1 files changed, 413 insertions, 0 deletions
diff --git a/gfx/skia/skia/src/effects/SkDashPathEffect.cpp b/gfx/skia/skia/src/effects/SkDashPathEffect.cpp
new file mode 100644
index 0000000000..49ed5fea1c
--- /dev/null
+++ b/gfx/skia/skia/src/effects/SkDashPathEffect.cpp
@@ -0,0 +1,413 @@
+/*
+ * Copyright 2006 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "include/effects/SkDashPathEffect.h"
+
+#include "include/core/SkFlattenable.h"
+#include "include/core/SkMatrix.h"
+#include "include/core/SkPaint.h"
+#include "include/core/SkPath.h"
+#include "include/core/SkPathEffect.h"
+#include "include/core/SkPoint.h"
+#include "include/core/SkRect.h"
+#include "include/core/SkStrokeRec.h"
+#include "include/private/base/SkAlign.h"
+#include "include/private/base/SkMalloc.h"
+#include "include/private/base/SkTemplates.h"
+#include "include/private/base/SkTo.h"
+#include "src/core/SkReadBuffer.h"
+#include "src/core/SkWriteBuffer.h"
+#include "src/effects/SkDashImpl.h"
+#include "src/utils/SkDashPathPriv.h"
+
+#include <algorithm>
+#include <cstdint>
+#include <cstring>
+
+using namespace skia_private;
+
+SkDashImpl::SkDashImpl(const SkScalar intervals[], int count, SkScalar phase)
+        : fPhase(0)
+        , fInitialDashLength(-1)
+        , fInitialDashIndex(0)
+        , fIntervalLength(0) {
+    SkASSERT(intervals);
+    SkASSERT(count > 1 && SkIsAlign2(count));
+
+    fIntervals = (SkScalar*)sk_malloc_throw(sizeof(SkScalar) * count);
+    fCount = count;
+    for (int i = 0; i < count; i++) {
+        fIntervals[i] = intervals[i];
+    }
+
+    // set the internal data members
+    SkDashPath::CalcDashParameters(phase, fIntervals, fCount,
+            &fInitialDashLength, &fInitialDashIndex, &fIntervalLength, &fPhase);
+}
+
+SkDashImpl::~SkDashImpl() {
+    sk_free(fIntervals);
+}
+
+bool SkDashImpl::onFilterPath(SkPath* dst, const SkPath& src, SkStrokeRec* rec,
+                              const SkRect* cullRect, const SkMatrix&) const {
+    return SkDashPath::InternalFilter(dst, src, rec, cullRect, fIntervals, fCount,
+                                      fInitialDashLength, fInitialDashIndex, fIntervalLength,
+                                      fPhase);
+}
+
+static void outset_for_stroke(SkRect* rect, const SkStrokeRec& rec) {
+    SkScalar radius = SkScalarHalf(rec.getWidth());
+    if (0 == radius) {
+        radius = SK_Scalar1;    // hairlines
+    }
+    if (SkPaint::kMiter_Join == rec.getJoin()) {
+        radius *= rec.getMiter();
+    }
+    rect->outset(radius, radius);
+}
+
+// Attempt to trim the line to minimally cover the cull rect (currently
+// only works for horizontal and vertical lines).
+// Return true if processing should continue; false otherwise.
+static bool cull_line(SkPoint* pts, const SkStrokeRec& rec,
+                      const SkMatrix& ctm, const SkRect* cullRect,
+                      const SkScalar intervalLength) {
+    if (nullptr == cullRect) {
+        SkASSERT(false); // Shouldn't ever occur in practice
+        return false;
+    }
+
+    SkScalar dx = pts[1].x() - pts[0].x();
+    SkScalar dy = pts[1].y() - pts[0].y();
+
+    if ((dx && dy) || (!dx && !dy)) {
+        return false;
+    }
+
+    SkRect bounds = *cullRect;
+    outset_for_stroke(&bounds, rec);
+
+    // cullRect is in device space while pts are in the local coordinate system
+    // defined by the ctm. We want our answer in the local coordinate system.
