commit d38f00a12a856c6ce41e659a2d02631d040a9204
author Ben Wagner <bungeman@google.com> Mon Jan 27 17:43:41 2020 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Thu Feb 13 16:22:42 2020 +0000
tree 326abc1290632d28b114523c2475c5fa1ebed116
parent 2979f95e1142b03f45678bc83edca5e4816cd9d8

Skip degenerate contours in glyphs.

Stroking in Skia follows the SVG rules of adding end caps to degenerate
contours. Skip all degenerate contours and degenerate curves on contours
to avoid this.

Bug: skia:9820
Change-Id: I320beeeb3728f39c764729454dcb128a05524d35
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/268166
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Herb Derby <herb@google.com>

src/utils/win/SkDWriteGeometrySink.cpp

diff --git a/src/utils/win/SkDWriteGeometrySink.cpp b/src/utils/win/SkDWriteGeometrySink.cpp
index 3979a13..cd5ae7c 100644
--- a/src/utils/win/SkDWriteGeometrySink.cpp
+++ b/src/utils/win/SkDWriteGeometrySink.cpp
@@ -16,7 +16,8 @@
 #include <dwrite.h>
 #include <d2d1.h>
 
-SkDWriteGeometrySink::SkDWriteGeometrySink(SkPath* path) : fRefCount(1), fPath(path) { }
+SkDWriteGeometrySink::SkDWriteGeometrySink(SkPath* path)
+    : fRefCount{1}, fPath{path}, fStarted{false}, fCurrent{0,0} {}
 
 SkDWriteGeometrySink::~SkDWriteGeometrySink() { }
 
@@ -67,15 +68,19 @@
 }
 
 SK_STDMETHODIMP_(void) SkDWriteGeometrySink::BeginFigure(D2D1_POINT_2F startPoint, D2D1_FIGURE_BEGIN figureBegin) {
-    fPath->moveTo(startPoint.x, startPoint.y);
     if (figureBegin == D2D1_FIGURE_BEGIN_HOLLOW) {
         SkDEBUGFAIL("Invalid D2D1_FIGURE_BEGIN value.");
     }
+    fStarted = false;
+    fCurrent = startPoint;
 }
 
 SK_STDMETHODIMP_(void) SkDWriteGeometrySink::AddLines(const D2D1_POINT_2F *points, UINT pointsCount) {
     for (const D2D1_POINT_2F *end = &points[pointsCount]; points < end; ++points) {
-        fPath->lineTo(points->x, points->y);
+        if (this->currentIsNot(*points)) {
+            this->goingTo(*points);
+            fPath->lineTo(points->x, points->y);
+        }
     }
 }
 
@@ -87,9 +92,9 @@
 typedef struct {
     float x;
     float y;
-} Cubic[4], Quadratic[3];
+} Cubic[4], Point;
 
-static bool check_quadratic(const Cubic& cubic, Quadratic& reduction) {
+static bool check_quadratic(const Cubic& cubic, Point& quadraticP1) {
     float dx10 = cubic[1].x - cubic[0].x;
     float dx23 = cubic[2].x - cubic[3].x;
     float midX = cubic[0].x + dx10 * 3 / 2;
@@ -104,38 +109,38 @@
     if (!approximately_equal(midY, (dy23 * 3 / 2) + cubic[3].y)) {
         return false;
     }
-    reduction[0] = cubic[0];
-    reduction[1].x = midX;
-    reduction[1].y = midY;
-    reduction[2] = cubic[3];
+    quadraticP1 = {midX, midY};
     return true;
 }
 
 SK_STDMETHODIMP_(void) SkDWriteGeometrySink::AddBeziers(const D2D1_BEZIER_SEGMENT *beziers, UINT beziersCount) {
-    SkPoint lastPt;
-    fPath->getLastPt(&lastPt);
-    D2D1_POINT_2F prevPt = { SkScalarToFloat(lastPt.fX), SkScalarToFloat(lastPt.fY) };
-
     for (const D2D1_BEZIER_SEGMENT *end = &beziers[beziersCount]; beziers < end; ++beziers) {
-        Cubic cubic = { { prevPt.x, prevPt.y },
-                        { beziers->point1.x, beziers->point1.y },
-                        { beziers->point2.x, beziers->point2.y },
-                        { beziers->point3.x, beziers->point3.y }, };
-        Quadratic quadratic;
-        if (check_quadratic(cubic, quadratic)) {
-            fPath->quadTo(quadratic[1].x, quadratic[1].y,
-                          quadratic[2].x, quadratic[2].y);
-        } else {
-            fPath->cubicTo(beziers->point1.x, beziers->point1.y,
-                           beziers->point2.x, beziers->point2.y,
-                           beziers->point3.x, beziers->point3.y);
+        if (this->currentIsNot(beziers->point1) ||
+            this->currentIsNot(beziers->point2) ||
+            this->currentIsNot(beziers->point3))
+        {
+            Cubic cubic = { {        fCurrent.x,        fCurrent.y },
+                            { beziers->point1.x, beziers->point1.y },
+                            { beziers->point2.x, beziers->point2.y },
+                            { beziers->point3.x, beziers->point3.y }, };
+            this->goingTo(beziers->point3);
+            Point quadraticP1;
+            if (check_quadratic(cubic, quadraticP1)) {
+                fPath->quadTo(    quadraticP1.x,     quadraticP1.y,
+                              beziers->point3.x, beziers->point3.y);
+            } else {
+                fPath->cubicTo(beziers->point1.x, beziers->point1.y,
+                               beziers->point2.x, beziers->point2.y,
+                               beziers->point3.x, beziers->point3.y);
+            }
         }
-        prevPt = beziers->point3;
     }
 }
 
 SK_STDMETHODIMP_(void) SkDWriteGeometrySink::EndFigure(D2D1_FIGURE_END figureEnd) {
-    fPath->close();
+    if (fStarted) {
+        fPath->close();
+    }
 }
 
 SK_STDMETHODIMP SkDWriteGeometrySink::Close() {