C++ SkColorGetB函数代码示例

SkColorFilter* SkColorFilter::CreateLightingFilter(SkColor mul, SkColor add) {
    mul &= 0x00FFFFFF;
    add &= 0x00FFFFFF;

    if (0xFFFFFF == mul) {
        if (0 == add) {
            return SkNEW(SkSimpleColorFilter);   // no change to the colors
        } else {
            return SkNEW_ARGS(SkLightingColorFilter_JustAdd, (mul, add));
        }
    }

    if (0 == add) {
        if (SkColorGetR(mul) == SkColorGetG(mul) &&
                SkColorGetR(mul) == SkColorGetB(mul)) {
            return SkNEW_ARGS(SkLightingColorFilter_SingleMul, (mul, add));
        } else {
            return SkNEW_ARGS(SkLightingColorFilter_JustMul, (mul, add));
        }
    }

    if (SkColorGetR(mul) + SkColorGetR(add) <= 255 &&
        SkColorGetG(mul) + SkColorGetG(add) <= 255 &&
        SkColorGetB(mul) + SkColorGetB(add) <= 255) {
            return SkNEW_ARGS(SkLightingColorFilter_NoPin, (mul, add));
    }

    return SkNEW_ARGS(SkLightingColorFilter, (mul, add));
}

    void setupShapePaint(SkCanvas* canvas, GrColor color, SkXfermode::Mode mode, SkPaint* paint) {
        paint->setColor(color);

        if (mode == SkXfermode::kPlus_Mode) {
            // Check for overflow, otherwise we might get confusing AA artifacts.
            int maxSum = SkTMax(SkTMax(SkColorGetA(kBGColor) + SkColorGetA(color),
                                       SkColorGetR(kBGColor) + SkColorGetR(color)),
                                SkTMax(SkColorGetG(kBGColor) + SkColorGetG(color),
                                       SkColorGetB(kBGColor) + SkColorGetB(color)));

            if (maxSum > 255) {
                SkPaint dimPaint;
                dimPaint.setAntiAlias(false);
                dimPaint.setXfermode(SkXfermode::Create(SkXfermode::kDstIn_Mode));
                if (255 != paint->getAlpha()) {
                    // Dim the src and dst colors.
                    dimPaint.setARGB(255 * 255 / maxSum, 0, 0, 0);
                    paint->setAlpha(255 * paint->getAlpha() / maxSum);
                } else {
                    // Just clear the dst, we need to preserve the paint's opacity.
                    dimPaint.setARGB(0, 0, 0, 0);
                }
                canvas->drawRectCoords(-kShapeSpacing/2, -kShapeSpacing/2,
                                       kShapeSpacing/2 + 3 * kShapeTypeSpacing,
                                       kShapeSpacing/2, dimPaint);
            }
        }
    }

 static SkColor GetColor(SkRandom* random, int i, int nextColor) {
     static SkColor colors[] = { SK_ColorRED,
                                 sk_tool_utils::color_to_565(0xFFFF7F00), // Orange
                                 SK_ColorYELLOW,
                                 SK_ColorGREEN,
                                 SK_ColorBLUE,
                                 sk_tool_utils::color_to_565(0xFF4B0082), // indigo
                                 sk_tool_utils::color_to_565(0xFF7F00FF) }; // violet
     SkColor color;
     int index = nextColor % SK_ARRAY_COUNT(colors);
     switch (i) {
         case 0:
             color = SK_ColorTRANSPARENT;
             break;
         case 1:
             color = SkColorSetARGB(0xff,
                                    SkColorGetR(colors[index]),
                                    SkColorGetG(colors[index]),
                                    SkColorGetB(colors[index]));
             break;
         default:
             uint8_t alpha = 0x80;
             color = SkColorSetARGB(alpha,
                                    SkColorGetR(colors[index]),
                                    SkColorGetG(colors[index]),
                                    SkColorGetB(colors[index]));
             break;
     }
     return color;
 }

