA(Image *nimg,
                          unsigned char *rgba,
                          bool flipY,
                          bool premultiply)
{

    int length;
    int k;
    const unsigned char *pixels;
    int width;

    nimg->m_Image->lockPixels();
    if ((pixels
         = static_cast<const unsigned char *>(nimg->m_Image->getPixels()))
        == NULL) {
        nimg->m_Image->unlockPixels();
        return false;
    }

    width  = nimg->getWidth();
    length = width * nimg->getHeight() * 4;
    width *= 4;
    k = flipY ? length - width : 0;

    for (int i = 0; i < length; i += 4) {
        const uint32_t pixel = *reinterpret_cast<const uint32_t *>(&pixels[i]);
        int alpha            = SkGetPackedA32(pixel);

        if (alpha != 0 && alpha != 255 && !premultiply) {
            SkColor unmultiplied = SkUnPreMultiply::PMColorToColor(pixel);
            rgba[k + 0]          = SkColorGetR(unmultiplied);
            rgba[k + 1]          = SkColorGetG(unmultiplied);
            rgba[k + 2]          = SkColorGetB(unmultiplied);
            rgba[k + 3]          = alpha;
        } else {
            rgba[k + 0] = SkGetPackedR32(pixel);
            rgba[k + 1] = SkGetPackedG32(pixel);
            rgba[k + 2] = SkGetPackedB32(pixel);
            rgba[k + 3] = alpha;
        }

        if (flipY && (i + 4) % width == 0) {
            k = length - (i + 4) - width;
        } else {
            k += 4;
        }
    }

    return true;
}

    virtual void xferA8(SK_RESTRICT SkAlpha dst[],
                        const SK_RESTRICT SkPMColor src[], int count,
                        const SK_RESTRICT SkAlpha aa[]) {
        SkASSERT(dst && src && count >= 0);

        if (NULL == aa) {
            for (int i = count - 1; i >= 0; --i) {
                dst[i] = SkToU8(SkGetPackedA32(src[i]));
            }
        } else {
            for (int i = count - 1; i >= 0; --i) {
                unsigned a = aa[i];
                if (0 != a) {
                    unsigned srcA = SkGetPackedA32(src[i]);
                    if (a == 0xFF) {
                        dst[i] = SkToU8(srcA);
                    } else {
                        dst[i] = SkToU8(SkAlphaBlend(srcA, dst[i], a));
                    }
                }
            }
        }
    }

static inline bool S32A_D565_Blend_2(SkPMColor sc, uint16_t dc, U8CPU alpha) {
    unsigned dst_scale = 255*255 - SkGetPackedA32(sc) * alpha;
    alpha *= 255;
    unsigned dr = (SkGetPackedR32(sc) >> 3) * alpha + SkGetPackedR16(dc) * dst_scale;
    unsigned dg = (SkGetPackedG32(sc) >> 2) * alpha + SkGetPackedG16(dc) * dst_scale;

    unsigned rr = SkDiv65025Round(dr);
    unsigned rg = SkDiv65025Round(dg);

    if (rr <= 31 && rg <= 63) {
        return true;
    }
    return false;
}

void alphaBlendNonPremultiplied(blink::ImageFrame& src,
                                blink::ImageFrame& dst,
                                int canvasY,
                                int left,
                                int width) {
  for (int x = 0; x < width; ++x) {
    int canvasX = left + x;
    blink::ImageFrame::PixelData& pixel = *src.getAddr(canvasX, canvasY);
    if (SkGetPackedA32(pixel) != 0xff) {
      blink::ImageFrame::PixelData prevPixel = *dst.getAddr(canvasX, canvasY);
      pixel = blendSrcOverDstNonPremultiplied(pixel, prevPixel);
    }
  }
}

