C++ SkMatrix::hasPerspective方法代码示例

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 GrAADistanceFieldPathRenderer::canDrawPath(const GrDrawTarget* target,
                                                const GrPipelineBuilder* pipelineBuilder,
                                                const SkMatrix& viewMatrix,
                                                const SkPath& path,
                                                const GrStrokeInfo& stroke,
                                                bool antiAlias) const {
    
    // TODO: Support inverse fill
    // TODO: Support strokes
    if (!target->caps()->shaderCaps()->shaderDerivativeSupport() || !antiAlias 
        || path.isInverseFillType() || path.isVolatile() || !stroke.isFillStyle()) {
        return false;
    }

    // currently don't support perspective
    if (viewMatrix.hasPerspective()) {
        return false;
    }
    
    // only support paths smaller than 64x64, scaled to less than 256x256
    // the goal is to accelerate rendering of lots of small paths that may be scaling
    SkScalar maxScale = viewMatrix.getMaxScale();
    const SkRect& bounds = path.getBounds();
    SkScalar maxDim = SkMaxScalar(bounds.width(), bounds.height());
    return maxDim < 64.f && maxDim * maxScale < 256.f;
}

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;
}

static void tesselate(intptr_t vertices,
                      size_t vertexStride,
                      GrColor color,
                      const SkMatrix& viewMatrix,
                      const SkRect& rect,
                      const GrQuad* localQuad) {
    SkPoint* positions = reinterpret_cast<SkPoint*>(vertices);

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

    if (!viewMatrix.hasPerspective()) {
        viewMatrix.mapPointsWithStride(positions, vertexStride,
                                       NonAAFillRectBatchBase::kVertsPerInstance);
    }

    // Setup local coords
    // TODO we should only do this if local coords are being read
    if (localQuad) {
        static const int kLocalOffset = sizeof(SkPoint) + sizeof(GrColor);
        for (int i = 0; i < NonAAFillRectBatchBase::kVertsPerInstance; i++) {
            SkPoint* coords = reinterpret_cast<SkPoint*>(vertices + kLocalOffset +
                              i * vertexStride);
            *coords = localQuad->point(i);
        }
    }

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

bool Append(GrBatch* origBatch,
            GrColor color,
            const SkMatrix& viewMatrix,
            const SkRect& rect,
            const SkRect* localRect,
            const SkMatrix* localMatrix) {
    bool usePerspective = viewMatrix.hasPerspective() ||
                          (localMatrix && localMatrix->hasPerspective());

    if (usePerspective && origBatch->classID() != NonAAFillRectBatchPerspective::ClassID()) {
        return false;
    }

    if (!usePerspective) {
        NonAAFillRectBatchSimple* batch = origBatch->cast<NonAAFillRectBatchSimple>();
        append_to_batch(batch, color, viewMatrix, rect, localRect, localMatrix);
        batch->updateBoundsAfterAppend();
    } else {
        NonAAFillRectBatchPerspective* batch = origBatch->cast<NonAAFillRectBatchPerspective>();
        const NonAAFillRectBatchPerspective::Geometry& geo = batch->geoData()->back();

        if (!geo.fViewMatrix.cheapEqualTo(viewMatrix) ||
                geo.fHasLocalRect != SkToBool(localRect) ||
                geo.fHasLocalMatrix != SkToBool(localMatrix) ||
                (geo.fHasLocalMatrix && !geo.fLocalMatrix.cheapEqualTo(*localMatrix))) {
            return false;
        }

        append_to_batch(batch, color, viewMatrix, rect, localRect, localMatrix);
        batch->updateBoundsAfterAppend();
    }

    return true;
}

bool check_bounds(const SkMatrix& viewMatrix, const SkRect& devBounds, void* vertices, int vCount)
{
    SkRect tolDevBounds = devBounds;
    // The bounds ought to be tight, but in perspective the below code runs the verts
    // through the view matrix to get back to dev coords, which can introduce imprecision.
    if (viewMatrix.hasPerspective()) {
        tolDevBounds.outset(SK_Scalar1 / 1000, SK_Scalar1 / 1000);
    } else {
        // Non-persp matrices cause this path renderer to draw in device space.
        SkASSERT(viewMatrix.isIdentity());
    }
    SkRect actualBounds;

