C++ SkPaint::getBlendMode方法代码示例

void draw(SkCanvas* canvas) {
   SkPaint paint;
   SkDebugf("kSrcOver %c= getBlendMode\n",
            SkBlendMode::kSrcOver == paint.getBlendMode() ? '=' : '!');
   paint.setBlendMode(SkBlendMode::kSrc);
   SkDebugf("kSrcOver %c= getBlendMode\n",
            SkBlendMode::kSrcOver == paint.getBlendMode() ? '=' : '!');
}

TEST(SkiaBehavior, porterDuffCreateIsCached) {
    SkPaint paint;
    paint.setBlendMode(SkBlendMode::kOverlay);
    auto expected = paint.getBlendMode();
    paint.setBlendMode(SkBlendMode::kClear);
    ASSERT_NE(expected, paint.getBlendMode());
    paint.setBlendMode(SkBlendMode::kOverlay);
    ASSERT_EQ(expected, paint.getBlendMode());
}

SkXfermodeInterpretation SkInterpretXfermode(const SkPaint& paint, bool dstIsOpaque) {
    switch (paint.getBlendMode()) {
        case SkBlendMode::kSrcOver:
            return kSrcOver_SkXfermodeInterpretation;
        case SkBlendMode::kSrc:
            if (just_solid_color(paint)) {
                return kSrcOver_SkXfermodeInterpretation;
            }
            return kNormal_SkXfermodeInterpretation;
        case SkBlendMode::kDst:
            return kSkipDrawing_SkXfermodeInterpretation;
        case SkBlendMode::kDstOver:
            if (dstIsOpaque) {
                return kSkipDrawing_SkXfermodeInterpretation;
            }
            return kNormal_SkXfermodeInterpretation;
        case SkBlendMode::kSrcIn:
            if (dstIsOpaque && just_solid_color(paint)) {
                return kSrcOver_SkXfermodeInterpretation;
            }
            return kNormal_SkXfermodeInterpretation;
        case SkBlendMode::kDstIn:
            if (just_solid_color(paint)) {
                return kSkipDrawing_SkXfermodeInterpretation;
            }
            return kNormal_SkXfermodeInterpretation;
        default:
            return kNormal_SkXfermodeInterpretation;
    }
}

    static bool Supports(const SkPixmap& dst, const SkPixmap& src, const SkPaint& paint) {
        if (dst.colorType() != src.colorType()) {
            return false;
        }
        if (dst.info().gammaCloseToSRGB() != src.info().gammaCloseToSRGB()) {
            return false;
        }
        if (paint.getMaskFilter() || paint.getColorFilter() || paint.getImageFilter()) {
            return false;
        }
        if (0xFF != paint.getAlpha()) {
            return false;
        }
        SkBlendMode mode = paint.getBlendMode();
        if (SkBlendMode::kSrc == mode) {
            return true;
        }
        if (SkBlendMode::kSrcOver == mode && src.isOpaque()) {
            return true;
        }

        // At this point memcpy can't be used. The following check for using SrcOver.

        if (dst.colorType() != kN32_SkColorType || !dst.info().gammaCloseToSRGB()) {
            return false;
        }

        return SkBlendMode::kSrcOver == mode;
    }

    void setup(const SkPixmap& dst, int left, int top, const SkPaint& paint) override {
        SkASSERT(Supports(dst, fSource, paint));
        this->INHERITED::setup(dst, left, top, paint);
        SkBlendMode mode = paint.getBlendMode();

        SkASSERT(mode == SkBlendMode::kSrcOver || mode == SkBlendMode::kSrc);

        if (mode == SkBlendMode::kSrcOver && !fSource.isOpaque()) {
            fUseMemcpy = false;
        }
    }

sk_sp<SkPDFDict> SkPDFGraphicState::GetGraphicStateForPaint(SkPDFCanon* canon,
                                                            const SkPaint& p) {
    SkASSERT(canon);
    if (SkPaint::kFill_Style == p.getStyle()) {
        SkPDFFillGraphicState fillKey = {p.getAlpha(), pdf_blend_mode(p.getBlendMode())};
        auto& fillMap = canon->fFillGSMap;
        if (sk_sp<SkPDFDict>* statePtr = fillMap.find(fillKey)) {
            return *statePtr;
        }
        auto state = sk_make_sp<SkPDFDict>();
        state->reserve(2);
        state->insertScalar("ca", fillKey.fAlpha / 255.0f);
        state->insertName("BM", as_pdf_blend_mode_name((SkBlendMode)fillKey.fBlendMode));
        fillMap.set(fillKey, state);
        return state;
    } else {
        SkPDFStrokeGraphicState strokeKey = {
            p.getStrokeWidth(), p.getStrokeMiter(),
            SkToU8(p.getStrokeCap()), SkToU8(p.getStrokeJoin()),
            p.getAlpha(), pdf_blend_mode(p.getBlendMode())};
        auto& sMap = canon->fStrokeGSMap;
        if (sk_sp<SkPDFDict>* statePtr = sMap.find(strokeKey)) {
            return *statePtr;
        }
        auto state = sk_make_sp<SkPDFDict>();
        state->reserve(8);
        state->insertScalar("CA", strokeKey.fAlpha / 255.0f);
        state->insertScalar("ca", strokeKey.fAlpha / 255.0f);
        state->insertInt("LC", to_stroke_cap(strokeKey.fStrokeCap));
        state->insertInt("LJ", to_stroke_join(strokeKey.fStrokeJoin));
        state->insertScalar("LW", strokeKey.fStrokeWidth);
        state->insertScalar("ML", strokeKey.fStrokeMiter);
        state->insertBool("SA", true);  // SA = Auto stroke adjustment.
        state->insertName("BM", as_pdf_blend_mode_name((SkBlendMode)strokeKey.fBlendMode));
        sMap.set(strokeKey, state);
        return state;
    }
}

