C++ SkSTArray::begin方法代码示例

bool SkSVGLinearGradient::onAsPaint(const SkSVGRenderContext& ctx, SkPaint* paint) const {
    const auto& lctx = ctx.lengthContext();
    const auto x1 = lctx.resolve(fX1, SkSVGLengthContext::LengthType::kHorizontal);
    const auto y1 = lctx.resolve(fY1, SkSVGLengthContext::LengthType::kVertical);
    const auto x2 = lctx.resolve(fX2, SkSVGLengthContext::LengthType::kHorizontal);
    const auto y2 = lctx.resolve(fY2, SkSVGLengthContext::LengthType::kVertical);

    const SkPoint pts[2] = { {x1, y1}, {x2, y2}};
    SkSTArray<2, SkColor , true> colors;
    SkSTArray<2, SkScalar, true> pos;

    this->collectColorStops(ctx, &pos, &colors);
    // TODO:
    //       * stop (lazy?) sorting
    //       * href loop detection
    //       * href attribute inheritance (not just color stops)
    //       * objectBoundingBox units support

    static_assert(static_cast<SkShader::TileMode>(SkSVGSpreadMethod::Type::kPad) ==
                  SkShader::kClamp_TileMode, "SkSVGSpreadMethod::Type is out of sync");
    static_assert(static_cast<SkShader::TileMode>(SkSVGSpreadMethod::Type::kRepeat) ==
                  SkShader::kRepeat_TileMode, "SkSVGSpreadMethod::Type is out of sync");
    static_assert(static_cast<SkShader::TileMode>(SkSVGSpreadMethod::Type::kReflect) ==
                  SkShader::kMirror_TileMode, "SkSVGSpreadMethod::Type is out of sync");
    const auto tileMode = static_cast<SkShader::TileMode>(fSpreadMethod.type());

    paint->setShader(SkGradientShader::MakeLinear(pts, colors.begin(), pos.begin(), colors.count(),
                                                  tileMode, 0, &fGradientTransform.value()));
    return true;
}

SkRect Text::onRevalidate(InvalidationController*, const SkMatrix&) {
    // TODO: we could potentially track invals which don't require rebuilding the blob.

    SkPaint font;
    font.setFlags(fFlags);
    font.setTypeface(fTypeface);
    font.setTextSize(fSize);
    font.setTextScaleX(fScaleX);
    font.setTextSkewX(fSkewX);
    font.setTextAlign(fAlign);
    font.setHinting(fHinting);

    // First, convert to glyphIDs.
    font.setTextEncoding(SkPaint::kUTF8_TextEncoding);
    SkSTArray<256, SkGlyphID, true> glyphs;
    glyphs.reset(font.textToGlyphs(fText.c_str(), fText.size(), nullptr));
    SkAssertResult(font.textToGlyphs(fText.c_str(), fText.size(), glyphs.begin()) == glyphs.count());
    font.setTextEncoding(SkPaint::kGlyphID_TextEncoding);

    // Next, build the cached blob.
    SkTextBlobBuilder builder;
    const auto& buf = builder.allocRun(font, glyphs.count(), 0, 0, nullptr);
    if (!buf.glyphs) {
        fBlob.reset();
        return SkRect::MakeEmpty();
    }

    memcpy(buf.glyphs, glyphs.begin(), glyphs.count() * sizeof(SkGlyphID));

    fBlob = builder.make();
    return fBlob
        ? fBlob->bounds().makeOffset(fPosition.x(), fPosition.y())
        : SkRect::MakeEmpty();
}

 void onExecute(GrOpFlushState* state) override {
     GrRenderTarget* rt = state->drawOpArgs().fRenderTarget;
     GrPipeline pipeline(rt, fScissorState, SkBlendMode::kSrc);
     SkSTArray<kNumMeshes, GrMesh> meshes;
     for (int i = 0; i < kNumMeshes; ++i) {
         GrMesh& mesh = meshes.emplace_back(GrPrimitiveType::kTriangleStrip);
         mesh.setNonIndexedNonInstanced(4);
         mesh.setVertexData(fVertexBuffer.get(), 4 * i);
     }
     state->commandBuffer()->draw(pipeline, GrPipelineDynamicStateTestProcessor(),
                                  meshes.begin(), kDynamicStates, 4,
                                  SkRect::MakeIWH(kScreenSize, kScreenSize));
 }

