Add SkRRect::transform.

src/core/SkRRect.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkRRect.h"
+#include "SkMatrix.h"
 
 ///////////////////////////////////////////////////////////////////////////////
 
 void SkRRect::setRectXY(const SkRect& rect, SkScalar xRad, SkScalar yRad) {
     if (rect.isEmpty()) {
         this->setEmpty();
         return;
     }
 
     if (xRad <= 0 || yRad <= 0) {
@@ skipping 228 matching lines @@
             fType = kOval_Type;
         } else {
             fType = kSimple_Type;
         }
         return;
     }
 
     fType = kComplex_Type;
 }
 
+static bool matrix_only_scale_and_translate(const SkMatrix& matrix) {
+    const SkMatrix::TypeMask m = (SkMatrix::TypeMask) (SkMatrix::kAffine_Mask
+                                    | SkMatrix::kPerspective_Mask);
+    return (matrix.getType() & m) == 0;
+}
+
+bool SkRRect::transform(const SkMatrix& matrix, SkRRect* dst) const {

[robertphillips, 2013/10/30 23:55:02]

This seems like a complete abrogation of the const contract.

[scroggo, 2013/10/31 17:40:35]

Agreed. This is to be consistent with SkPath::transform. If I change this one,
should I fix SkPath or have them work differently?

+    if (NULL == dst) {
+        dst = const_cast<SkRRect*>(this);
+    }
+
+    if (matrix.isIdentity()) {
+        *dst = *this;
+        return true;
+    }
+
+    if (!matrix_only_scale_and_translate(matrix)) {
+        return false;
+    }
+
+    SkRect newRect;
+    if (!matrix.mapRect(&newRect, fRect)) {
+        return false;
+    }
+

[robertphillips, 2013/10/30 23:55:02]

Will this do the right thing if the matrix is a reflection and the RR isn't
symmetric?

[scroggo, 2013/10/31 17:40:35]

No. Fixed.

+    // Now scale each corner
+    SkScalar xScale = matrix.getScaleX();
+    if (xScale < 0) {
+        xScale = -xScale;
+    }
+    SkScalar yScale = matrix.getScaleY();
+    if (yScale < 0) {
+        yScale = -yScale;
+    }

[robertphillips, 2013/10/30 23:55:02]

Do we actually need "radii" here? Can't we do this in place in dst?

[scroggo, 2013/10/31 17:40:35]

Done.

+    SkVector radii[4];
+    for (int i = 0; i < 4; ++i) {
+        radii[i].fX = fRadii[i].fX * xScale;
+        radii[i].fY = fRadii[i].fY * yScale;
+    }
+    dst->setRectRadii(newRect, radii);
+    return true;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 void SkRRect::inset(SkScalar dx, SkScalar dy, SkRRect* dst) const {
     SkRect r = fRect;
 
     r.inset(dx, dy);
     if (r.isEmpty()) {
         dst->setEmpty();
         return;
     }
@@ skipping 85 matching lines @@
             SkASSERT(!allRadiiZero && !allRadiiSame && !allCornersSquare);
             break;
         case kUnknown_Type:
             // no limits on this
             break;
     }
 }
 #endif // SK_DEBUG
 
 ///////////////////////////////////////////////////////////////////////////////