 SkLightingColorFilter_SingleMul(SkColor mul, SkColor add)
         : INHERITED(mul, add) {
     SkASSERT(SkColorGetR(add) == 0);
     SkASSERT(SkColorGetG(add) == 0);
     SkASSERT(SkColorGetB(add) == 0);
     SkASSERT(SkColorGetR(mul) == SkColorGetG(mul));
     SkASSERT(SkColorGetR(mul) == SkColorGetB(mul));
 }

void draw_shadow(SkCanvas* canvas, const SkPath& path, SkScalar height, SkColor color,
                 SkPoint3 lightPos, SkScalar lightR, bool isAmbient, uint32_t flags) {
    SkScalar ambientAlpha = isAmbient ? .5f : 0.f;
    SkScalar spotAlpha = isAmbient ? 0.f : .5f;
    SkColor ambientColor = SkColorSetARGB(ambientAlpha*SkColorGetA(color), SkColorGetR(color),
                                          SkColorGetG(color), SkColorGetB(color));
    SkColor spotColor = SkColorSetARGB(spotAlpha*SkColorGetA(color), SkColorGetR(color),
                                       SkColorGetG(color), SkColorGetB(color));
    SkShadowUtils::DrawShadow(canvas, path, SkPoint3{ 0, 0, height}, lightPos, lightR,
                              ambientColor, spotColor, flags);
}

SkColorFilter* SkColorFilter::CreateLightingFilter(SkColor mul, SkColor add) {
    SkColorMatrix matrix;
    matrix.setScale(byte_to_scale(SkColorGetR(mul)),
                    byte_to_scale(SkColorGetG(mul)),
                    byte_to_scale(SkColorGetB(mul)),
                    1);
    matrix.postTranslate(SkIntToScalar(SkColorGetR(add)),
                         SkIntToScalar(SkColorGetG(add)),
                         SkIntToScalar(SkColorGetB(add)),
                         0);
    return SkColorMatrixFilter::Create(matrix);
}

DEF_TEST(SkColorSpace_New_TransferFnStages, r) {
    // We'll create a little SkRasterPipelineBlitter-like scenario,
    // blending the same src color over the same dst color, but with
    // three different transfer functions, for simplicity the same for src and dst.
    SkColor src = 0x7f7f0000;

    SkColor dsts[3];
    for (SkColor& dst : dsts) {
        dst = 0xff007f00;
    }

    auto gamut = SkMatrix44::I();
    auto blending = SkColorSpace_New::Blending::Linear;
    SkColorSpace_New linear{SkColorSpace_New::TransferFn::MakeLinear(), gamut, blending},
                       srgb{SkColorSpace_New::TransferFn::MakeSRGB(),   gamut, blending},
                      gamma{SkColorSpace_New::TransferFn::MakeGamma(3), gamut, blending};
    SkColor* dst = dsts;
    for (const SkColorSpace_New* cs : {&linear, &srgb, &gamma}) {
        SkJumper_MemoryCtx src_ctx = {  &src, 0 },
                           dst_ctx = { dst++, 0 };

        SkRasterPipeline_<256> p;

        p.append(SkRasterPipeline::load_8888, &src_ctx);
        cs->transferFn().linearizeSrc(&p);
        p.append(SkRasterPipeline::premul);

        p.append(SkRasterPipeline::load_8888_dst, &dst_ctx);
        cs->transferFn().linearizeDst(&p);
        p.append(SkRasterPipeline::premul_dst);

        p.append(SkRasterPipeline::srcover);
        p.append(SkRasterPipeline::unpremul);
        cs->transferFn().encodeSrc(&p);
        p.append(SkRasterPipeline::store_8888, &dst_ctx);
        p.run(0,0,1,1);
    }

    // Double check the uninteresting channels: alpha's opaque, no blue.
    REPORTER_ASSERT(r, SkColorGetA(dsts[0]) == 0xff && SkColorGetB(dsts[0]) == 0x00);
    REPORTER_ASSERT(r, SkColorGetA(dsts[1]) == 0xff && SkColorGetB(dsts[1]) == 0x00);
    REPORTER_ASSERT(r, SkColorGetA(dsts[2]) == 0xff && SkColorGetB(dsts[2]) == 0x00);

    // Because we're doing linear blending, a more-exponential transfer function will
    // brighten the encoded values more when linearizing. So we expect to see that
    // linear is darker than sRGB, and sRGB in turn is darker than gamma 3.
    REPORTER_ASSERT(r, SkColorGetR(dsts[0]) < SkColorGetR(dsts[1]));
    REPORTER_ASSERT(r, SkColorGetR(dsts[1]) < SkColorGetR(dsts[2]));