static bool is_linear_inner(const SkDQuad& q1, double t1s, double t1e, const SkDQuad& q2,
                            double t2s, double t2e, SkIntersections* i, bool* subDivide) {
    SkDQuad hull = q1.subDivide(t1s, t1e);
    SkDLine line = {{hull[2], hull[0]}};
    const SkDLine* testLines[] = { &line, (const SkDLine*) &hull[0], (const SkDLine*) &hull[1] };
    const size_t kTestCount = SK_ARRAY_COUNT(testLines);
    SkSTArray<kTestCount * 2, double, true> tsFound;
    for (size_t index = 0; index < kTestCount; ++index) {
        SkIntersections rootTs;
        rootTs.allowNear(false);
        int roots = rootTs.intersect(q2, *testLines[index]);
        for (int idx2 = 0; idx2 < roots; ++idx2) {
            double t = rootTs[0][idx2];
#ifdef SK_DEBUG
            SkDPoint qPt = q2.ptAtT(t);
            SkDPoint lPt = testLines[index]->ptAtT(rootTs[1][idx2]);
            SkASSERT(qPt.approximatelyEqual(lPt));
#endif
            if (approximately_negative(t - t2s) || approximately_positive(t - t2e)) {
                continue;
            }
            tsFound.push_back(rootTs[0][idx2]);
        }
    }
    int tCount = tsFound.count();
    if (tCount <= 0) {
        return true;
    }
    double tMin, tMax;
    if (tCount == 1) {
        tMin = tMax = tsFound[0];
    } else {
        SkASSERT(tCount > 1);
        SkTQSort<double>(tsFound.begin(), tsFound.end() - 1);
        tMin = tsFound[0];
        tMax = tsFound[tsFound.count() - 1];
    }
    SkDPoint end = q2.ptAtT(t2s);
    bool startInTriangle = hull.pointInHull(end);
    if (startInTriangle) {
        tMin = t2s;
    }
    end = q2.ptAtT(t2e);
    bool endInTriangle = hull.pointInHull(end);
    if (endInTriangle) {
        tMax = t2e;
    }
    int split = 0;
    SkDVector dxy1, dxy2;
    if (tMin != tMax || tCount > 2) {
        dxy2 = q2.dxdyAtT(tMin);
        for (int index = 1; index < tCount; ++index) {
            dxy1 = dxy2;
            dxy2 = q2.dxdyAtT(tsFound[index]);
            double dot = dxy1.dot(dxy2);
            if (dot < 0) {
                split = index - 1;
                break;
            }
        }
    }
    if (split == 0) {  // there's one point
        if (add_intercept(q1, q2, tMin, tMax, i, subDivide)) {
            return true;
        }
        i->swap();
        return is_linear_inner(q2, tMin, tMax, q1, t1s, t1e, i, subDivide);
    }
    // At this point, we have two ranges of t values -- treat each separately at the split
    bool result;
    if (add_intercept(q1, q2, tMin, tsFound[split - 1], i, subDivide)) {
        result = true;
    } else {
        i->swap();
        result = is_linear_inner(q2, tMin, tsFound[split - 1], q1, t1s, t1e, i, subDivide);
    }
    if (add_intercept(q1, q2, tsFound[split], tMax, i, subDivide)) {
        result = true;
    } else {
        i->swap();
        result |= is_linear_inner(q2, tsFound[split], tMax, q1, t1s, t1e, i, subDivide);
    }
    return result;
}

static bool get_analytic_clip_processor(const GrReducedClip::ElementList& elements,
                                        bool abortIfAA,
                                        SkVector& clipToRTOffset,
                                        const SkRect* drawBounds,
                                        sk_sp<GrFragmentProcessor>* resultFP) {
    SkRect boundsInClipSpace;
    if (drawBounds) {
        boundsInClipSpace = *drawBounds;
        boundsInClipSpace.offset(-clipToRTOffset.fX, -clipToRTOffset.fY);
    }
    SkASSERT(elements.count() <= kMaxAnalyticElements);
    SkSTArray<kMaxAnalyticElements, sk_sp<GrFragmentProcessor>> fps;
    GrReducedClip::ElementList::Iter iter(elements);
    while (iter.get()) {
        SkRegion::Op op = iter.get()->getOp();
        bool invert;
        bool skip = false;
        switch (op) {
            case SkRegion::kReplace_Op:
                SkASSERT(iter.get() == elements.head());
                // Fallthrough, handled same as intersect.
            case SkRegion::kIntersect_Op:
                invert = false;
                if (drawBounds && iter.get()->contains(boundsInClipSpace)) {
                    skip = true;
                }
                break;
            case SkRegion::kDifference_Op:
                invert = true;
                // We don't currently have a cheap test for whether a rect is fully outside an
                // element's primitive, so don't attempt to set skip.
                break;
            default:
                return false;
        }
        if (!skip) {
            GrPrimitiveEdgeType edgeType;
            if (iter.get()->isAA()) {
                if (abortIfAA) {
                    return false;
                }
                edgeType =
                    invert ? kInverseFillAA_GrProcessorEdgeType : kFillAA_GrProcessorEdgeType;
            } else {
                edgeType =
                    invert ? kInverseFillBW_GrProcessorEdgeType : kFillBW_GrProcessorEdgeType;
            }

