Handle post-record-time clipPath scaling

bug:29547149

Change-Id: I268210b240d2d8e08638114715f9622840fc02f7
diff --git a/libs/hwui/ClipArea.cpp b/libs/hwui/ClipArea.cpp
index fe68239..39b8d3d 100644
--- a/libs/hwui/ClipArea.cpp
+++ b/libs/hwui/ClipArea.cpp
@@ -464,10 +464,7 @@
             }
             case ClipMode::Region:
                 other = getRegion(recordedClip);
-
-                // TODO: handle non-translate transforms properly!
-                other.translate(recordedClipTransform.getTranslateX(),
-                        recordedClipTransform.getTranslateY());
+                applyTransformToRegion(recordedClipTransform, &other);
             }
 
             ClipRegion* regionClip = allocator.create<ClipRegion>();
@@ -527,11 +524,29 @@
         }
     } else {
         SkRegion region(getRegion(clip));
-        // TODO: handle non-translate transforms properly!
-        region.translate(transform.getTranslateX(), transform.getTranslateY());
+        applyTransformToRegion(transform, &region);
         clipRegion(region, SkRegion::kIntersect_Op);
     }
 }
 
+void ClipArea::applyTransformToRegion(const Matrix4& transform, SkRegion* region) {
+    if (transform.isSimple() && !transform.isPureTranslate()) {
+        // handle matrices with scale manually by mapping each rect
+        SkRegion other;
+        SkRegion::Iterator it(*region);
+        while (!it.done()) {
+            Rect rect(it.rect());
+            transform.mapRect(rect);
+            rect.roundOut();
+            other.op(rect.left, rect.top, rect.right, rect.bottom, SkRegion::kUnion_Op);
+            it.next();
+        }
+        region->swap(other);
+    } else {
+        // TODO: handle non-translate transforms properly!
+        region->translate(transform.getTranslateX(), transform.getTranslateY());
+    }
+}
+
 } /* namespace uirenderer */
 } /* namespace android */