    VertexType* verts = reinterpret_cast<VertexType*>(vertices);
    bool first = true;
    for (int i = 0; i < vCount; ++i) {
        SkPoint pos = verts[i].fPos;
        // This is a hack to workaround the fact that we move some degenerate segments offscreen.
        if (SK_ScalarMax == pos.fX) {
            continue;
        }
        viewMatrix.mapPoints(&pos, 1);
        if (first) {
            actualBounds.set(pos.fX, pos.fY, pos.fX, pos.fY);
            first = false;
        } else {
            actualBounds.growToInclude(pos.fX, pos.fY);
        }
    }
    if (!first) {
        return tolDevBounds.contains(actualBounds);
    }

    return true;
}

bool GrAAHairLinePathRenderer::createGeom(
            const SkPath& path,
            GrDrawTarget* target,
            int* lineCnt,
            int* quadCnt,
            GrDrawTarget::AutoReleaseGeometry* arg) {
    const GrDrawState& drawState = target->getDrawState();
    int rtHeight = drawState.getRenderTarget()->height();

    GrIRect devClipBounds;
    target->getClip()->getConservativeBounds(drawState.getRenderTarget(),
                                             &devClipBounds);

    GrVertexLayout layout = GrDrawState::kEdge_VertexLayoutBit;
    SkMatrix viewM = drawState.getViewMatrix();

    PREALLOC_PTARRAY(128) lines;
    PREALLOC_PTARRAY(128) quads;
    IntArray qSubdivs;
    *quadCnt = generate_lines_and_quads(path, viewM, devClipBounds,
                                        &lines, &quads, &qSubdivs);

    *lineCnt = lines.count() / 2;
    int vertCnt = kVertsPerLineSeg * *lineCnt + kVertsPerQuad * *quadCnt;

    GrAssert(sizeof(Vertex) == GrDrawState::VertexSize(layout));

    if (!arg->set(target, layout, vertCnt, 0)) {
        return false;
    }

    Vertex* verts = reinterpret_cast<Vertex*>(arg->vertices());

    const SkMatrix* toDevice = NULL;
    const SkMatrix* toSrc = NULL;
    SkMatrix ivm;

    if (viewM.hasPerspective()) {
        if (viewM.invert(&ivm)) {
            toDevice = &viewM;
            toSrc = &ivm;
        }
    }

    for (int i = 0; i < *lineCnt; ++i) {
        add_line(&lines[2*i], rtHeight, toSrc, &verts);
    }

    int unsubdivQuadCnt = quads.count() / 3;
    for (int i = 0; i < unsubdivQuadCnt; ++i) {
        GrAssert(qSubdivs[i] >= 0);
        add_quads(&quads[3*i], qSubdivs[i], toDevice, toSrc, &verts);
    }

    return true;
}

SkAxisAlignment SkComputeAxisAlignmentForHText(const SkMatrix& matrix) {
    SkASSERT(!matrix.hasPerspective());
    
    if (0 == matrix[SkMatrix::kMSkewY]) {
        return kX_SkAxisAlignment;
    }
    if (0 == matrix[SkMatrix::kMScaleX]) {
        return kY_SkAxisAlignment;
    }
    return kNone_SkAxisAlignment;
}

SkShader::Context::MatrixClass SkShader::Context::ComputeMatrixClass(const SkMatrix& mat) {
    MatrixClass mc = kLinear_MatrixClass;

    if (mat.hasPerspective()) {
        if (mat.isFixedStepInX()) {
            mc = kFixedStepInX_MatrixClass;
        } else {
            mc = kPerspective_MatrixClass;
        }
    }
    return mc;
}

void GrDrawContext::drawPaint(GrRenderTarget* rt,
                              const GrClip& clip,
                              const GrPaint& origPaint,
                              const SkMatrix& viewMatrix) {
    RETURN_IF_ABANDONED
    // set rect to be big enough to fill the space, but not super-huge, so we
    // don't overflow fixed-point implementations
    SkRect r;
    r.setLTRB(0, 0,
              SkIntToScalar(rt->width()),
              SkIntToScalar(rt->height()));
    SkTCopyOnFirstWrite<GrPaint> paint(origPaint);