            switch (iter.get()->getType()) {
                case SkClipStack::Element::kPath_Type:
                    fps.emplace_back(GrConvexPolyEffect::Make(edgeType, iter.get()->getPath(),
                                                              &clipToRTOffset));
                    break;
                case SkClipStack::Element::kRRect_Type: {
                    SkRRect rrect = iter.get()->getRRect();
                    rrect.offset(clipToRTOffset.fX, clipToRTOffset.fY);
                    fps.emplace_back(GrRRectEffect::Make(edgeType, rrect));
                    break;
                }
                case SkClipStack::Element::kRect_Type: {
                    SkRect rect = iter.get()->getRect();
                    rect.offset(clipToRTOffset.fX, clipToRTOffset.fY);
                    fps.emplace_back(GrConvexPolyEffect::Make(edgeType, rect));
                    break;
                }
                default:
                    break;
            }
            if (!fps.back()) {
                return false;
            }
        }
        iter.next();
    }

    *resultFP = nullptr;
    if (fps.count()) {
        *resultFP = GrFragmentProcessor::RunInSeries(fps.begin(), fps.count());
    }
    return true;
}

// TODO(egouriou): Take advantage of periods in the convolution.
// Practical resizing filters are periodic outside of the border area.
// For Lanczos, a scaling by a (reduced) factor of p/q (q pixels in the
// source become p pixels in the destination) will have a period of p.
// A nice consequence is a period of 1 when downscaling by an integral
// factor. Downscaling from typical display resolutions is also bound
// to produce interesting periods as those are chosen to have multiple
// small factors.
// Small periods reduce computational load and improve cache usage if
// the coefficients can be shared. For periods of 1 we can consider
// loading the factors only once outside the borders.
void SkResizeFilter::computeFilters(int srcSize,
                                  float destSubsetLo, float destSubsetSize,
                                  float scale,
                                  SkConvolutionFilter1D* output,
                                  const SkConvolutionProcs& convolveProcs) {
  float destSubsetHi = destSubsetLo + destSubsetSize;  // [lo, hi)

  // When we're doing a magnification, the scale will be larger than one. This
  // means the destination pixels are much smaller than the source pixels, and
  // that the range covered by the filter won't necessarily cover any source
  // pixel boundaries. Therefore, we use these clamped values (max of 1) for
  // some computations.
  float clampedScale = SkTMin(1.0f, scale);

  // This is how many source pixels from the center we need to count
  // to support the filtering function.
  float srcSupport = fBitmapFilter->width() / clampedScale;

  float invScale = 1.0f / scale;

  SkSTArray<64, float, true> filterValuesArray;
  SkSTArray<64, SkConvolutionFilter1D::ConvolutionFixed, true> fixedFilterValuesArray;

  // Loop over all pixels in the output range. We will generate one set of
  // filter values for each one. Those values will tell us how to blend the
  // source pixels to compute the destination pixel.

  // This is the pixel in the source directly under the pixel in the dest.
  // Note that we base computations on the "center" of the pixels. To see
  // why, observe that the destination pixel at coordinates (0, 0) in a 5.0x
  // downscale should "cover" the pixels around the pixel with *its center*
  // at coordinates (2.5, 2.5) in the source, not those around (0, 0).
  // Hence we need to scale coordinates (0.5, 0.5), not (0, 0).
  destSubsetLo = SkScalarFloorToScalar(destSubsetLo);
  destSubsetHi = SkScalarCeilToScalar(destSubsetHi);
  float srcPixel = (destSubsetLo + 0.5f) * invScale;
  int destLimit = SkScalarTruncToInt(destSubsetHi - destSubsetLo);
  output->reserveAdditional(destLimit, SkScalarCeilToInt(destLimit * srcSupport * 2));
  for (int destI = 0; destI < destLimit; srcPixel += invScale, destI++)
  {
    // Compute the (inclusive) range of source pixels the filter covers.
    float srcBegin = SkTMax(0.f, SkScalarFloorToScalar(srcPixel - srcSupport));
    float srcEnd = SkTMin(srcSize - 1.f, SkScalarCeilToScalar(srcPixel + srcSupport));

    // Compute the unnormalized filter value at each location of the source
    // it covers.

