add SkRRect::inset(), which mimics stroking

git-svn-id: http://skia.googlecode.com/svn/trunk@6935 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 50 insertions, 6 deletions

diff --git a/include/core/SkRRect.h b/include/core/SkRRect.h
index b09d27ac20..d6187f415a 100644
--- a/include/core/SkRRect.h
+++ b/include/core/SkRRect.h
@@ -220,18 +220,34 @@ public:
      */
     bool contains(SkScalar x, SkScalar y) const;
 
-#if 0
+    /**
+     *  Call inset on the bounds, and adjust the radii to reflect what happens
+     *  in stroking: If the corner is sharp (no curvature), leave it alone,
+     *  otherwise we grow/shrink the radii by the amount of the inset. If a
+     *  given radius becomes negative, it is pinned to 0.
+     *
+     *  It is valid for dst == this.
+     */
     void inset(SkScalar dx, SkScalar dy, SkRRect* dst) const;
+
     void inset(SkScalar dx, SkScalar dy) {
         this->inset(dx, dy, this);
     }
+
+    /**
+     *  Call outset on the bounds, and adjust the radii to reflect what happens
+     *  in stroking: If the corner is sharp (no curvature), leave it alone,
+     *  otherwise we grow/shrink the radii by the amount of the inset. If a
+     *  given radius becomes negative, it is pinned to 0.
+     *
+     *  It is valid for dst == this.
+     */
     void outset(SkScalar dx, SkScalar dy, SkRRect* dst) const {
         this->inset(-dx, -dy, dst);
     }
     void outset(SkScalar dx, SkScalar dy) {
         this->inset(-dx, -dy, this);
     }
-#endif
 
     SkDEBUGCODE(void validate() const;)
 
diff --git a/src/core/SkRRect.cpp b/src/core/SkRRect.cpp
index 0d137ec953..f27400c7c0 100644
--- a/src/core/SkRRect.cpp
+++ b/src/core/SkRRect.cpp
@@ -228,10 +228,10 @@ void SkRRect::computeType() const {
 }
 
 ///////////////////////////////////////////////////////////////////////////////
-#if 0
-void SkRRect::inset(SkScalar dx, SkScalar dy, SkRRect* dst) const {
 
+void SkRRect::inset(SkScalar dx, SkScalar dy, SkRRect* dst) const {
     SkRect r = fRect;
+    
     r.inset(dx, dy);
     if (r.isEmpty()) {
         dst->setEmpty();
@@ -239,12 +239,18 @@ void SkRRect::inset(SkScalar dx, SkScalar dy, SkRRect* dst) const {
     }
 
     SkVector radii[4];
+    memcpy(radii, fRadii, sizeof(radii));
     for (int i = 0; i < 4; ++i) {
-        radii[i].set(fRadii[i].fX - dx, fRadii[i].fY - dy);
+        if (radii[i].fX) {
+            radii[i].fX -= dx;
+        }
+        if (radii[i].fY) {
+            radii[i].fY -= dy;
+        }
     }
     dst->setRectRadii(r, radii);
 }
-#endif
+
 ///////////////////////////////////////////////////////////////////////////////
 
 uint32_t SkRRect::writeToMemory(void* buffer) const {
diff --git a/tests/RoundRectTest.cpp b/tests/RoundRectTest.cpp
index e88ed8ad8b..7a2c66e4cf 100644
--- a/tests/RoundRectTest.cpp
+++ b/tests/RoundRectTest.cpp
@@ -11,6 +11,27 @@
 static const SkScalar kWidth = 100.0f;
 static const SkScalar kHeight = 100.0f;
 
+static void test_inset(skiatest::Reporter* reporter) {
+    SkRRect rr, rr2;
+    SkRect r = { 0, 0, 100, 100 };
+
+    rr.setRect(r);
+    rr.inset(-20, -20, &rr2);
+    REPORTER_ASSERT(reporter, rr2.isRect());
+
+    rr.inset(20, 20, &rr2);
+    REPORTER_ASSERT(reporter, rr2.isRect());
+    
+    rr.inset(r.width()/2, r.height()/2, &rr2);
+    REPORTER_ASSERT(reporter, rr2.isEmpty());
+
+    rr.setRectXY(r, 20, 20);
+    rr.inset(19, 19, &rr2);
+    REPORTER_ASSERT(reporter, rr2.isSimple());
+    rr.inset(20, 20, &rr2);
+    REPORTER_ASSERT(reporter, rr2.isRect());
+}
+
 // Test out the basic API entry points
 static void test_round_rect_basic(skiatest::Reporter* reporter) {
     // Test out initialization methods
@@ -302,6 +323,7 @@ static void TestRoundRect(skiatest::Reporter* reporter) {
     test_round_rect_ovals(reporter);
     test_round_rect_general(reporter);
     test_round_rect_iffy_parameters(reporter);
+    test_inset(reporter);
 }
 
 #include "TestClassDef.h"