    REPORTER_ASSERT(r, SkColorGetG(dsts[0]) < SkColorGetG(dsts[1]));
    REPORTER_ASSERT(r, SkColorGetG(dsts[1]) < SkColorGetG(dsts[2]));

}

static bool write_bitmap(const char outName[], const SkBitmap& bm) {
    SkISize size = opaqueSize(bm);
    SkBitmap dst;
    setup_bitmap(&dst, size.width(), size.height());

    for (int y = 0 ; y < dst.height(); y++) {
        for (int x = 0 ; x < dst.width(); x++) {
            SkColor color = bm.getColor(x, y);
            if (SkColorGetA(color) != 0xff) {
                int a = SkColorGetA(color);
                int r = SkColorGetR(color);
                int g = SkColorGetG(color);
                int b = SkColorGetB(color);
                if (a == 0) {
                    r = g = b = 0;
                } else {
                    r = (r * a) / 255;
                    g = (g * a) / 255;
                    b = (b * a) / 255;
                    a = 255;
                }
                color = SkColorSetARGB((U8CPU)a, (U8CPU)r, (U8CPU)g, (U8CPU)b);
            }
            *dst.getAddr32(x, y) = color;
        }
    }

    return SkImageEncoder::EncodeFile(outName, dst, SkImageEncoder::kPNG_Type, 100);
}

/**
 * Removes the alpha component of an ARGB color (including unpremultiply) while
 * keeping the output in the same format as the input.
 */
static uint32_t remove_alpha_argb8888(uint32_t pmColor) {
    SkColor color = SkUnPreMultiply::PMColorToColor(pmColor);
    return SkPackARGB32NoCheck(SK_AlphaOPAQUE,
                               SkColorGetR(color),
                               SkColorGetG(color),
                               SkColorGetB(color));
}

// Set a bitmap shader that mimics dashing by width-on, width-off.
// Returns false if it could not succeed (e.g. there was an existing shader)
static bool setBitmapDash(SkPaint* paint, int width) {
    if (width <= 0 || paint->getShader())
        return false;

    SkColor c = paint->getColor();

    SkBitmap bm;
    bm.setConfig(SkBitmap::kARGB_8888_Config, 2, 1);
    bm.allocPixels();
    bm.lockPixels();

    // set the ON pixel
    *bm.getAddr32(0, 0) = SkPreMultiplyARGB(0xFF, SkColorGetR(c),
                                            SkColorGetG(c), SkColorGetB(c));
    // set the OFF pixel
    *bm.getAddr32(1, 0) = 0;
    bm.unlockPixels();

    SkMatrix matrix;
    matrix.setScale(SkIntToScalar(width), SK_Scalar1);

    SkShader* s = SkShader::CreateBitmapShader(bm, SkShader::kRepeat_TileMode,
                                               SkShader::kClamp_TileMode);
    s->setLocalMatrix(matrix);

    paint->setShader(s)->unref();
    return true;
}

SkColorShader::ColorShaderContext::ColorShaderContext(const SkColorShader& shader,
                                                      const ContextRec& rec)
    : INHERITED(shader, rec)
{
    SkColor color = shader.fColor;
    unsigned a = SkAlphaMul(SkColorGetA(color), SkAlpha255To256(rec.fPaint->getAlpha()));

    unsigned r = SkColorGetR(color);
    unsigned g = SkColorGetG(color);
    unsigned b = SkColorGetB(color);

    // we want this before we apply any alpha
    fColor16 = SkPack888ToRGB16(r, g, b);

    if (a != 255) {
        r = SkMulDiv255Round(r, a);
        g = SkMulDiv255Round(g, a);
        b = SkMulDiv255Round(b, a);
    }
    fPMColor = SkPackARGB32(a, r, g, b);

    fFlags = kConstInY32_Flag;
    if (255 == a) {
        fFlags |= kOpaqueAlpha_Flag;
        if (rec.fPaint->isDither() == false) {
            fFlags |= kHasSpan16_Flag;
        }
    }
}

SkARGB4444_Blitter::SkARGB4444_Blitter(const SkBitmap& device,
                                   const SkPaint& paint) : INHERITED(device) {
    // cache premultiplied versions in 4444
    SkPMColor c = SkPreMultiplyColor(paint.getColor());
    fPMColor16 = SkPixel32ToPixel4444(c);
    if (paint.isDither()) {
        fPMColor16Other = SkDitherPixel32To4444(c);
    } else {
        fPMColor16Other = fPMColor16;
    }

