Exemple #1
0
std::unique_ptr<GrFragmentProcessor> SkColor4Shader::asFragmentProcessor(
        const GrFPArgs& args) const {
    // Construct an xform assuming float inputs. The color space can have a transfer function on
    // it, which will be applied below.
    auto colorSpaceXform = GrColorSpaceXform::Make(fColorSpace.get(), kRGBA_float_GrPixelConfig,
                                                   args.fDstColorSpaceInfo->colorSpace());
    GrColor4f color = GrColor4f::FromSkColor4f(fColor4);
    if (colorSpaceXform) {
        color = colorSpaceXform->clampedXform(color);
    }
    return GrConstColorProcessor::Make(color.premul(),
                                       GrConstColorProcessor::InputMode::kModulateA);
}
static inline bool skpaint_to_grpaint_impl(GrContext* context,
                                           const GrColorSpaceInfo& colorSpaceInfo,
                                           const SkPaint& skPaint,
                                           const SkMatrix& viewM,
                                           std::unique_ptr<GrFragmentProcessor>* shaderProcessor,
                                           SkBlendMode* primColorMode,
                                           GrPaint* grPaint) {
    grPaint->setAllowSRGBInputs(colorSpaceInfo.isGammaCorrect());

    // Convert SkPaint color to 4f format, including optional linearizing and gamut conversion.
    GrColor4f origColor = SkColorToUnpremulGrColor4f(skPaint.getColor(), colorSpaceInfo);

    const GrFPArgs fpArgs(context, &viewM, skPaint.getFilterQuality(), &colorSpaceInfo);

    // Setup the initial color considering the shader, the SkPaint color, and the presence or not
    // of per-vertex colors.
    std::unique_ptr<GrFragmentProcessor> shaderFP;
    if (!primColorMode || blend_requires_shader(*primColorMode)) {
        if (shaderProcessor) {
            shaderFP = std::move(*shaderProcessor);
        } else if (const auto* shader = as_SB(skPaint.getShader())) {
            shaderFP = shader->asFragmentProcessor(fpArgs);
            if (!shaderFP) {
                return false;
            }
        }
    }

    // Set this in below cases if the output of the shader/paint-color/paint-alpha/primXfermode is
    // a known constant value. In that case we can simply apply a color filter during this
    // conversion without converting the color filter to a GrFragmentProcessor.
    bool applyColorFilterToPaintColor = false;
    if (shaderFP) {
        if (primColorMode) {
            // There is a blend between the primitive color and the shader color. The shader sees
            // the opaque paint color. The shader's output is blended using the provided mode by
            // the primitive color. The blended color is then modulated by the paint's alpha.

            // The geometry processor will insert the primitive color to start the color chain, so
            // the GrPaint color will be ignored.

            GrColor4f shaderInput = origColor.opaque();
            shaderFP = GrFragmentProcessor::OverrideInput(std::move(shaderFP), shaderInput);
            shaderFP = GrXfermodeFragmentProcessor::MakeFromSrcProcessor(std::move(shaderFP),
                                                                         *primColorMode);

            // 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;
}