    // Sum of the filter values for normalizing.
    // Distance from the center of the filter, this is the filter coordinate
    // in source space. We also need to consider the center of the pixel
    // when comparing distance against 'srcPixel'. In the 5x downscale
    // example used above the distance from the center of the filter to
    // the pixel with coordinates (2, 2) should be 0, because its center
    // is at (2.5, 2.5).
    float destFilterDist = (srcBegin + 0.5f - srcPixel) * clampedScale;
    int filterCount = SkScalarTruncToInt(srcEnd - srcBegin) + 1;
    if (filterCount <= 0) {
        // true when srcSize is equal to srcPixel - srcSupport; this may be a bug
        return;
    }
    filterValuesArray.reset(filterCount);
    float filterSum = fBitmapFilter->evaluate_n(destFilterDist, clampedScale, filterCount,
                                                filterValuesArray.begin());

    // The filter must be normalized so that we don't affect the brightness of
    // the image. Convert to normalized fixed point.
    int fixedSum = 0;
    fixedFilterValuesArray.reset(filterCount);
    const float* filterValues = filterValuesArray.begin();
    SkConvolutionFilter1D::ConvolutionFixed* fixedFilterValues = fixedFilterValuesArray.begin();
    float invFilterSum = 1 / filterSum;
    for (int fixedI = 0; fixedI < filterCount; fixedI++) {
      int curFixed = SkConvolutionFilter1D::FloatToFixed(filterValues[fixedI] * invFilterSum);
      fixedSum += curFixed;
      fixedFilterValues[fixedI] = SkToS16(curFixed);
    }
    SkASSERT(fixedSum <= 0x7FFF);

    // The conversion to fixed point will leave some rounding errors, which
    // we add back in to avoid affecting the brightness of the image. We
    // arbitrarily add this to the center of the filter array (this won't always
    // be the center of the filter function since it could get clipped on the
    // edges, but it doesn't matter enough to worry about that case).
    int leftovers = SkConvolutionFilter1D::FloatToFixed(1) - fixedSum;
    fixedFilterValues[filterCount / 2] += leftovers;

    // Now it's ready to go.
    output->AddFilter(SkScalarFloorToInt(srcBegin), fixedFilterValues, filterCount);
  }
//.........这里部分代码省略.........

void SkIntersections::cubicNearEnd(const SkDCubic& cubic1, bool start, const SkDCubic& cubic2,
                         const SkDRect& bounds2) {
    SkDLine line;
    int t1Index = start ? 0 : 3;
    double testT = (double) !start;
   // don't bother if the two cubics are connnected
    static const int kPointsInCubic = 4; // FIXME: move to DCubic, replace '4' with this
    static const int kMaxLineCubicIntersections = 3;
    SkSTArray<(kMaxLineCubicIntersections - 1) * kMaxLineCubicIntersections, double, true> tVals;
    line[0] = cubic1[t1Index];
    // this variant looks for intersections with the end point and lines parallel to other points
    for (int index = 0; index < kPointsInCubic; ++index) {
        if (index == t1Index) {
            continue;
        }
        SkDVector dxy1 = cubic1[index] - line[0];
        dxy1 /= SkDCubic::gPrecisionUnit;
        line[1] = line[0] + dxy1;
        SkDRect lineBounds;
        lineBounds.setBounds(line);
        if (!bounds2.intersects(&lineBounds)) {
            continue;
        }
        SkIntersections local;
        if (!local.intersect(cubic2, line)) {
            continue;
        }
        for (int idx2 = 0; idx2 < local.used(); ++idx2) {
            double foundT = local[0][idx2];
            if (approximately_less_than_zero(foundT)
                    || approximately_greater_than_one(foundT)) {
                continue;
            }
            if (local.pt(idx2).approximatelyEqual(line[0])) {
                if (swapped()) {  // FIXME: insert should respect swap
                    insert(foundT, testT, line[0]);
                } else {
                    insert(testT, foundT, line[0]);
                }
            } else {
                tVals.push_back(foundT);
            }
        }
    }
    if (tVals.count() == 0) {
        return;
    }
    SkTQSort<double>(tVals.begin(), tVals.end() - 1);
    double tMin1 = start ? 0 : 1 - LINE_FRACTION;
    double tMax1 = start ? LINE_FRACTION : 1;
    int tIdx = 0;
    do {
        int tLast = tIdx;
        while (tLast + 1 < tVals.count() && roughly_equal(tVals[tLast + 1], tVals[tIdx])) {
            ++tLast;
        }
        double tMin2 = SkTMax(tVals[tIdx] - LINE_FRACTION, 0.0);
        double tMax2 = SkTMin(tVals[tLast] + LINE_FRACTION, 1.0);
        int lastUsed = used();
        if (start ? tMax1 < tMin2 : tMax2 < tMin1) {
            ::intersect(cubic1, tMin1, tMax1, cubic2, tMin2, tMax2, 1, *this);
        }
        if (lastUsed == used()) {
            tMin2 = SkTMax(tVals[tIdx] - (1.0 / SkDCubic::gPrecisionUnit), 0.0);
            tMax2 = SkTMin(tVals[tLast] + (1.0 / SkDCubic::gPrecisionUnit), 1.0);
            if (start ? tMax1 < tMin2 : tMax2 < tMin1) {
                ::intersect(cubic1, tMin1, tMax1, cubic2, tMin2, tMax2, 1, *this);
            }
        }
        tIdx = tLast + 1;
    } while (tIdx < tVals.count());
    return;
}