    // by definition this fills the entire clip, no need for AA
    if (paint->isAntiAlias()) {
        paint.writable()->setAntiAlias(false);
    }

    bool isPerspective = viewMatrix.hasPerspective();

    // We attempt to map r by the inverse matrix and draw that. mapRect will
    // map the four corners and bound them with a new rect. This will not
    // produce a correct result for some perspective matrices.
    if (!isPerspective) {
        SkMatrix inverse;
        if (!viewMatrix.invert(&inverse)) {
            SkDebugf("Could not invert matrix\n");
            return;
        }
        inverse.mapRect(&r);
        this->drawRect(rt, clip, *paint, viewMatrix, r);
    } else {
        SkMatrix localMatrix;
        if (!viewMatrix.invert(&localMatrix)) {
            SkDebugf("Could not invert matrix\n");
            return;
        }

        AutoCheckFlush acf(fContext);
        if (!this->prepareToDraw(rt)) {
            return;
        }

        GrPipelineBuilder pipelineBuilder(*paint, rt, clip);
        fDrawTarget->drawBWRect(pipelineBuilder,
                                paint->getColor(),
                                SkMatrix::I(),
                                r,
                                NULL,
                                &localMatrix);
    }
}

void GrTextUtils::InitDistanceFieldPaint(GrAtlasTextBlob* blob,
                                         SkPaint* skPaint,
                                         SkScalar* textRatio,
                                         const SkMatrix& viewMatrix) {
    // getMaxScale doesn't support perspective, so neither do we at the moment
    SkASSERT(!viewMatrix.hasPerspective());
    SkScalar maxScale = viewMatrix.getMaxScale();
    SkScalar textSize = skPaint->getTextSize();
    SkScalar scaledTextSize = textSize;
    // if we have non-unity scale, we need to choose our base text size
    // based on the SkPaint's text size multiplied by the max scale factor
    // TODO: do we need to do this if we're scaling down (i.e. maxScale < 1)?
    if (maxScale > 0 && !SkScalarNearlyEqual(maxScale, SK_Scalar1)) {
        scaledTextSize *= maxScale;
    }

    // We have three sizes of distance field text, and within each size 'bucket' there is a floor
    // and ceiling.  A scale outside of this range would require regenerating the distance fields
    SkScalar dfMaskScaleFloor;
    SkScalar dfMaskScaleCeil;
    if (scaledTextSize <= kSmallDFFontLimit) {
        dfMaskScaleFloor = kMinDFFontSize;
        dfMaskScaleCeil = kSmallDFFontLimit;
        *textRatio = textSize / kSmallDFFontSize;
        skPaint->setTextSize(SkIntToScalar(kSmallDFFontSize));
    } else if (scaledTextSize <= kMediumDFFontLimit) {
        dfMaskScaleFloor = kSmallDFFontLimit;
        dfMaskScaleCeil = kMediumDFFontLimit;
        *textRatio = textSize / kMediumDFFontSize;
        skPaint->setTextSize(SkIntToScalar(kMediumDFFontSize));
    } else {
        dfMaskScaleFloor = kMediumDFFontLimit;
        dfMaskScaleCeil = kLargeDFFontLimit;
        *textRatio = textSize / kLargeDFFontSize;
        skPaint->setTextSize(SkIntToScalar(kLargeDFFontSize));
    }