static void test_backToFront(skiatest::Reporter* reporter) {
    SkLayerDrawLooper::Builder looperBuilder;
    SkLayerDrawLooper::LayerInfo layerInfo;

    // Add the back layer, with the defaults.
    (void)looperBuilder.addLayerOnTop(layerInfo);

    // Add the front layer, with some layer info set.
    layerInfo.fOffset.set(10.0f, 20.0f);
    layerInfo.fPaintBits |= SkLayerDrawLooper::kXfermode_Bit;
    SkPaint* layerPaint = looperBuilder.addLayerOnTop(layerInfo);
    layerPaint->setBlendMode(SkBlendMode::kSrc);

    FakeDevice device;
    SkCanvas canvas(&device);
    SkPaint paint;
    auto looper(looperBuilder.detach());
    SkArenaAlloc alloc{48};
    SkDrawLooper::Context* context = looper->makeContext(&canvas, &alloc);

    // The back layer should come first.
    REPORTER_ASSERT(reporter, context->next(&canvas, &paint));
    REPORTER_ASSERT(reporter, paint.getBlendMode() == SkBlendMode::kSrcOver);
    canvas.drawRect(SkRect::MakeWH(50.0f, 50.0f), paint);
    REPORTER_ASSERT(reporter, 0.0f == device.fLastMatrix.getTranslateX());
    REPORTER_ASSERT(reporter, 0.0f == device.fLastMatrix.getTranslateY());
    paint.reset();

    // Then the front layer.
    REPORTER_ASSERT(reporter, context->next(&canvas, &paint));
    REPORTER_ASSERT(reporter, paint.getBlendMode() == SkBlendMode::kSrc);
    canvas.drawRect(SkRect::MakeWH(50.0f, 50.0f), paint);
    REPORTER_ASSERT(reporter, 10.0f == device.fLastMatrix.getTranslateX());
    REPORTER_ASSERT(reporter, 20.0f == device.fLastMatrix.getTranslateY());

    // Only two layers were added, so that should be the end.
    REPORTER_ASSERT(reporter, !context->next(&canvas, &paint));
}

    static bool Supports(const SkPixmap& dst, const SkPixmap& src, const SkPaint& paint) {
        // the caller has already inspected the colorspace on src and dst
        SkASSERT(!SkColorSpaceXformSteps::Required(src.colorSpace(), dst.colorSpace()));

        if (dst.colorType() != src.colorType()) {
            return false;
        }
        if (paint.getMaskFilter() || paint.getColorFilter() || paint.getImageFilter()) {
            return false;
        }
        if (0xFF != paint.getAlpha()) {
            return false;
        }
        SkBlendMode mode = paint.getBlendMode();
        return SkBlendMode::kSrc == mode || (SkBlendMode::kSrcOver == mode && src.isOpaque());
    }

 static bool Supports(const SkPixmap& dst, const SkPixmap& src, const SkPaint& paint) {
     if (dst.colorType() != src.colorType()) {
         return false;
     }
     if (!SkColorSpace::Equals(dst.colorSpace(), src.colorSpace())) {
         return false;
     }
     if (paint.getMaskFilter() || paint.getColorFilter() || paint.getImageFilter()) {
         return false;
     }
     if (0xFF != paint.getAlpha()) {
         return false;
     }
     SkBlendMode mode = paint.getBlendMode();
     return SkBlendMode::kSrc == mode || (SkBlendMode::kSrcOver == mode && src.isOpaque());
 }

