C++ SkPaint::getMaskFilter方法代码示例

    virtual void onDrawContent(SkCanvas* canvas) {
        const char* str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        SkPaint paint;
        SkScalar    x = SkIntToScalar(10);
        SkScalar    y = SkIntToScalar(20);

        paint.setFlags(0x105);

        paint.setARGB(fByte, 0xFF, 0xFF, 0xFF);

        paint.setMaskFilter(SkBlurMaskFilter::Create(SkIntToScalar(3),
                                        SkBlurMaskFilter::kNormal_BlurStyle));
        paint.getMaskFilter()->unref();

        SkRandom rand;

        for (int ps = 6; ps <= 35; ps++) {
            paint.setColor(rand.nextU() | (0xFF << 24));
            paint.setTextSize(SkIntToScalar(ps));
            paint.setTextSize(SkIntToScalar(24));
            canvas->drawText(str, strlen(str), x, y, paint);
            y += paint.getFontMetrics(NULL);
        }
        if (false) { // avoid bit rot, suppress warning
            check_for_nonwhite(canvas->getDevice()->accessBitmap(false), fByte);
            SkDebugf("------ byte %x\n", fByte);
        }

        if (false) {
            fByte += 1;
            fByte &= 0xFF;
            this->inval(NULL);
        }
    }

 static bool Supports(const SkPixmap& dst, const SkPixmap& src, const SkPaint& paint) {
     if (dst.colorType() != src.colorType()) {
         return false;
     }
     if (dst.info().profileType() != src.info().profileType()) {
         return false;
     }
     if (paint.getMaskFilter() || paint.getColorFilter() || paint.getImageFilter()) {
         return false;
     }
     if (0xFF != paint.getAlpha()) {
         return false;
     }
     SkXfermode::Mode mode;
     if (!SkXfermode::AsMode(paint.getXfermode(), &mode)) {
         return false;
     }
     if (SkXfermode::kSrc_Mode == mode) {
         return true;
     }
     if (SkXfermode::kSrcOver_Mode == mode && src.isOpaque()) {
         return true;
     }
     return false;
 }

bool GrDistanceFieldTextContext::canDraw(const SkPaint& paint, const SkMatrix& viewMatrix) {
    // TODO: support perspective (need getMaxScale replacement)
    if (viewMatrix.hasPerspective()) {
        return false;
    }

    SkScalar maxScale = viewMatrix.getMaxScale();
    SkScalar scaledTextSize = maxScale*paint.getTextSize();
    // Scaling up beyond 2x yields undesireable artifacts
    if (scaledTextSize > 2*kLargeDFFontSize) {
        return false;
    }

    if (!fEnableDFRendering && !paint.isDistanceFieldTextTEMP() &&
        scaledTextSize < kLargeDFFontSize) {
        return false;
    }

    // rasterizers and mask filters modify alpha, which doesn't
    // translate well to distance
    if (paint.getRasterizer() || paint.getMaskFilter() ||
        !fContext->getTextTarget()->caps()->shaderDerivativeSupport()) {
        return false;
    }

    // TODO: add some stroking support
    if (paint.getStyle() != SkPaint::kFill_Style) {
        return false;
    }

    return true;
}

bool GrStencilAndCoverTextContext::canDraw(const GrRenderTarget* rt,
                                           const GrClip& clip,
                                           const GrPaint& paint,
                                           const SkPaint& skPaint,
                                           const SkMatrix& viewMatrix) {
    if (skPaint.getRasterizer()) {
        return false;
    }
    if (skPaint.getMaskFilter()) {
        return false;
    }
    if (SkPathEffect* pe = skPaint.getPathEffect()) {
        if (pe->asADash(NULL) != SkPathEffect::kDash_DashType) {
            return false;
        }
    }

    // No hairlines unless we can map the 1 px width to the object space.
    if (skPaint.getStyle() == SkPaint::kStroke_Style
        && skPaint.getStrokeWidth() == 0
        && viewMatrix.hasPerspective()) {
        return false;
    }

    // No color bitmap fonts.
    SkScalerContext::Rec    rec;
    SkScalerContext::MakeRec(skPaint, &fDeviceProperties, NULL, &rec);
    return rec.getFormat() != SkMask::kARGB32_Format;
}

bool GrDistanceFieldTextContext::canDraw(const SkPaint& paint) {
    if (!fEnableDFRendering && !paint.isDistanceFieldTextTEMP()) {
        return false;
    }

    // rasterizers and mask filters modify alpha, which doesn't
    // translate well to distance
    if (paint.getRasterizer() || paint.getMaskFilter() ||
        !fContext->getTextTarget()->caps()->shaderDerivativeSupport()) {
        return false;
    }

