C++ SkPoint类代码示例

static SkShader* make_radial_gradient(const SkPoint pts[2], const SkMatrix& localMatrix) {
    SkPoint center;
    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
               SkScalarAve(pts[0].fY, pts[1].fY));
    float radius = (center - pts[0]).length();
    return SkGradientShader::CreateRadial(center, radius, gColors, NULL, SK_ARRAY_COUNT(gColors),
                                          SkShader::kClamp_TileMode, 0, &localMatrix);
}

void SkAnnotateNamedDestination(SkCanvas* canvas, const SkPoint& point, SkData* name) {
    if (nullptr == name) {
        return;
    }
    SkPaint paint;
    annotate_paint(paint, SkAnnotationKeys::Define_Named_Dest_Key(), name);
    canvas->drawPoint(point.x(), point.y(), paint);
}

static SkShader* MakeSweep(const SkPoint pts[2], const GradData& data,
                           SkShader::TileMode, const SkMatrix& localMatrix) {
    SkPoint center;
    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
               SkScalarAve(pts[0].fY, pts[1].fY));
    return SkGradientShader::CreateSweep(center.fX, center.fY, data.fColors,
                                         data.fPos, data.fCount, 0, &localMatrix);
}

    virtual void onDraw(SkCanvas* canvas) {
        SkMatrix m;
        m.reset();
        m.setRotate(33 * SK_Scalar1);
        m.postScale(3000 * SK_Scalar1, 3000 * SK_Scalar1);
        m.postTranslate(6000 * SK_Scalar1, -5000 * SK_Scalar1);
        canvas->concat(m);

        SkPaint paint;
        paint.setColor(SK_ColorRED);
        paint.setAntiAlias(true);

        bool success = m.invert(&m);
        SkASSERT(success);
        (void) success; // silence compiler :(

        SkPath path;

        SkPoint pt = {10 * SK_Scalar1, 10 * SK_Scalar1};
        SkScalar small = 1 / (500 * SK_Scalar1);

        m.mapPoints(&pt, 1);
        path.addCircle(pt.fX, pt.fY, small);
        canvas->drawPath(path, paint);

        pt.set(30 * SK_Scalar1, 10 * SK_Scalar1);
        m.mapPoints(&pt, 1);
        SkRect rect = {pt.fX - small, pt.fY - small,
                       pt.fX + small, pt.fY + small};
        canvas->drawRect(rect, paint);

        SkBitmap bmp;
        bmp.setConfig(SkBitmap::kARGB_8888_Config, 2, 2);
        bmp.allocPixels();
        bmp.lockPixels();
        uint32_t* pixels = reinterpret_cast<uint32_t*>(bmp.getPixels());
        pixels[0] = SkPackARGB32(0xFF, 0xFF, 0x00, 0x00);
        pixels[1] = SkPackARGB32(0xFF, 0x00, 0xFF, 0x00);
        pixels[2] = SkPackARGB32(0x80, 0x00, 0x00, 0x00);
        pixels[3] = SkPackARGB32(0xFF, 0x00, 0x00, 0xFF);
        bmp.unlockPixels();
        pt.set(30 * SK_Scalar1, 30 * SK_Scalar1);
        m.mapPoints(&pt, 1);
        SkShader* shader = SkShader::CreateBitmapShader(
                                            bmp,
                                            SkShader::kRepeat_TileMode,
                                            SkShader::kRepeat_TileMode);
        SkMatrix s;
        s.reset();
        s.setScale(SK_Scalar1 / 1000, SK_Scalar1 / 1000);
        shader->setLocalMatrix(s);
        paint.setShader(shader)->unref();
        paint.setAntiAlias(false);
        paint.setFilterLevel(SkPaint::kLow_FilterLevel);
        rect.setLTRB(pt.fX - small, pt.fY - small,
                     pt.fX + small, pt.fY + small);
        canvas->drawRect(rect, paint);
    }

