Fix transforms to be preconcat like skia so multiple transforms are accumulated with each call to TranslateInt/ScaleInt.

BUG=none
TEST=see unittest

Review URL: http://codereview.chromium.org/3025010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@53232 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 35 insertions, 4 deletions

diff --git a/gfx/canvas_direct2d.cc b/gfx/canvas_direct2d.cc
index e69de1d..b187455 100644
--- a/gfx/canvas_direct2d.cc
+++ b/gfx/canvas_direct2d.cc
@@ -117,13 +117,23 @@ bool CanvasDirect2D::ClipRectInt(int x, int y, int w, int h) {
 }
 
 void CanvasDirect2D::TranslateInt(int x, int y) {
-  rt_->SetTransform(D2D1::Matrix3x2F::Translation(static_cast<float>(x),
-                                                  static_cast<float>(y)));
+  D2D1_MATRIX_3X2_F raw;
+  rt_->GetTransform(&raw);
+  D2D1::Matrix3x2F transform(raw._11, raw._12, raw._21, raw._22, raw._31,
+                             raw._32);
+  transform = D2D1::Matrix3x2F::Translation(static_cast<float>(x),
+                                            static_cast<float>(y)) * transform;
+  rt_->SetTransform(transform);
 }
 
 void CanvasDirect2D::ScaleInt(int x, int y) {
-  rt_->SetTransform(D2D1::Matrix3x2F::Scale(static_cast<float>(x),
-                                            static_cast<float>(y)));
+  D2D1_MATRIX_3X2_F raw;
+  rt_->GetTransform(&raw);
+  D2D1::Matrix3x2F transform(raw._11, raw._12, raw._21, raw._22, raw._31,
+                             raw._32);
+  transform = D2D1::Matrix3x2F::Scale(static_cast<float>(x),
+                                      static_cast<float>(y)) * transform;
+  rt_->SetTransform(transform);
 }
 
 void CanvasDirect2D::FillRectInt(int x, int y, int w, int h,
diff --git a/gfx/canvas_direct2d_unittest.cc b/gfx/canvas_direct2d_unittest.cc
index 7e2c734..541e3f0 100644
--- a/gfx/canvas_direct2d_unittest.cc
+++ b/gfx/canvas_direct2d_unittest.cc
@@ -181,3 +181,24 @@ TEST(CanvasDirect2D, ClipRectWithTranslate) {
   canvas.FillRectInt(SK_ColorRED, 0, 0, 500, 500);
   canvas.Restore();
 }
+
+TEST(CanvasDirect2D, ClipRectWithScale) {
+  TestWindow window;
+  gfx::CanvasDirect2D canvas(window.rt());
+
+  // Repeat the same rendering as in ClipRect...
+  canvas.Save();
+  canvas.FillRectInt(SK_ColorGREEN, 0, 0, 500, 500);
+  canvas.ClipRectInt(20, 20, 120, 120);
+  canvas.FillRectInt(SK_ColorBLUE, 0, 0, 500, 500);
+  canvas.Restore();
+
+  // ... then translate and scale, clip and fill again relative to the new
+  // origin.
+  canvas.Save();
+  canvas.TranslateInt(150, 150);
+  canvas.ScaleInt(2, 2);
+  canvas.ClipRectInt(10, 10, 110, 110);
+  canvas.FillRectInt(SK_ColorRED, 0, 0, 500, 500);
+  canvas.Restore();
+}