    // TODO: add some stroking support
    if (paint.getStyle() != SkPaint::kFill_Style) {
        return false;
    }

    // TODO: choose an appropriate maximum scale for distance fields and
    //       enable perspective
    if (SkDraw::ShouldDrawTextAsPaths(paint, fContext->getMatrix())) {
        return false;
    }

    return true;
}

    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 GrBlurUtils::drawPathWithMaskFilter(GrContext* context,
                                         GrDrawContext* drawContext,
                                         const GrClip& clip,
                                         const SkPath& origPath,
                                         const SkPaint& paint,
                                         const SkMatrix& origViewMatrix,
                                         const SkMatrix* prePathMatrix,
                                         const SkIRect& clipBounds,
                                         bool pathIsMutable) {
    SkASSERT(!pathIsMutable || origPath.isVolatile());

    GrStyle style(paint);
    // If we have a prematrix, apply it to the path, optimizing for the case
    // where the original path can in fact be modified in place (even though
    // its parameter type is const).

    const SkPath* path = &origPath;
    SkTLazy<SkPath> tmpPath;

    SkMatrix viewMatrix = origViewMatrix;

    if (prePathMatrix) {
        // Styling, blurs, and shading are supposed to be applied *after* the prePathMatrix.
        if (!paint.getMaskFilter() && !paint.getShader() && !style.applies()) {
            viewMatrix.preConcat(*prePathMatrix);
        } else {
            SkPath* result = pathIsMutable ? const_cast<SkPath*>(path) : tmpPath.init();
            pathIsMutable = true;
            path->transform(*prePathMatrix, result);
            path = result;
            result->setIsVolatile(true);
        }
    }
    // at this point we're done with prePathMatrix
    SkDEBUGCODE(prePathMatrix = (const SkMatrix*)0x50FF8001;)

bool GrTextUtils::ShouldDisableLCD(const SkPaint& paint) {
    return !SkXfermode::AsMode(paint.getXfermode(), nullptr) ||
           paint.getMaskFilter() ||
           paint.getRasterizer() ||
           paint.getPathEffect() ||
           paint.isFakeBoldText() ||
           paint.getStyle() != SkPaint::kFill_Style;
}

static inline bool CanApplyDstMatrixAsCTM(const SkMatrix& m, const SkPaint& paint) {
    if (!paint.getMaskFilter()) {
        return true;
    }

    // Some mask filters parameters (sigma) depend on the CTM/scale.
    return m.getType() <= SkMatrix::kTranslate_Mask;
}

static bool fold_opacity_layer_color_to_paint(const SkPaint& layerPaint,
                                              bool isSaveLayer,
                                              SkPaint* paint) {
    // We assume layerPaint is always from a saveLayer.  If isSaveLayer is
    // true, we assume paint is too.

    // The alpha folding can proceed if the filter layer paint does not have properties which cause
    // the resulting filter layer to be "blended" in complex ways to the parent layer. For example,
    // looper drawing unmodulated filter layer twice and then modulating the result produces
    // different image to drawing modulated filter layer twice.
    // TODO: most likely the looper and only some xfer modes are the hard constraints
    if (paint->getXfermode() || paint->getLooper()) {
        return false;
    }

    if (!isSaveLayer && paint->getImageFilter()) {
        // For normal draws, the paint color is used as one input for the color for the draw. Image
        // filter will operate on the result, and thus we can not change the input.
        // For layer saves, the image filter is applied to the layer contents. The layer is then
        // modulated with the paint color, so it's fine to proceed with the fold for saveLayer
        // paints with image filters.
        return false;
    }

    if (paint->getColorFilter()) {
        // Filter input depends on the paint color.

        // Here we could filter the color if we knew the draw is going to be uniform color.  This
        // should be detectable as drawPath/drawRect/.. without a shader being uniform, while
        // drawBitmap/drawSprite or a shader being non-uniform. However, current matchers don't
        // give the type out easily, so just do not optimize that at the moment.
        return false;
    }

    const uint32_t layerColor = layerPaint.getColor();
    // The layer paint color must have only alpha component.
    if (SK_ColorTRANSPARENT != SkColorSetA(layerColor, SK_AlphaTRANSPARENT)) {
        return false;
    }