/*
 *  Header:
 *      paint flags     : 32
 *      non_def bits    : 16
 *      xfermode enum   : 8
 *      pad zeros       : 8
 */
static void write_paint(SkWriteBuffer& writer, const SkPaint& paint, unsigned usage) {
    uint32_t packedFlags = pack_paint_flags(paint.getFlags(), paint.getHinting(),
                                            paint.getTextAlign(), paint.getFilterQuality(),
                                            paint.getStyle(), paint.getStrokeCap(),
                                            paint.getStrokeJoin(), paint.getTextEncoding());
    writer.write32(packedFlags);

    unsigned nondef = compute_nondef(paint, (PaintUsage)usage);
    const uint8_t pad = 0;
    writer.write32((nondef << 16) | ((unsigned)paint.getBlendMode() << 8) | pad);

    CHECK_WRITE_SCALAR(writer, nondef, paint, TextSize);
    CHECK_WRITE_SCALAR(writer, nondef, paint, TextScaleX);
    CHECK_WRITE_SCALAR(writer, nondef, paint, TextSkewX);
    CHECK_WRITE_SCALAR(writer, nondef, paint, StrokeWidth);
    CHECK_WRITE_SCALAR(writer, nondef, paint, StrokeMiter);

    if (nondef & kColor_NonDef) {
        writer.write32(paint.getColor());
    }
    if (nondef & kTypeface_NonDef) {
        // TODO: explore idea of writing bits indicating "use the prev (or prev N) face"
        // e.g. 1-N bits is an index into a ring buffer of typefaces
        SkTypeface* tf = paint.getTypeface();
        SkASSERT(tf);
        writer.writeTypeface(tf);
    }

    CHECK_WRITE_FLATTENABLE(writer, nondef, paint, PathEffect);
    CHECK_WRITE_FLATTENABLE(writer, nondef, paint, Shader);
    CHECK_WRITE_FLATTENABLE(writer, nondef, paint, MaskFilter);
    CHECK_WRITE_FLATTENABLE(writer, nondef, paint, ColorFilter);
    CHECK_WRITE_FLATTENABLE(writer, nondef, paint, Rasterizer);
    CHECK_WRITE_FLATTENABLE(writer, nondef, paint, ImageFilter);
    CHECK_WRITE_FLATTENABLE(writer, nondef, paint, DrawLooper);
}

// Even with kEntirePaint_Bits, we always ensure that the master paint's
// text-encoding is respected, since that controls how we interpret the
// text/length parameters of a draw[Pos]Text call.
void SkLayerDrawLooper::LayerDrawLooperContext::ApplyInfo(
        SkPaint* dst, const SkPaint& src, const LayerInfo& info) {
    SkColor4f srcColor = src.getColor4f();
#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
    // The framework may respect the alpha value on the original paint.
    // Match this legacy behavior.
    if (src.getAlpha() == 255) {
        srcColor.fA = dst->getColor4f().fA;
    }
#endif
    dst->setColor4f(xferColor(srcColor, dst->getColor4f(), (SkBlendMode)info.fColorMode),
                    sk_srgb_singleton());

    BitFlags bits = info.fPaintBits;
    SkPaint::TextEncoding encoding = dst->getTextEncoding();

    if (0 == bits) {
        return;
    }
    if (kEntirePaint_Bits == bits) {
        // we've already computed these, so save it from the assignment
        uint32_t f = dst->getFlags();
        SkColor4f c = dst->getColor4f();
        *dst = src;
        dst->setFlags(f);
        dst->setColor4f(c, sk_srgb_singleton());
        dst->setTextEncoding(encoding);
        return;
    }

    if (bits & kStyle_Bit) {
        dst->setStyle(src.getStyle());
        dst->setStrokeWidth(src.getStrokeWidth());
        dst->setStrokeMiter(src.getStrokeMiter());
        dst->setStrokeCap(src.getStrokeCap());
        dst->setStrokeJoin(src.getStrokeJoin());
    }

    if (bits & kTextSkewX_Bit) {
        dst->setTextSkewX(src.getTextSkewX());
    }

    if (bits & kPathEffect_Bit) {
        dst->setPathEffect(src.refPathEffect());
    }
    if (bits & kMaskFilter_Bit) {
        dst->setMaskFilter(src.refMaskFilter());
    }
    if (bits & kShader_Bit) {
        dst->setShader(src.refShader());
    }
    if (bits & kColorFilter_Bit) {
        dst->setColorFilter(src.refColorFilter());
    }
    if (bits & kXfermode_Bit) {
        dst->setBlendMode(src.getBlendMode());
    }

    // we don't override these
#if 0
    dst->setTypeface(src.getTypeface());
    dst->setTextSize(src.getTextSize());
    dst->setTextScaleX(src.getTextScaleX());
    dst->setRasterizer(src.getRasterizer());
    dst->setLooper(src.getLooper());
    dst->setTextEncoding(src.getTextEncoding());
    dst->setHinting(src.getHinting());
#endif
}

 Sprite_4f(const SkPixmap& src, const SkPaint& paint) : INHERITED(src) {
     fXfer = SkXfermode::Peek(paint.getBlendMode());
     fLoader = SkLoadSpanProc_Choose(src.info());
     fFilter = SkFilterSpanProc_Choose(paint);
     fBuffer.reset(src.width());
 }

//.........这里部分代码省略.........