/// Ignores scale
static SkShader* MakeSweep(const SkPoint pts[2], const GradData& data,
                           SkShader::TileMode tm, SkUnitMapper* mapper,
                           float scale) {
    SkPoint center;
    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
               SkScalarAve(pts[0].fY, pts[1].fY));
    return SkGradientShader::CreateSweep(center.fX, center.fY, data.fColors,
                                         data.fPos, data.fCount, mapper);
}

 void onDrawPoints(PointMode mode, size_t count, const SkPoint pts[], const SkPaint& paint) override
 {
     if (!paint.getAnnotation())
         return;
     ASSERT_EQ(1u, count); // Only called from drawPoint().
     SkPoint point = getTotalMatrix().mapXY(pts[0].x(), pts[0].y());
     Operation operation = { DrawPoint, SkRect::MakeXYWH(point.x(), point.y(), 0, 0) };
     m_recordedOperations.append(operation);
 }

static sk_sp<SkShader> MakeSweep4f(const SkPoint pts[2], const GradData& data,
                                   SkShader::TileMode, const SkMatrix& localMatrix) {
    SkPoint center;
    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
               SkScalarAve(pts[0].fY, pts[1].fY));
    auto srgb = SkColorSpace::MakeSRGBLinear();
    return SkGradientShader::MakeSweep(center.fX, center.fY, data.fColors4f, srgb, data.fPos,
                                       data.fCount, 0, &localMatrix);
}

SkFlattenable* SkSweepGradient::CreateProc(SkReadBuffer& buffer) {
    DescriptorScope desc;
    if (!desc.unflatten(buffer)) {
        return NULL;
    }
    const SkPoint center = buffer.readPoint();
    return SkGradientShader::CreateSweep(center.x(), center.y(), desc.fColors, desc.fPos,
                                         desc.fCount, desc.fGradFlags, desc.fLocalMatrix);
}

SkScalar SkPerlinNoiseShader::PerlinNoiseShaderContext::noise2D(
        int channel, const StitchData& stitchData, const SkPoint& noiseVector) const {
    struct Noise {
        int noisePositionIntegerValue;
        int nextNoisePositionIntegerValue;
        SkScalar noisePositionFractionValue;
        Noise(SkScalar component)
        {
            SkScalar position = component + kPerlinNoise;
            noisePositionIntegerValue = SkScalarFloorToInt(position);
            noisePositionFractionValue = position - SkIntToScalar(noisePositionIntegerValue);
            nextNoisePositionIntegerValue = noisePositionIntegerValue + 1;
        }
    };
    Noise noiseX(noiseVector.x());
    Noise noiseY(noiseVector.y());
    SkScalar u, v;
    const SkPerlinNoiseShader& perlinNoiseShader = static_cast<const SkPerlinNoiseShader&>(fShader);
    // If stitching, adjust lattice points accordingly.
    if (perlinNoiseShader.fStitchTiles) {
        noiseX.noisePositionIntegerValue =
            checkNoise(noiseX.noisePositionIntegerValue, stitchData.fWrapX, stitchData.fWidth);
        noiseY.noisePositionIntegerValue =
            checkNoise(noiseY.noisePositionIntegerValue, stitchData.fWrapY, stitchData.fHeight);
        noiseX.nextNoisePositionIntegerValue =
            checkNoise(noiseX.nextNoisePositionIntegerValue, stitchData.fWrapX, stitchData.fWidth);
        noiseY.nextNoisePositionIntegerValue =
            checkNoise(noiseY.nextNoisePositionIntegerValue, stitchData.fWrapY, stitchData.fHeight);
    }
    noiseX.noisePositionIntegerValue &= kBlockMask;
    noiseY.noisePositionIntegerValue &= kBlockMask;
    noiseX.nextNoisePositionIntegerValue &= kBlockMask;
    noiseY.nextNoisePositionIntegerValue &= kBlockMask;
    int i =
        fPaintingData->fLatticeSelector[noiseX.noisePositionIntegerValue];
    int j =
        fPaintingData->fLatticeSelector[noiseX.nextNoisePositionIntegerValue];
    int b00 = (i + noiseY.noisePositionIntegerValue) & kBlockMask;
    int b10 = (j + noiseY.noisePositionIntegerValue) & kBlockMask;
    int b01 = (i + noiseY.nextNoisePositionIntegerValue) & kBlockMask;
    int b11 = (j + noiseY.nextNoisePositionIntegerValue) & kBlockMask;
    SkScalar sx = smoothCurve(noiseX.noisePositionFractionValue);
    SkScalar sy = smoothCurve(noiseY.noisePositionFractionValue);
    // This is taken 1:1 from SVG spec: http://www.w3.org/TR/SVG11/filters.html#feTurbulenceElement
    SkPoint fractionValue = SkPoint::Make(noiseX.noisePositionFractionValue,
                                          noiseY.noisePositionFractionValue); // Offset (0,0)
    u = fPaintingData->fGradient[channel][b00].dot(fractionValue);
    fractionValue.fX -= SK_Scalar1; // Offset (-1,0)
    v = fPaintingData->fGradient[channel][b10].dot(fractionValue);
    SkScalar a = SkScalarInterp(u, v, sx);
    fractionValue.fY -= SK_Scalar1; // Offset (-1,-1)
    v = fPaintingData->fGradient[channel][b11].dot(fractionValue);
    fractionValue.fX = noiseX.noisePositionFractionValue; // Offset (0,-1)
    u = fPaintingData->fGradient[channel][b01].dot(fractionValue);
    SkScalar b = SkScalarInterp(u, v, sx);
    return SkScalarInterp(a, b, sy);
}

static void draw_label(SkCanvas* canvas, const char* label,
                       const SkPoint& offset) {
    SkPaint paint;
    size_t len = strlen(label);