+
+    SkASSERT(ctm.rectStaysRect());
+    SkMatrix inv;
+    if (!ctm.invert(&inv)) {
+        return false;
+    }
+
+    inv.mapRect(&bounds);
+
+    if (dx) {
+        SkASSERT(dx && !dy);
+        SkScalar minX = pts[0].fX;
+        SkScalar maxX = pts[1].fX;
+
+        if (dx < 0) {
+            using std::swap;
+            swap(minX, maxX);
+        }
+
+        SkASSERT(minX < maxX);
+        if (maxX <= bounds.fLeft || minX >= bounds.fRight) {
+            return false;
+        }
+
+        // Now we actually perform the chop, removing the excess to the left and
+        // right of the bounds (keeping our new line "in phase" with the dash,
+        // hence the (mod intervalLength).
+
+        if (minX < bounds.fLeft) {
+            minX = bounds.fLeft - SkScalarMod(bounds.fLeft - minX, intervalLength);
+        }
+        if (maxX > bounds.fRight) {
+            maxX = bounds.fRight + SkScalarMod(maxX - bounds.fRight, intervalLength);
+        }
+
+        SkASSERT(maxX > minX);
+        if (dx < 0) {
+            using std::swap;
+            swap(minX, maxX);
+        }
+        pts[0].fX = minX;
+        pts[1].fX = maxX;
+    } else {
+        SkASSERT(dy && !dx);
+        SkScalar minY = pts[0].fY;
+        SkScalar maxY = pts[1].fY;
+
+        if (dy < 0) {
+            using std::swap;
+            swap(minY, maxY);
+        }
+
+        SkASSERT(minY < maxY);
+        if (maxY <= bounds.fTop || minY >= bounds.fBottom) {
+            return false;
+        }
+
+        // Now we actually perform the chop, removing the excess to the top and
+        // bottom of the bounds (keeping our new line "in phase" with the dash,
+        // hence the (mod intervalLength).
+
+        if (minY < bounds.fTop) {
+            minY = bounds.fTop - SkScalarMod(bounds.fTop - minY, intervalLength);
+        }
+        if (maxY > bounds.fBottom) {
+            maxY = bounds.fBottom + SkScalarMod(maxY - bounds.fBottom, intervalLength);
+        }
+
+        SkASSERT(maxY > minY);
+        if (dy < 0) {
+            using std::swap;
+            swap(minY, maxY);
+        }
+        pts[0].fY = minY;
+        pts[1].fY = maxY;
+    }
+
+    return true;
+}
+
+// Currently asPoints is more restrictive then it needs to be. In the future
+// we need to:
+//      allow kRound_Cap capping (could allow rotations in the matrix with this)
+//      allow paths to be returned
+bool SkDashImpl::onAsPoints(PointData* results, const SkPath& src, const SkStrokeRec& rec,
+                            const SkMatrix& matrix, const SkRect* cullRect) const {
+    // width < 0 -> fill && width == 0 -> hairline so requiring width > 0 rules both out
+    if (0 >= rec.getWidth()) {
+        return false;
+    }
+
+    // TODO: this next test could be eased up. We could allow any number of
+    // intervals as long as all the ons match and all the offs match.
+    // Additionally, they do not necessarily need to be integers.
+    // We cannot allow arbitrary intervals since we want the returned points
+    // to be uniformly sized.
+    if (fCount != 2 ||
+        !SkScalarNearlyEqual(fIntervals[0], fIntervals[1]) ||
+        !SkScalarIsInt(fIntervals[0]) ||
+        !SkScalarIsInt(fIntervals[1])) {
+        return false;
+    }
+
+    SkPoint pts[2];
+
+    if (!src.isLine(pts)) {
+        return false;
+    }
+
+    // TODO: this test could be eased up to allow circles
+    if (SkPaint::kButt_Cap != rec.getCap()) {
+        return false;
+    }
+
+    // TODO: this test could be eased up for circles. Rotations could be allowed.
+    if (!matrix.rectStaysRect()) {
+        return false;
+    }
+
+    // See if the line can be limited to something plausible.
