commit 73be50da2a1fe8944f2623a511fda1957eed708a
author Mike Reed <reed@google.com> Fri Jun 22 16:42:57 2018 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Fri Jun 22 21:13:57 2018 +0000
tree 51e90fc8d09b72c262b26160f72f3dfbab0b8cdb
parent 37a06c063c9a9bb53f8840e8304706c3ff7fe141

flush to zero tiny radii

Bug: 850350
Change-Id: If1f8efdb02782d520195a6b66bd159628c89f811
Reviewed-on: https://skia-review.googlesource.com/137220
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Auto-Submit: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>

src/core/SkRRect.cpp

diff --git a/src/core/SkRRect.cpp b/src/core/SkRRect.cpp
index 01e76d5..6a6b24b 100644
--- a/src/core/SkRRect.cpp
+++ b/src/core/SkRRect.cpp
@@ -173,8 +173,20 @@
     return true;
 }
 
-void SkRRect::scaleRadii(const SkRect& rect) {
+// If we can't distinguish one of the radii relative to the other, force it to zero so it
+// doesn't confuse us later. See crbug.com/850350
+//
+static void flush_to_zero(SkScalar& a, SkScalar& b) {
+    SkASSERT(a >= 0);
+    SkASSERT(b >= 0);
+    if (a + b == a) {
+        b = 0;
+    } else if (a + b == b) {
+        a = 0;
+    }
+}
 
+void SkRRect::scaleRadii(const SkRect& rect) {
     // Proportionally scale down all radii to fit. Find the minimum ratio
     // of a side and the radii on that side (for all four sides) and use
     // that to scale down _all_ the radii. This algorithm is from the
@@ -195,6 +207,11 @@
     scale = compute_min_scale(fRadii[2].fX, fRadii[3].fX, width,  scale);
     scale = compute_min_scale(fRadii[3].fY, fRadii[0].fY, height, scale);
 
+    flush_to_zero(fRadii[0].fX, fRadii[1].fX);
+    flush_to_zero(fRadii[1].fY, fRadii[2].fY);
+    flush_to_zero(fRadii[2].fX, fRadii[3].fX);
+    flush_to_zero(fRadii[3].fY, fRadii[0].fY);
+
     if (scale < 1.0) {
         SkScaleToSides::AdjustRadii(width,  scale, &fRadii[0].fX, &fRadii[1].fX);
         SkScaleToSides::AdjustRadii(height, scale, &fRadii[1].fY, &fRadii[2].fY);

tests/RegionTest.cpp

diff --git a/tests/RegionTest.cpp b/tests/RegionTest.cpp
index cdfb2b1..0b8872a 100644
--- a/tests/RegionTest.cpp
+++ b/tests/RegionTest.cpp
@@ -444,7 +444,7 @@
     rgn.setPath(path, SkRegion(ir));
 }
 
-DEF_TEST(rrect_region, reporter) {
+DEF_TEST(rrect_region_crbug_850350, reporter) {
     SkMatrix m;
     m.reset();
     m[1] = 0.753662348f;
@@ -464,9 +464,6 @@
     path.transform(m);
 
     SkRegion rgn;
-    if (false) {
-        // this assserts in the debug build. see crbug.com/850350
-        rgn.setPath(path, SkRegion{SkIRect{0, 0, 24, 24}});
-    }
+    rgn.setPath(path, SkRegion{SkIRect{0, 0, 24, 24}});
 }