    // The layer paint can not have any effects.
    if (layerPaint.getPathEffect() ||
        layerPaint.getShader()      ||
        layerPaint.getXfermode()    ||
        layerPaint.getMaskFilter()  ||
        layerPaint.getColorFilter() ||
        layerPaint.getRasterizer()  ||
        layerPaint.getLooper()      ||
        layerPaint.getImageFilter()) {
        return false;
    }

    paint->setAlpha(SkMulDiv255Round(paint->getAlpha(), SkColorGetA(layerColor)));

    return true;
}

// Is the supplied paint simply a color?
static bool is_simple(const SkPaint& p) {
    return NULL == p.getPathEffect() &&
           NULL == p.getShader() &&
           NULL == p.getXfermode() &&
           NULL == p.getMaskFilter() &&
           NULL == p.getColorFilter() &&
           NULL == p.getRasterizer() &&
           NULL == p.getLooper() &&
           NULL == p.getImageFilter();
}

 static bool HasAnyEffect(const SkPaint& paint) {
     return paint.getPathEffect()  ||
            paint.getShader()      ||
            paint.getXfermode()    ||
            paint.getMaskFilter()  ||
            paint.getColorFilter() ||
            paint.getRasterizer()  ||
            paint.getLooper()      ||
            paint.getImageFilter();
 }

static uint16_t compute_nondef(const SkPaint& paint, PaintUsage usage) {
    // kRespectsStroke_PaintUsage is only valid if other bits are also set
    SkASSERT(0 != (usage & ~kRespectsStroke_PaintUsage));

    const SkScalar kTextSize_Default    = 12;
    const SkScalar kTextScaleX_Default  = 1;
    const SkScalar kTextSkewX_Default   = 0;
    const SkScalar kStrokeWidth_Default = 0;
    const SkScalar kStrokeMiter_Default = 4;
    const SkColor  kColor_Default       = SK_ColorBLACK;

    unsigned bits = (paint.getColor() != kColor_Default) ? kColor_NonDef : 0;

    if (usage & kText_PaintUsage) {
        bits |= (paint.getTextSize() != kTextSize_Default       ? kTextSize_NonDef : 0);
        bits |= (paint.getTextScaleX() != kTextScaleX_Default   ? kTextScaleX_NonDef : 0);
        bits |= (paint.getTextSkewX() != kTextSkewX_Default     ? kTextSkewX_NonDef : 0);
        bits |= (paint.getTypeface()                            ? kTypeface_NonDef : 0);
    }

    // TODO: kImage_PaintUsage only needs the shader/maskfilter IF its colortype is kAlpha_8

    if (usage & (kVertices_PaintUsage | kDrawPaint_PaintUsage | kImage_PaintUsage |
                 kText_PaintUsage | kGeometry_PaintUsage | kTextBlob_PaintUsage)) {
        bits |= (paint.getShader()      ? kShader_NonDef : 0);
    }

    if (usage & (kText_PaintUsage | kGeometry_PaintUsage | kTextBlob_PaintUsage)) {
        bits |= (paint.getPathEffect()  ? kPathEffect_NonDef : 0);
        bits |= (paint.getRasterizer()  ? kRasterizer_NonDef : 0);

        if (paint.getStyle() != SkPaint::kFill_Style || (usage & kRespectsStroke_PaintUsage)) {
            bits |= (paint.getStrokeWidth() != kStrokeWidth_Default ? kStrokeWidth_NonDef : 0);
            bits |= (paint.getStrokeMiter() != kStrokeMiter_Default ? kStrokeMiter_NonDef : 0);
        }
    }

    if (usage &
        (kText_PaintUsage | kGeometry_PaintUsage | kImage_PaintUsage | kTextBlob_PaintUsage))
    {
        bits |= (paint.getMaskFilter()  ? kMaskFilter_NonDef : 0);
    }

    bits |= (paint.getColorFilter() ? kColorFilter_NonDef : 0);
    bits |= (paint.getImageFilter() ? kImageFilter_NonDef : 0);
    bits |= (paint.getDrawLooper()  ? kDrawLooper_NonDef : 0);

    return SkToU16(bits);
}

bool GrStencilAndCoverTextContext::internalCanDraw(const SkPaint& skPaint) {
    if (skPaint.getRasterizer()) {
        return false;
    }
    if (skPaint.getMaskFilter()) {
        return false;
    }
    if (SkPathEffect* pe = skPaint.getPathEffect()) {
        if (pe->asADash(nullptr) != SkPathEffect::kDash_DashType) {
            return false;
        }
    }
    // No hairlines. They would require new paths with customized strokes for every new draw matrix.
    return SkPaint::kStroke_Style != skPaint.getStyle() || 0 != skPaint.getStrokeWidth();
}

bool SkPaintPriv::ShouldDither(const SkPaint& p, SkColorType dstCT) {
    // The paint dither flag can veto.
    if (!p.isDither()) {
        return false;
    }

    // We always dither 565 or 4444 when requested.
    if (dstCT == kRGB_565_SkColorType || dstCT == kARGB_4444_SkColorType) {
        return true;
    }

    // Otherwise, dither is only needed for non-const paints.
    return p.getImageFilter() || p.getMaskFilter()
        || !p.getShader() || !as_SB(p.getShader())->isConstant();
}