commit bb094b947bb53374f5ad3df1b0cc71f41d43d9bf
author reed@google.com <reed@google.com@2bbb7eff-a529-9590-31e7-b0007b416f81> Wed Nov 07 14:23:42 2012 +0000
committer reed@google.com <reed@google.com@2bbb7eff-a529-9590-31e7-b0007b416f81> Wed Nov 07 14:23:42 2012 +0000
tree 7dfabffd5159e7026e45993bbfa2f72794e012fc
parent 3302783ea7edf667794b088e5fc0656946b99816

fix SkRegion::intersects(rect) where the part of the rgn that we intersect is
the last run. The old bug was that we did an early exit from the loop because
we were comparing against the next rgn.bottom, instead of the current one.

inspired and fixed by danakj http://code.google.com/p/skia/issues/detail?id=958
Review URL: https://codereview.appspot.com/6812099

git-svn-id: http://skia.googlecode.com/svn/trunk@6327 2bbb7eff-a529-9590-31e7-b0007b416f81

src/core/SkRegion.cpp

diff --git a/src/core/SkRegion.cpp b/src/core/SkRegion.cpp
index f6fc2dc..776f3e8 100644
--- a/src/core/SkRegion.cpp
+++ b/src/core/SkRegion.cpp
@@ -313,8 +313,8 @@
     if (this->isRect()) {
         return true;
     }
-
     SkASSERT(this->isComplex());
+
     const RunType* runs = fRunHead->findScanline(y);
 
     // Skip the Bottom and IntervalCount
@@ -371,17 +371,18 @@
     if (this->isRect()) {
         return true;
     }
-
     SkASSERT(this->isComplex());
+
     const RunType* scanline = fRunHead->findScanline(r.fTop);
-    RunType bottom;
-    do {
+    for (;;) {
         if (!scanline_contains(scanline, r.fLeft, r.fRight)) {
             return false;
         }
-        bottom = scanline_bottom(scanline);
+        if (r.fBottom <= scanline_bottom(scanline)) {
+            break;
+        }
         scanline = scanline_next(scanline);
-    } while (r.fBottom > bottom);
+    }
     return true;
 }
 
@@ -455,14 +456,18 @@
     if (this->isRect()) {
         return true;
     }
+    SkASSERT(this->isComplex());
 
     const RunType* scanline = fRunHead->findScanline(sect.fTop);
-    do {
+    for (;;) {
         if (scanline_intersects(scanline, sect.fLeft, sect.fRight)) {
             return true;
         }
+        if (sect.fBottom <= scanline_bottom(scanline)) {
+            break;
+        }
         scanline = scanline_next(scanline);
-    } while (sect.fBottom >= scanline[0]);
+    }
     return false;
 }
 

tests/RegionTest.cpp

diff --git a/tests/RegionTest.cpp b/tests/RegionTest.cpp
index e629a9e..a8ce0e0 100644
--- a/tests/RegionTest.cpp
+++ b/tests/RegionTest.cpp
@@ -67,6 +67,13 @@
     Union(&container, SkIRect::MakeXYWH(30, 20, 10, 20));
     TEST_NO_CONTAINS(container, SkIRect::MakeXYWH(0, 0, 10, 39));
     TEST_NO_CONTAINS(container, SkIRect::MakeXYWH(29, 0, 10, 39));
+
+    {
+        SkRegion rgn;
+        Union(&rgn, SkIRect::MakeXYWH(0, 0, 10, 10));
+        Union(&rgn, SkIRect::MakeLTRB(5, 10, 20, 20));
+        TEST_INTERSECT(rgn, SkIRect::MakeXYWH(15, 0, 5, 11));
+    }
 }
 
 static void test_empties(skiatest::Reporter* reporter) {