inline SkPMColor cubicBlend(const SkScalar c[16], SkScalar t, SkPMColor c0, SkPMColor c1, SkPMColor c2, SkPMColor c3) {
    SkScalar t2 = t * t, t3 = t2 * t;
    SkScalar cc[4];
    // FIXME:  For the fractx case, this should be refactored out of this function.
    cc[0] = c[0]  + SkScalarMul(c[1], t) + SkScalarMul(c[2], t2) + SkScalarMul(c[3], t3);
    cc[1] = c[4]  + SkScalarMul(c[5], t) + SkScalarMul(c[6], t2) + SkScalarMul(c[7], t3);
    cc[2] = c[8]  + SkScalarMul(c[9], t) + SkScalarMul(c[10], t2) + SkScalarMul(c[11], t3);
    cc[3] = c[12] + SkScalarMul(c[13], t) + SkScalarMul(c[14], t2) + SkScalarMul(c[15], t3);
    SkScalar a = SkScalarClampMax(SkScalarMul(cc[0], SkGetPackedA32(c0)) + SkScalarMul(cc[1], SkGetPackedA32(c1)) + SkScalarMul(cc[2], SkGetPackedA32(c2)) + SkScalarMul(cc[3], SkGetPackedA32(c3)), 255);
    SkScalar r = SkScalarMul(cc[0], SkGetPackedR32(c0)) + SkScalarMul(cc[1], SkGetPackedR32(c1)) + SkScalarMul(cc[2], SkGetPackedR32(c2)) + SkScalarMul(cc[3], SkGetPackedR32(c3));
    SkScalar g = SkScalarMul(cc[0], SkGetPackedG32(c0)) + SkScalarMul(cc[1], SkGetPackedG32(c1)) + SkScalarMul(cc[2], SkGetPackedG32(c2)) + SkScalarMul(cc[3], SkGetPackedG32(c3));
    SkScalar b = SkScalarMul(cc[0], SkGetPackedB32(c0)) + SkScalarMul(cc[1], SkGetPackedB32(c1)) + SkScalarMul(cc[2], SkGetPackedB32(c2)) + SkScalarMul(cc[3], SkGetPackedB32(c3));
    return SkPackARGB32(SkScalarRoundToInt(a),
                        SkScalarRoundToInt(SkScalarClampMax(r, a)),
                        SkScalarRoundToInt(SkScalarClampMax(g, a)),
                        SkScalarRoundToInt(SkScalarClampMax(b, a)));
}

static inline bool S32A_D565_Blend_02(SkPMColor sc, uint16_t dc, U8CPU alpha) {
    unsigned dst_scale = 255 - SkMulDiv255Round(SkGetPackedA32(sc), alpha);
    unsigned dr = SkMulS16(SkGetPackedR32(sc), alpha) + SkMulS16(GetPackedR16As32(dc), dst_scale);
    unsigned dg = SkMulS16(SkGetPackedG32(sc), alpha) + SkMulS16(GetPackedG16As32(dc), dst_scale);
    unsigned db = SkMulS16(SkGetPackedB32(sc), alpha) + SkMulS16(GetPackedB16As32(dc), dst_scale);
    int rc = SkPack888ToRGB16(SkDiv255Round(dr),
                              SkDiv255Round(dg),
                              SkDiv255Round(db));

    unsigned rr = SkGetPackedR16(rc);
    unsigned rg = SkGetPackedG16(rc);

    if (rr <= 31 && rg <= 63) {
        return true;
    }
    return false;
}

static inline void D16_S32A_Blend_Pixel_helper(uint16_t* dst, SkPMColor sc,
                                               unsigned src_scale) {
    uint16_t dc = *dst;
    unsigned sa = SkGetPackedA32(sc);
    unsigned dr, dg, db;

    if (255 == sa) {
        dr = SkAlphaBlend(SkPacked32ToR16(sc), SkGetPackedR16(dc), src_scale);
        dg = SkAlphaBlend(SkPacked32ToG16(sc), SkGetPackedG16(dc), src_scale);
        db = SkAlphaBlend(SkPacked32ToB16(sc), SkGetPackedB16(dc), src_scale);
    } else {
        unsigned dst_scale = 255 - SkAlphaMul(sa, src_scale);
        dr = (SkPacked32ToR16(sc) * src_scale + SkGetPackedR16(dc) * dst_scale) >> 8;
        dg = (SkPacked32ToG16(sc) * src_scale + SkGetPackedG16(dc) * dst_scale) >> 8;
        db = (SkPacked32ToB16(sc) * src_scale + SkGetPackedB16(dc) * dst_scale) >> 8;
    }
    *dst = SkPackRGB16(dr, dg, db);
}

 virtual void filterSpan(const SkPMColor shader[], int count,
                         SkPMColor result[]) {
     unsigned scaleR = SkAlpha255To256(SkColorGetR(fMul));
     unsigned scaleG = SkAlpha255To256(SkColorGetG(fMul));
     unsigned scaleB = SkAlpha255To256(SkColorGetB(fMul));
     