    // cache raw versions in 4444
    fRawColor16 = SkPackARGB4444(0xFF >> 4, SkColorGetR(c) >> 4,
                                 SkColorGetG(c) >> 4, SkColorGetB(c) >> 4);
    if (paint.isDither()) {
        fRawColor16Other = SkDitherARGB32To4444(0xFF, SkColorGetR(c),
                                                SkColorGetG(c), SkColorGetB(c));
    } else {
        fRawColor16Other = fRawColor16;
    }

    fScale16 = SkAlpha15To16(SkGetPackedA4444(fPMColor16Other));
    if (16 == fScale16) {
        // force the original to also be opaque
        fPMColor16 |= (0xF << SK_A4444_SHIFT);
    }
}

void ImageBuffer::transformColorSpace(ColorSpace srcColorSpace, ColorSpace dstColorSpace)
{
    const uint8_t* lookUpTable = ColorSpaceUtilities::getConversionLUT(dstColorSpace, srcColorSpace);
    if (!lookUpTable)
        return;

    // FIXME: Disable color space conversions on accelerated canvases (for now).
    if (context()->isAccelerated() || !isSurfaceValid())
        return;

    const SkBitmap& bitmap = m_surface->bitmap();
    if (bitmap.isNull())
        return;

    ASSERT(bitmap.colorType() == kN32_SkColorType);
    IntSize size = m_surface->size();
    SkAutoLockPixels bitmapLock(bitmap);
    for (int y = 0; y < size.height(); ++y) {
        uint32_t* srcRow = bitmap.getAddr32(0, y);
        for (int x = 0; x < size.width(); ++x) {
            SkColor color = SkPMColorToColor(srcRow[x]);
            srcRow[x] = SkPreMultiplyARGB(
                SkColorGetA(color),
                lookUpTable[SkColorGetR(color)],
                lookUpTable[SkColorGetG(color)],
                lookUpTable[SkColorGetB(color)]);
        }
    }
}

bool SkColorShader::setContext(const SkBitmap& device, const SkPaint& paint,
                               const SkMatrix& matrix) {
    if (!this->INHERITED::setContext(device, paint, matrix)) {
        return false;
    }

    SkColor c;
    unsigned a;
    
    if (fInheritColor) {
        c = paint.getColor();
        a = SkColorGetA(c);
    } else {
        c = fColor;
        a = SkAlphaMul(SkColorGetA(c), SkAlpha255To256(paint.getAlpha()));
    }

    unsigned r = SkColorGetR(c);
    unsigned g = SkColorGetG(c);
    unsigned b = SkColorGetB(c);

    // we want this before we apply any alpha
    fColor16 = SkPack888ToRGB16(r, g, b);

    if (a != 255) {
        a = SkAlpha255To256(a);
        r = SkAlphaMul(r, a);
        g = SkAlphaMul(g, a);
        b = SkAlphaMul(b, a);
    }
    fPMColor = SkPackARGB32(a, r, g, b);

    return true;
}

static SkScalar RGB_to_HSV(SkColor color, HSV_Choice choice) {
    SkScalar red = SkIntToScalar(SkColorGetR(color));
    SkScalar green = SkIntToScalar(SkColorGetG(color));
    SkScalar blue = SkIntToScalar(SkColorGetB(color));
    SkScalar min = SkMinScalar(SkMinScalar(red, green), blue);
    SkScalar value = SkMaxScalar(SkMaxScalar(red, green), blue);
    if (choice == kGetValue)
        return value/255;
    SkScalar delta = value - min;
    SkScalar saturation = value == 0 ? 0 : SkScalarDiv(delta, value);
    if (choice == kGetSaturation)
        return saturation;
    SkScalar hue;
    if (saturation == 0)
        hue = 0;
    else {
        SkScalar part60 = SkScalarDiv(60 * SK_Scalar1, delta);
        if (red == value) {
            hue = SkScalarMul(green - blue, part60);
            if (hue < 0)
                hue += 360 * SK_Scalar1;
        }
        else if (green == value)
            hue = 120 * SK_Scalar1 + SkScalarMul(blue - red, part60);
        else  // blue == value
            hue = 240 * SK_Scalar1 + SkScalarMul(red - green, part60);
    }
    SkASSERT(choice == kGetHue);
    return hue;
}