fix path is rect flaw exposed by gold

One of the path is rect bug fixes changed
the behavior of zero-length strokes which
showed up as a change in Gold.

The bug is if a rect is defined by a
series of colinear movetos, the bounds
did not work out if the rect started
and stopped in the middle of a side.

R=robertphillips@google.com
Bug: 824145,skia:7792
Change-Id: I226545efeda03dedd928eebc120d2508b428fef0
Reviewed-on: https://skia-review.googlesource.com/122002
Auto-Submit: Cary Clark <caryclark@skia.org>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Cary Clark <caryclark@skia.org>

3 files changed, 41 insertions, 16 deletions

diff --git a/gm/pathfill.cpp b/gm/pathfill.cpp
index ebe6d4a340..23fd5302ae 100644
--- a/gm/pathfill.cpp
+++ b/gm/pathfill.cpp
@@ -576,4 +576,16 @@ DEF_SIMPLE_GM(bug7792, canvas, 800, 800) {
     path.lineTo(75, 150);
     path.lineTo(75, 100);
     canvas->drawPath(path, p);
+    // from zero_length_paths_aa
+    canvas->translate(0, 200);
+    path.reset();
+    path.moveTo(150, 100);
+    path.lineTo(150, 100);
+    path.lineTo(150, 150);
+    path.lineTo(75, 150);
+    path.lineTo(75, 100);
+    path.lineTo(75, 75);
+    path.lineTo(150, 75);
+    path.close();
+    canvas->drawPath(path, p);
 }
diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp
index 7110a3086a..0bfeae1d91 100644
--- a/src/core/SkPath.cpp
+++ b/src/core/SkPath.cpp
@@ -506,6 +506,9 @@ bool SkPath::isRectContour(bool allowPartial, int* currVerb, const SkPoint** pts
                 closedOrMoved = autoClose;
                 lineStart = lineEnd;
                 if (directions[corners - 1] == nextDirection) {
+                    if (3 == corners && kLine_Verb == verb) {
+                        lastCountedPt = lastPt;
+                    }
                     break; // colinear segment
                 }
                 if (corners >= 4) {
@@ -513,12 +516,12 @@ bool SkPath::isRectContour(bool allowPartial, int* currVerb, const SkPoint** pts
                 }
                 directions[corners++] = nextDirection;
                 // opposite lines must point in opposite directions; xoring them should equal 2
-                if (corners == 3) {
+                if (3 == corners) {
                     if ((directions[0] ^ directions[2]) != 2) {
                         return false;
                     }
                     accumulatingRect = false;
-                } else if (corners == 4) {
+                } else if (4 == corners) {
                     if ((directions[1] ^ directions[3]) != 2) {
                         return false;
                     }
@@ -575,7 +578,7 @@ addMissingClose:
         //
         int closeDirection = rect_make_dir(closeXY.fX, closeXY.fY);
         // make sure the close-segment doesn't double-back on itself
-        if (3 == corners || (closeDirection ^ directions[1]) == 2) {
+        if (3 == corners || 2 == (closeDirection ^ directions[1])) {
             result = true;
             autoClose = false;  // we are not closed
         }
diff --git a/tests/PathTest.cpp b/tests/PathTest.cpp
index 611393becd..b108b7f1bf 100644
--- a/tests/PathTest.cpp
+++ b/tests/PathTest.cpp
@@ -4934,18 +4934,18 @@ DEF_TEST(Path_isRect, reporter) {
     SkRect rect;
     SkPoint points[] = { {10, 10}, {75, 75}, {150, 75}, {150, 150}, {75, 150} };
     SkPath path = makePath(points, SK_ARRAY_COUNT(points), false);
-    REPORTER_ASSERT(reporter, path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, path.isRect(&rect));
     SkRect compare;
     compare.set(&points[1], SK_ARRAY_COUNT(points) - 1);
     REPORTER_ASSERT(reporter, rect == compare);
     // isolated from skbug.com/7792#c3
     SkPoint points3[] = { {75, 50}, {100, 75}, {150, 75}, {150, 150}, {75, 150}, {75, 50} };
     path = makePath(points3, SK_ARRAY_COUNT(points3), true);
-    REPORTER_ASSERT(reporter, !path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, !path.isRect(&rect));
     // isolated from skbug.com/7792#c9
     SkPoint points9[] = { {10, 10}, {75, 75}, {150, 75}, {150, 150}, {75, 150} };
     path = makePath(points9, SK_ARRAY_COUNT(points9), true);
-    REPORTER_ASSERT(reporter, path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, path.isRect(&rect));
     compare.set(&points9[1], SK_ARRAY_COUNT(points9) - 1);
     REPORTER_ASSERT(reporter, rect == compare);
     // isolated from skbug.com/7792#c11
@@ -4953,7 +4953,7 @@ DEF_TEST(Path_isRect, reporter) {
                                SkPath::kLine_Verb, SkPath::kLine_Verb, SkPath::kMove_Verb };
     SkPoint points11[] = { {75, 150}, {75, 75}, {150, 75}, {150, 150}, {75, 150}, {75, 150} };
     path = makePath2(points11, verbs11, SK_ARRAY_COUNT(verbs11));
-    REPORTER_ASSERT(reporter, path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, path.isRect(&rect));
     compare.set(&points11[0], SK_ARRAY_COUNT(points11));
     REPORTER_ASSERT(reporter, rect == compare);
     // isolated from skbug.com/7792#c14
@@ -4964,19 +4964,19 @@ DEF_TEST(Path_isRect, reporter) {
     SkPoint points14[] = { {250, 75}, {250, 75}, {250, 75}, {100, 75},