    // Because there can be multiple runs in the blob, we want the overall maxMinScale, and
    // minMaxScale to make regeneration decisions.  Specifically, we want the maximum minimum scale
    // we can tolerate before we'd drop to a lower mip size, and the minimum maximum scale we can
    // tolerate before we'd have to move to a large mip size.  When we actually test these values
    // we look at the delta in scale between the new viewmatrix and the old viewmatrix, and test
    // against these values to decide if we can reuse or not(ie, will a given scale change our mip
    // level)
    SkASSERT(dfMaskScaleFloor <= scaledTextSize && scaledTextSize <= dfMaskScaleCeil);
    blob->setMinAndMaxScale(dfMaskScaleFloor / scaledTextSize, dfMaskScaleCeil / scaledTextSize);

    skPaint->setLCDRenderText(false);
    skPaint->setAutohinted(false);
    skPaint->setHinting(SkPaint::kNormal_Hinting);
    skPaint->setSubpixelText(true);
}

static inline bool get_direction(const SkPath& path, const SkMatrix& m, SkPath::Direction* dir) {
    if (!path.cheapComputeDirection(dir)) {
        return false;
    }
    // check whether m reverses the orientation
    SkASSERT(!m.hasPerspective());
    SkScalar det2x2 = SkScalarMul(m.get(SkMatrix::kMScaleX), m.get(SkMatrix::kMScaleY)) -
                      SkScalarMul(m.get(SkMatrix::kMSkewX), m.get(SkMatrix::kMSkewY));
    if (det2x2 < 0) {
        *dir = SkPath::OppositeDirection(*dir);
    }
    return true;
}

GrCCPathCache::MaskTransform::MaskTransform(const SkMatrix& m, SkIVector* shift)
        : fMatrix2x2{m.getScaleX(), m.getSkewX(), m.getSkewY(), m.getScaleY()} {
    SkASSERT(!m.hasPerspective());
    Sk2f translate = Sk2f(m.getTranslateX(), m.getTranslateY());
    Sk2f transFloor;
#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
    // On Android framework we pre-round view matrix translates to integers for better caching.
    transFloor = translate;
#else
    transFloor = translate.floor();
    (translate - transFloor).store(fSubpixelTranslate);
#endif
    shift->set((int)transFloor[0], (int)transFloor[1]);
    SkASSERT((float)shift->fX == transFloor[0]);  // Make sure transFloor had integer values.
    SkASSERT((float)shift->fY == transFloor[1]);
}

inline static void append_to_batch(NonAAFillRectBatchPerspective* batch, GrColor color,
                                   const SkMatrix& viewMatrix, const SkRect& rect,
                                   const SkRect* localRect, const SkMatrix* localMatrix) {
    SkASSERT(viewMatrix.hasPerspective() || (localMatrix && localMatrix->hasPerspective()));
    NonAAFillRectBatchPerspective::Geometry& geo = batch->geoData()->push_back();

    geo.fColor = color;
    geo.fViewMatrix = viewMatrix;
    geo.fRect = rect;
    geo.fHasLocalRect = SkToBool(localRect);
    geo.fHasLocalMatrix = SkToBool(localMatrix);
    if (localMatrix) {
        geo.fLocalMatrix = *localMatrix;
    }
    if (localRect) {
        geo.fLocalRect = *localRect;
    }

}

bool GrTextUtils::CanDrawAsDistanceFields(const SkPaint& skPaint, const SkMatrix& viewMatrix,
                                          const SkSurfaceProps& props, const GrShaderCaps& caps) {
    // TODO: support perspective (need getMaxScale replacement)
    if (viewMatrix.hasPerspective()) {
        return false;
    }

    SkScalar maxScale = viewMatrix.getMaxScale();
    SkScalar scaledTextSize = maxScale*skPaint.getTextSize();
    // Hinted text looks far better at small resolutions
    // Scaling up beyond 2x yields undesireable artifacts
    if (scaledTextSize < kMinDFFontSize ||
        scaledTextSize > kLargeDFFontLimit) {
        return false;
    }

    bool useDFT = props.isUseDeviceIndependentFonts();
#if SK_FORCE_DISTANCE_FIELD_TEXT
    useDFT = true;
#endif

    if (!useDFT && scaledTextSize < kLargeDFFontSize) {
        return false;
    }

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

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

    return true;
}