void GrCCFillGeometry::cubicTo(const SkPoint P[4], float inflectPad, float loopIntersectPad) {
    SkASSERT(fBuildingContour);
    SkASSERT(P[0] == fPoints.back());

    // Don't crunch on the curve or inflate geometry if it is nearly flat (or just very small).
    // Flat curves can break the math below.
    if (are_collinear(P)) {
        Sk2f p0 = Sk2f::Load(P);
        Sk2f p3 = Sk2f::Load(P+3);
        this->appendLine(p0, p3);
        return;
    }

    Sk2f p0 = Sk2f::Load(P);
    Sk2f p1 = Sk2f::Load(P+1);
    Sk2f p2 = Sk2f::Load(P+2);
    Sk2f p3 = Sk2f::Load(P+3);

    // Also detect near-quadratics ahead of time.
    Sk2f tan0, tan1, c;
    get_cubic_tangents(p0, p1, p2, p3, &tan0, &tan1);
    if (is_cubic_nearly_quadratic(p0, p1, p2, p3, tan0, tan1, &c)) {
        this->appendQuadratics(p0, c, p3);
        return;
    }

    double tt[2], ss[2], D[4];
    fCurrCubicType = SkClassifyCubic(P, tt, ss, D);
    SkASSERT(!SkCubicIsDegenerate(fCurrCubicType));
    Sk2f t = Sk2f(static_cast<float>(tt[0]), static_cast<float>(tt[1]));
    Sk2f s = Sk2f(static_cast<float>(ss[0]), static_cast<float>(ss[1]));

    ExcludedTerm skipTerm = (std::abs(D[2]) > std::abs(D[1]))
                                    ? ExcludedTerm::kQuadraticTerm
                                    : ExcludedTerm::kLinearTerm;
    Sk2f C0 = SkNx_fma(Sk2f(3), p1 - p2, p3 - p0);
    Sk2f C1 = (ExcludedTerm::kLinearTerm == skipTerm
                       ? SkNx_fma(Sk2f(-2), p1, p0 + p2)
                       : p1 - p0) * 3;
    Sk2f C0x1 = C0 * SkNx_shuffle<1,0>(C1);
    float Cdet = C0x1[0] - C0x1[1];

    SkSTArray<4, float> chops;
    if (SkCubicType::kLoop != fCurrCubicType) {
        find_chops_around_inflection_points(inflectPad, t, s, C0, C1, skipTerm, Cdet, &chops);
    } else {
        find_chops_around_loop_intersection(loopIntersectPad, t, s, C0, C1, skipTerm, Cdet, &chops);
    }
    if (4 == chops.count() && chops[1] >= chops[2]) {
        // This just the means the KLM roots are so close that their paddings overlap. We will
        // approximate the entire middle section, but still have it chopped midway. For loops this
        // chop guarantees the append code only sees convex segments. Otherwise, it means we are (at
        // least almost) a cusp and the chop makes sure we get a sharp point.
        Sk2f ts = t * SkNx_shuffle<1,0>(s);
        chops[1] = chops[2] = (ts[0] + ts[1]) / (2*s[0]*s[1]);
    }

#ifdef SK_DEBUG
    for (int i = 1; i < chops.count(); ++i) {
        SkASSERT(chops[i] >= chops[i - 1]);
    }
#endif
    this->appendCubics(AppendCubicMode::kLiteral, p0, p1, p2, p3, chops.begin(), chops.count());
}