+    if (!cull_line(pts, rec, matrix, cullRect, fIntervalLength)) {
+        return false;
+    }
+
+    SkScalar length = SkPoint::Distance(pts[1], pts[0]);
+
+    SkVector tangent = pts[1] - pts[0];
+    if (tangent.isZero()) {
+        return false;
+    }
+
+    tangent.scale(SkScalarInvert(length));
+
+    // TODO: make this test for horizontal & vertical lines more robust
+    bool isXAxis = true;
+    if (SkScalarNearlyEqual(SK_Scalar1, tangent.fX) ||
+        SkScalarNearlyEqual(-SK_Scalar1, tangent.fX)) {
+        results->fSize.set(SkScalarHalf(fIntervals[0]), SkScalarHalf(rec.getWidth()));
+    } else if (SkScalarNearlyEqual(SK_Scalar1, tangent.fY) ||
+               SkScalarNearlyEqual(-SK_Scalar1, tangent.fY)) {
+        results->fSize.set(SkScalarHalf(rec.getWidth()), SkScalarHalf(fIntervals[0]));
+        isXAxis = false;
+    } else if (SkPaint::kRound_Cap != rec.getCap()) {
+        // Angled lines don't have axis-aligned boxes.
+        return false;
+    }
+
+    if (results) {
+        results->fFlags = 0;
+        SkScalar clampedInitialDashLength = std::min(length, fInitialDashLength);
+
+        if (SkPaint::kRound_Cap == rec.getCap()) {
+            results->fFlags |= PointData::kCircles_PointFlag;
+        }
+
+        results->fNumPoints = 0;
+        SkScalar len2 = length;
+        if (clampedInitialDashLength > 0 || 0 == fInitialDashIndex) {
+            SkASSERT(len2 >= clampedInitialDashLength);
+            if (0 == fInitialDashIndex) {
+                if (clampedInitialDashLength > 0) {
+                    if (clampedInitialDashLength >= fIntervals[0]) {
+                        ++results->fNumPoints;  // partial first dash
+                    }
+                    len2 -= clampedInitialDashLength;
+                }
+                len2 -= fIntervals[1];  // also skip first space
+                if (len2 < 0) {
+                    len2 = 0;
+                }
+            } else {
+                len2 -= clampedInitialDashLength; // skip initial partial empty
+            }
+        }
+        // Too many midpoints can cause results->fNumPoints to overflow or
+        // otherwise cause the results->fPoints allocation below to OOM.
+        // Cap it to a sane value.
+        SkScalar numIntervals = len2 / fIntervalLength;
+        if (!SkScalarIsFinite(numIntervals) || numIntervals > SkDashPath::kMaxDashCount) {
+            return false;
+        }
+        int numMidPoints = SkScalarFloorToInt(numIntervals);
+        results->fNumPoints += numMidPoints;
+        len2 -= numMidPoints * fIntervalLength;
+        bool partialLast = false;
+        if (len2 > 0) {
+            if (len2 < fIntervals[0]) {
+                partialLast = true;
+            } else {
+                ++numMidPoints;
+                ++results->fNumPoints;
+            }
+        }
+
+        results->fPoints = new SkPoint[results->fNumPoints];
+
+        SkScalar    distance = 0;
+        int         curPt = 0;
+
+        if (clampedInitialDashLength > 0 || 0 == fInitialDashIndex) {
+            SkASSERT(clampedInitialDashLength <= length);
+
+            if (0 == fInitialDashIndex) {
+                if (clampedInitialDashLength > 0) {
+                    // partial first block
+                    SkASSERT(SkPaint::kRound_Cap != rec.getCap()); // can't handle partial circles
+                    SkScalar x = pts[0].fX + tangent.fX * SkScalarHalf(clampedInitialDashLength);
+                    SkScalar y = pts[0].fY + tangent.fY * SkScalarHalf(clampedInitialDashLength);
+                    SkScalar halfWidth, halfHeight;
+                    if (isXAxis) {
+                        halfWidth = SkScalarHalf(clampedInitialDashLength);
+                        halfHeight = SkScalarHalf(rec.getWidth());
+                    } else {
