Allow Views to support an optional hit-test mask. Make hittest use this.

Make GetViewForPoint call HitTest instead of rolling its own crude hit testing.
Update custom-shaped views to use this framework instead of overriding hittest themselves.

B=2273

Review URL: http://codereview.chromium.org/3051

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@2255 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 125 insertions, 29 deletions

diff --git a/chrome/browser/views/tabs/tab.cc b/chrome/browser/views/tabs/tab.cc
index bf5dc89..ec2ec29 100644
--- a/chrome/browser/views/tabs/tab.cc
+++ b/chrome/browser/views/tabs/tab.cc
@@ -126,11 +126,12 @@ bool Tab::IsSelected() const {
 ///////////////////////////////////////////////////////////////////////////////
 // Tab, ChromeViews::View overrides:
 
-bool Tab::HitTest(const CPoint &l) const {
-  gfx::Path path;
-  MakePathForTab(&path);
-  ScopedHRGN rgn(path.CreateHRGN());
-  return !!PtInRegion(rgn, l.x, l.y);
+bool Tab::HasHitTestMask() const {
+  return true;
+}
+
+void Tab::GetHitTestMask(gfx::Path* mask) const {
+  MakePathForTab(mask);
 }
 
 bool Tab::OnMousePressed(const ChromeViews::MouseEvent& event) {
diff --git a/chrome/browser/views/tabs/tab.h b/chrome/browser/views/tabs/tab.h
index 753e1a9..369a39d 100644
--- a/chrome/browser/views/tabs/tab.h
+++ b/chrome/browser/views/tabs/tab.h
@@ -84,10 +84,10 @@ class Tab : public TabRenderer,
   // TabRenderer overrides:
   virtual bool IsSelected() const;
 
-  // ChromeViews::View overrides:
-  virtual bool HitTest(const CPoint &l) const;
  private:
   // ChromeViews::View overrides:
+  virtual bool HasHitTestMask() const;
+  virtual void GetHitTestMask(gfx::Path* mask) const;
   virtual bool OnMousePressed(const ChromeViews::MouseEvent& event);
   virtual bool OnMouseDragged(const ChromeViews::MouseEvent& event);
   virtual void OnMouseReleased(const ChromeViews::MouseEvent& event,
diff --git a/chrome/browser/views/tabs/tab_strip.cc b/chrome/browser/views/tabs/tab_strip.cc
index 748b9e7..6182e9b 100644
--- a/chrome/browser/views/tabs/tab_strip.cc
+++ b/chrome/browser/views/tabs/tab_strip.cc
@@ -67,15 +67,10 @@ class NewTabButton : public ChromeViews::Button {
 
  protected:
   // Overridden from ChromeViews::View:
-  virtual bool HitTest(const CPoint &l) const {
-    gfx::Path path;
-    MakePathForButton(&path);
-    ScopedHRGN rgn(path.CreateHRGN());
-    return !!PtInRegion(rgn, l.x, l.y);
+  virtual bool HasHitTestMask() const {
+    return true;
   }
-
- private:
-  void MakePathForButton(gfx::Path* path) const {
+  virtual void GetHitTestMask(gfx::Path* path) const {
     DCHECK(path);
 
     SkScalar h = SkIntToScalar(GetHeight());
@@ -95,6 +90,7 @@ class NewTabButton : public ChromeViews::Button {
     path->close();
   }
 
+ private:
   DISALLOW_COPY_AND_ASSIGN(NewTabButton);
 };
 
diff --git a/chrome/views/view.cc b/chrome/views/view.cc
index 45543cc..18dfd65 100644
--- a/chrome/views/view.cc
+++ b/chrome/views/view.cc
@@ -12,9 +12,11 @@
 