    SkScalar width = paint.measureText(label, len);
    canvas->drawText(label, len, offset.x() - width / 2, offset.y(),
                     paint);
}

    void onPrepareDraws(Target* target) override {
        SkAutoTUnref<const GrGeometryProcessor> gp(create_gp(fOverrides.readsCoverage()));
        if (!gp) {
            SkDebugf("Couldn't create GrGeometryProcessor\n");
            return;
        }

        target->initDraw(gp, this->pipeline());

        size_t vertexStride = gp->getVertexStride();
        int instanceCount = fGeoData.count();

        SkAutoTUnref<const GrIndexBuffer> indexBuffer(
                target->resourceProvider()->refQuadIndexBuffer());
        InstancedHelper helper;
        void* vertices = helper.init(target, kTriangles_GrPrimitiveType, vertexStride,
                                     indexBuffer, kVertsPerRect,
                                     kIndicesPerRect, instanceCount * kRectsPerInstance);
        if (!vertices || !indexBuffer) {
            SkDebugf("Could not allocate vertices\n");
            return;
        }

        for (int i = 0; i < instanceCount; i++) {
            intptr_t verts = reinterpret_cast<intptr_t>(vertices) +
                             i * kRectsPerInstance * kVertsPerRect * vertexStride;

            Geometry& geo = fGeoData[i];
            SkNinePatchIter iter(fImageWidth, fImageHeight, geo.fCenter, geo.fDst);

            SkRect srcR, dstR;
            while (iter.next(&srcR, &dstR)) {
                SkPoint* positions = reinterpret_cast<SkPoint*>(verts);

                positions->setRectFan(dstR.fLeft, dstR.fTop,
                                      dstR.fRight, dstR.fBottom, vertexStride);

                SkASSERT(!geo.fViewMatrix.hasPerspective());
                geo.fViewMatrix.mapPointsWithStride(positions, vertexStride, kVertsPerRect);

                // Setup local coords
                static const int kLocalOffset = sizeof(SkPoint) + sizeof(GrColor);
                SkPoint* coords = reinterpret_cast<SkPoint*>(verts + kLocalOffset);
                coords->setRectFan(srcR.fLeft, srcR.fTop, srcR.fRight, srcR.fBottom, vertexStride);

                static const int kColorOffset = sizeof(SkPoint);
                GrColor* vertColor = reinterpret_cast<GrColor*>(verts + kColorOffset);
                for (int j = 0; j < 4; ++j) {
                    *vertColor = geo.fColor;
                    vertColor = (GrColor*) ((intptr_t) vertColor + vertexStride);
                }
                verts += kVertsPerRect * vertexStride;
            }
        }
        helper.recordDraw(target);
    }

static SkShader* Make2ConicalConcentric(const SkPoint pts[2], const GradData& data,
                                       SkShader::TileMode tm) {
    SkPoint center;
    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
               SkScalarAve(pts[0].fY, pts[1].fY));
    return SkGradientShader::CreateTwoPointConical(
                            center, (pts[1].fX - pts[0].fX) / 7,
                            center, (pts[1].fX - pts[0].fX) / 2,
                            data.fColors, data.fPos, data.fCount, tm);
}

        void updateDom() {
            const SkPoint corner = pos - SkPoint::Make(size.width() / 2, size.height() / 2);
            update_pos(objectNode, corner);