            // The above may return null if compose results in a pass through of the prim color.
            if (shaderFP) {
                grPaint->addColorFragmentProcessor(std::move(shaderFP));
            }

            // We can ignore origColor here - alpha is unchanged by gamma
            GrColor paintAlpha = SkColorAlphaToGrColor(skPaint.getColor());
            if (GrColor_WHITE != paintAlpha) {
                // No gamut conversion - paintAlpha is a (linear) alpha value, splatted to all
                // color channels. It's value should be treated as the same in ANY color space.
                grPaint->addColorFragmentProcessor(GrConstColorProcessor::Make(
                    GrColor4f::FromGrColor(paintAlpha),
                    GrConstColorProcessor::InputMode::kModulateRGBA));
            }
        } else {
            // The shader's FP sees the paint unpremul color
            grPaint->setColor4f(origColor);
            grPaint->addColorFragmentProcessor(std::move(shaderFP));
        }
    } else {
        if (primColorMode) {
            // There is a blend between the primitive color and the paint color. The blend considers
            // the opaque paint color. The paint's alpha is applied to the post-blended color.
            auto processor = GrConstColorProcessor::Make(origColor.opaque(),
                                                         GrConstColorProcessor::InputMode::kIgnore);
            processor = GrXfermodeFragmentProcessor::MakeFromSrcProcessor(std::move(processor),
                                                                          *primColorMode);
            if (processor) {
                grPaint->addColorFragmentProcessor(std::move(processor));
            }

            grPaint->setColor4f(origColor.opaque());

            // We can ignore origColor here - alpha is unchanged by gamma
            GrColor paintAlpha = SkColorAlphaToGrColor(skPaint.getColor());
            if (GrColor_WHITE != paintAlpha) {
                // No gamut conversion - paintAlpha is a (linear) alpha value, splatted to all
                // color channels. It's value should be treated as the same in ANY color space.
                grPaint->addColorFragmentProcessor(GrConstColorProcessor::Make(
                    GrColor4f::FromGrColor(paintAlpha),
                    GrConstColorProcessor::InputMode::kModulateRGBA));
            }
        } else {
            // No shader, no primitive color.
            grPaint->setColor4f(origColor.premul());
            applyColorFilterToPaintColor = true;
        }
    }

    SkColorFilter* colorFilter = skPaint.getColorFilter();
    if (colorFilter) {
        if (applyColorFilterToPaintColor) {
            // If we're in legacy mode, we *must* avoid using the 4f version of the color filter,
            // because that will combine with the linearized version of the stored color.
            if (colorSpaceInfo.isGammaCorrect()) {
                grPaint->setColor4f(GrColor4f::FromSkColor4f(
                    colorFilter->filterColor4f(origColor.toSkColor4f())).premul());
            } else {
                grPaint->setColor4f(SkColorToPremulGrColor4fLegacy(
                        colorFilter->filterColor(skPaint.getColor())));
            }
        } else {
            auto cfFP = colorFilter->asFragmentProcessor(context, colorSpaceInfo);
            if (cfFP) {
                grPaint->addColorFragmentProcessor(std::move(cfFP));
            } else {
                return false;
            }
        }
    }

    SkMaskFilterBase* maskFilter = as_MFB(skPaint.getMaskFilter());
    if (maskFilter) {
        if (auto mfFP = maskFilter->asFragmentProcessor(fpArgs)) {
            grPaint->addCoverageFragmentProcessor(std::move(mfFP));
        }
    }

    // When the xfermode is null on the SkPaint (meaning kSrcOver) we need the XPFactory field on
    // the GrPaint to also be null (also kSrcOver).
    SkASSERT(!grPaint->getXPFactory());
    if (!skPaint.isSrcOver()) {
        grPaint->setXPFactory(SkBlendMode_AsXPFactory(skPaint.getBlendMode()));
    }

#ifndef SK_IGNORE_GPU_DITHER
    // Conservative default, in case GrPixelConfigToColorType() fails.
    SkColorType ct = SkColorType::kRGB_565_SkColorType;
    GrPixelConfigToColorType(colorSpaceInfo.config(), &ct);
    if (SkPaintPriv::ShouldDither(skPaint, ct) && grPaint->numColorFragmentProcessors() > 0 &&
        !colorSpaceInfo.isGammaCorrect()) {
        auto ditherFP = GrDitherEffect::Make(colorSpaceInfo.config());
        if (ditherFP) {
            grPaint->addColorFragmentProcessor(std::move(ditherFP));
        }
    }
#endif
    return true;
}