 #include "base/logging.h"
 #include "base/message_loop.h"
+#include "base/scoped_handle.h"
 #include "base/string_util.h"
 #include "chrome/common/drag_drop_types.h"
 #include "chrome/common/gfx/chrome_canvas.h"
+#include "chrome/common/gfx/path.h"
 #include "chrome/common/l10n_util.h"
 #include "chrome/common/os_exchange_data.h"
 #include "chrome/views/accessibility/accessible_wrapper.h"
@@ -712,6 +714,14 @@ bool View::IsProcessingPaint() const {
 }
 #endif
 
+bool View::HasHitTestMask() const {
+  return false;
+}
+
+void View::GetHitTestMask(gfx::Path* mask) const {
+  DCHECK(mask);
+}
+
 void View::ViewHierarchyChanged(bool is_add, View *parent, View *child) {
 }
 
@@ -768,16 +778,13 @@ View* View::GetViewForPoint(const CPoint& point, bool can_create_floating) {
   // tightly encloses the specified point.
   for (int i = GetChildViewCount() - 1 ; i >= 0 ; --i) {
     View* child = GetChildViewAt(i);
-    if (!child->IsVisible()) {
+    if (!child->IsVisible())
       continue;
-    }
-    CRect bounds;
-    child->GetBounds(&bounds, APPLY_MIRRORING_TRANSFORMATION);
-    if (bounds.PtInRect(point)) {
-      CPoint cl(point);
-      cl.Offset(-bounds.left, -bounds.top);
-      return child->GetViewForPoint(cl, true);
-    }
+
+    CPoint point_in_child_coords(point);
+    View::ConvertPointToView(this, child, &point_in_child_coords);
+    if (child->HitTest(point_in_child_coords))
+      return child->GetViewForPoint(point_in_child_coords, true);
   }
 
   // We haven't found a view for the point. Try to create floating views
@@ -1437,13 +1444,19 @@ bool View::IsVisibleInRootView() const {
     return false;
 }
 
-bool View::HitTest(const CPoint &l) const {
-  if (l.x >= 0 && l.x < static_cast<int>(GetWidth()) &&
-      l.y >= 0 && l.y < static_cast<int>(GetHeight())) {
+bool View::HitTest(const CPoint& l) const {
+  if (l.x >= 0 && l.x < GetWidth() && l.y >= 0 && l.y < GetHeight()) {
+    if (HasHitTestMask()) {
+      gfx::Path mask;
+      GetHitTestMask(&mask);
+      ScopedHRGN rgn(mask.CreateHRGN());
+      return !!PtInRegion(rgn, l.x, l.y);
+    }
+    // No mask, but inside our bounds.
     return true;
-  } else {
-    return false;
   }
+  // Outside our bounds.
+  return false;
 }
 
 HCURSOR View::GetCursorForPoint(Event::EventType event_type, int x, int y) {
diff --git a/chrome/views/view.h b/chrome/views/view.h
index c758418..a4ae692 100644
--- a/chrome/views/view.h
+++ b/chrome/views/view.h
@@ -19,6 +19,7 @@
 
 namespace gfx {
 class Insets;
+class Path;
 }
 
 class AccessibleWrapper;
@@ -973,6 +974,7 @@ class View : public AcceleratorTarget {
                                      bool is_horizontal, bool is_positive);
 
  protected:
+  // TODO(beng): these members should NOT be protected per style guide.
   // This View's bounds in the parent coordinate system.
   CRect bounds_;
 
@@ -989,6 +991,16 @@ class View : public AcceleratorTarget {
   virtual bool IsProcessingPaint() const;
 #endif
 