            // Simulate parallax shadow for a centered light source.
            SkPoint shadowOffset = pos - SkPoint::Make(kBounds.centerX(), kBounds.centerY());
            shadowOffset.scale(kShadowParallax);
            const SkPoint shadowCorner = corner + shadowOffset;

            update_pos(shadowNode, shadowCorner);
        }

    void generateGeometry(GrBatchTarget* batchTarget) override {
        SkAutoTUnref<const GrGeometryProcessor> gp(this->createRectGP());
        if (!gp) {
            SkDebugf("Could not create GrGeometryProcessor\n");
            return;
        }

        batchTarget->initDraw(gp, this->pipeline());

        int instanceCount = fGeoData.count();
        size_t vertexStride = gp->getVertexStride();
        SkASSERT(this->hasLocalRect() ?
                 vertexStride == sizeof(GrDefaultGeoProcFactory::PositionColorLocalCoordAttr) :
                 vertexStride == sizeof(GrDefaultGeoProcFactory::PositionColorAttr));
        QuadHelper helper;
        void* vertices = helper.init(batchTarget, vertexStride, instanceCount);

        if (!vertices) {
            return;
        }

        for (int i = 0; i < instanceCount; i++) {
            const Geometry& geom = fGeoData[i];

            intptr_t offset = reinterpret_cast<intptr_t>(vertices) +
                              kVerticesPerQuad * i * vertexStride;
            SkPoint* positions = reinterpret_cast<SkPoint*>(offset);

            positions->setRectFan(geom.fRect.fLeft, geom.fRect.fTop,
                                  geom.fRect.fRight, geom.fRect.fBottom, vertexStride);
            geom.fViewMatrix.mapPointsWithStride(positions, vertexStride, kVerticesPerQuad);

            // TODO we should only do this if local coords are being read
            if (geom.fHasLocalRect) {
                static const int kLocalOffset = sizeof(SkPoint) + sizeof(GrColor);
                SkPoint* coords = reinterpret_cast<SkPoint*>(offset + kLocalOffset);
                coords->setRectFan(geom.fLocalRect.fLeft, geom.fLocalRect.fTop,
                                   geom.fLocalRect.fRight, geom.fLocalRect.fBottom,
                                   vertexStride);
                if (geom.fHasLocalMatrix) {
                    geom.fLocalMatrix.mapPointsWithStride(coords, vertexStride, kVerticesPerQuad);
                }
            }

            static const int kColorOffset = sizeof(SkPoint);
            GrColor* vertColor = reinterpret_cast<GrColor*>(offset + kColorOffset);
            for (int j = 0; j < 4; ++j) {
                *vertColor = geom.fColor;
                vertColor = (GrColor*) ((intptr_t) vertColor + vertexStride);
            }
        }

        helper.issueDraw(batchTarget);
    }

SkShader* SkPictureShader::refBitmapShader(const SkMatrix& matrix, const SkMatrix* localM) const {
    SkASSERT(fPicture && fPicture->width() > 0 && fPicture->height() > 0);

    SkMatrix m;
    m.setConcat(matrix, this->getLocalMatrix());
    if (localM) {
        m.preConcat(*localM);
    }

    // Use a rotation-invariant scale
    SkPoint scale;
    if (!SkDecomposeUpper2x2(m, NULL, &scale, NULL)) {
        // Decomposition failed, use an approximation.
        scale.set(SkScalarSqrt(m.getScaleX() * m.getScaleX() + m.getSkewX() * m.getSkewX()),
                  SkScalarSqrt(m.getScaleY() * m.getScaleY() + m.getSkewY() * m.getSkewY()));
    }
    SkSize scaledSize = SkSize::Make(scale.x() * fPicture->width(), scale.y() * fPicture->height());

    SkISize tileSize = scaledSize.toRound();
    if (tileSize.isEmpty()) {
        return NULL;
    }

    // The actual scale, compensating for rounding.
    SkSize tileScale = SkSize::Make(SkIntToScalar(tileSize.width()) / fPicture->width(),
                                    SkIntToScalar(tileSize.height()) / fPicture->height());

    SkAutoMutexAcquire ama(fCachedBitmapShaderMutex);

    if (!fCachedBitmapShader || tileScale != fCachedTileScale) {
        SkBitmap bm;
        if (!bm.allocN32Pixels(tileSize.width(), tileSize.height())) {
            return NULL;
        }
        bm.eraseColor(SK_ColorTRANSPARENT);

        SkCanvas canvas(bm);
        canvas.scale(tileScale.width(), tileScale.height());
        canvas.drawPicture(fPicture);

        fCachedTileScale = tileScale;

        SkMatrix shaderMatrix = this->getLocalMatrix();
        shaderMatrix.preScale(1 / tileScale.width(), 1 / tileScale.height());
        fCachedBitmapShader.reset(CreateBitmapShader(bm, fTmx, fTmy, &shaderMatrix));
    }

    // Increment the ref counter inside the mutex to ensure the returned pointer is still valid.
    // Otherwise, the pointer may have been overwritten on a different thread before the object's
    // ref count was incremented.
    fCachedBitmapShader.get()->ref();
    return fCachedBitmapShader;
}