+                        halfWidth = SkScalarHalf(rec.getWidth());
+                        halfHeight = SkScalarHalf(clampedInitialDashLength);
+                    }
+                    if (clampedInitialDashLength < fIntervals[0]) {
+                        // This one will not be like the others
+                        results->fFirst.addRect(x - halfWidth, y - halfHeight,
+                                                x + halfWidth, y + halfHeight);
+                    } else {
+                        SkASSERT(curPt < results->fNumPoints);
+                        results->fPoints[curPt].set(x, y);
+                        ++curPt;
+                    }
+
+                    distance += clampedInitialDashLength;
+                }
+
+                distance += fIntervals[1];  // skip over the next blank block too
+            } else {
+                distance += clampedInitialDashLength;
+            }
+        }
+
+        if (0 != numMidPoints) {
+            distance += SkScalarHalf(fIntervals[0]);
+
+            for (int i = 0; i < numMidPoints; ++i) {
+                SkScalar x = pts[0].fX + tangent.fX * distance;
+                SkScalar y = pts[0].fY + tangent.fY * distance;
+
+                SkASSERT(curPt < results->fNumPoints);
+                results->fPoints[curPt].set(x, y);
+                ++curPt;
+
+                distance += fIntervalLength;
+            }
+
+            distance -= SkScalarHalf(fIntervals[0]);
+        }
+
+        if (partialLast) {
+            // partial final block
+            SkASSERT(SkPaint::kRound_Cap != rec.getCap()); // can't handle partial circles
+            SkScalar temp = length - distance;
+            SkASSERT(temp < fIntervals[0]);
+            SkScalar x = pts[0].fX + tangent.fX * (distance + SkScalarHalf(temp));
+            SkScalar y = pts[0].fY + tangent.fY * (distance + SkScalarHalf(temp));
+            SkScalar halfWidth, halfHeight;
+            if (isXAxis) {
+                halfWidth = SkScalarHalf(temp);
+                halfHeight = SkScalarHalf(rec.getWidth());
+            } else {
+                halfWidth = SkScalarHalf(rec.getWidth());
+                halfHeight = SkScalarHalf(temp);
+            }
+            results->fLast.addRect(x - halfWidth, y - halfHeight,
+                                   x + halfWidth, y + halfHeight);
+        }
+
+        SkASSERT(curPt == results->fNumPoints);
+    }
+
+    return true;
+}
+
+SkPathEffect::DashType SkDashImpl::onAsADash(DashInfo* info) const {
+    if (info) {
+        if (info->fCount >= fCount && info->fIntervals) {
+            memcpy(info->fIntervals, fIntervals, fCount * sizeof(SkScalar));
+        }
+        info->fCount = fCount;
+        info->fPhase = fPhase;
+    }
+    return kDash_DashType;
+}
+
+void SkDashImpl::flatten(SkWriteBuffer& buffer) const {
+    buffer.writeScalar(fPhase);
+    buffer.writeScalarArray(fIntervals, fCount);
+}
+
+sk_sp<SkFlattenable> SkDashImpl::CreateProc(SkReadBuffer& buffer) {
+    const SkScalar phase = buffer.readScalar();
+    uint32_t count = buffer.getArrayCount();
+
+    // Don't allocate gigantic buffers if there's not data for them.
+    if (!buffer.validateCanReadN<SkScalar>(count)) {
+        return nullptr;
+    }
+
+    AutoSTArray<32, SkScalar> intervals(count);
+    if (buffer.readScalarArray(intervals.get(), count)) {
+        return SkDashPathEffect::Make(intervals.get(), SkToInt(count), phase);
+    }
+    return nullptr;
+}
+
+//////////////////////////////////////////////////////////////////////////////////////////////////
+
+sk_sp<SkPathEffect> SkDashPathEffect::Make(const SkScalar intervals[], int count, SkScalar phase) {
+    if (!SkDashPath::ValidDashPath(phase, intervals, count)) {
+        return nullptr;
+    }
+    return sk_sp<SkPathEffect>(new SkDashImpl(intervals, count, phase));
+}