                            {150, 75}, {150, 150}, {75, 150}, {75, 75}, {0, 0} };
     path = makePath2(points14, verbs14, SK_ARRAY_COUNT(verbs14));
-    REPORTER_ASSERT(reporter, !path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, !path.isRect(&rect));
     // isolated from skbug.com/7792#c15
     SkPath::Verb verbs15[] = { SkPath::kMove_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
                                SkPath::kLine_Verb, SkPath::kMove_Verb };
     SkPoint points15[] = { {75, 75}, {150, 75}, {150, 150}, {75, 150}, {250, 75} };
     path = makePath2(points15, verbs15, SK_ARRAY_COUNT(verbs15));
-    REPORTER_ASSERT(reporter, path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, path.isRect(&rect));
     compare.set(&points15[0], SK_ARRAY_COUNT(points15) - 1);
     REPORTER_ASSERT(reporter, rect == compare);
     // isolated from skbug.com/7792#c17
     SkPoint points17[] = { {75, 10}, {75, 75}, {150, 75}, {150, 150}, {75, 150}, {75, 10} };
     path = makePath(points17, SK_ARRAY_COUNT(points17), true);
-    REPORTER_ASSERT(reporter, !path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, !path.isRect(&rect));
     // isolated from skbug.com/7792#c19
     SkPath::Verb verbs19[] = { SkPath::kMove_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
                                SkPath::kLine_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
@@ -4985,7 +4985,7 @@ DEF_TEST(Path_isRect, reporter) {
     SkPoint points19[] = { {75, 75}, {75, 75}, {75, 75}, {75, 75}, {150, 75}, {150, 150},
                            {75, 150}, {10, 10}, {30, 10}, {10, 30} };
     path = makePath2(points19, verbs19, SK_ARRAY_COUNT(verbs19));
-    REPORTER_ASSERT(reporter, !path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, !path.isRect(&rect));
     // isolated from skbug.com/7792#c23
     SkPath::Verb verbs23[] = { SkPath::kMove_Verb, SkPath::kLine_Verb, SkPath::kMove_Verb,
                                SkPath::kLine_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
@@ -4993,7 +4993,7 @@ DEF_TEST(Path_isRect, reporter) {
     SkPoint points23[] = { {75, 75}, {75, 75}, {75, 75}, {75, 75}, {150, 75}, {150, 150},
                            {75, 150} };
     path = makePath2(points23, verbs23, SK_ARRAY_COUNT(verbs23));
-    REPORTER_ASSERT(reporter, path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, path.isRect(&rect));
     compare.set(&points23[0], SK_ARRAY_COUNT(points23));
     REPORTER_ASSERT(reporter, rect == compare);
     // isolated from skbug.com/7792#c29
@@ -5002,14 +5002,14 @@ DEF_TEST(Path_isRect, reporter) {
                                SkPath::kClose_Verb };
     SkPoint points29[] = { {75, 75}, {150, 75}, {150, 150}, {75, 150}, {75, 250}, {75, 75} };
     path = makePath2(points29, verbs29, SK_ARRAY_COUNT(verbs29));
-    REPORTER_ASSERT(reporter, !path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, !path.isRect(&rect));
     // isolated from skbug.com/7792#c31
     SkPath::Verb verbs31[] = { SkPath::kMove_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
                                SkPath::kLine_Verb, SkPath::kLine_Verb, SkPath::kMove_Verb,
                                SkPath::kClose_Verb };
     SkPoint points31[] = { {75, 75}, {150, 75}, {150, 150}, {75, 150}, {75, 10}, {75, 75} };
     path = makePath2(points31, verbs31, SK_ARRAY_COUNT(verbs31));
-    REPORTER_ASSERT(reporter, path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, path.isRect(&rect));
     compare.set(&points31[0], 4);
     REPORTER_ASSERT(reporter, rect == compare);
     // isolated from skbug.com/7792#c36
@@ -5017,11 +5017,21 @@ DEF_TEST(Path_isRect, reporter) {
                                SkPath::kLine_Verb, SkPath::kMove_Verb, SkPath::kLine_Verb  };
     SkPoint points36[] = { {75, 75}, {150, 75}, {150, 150}, {10, 150}, {75, 75}, {75, 75} };
     path = makePath2(points36, verbs36, SK_ARRAY_COUNT(verbs36));
-    REPORTER_ASSERT(reporter, !path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, !path.isRect(&rect));
     // isolated from skbug.com/7792#c39
     SkPath::Verb verbs39[] = { SkPath::kMove_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
                                SkPath::kLine_Verb  };
     SkPoint points39[] = { {150, 75}, {150, 150}, {75, 150}, {75, 100} };
     path = makePath2(points39, verbs39, SK_ARRAY_COUNT(verbs39));
-    REPORTER_ASSERT(reporter, !path.isRect(&rect, nullptr, nullptr));
+    REPORTER_ASSERT(reporter, !path.isRect(&rect));
+    // from zero_length_paths_aa
+    SkPath::Verb verbsAA[] = { SkPath::kMove_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
+                               SkPath::kLine_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
+                               SkPath::kLine_Verb, SkPath::kClose_Verb };
+    SkPoint pointsAA[] = { {32, 9.5f}, {32, 9.5f}, {32, 17}, {17, 17}, {17, 9.5f}, {17, 2},
+                           {32, 2} };
+    path = makePath2(pointsAA, verbsAA, SK_ARRAY_COUNT(verbsAA));
+    REPORTER_ASSERT(reporter, path.isRect(&rect));
+    compare.set(&pointsAA[0], SK_ARRAY_COUNT(pointsAA));
+    REPORTER_ASSERT(reporter, rect == compare);
 }