     for (int i = 0; i < count; i++) {
         SkPMColor c = shader[i];
         if (c) {
             unsigned a = SkGetPackedA32(c);
             unsigned r = SkAlphaMul(SkGetPackedR32(c), scaleR);
             unsigned g = SkAlphaMul(SkGetPackedG32(c), scaleG);
             unsigned b = SkAlphaMul(SkGetPackedB32(c), scaleB);
             c = SkPackARGB32(a, r, g, b);
         }
         result[i] = c;
     }
 }

bool check_gamma(uint32_t src, uint32_t dst, bool toSRGB, float error,
                 uint32_t* expected) {
    bool result = true;
    uint32_t expectedColor = src & 0xff000000;

    // Alpha should always be exactly preserved.
    if ((src & 0xff000000) != (dst & 0xff000000)) {
        result = false;
    }

    // need to unpremul before we can perform srgb magic
    float invScale = 0;
    float alpha = SkGetPackedA32(src);
    if (alpha) {
        invScale = 255.0f / alpha;
    }

    for (int c = 0; c < 3; ++c) {
        float srcComponent = ((src & (0xff << (c * 8))) >> (c * 8)) * invScale;
        float lower = SkTMax(0.f, srcComponent - error);
        float upper = SkTMin(255.f, srcComponent + error);
        if (toSRGB) {
            lower = linear_to_srgb(lower / 255.f);
            upper = linear_to_srgb(upper / 255.f);
        } else {
            lower = srgb_to_linear(lower / 255.f);
            upper = srgb_to_linear(upper / 255.f);
        }
        lower *= alpha;
        upper *= alpha;
        SkASSERT(lower >= 0.f && lower <= 255.f);
        SkASSERT(upper >= 0.f && upper <= 255.f);
        uint8_t dstComponent = (dst & (0xff << (c * 8))) >> (c * 8);
        if (dstComponent < SkScalarFloorToInt(lower) ||
            dstComponent > SkScalarCeilToInt(upper)) {
            result = false;
        }
        uint8_t expectedComponent = SkScalarRoundToInt((lower + upper) * 0.5f);
        expectedColor |= expectedComponent << (c * 8);
    }

    *expected = expectedColor;
    return result;
}

static void extract_alpha(const SkMask& dst,
                          const SkPMColor* srcRow, size_t srcRB) {
    int width = dst.fBounds.width();
    int height = dst.fBounds.height();
    int dstRB = dst.fRowBytes;
    uint8_t* dstRow = dst.fImage;

    for (int y = 0; y < height; ++y) {
        for (int x = 0; x < width; ++x) {
            dstRow[x] = SkGetPackedA32(srcRow[x]);
        }
        // zero any padding on each row
        for (int x = width; x < dstRB; ++x) {
            dstRow[x] = 0;
        }
        dstRow += dstRB;
        srcRow = (const SkPMColor*)((const char*)srcRow + srcRB);
    }
}

 virtual void xfer32(SK_RESTRICT SkPMColor dst[],
                     const SK_RESTRICT SkPMColor src[], int count,
                     const SK_RESTRICT SkAlpha aa[]) {
     SkASSERT(dst && src);
     
     if (count <= 0) {
         return;
     }
     if (NULL != aa) {
         return this->INHERITED::xfer32(dst, src, count, aa);
     }
     
     do {
         unsigned a = SkGetPackedA32(*src);
         *dst = SkAlphaMulQ(*dst, SkAlpha255To256(255 - a));
         dst++;
         src++;
     } while (--count != 0);
 }

void SkARGB32_Blitter::blitV(int x, int y, int height, SkAlpha alpha) {
    if (alpha == 0 || fSrcA == 0) {
        return;
    }

    uint32_t* device = fDevice.getAddr32(x, y);
    uint32_t  color = fPMColor;

    if (alpha != 255) {
        color = SkAlphaMulQ(color, SkAlpha255To256(alpha));
    }

    unsigned dst_scale = 255 - SkGetPackedA32(color);
    uint32_t rowBytes = fDevice.rowBytes();
    while (--height >= 0) {
        device[0] = color + SkAlphaMulQ(device[0], dst_scale);
        device = (uint32_t*)((char*)device + rowBytes);
    }
}