+  // Called by HitTest to see if this View has a custom hit test mask. If the
+  // return value is true, GetHitTestMask will be called to obtain the mask.
+  // Default value is false, in which case the View will hit-test against its
+  // bounds.
+  virtual bool HasHitTestMask() const;
+
+  // Called by HitTest to retrieve a mask for hit-testing against. Subclasses
+  // override to provide custom shaped hit test regions.
+  virtual void GetHitTestMask(gfx::Path* mask) const;
+
   // This method is invoked when the tree changes.
   //
   // When a view is removed, it is invoked for all children and grand
diff --git a/chrome/views/view_unittest.cc b/chrome/views/view_unittest.cc
index a658132..e404102 100644
--- a/chrome/views/view_unittest.cc
+++ b/chrome/views/view_unittest.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "chrome/common/gfx/chrome_canvas.h"
+#include "chrome/common/gfx/path.h"
 #include "chrome/views/background.h"
 #include "chrome/views/event.h"
 #include "chrome/views/root_view.h"
@@ -506,3 +507,76 @@ TEST_F(ViewTest, RemoveNotification) {
       NOTIFY_VIEW_REMOVED, NotificationService::AllSources());
 }
 
+namespace {
+class HitTestView : public ChromeViews::View {
+ public:
+  explicit HitTestView(bool has_hittest_mask)
+      : has_hittest_mask_(has_hittest_mask) {
+  }
+  virtual ~HitTestView() {}
+
+ protected:
+  // Overridden from ChromeViews::View:
+  virtual bool HasHitTestMask() const {
+    return has_hittest_mask_;
+  }
+  virtual void GetHitTestMask(gfx::Path* mask) const {
+    DCHECK(has_hittest_mask_);
+    DCHECK(mask);
+
+    SkScalar w = SkIntToScalar(GetWidth());
+    SkScalar h = SkIntToScalar(GetHeight());
+
+    // Create a triangular mask within the bounds of this View.
+    mask->moveTo(w / 2, 0);
+    mask->lineTo(w, h);
+    mask->lineTo(0, h);
+    mask->close();
+  }
+
+ private:
+  bool has_hittest_mask_;
+
+  DISALLOW_COPY_AND_ASSIGN(HitTestView);
+};
+
+POINT ConvertPointToView(ChromeViews::View* view, const POINT& p) {
+  CPoint tmp = p;
+  ChromeViews::View::ConvertPointToView(view->GetRootView(), view, &tmp);
+  return tmp;
+}
+}
+
+TEST_F(ViewTest, HitTestMasks) {
+  ChromeViews::HWNDViewContainer* window = new ChromeViews::HWNDViewContainer;
+  ChromeViews::RootView* root_view = window->GetRootView();
+  root_view->SetBounds(0, 0, 500, 500);
+
+  gfx::Rect v1_bounds = gfx::Rect(0, 0, 100, 100);
+  HitTestView* v1 = new HitTestView(false);
+  v1->SetBounds(v1_bounds.ToRECT());
+  root_view->AddChildView(v1);
+
+  gfx::Rect v2_bounds = gfx::Rect(105, 0, 100, 100);
+  HitTestView* v2 = new HitTestView(true);
+  v2->SetBounds(v2_bounds.ToRECT());
+  root_view->AddChildView(v2);
+
+  POINT v1_centerpoint = v1_bounds.CenterPoint().ToPOINT();
+  POINT v2_centerpoint = v2_bounds.CenterPoint().ToPOINT();
+  POINT v1_origin = v1_bounds.origin().ToPOINT();
+  POINT v2_origin = v2_bounds.origin().ToPOINT();
+
+  // Test HitTest
+  EXPECT_EQ(true, v1->HitTest(ConvertPointToView(v1, v1_centerpoint)));
+  EXPECT_EQ(true, v2->HitTest(ConvertPointToView(v2, v2_centerpoint)));
+
+  EXPECT_EQ(true, v1->HitTest(ConvertPointToView(v1, v1_origin)));
+  EXPECT_EQ(false, v2->HitTest(ConvertPointToView(v2, v2_origin)));
+
+  // Test GetViewForPoint
+  EXPECT_EQ(v1, root_view->GetViewForPoint(v1_centerpoint));
+  EXPECT_EQ(v2, root_view->GetViewForPoint(v2_centerpoint));
+  EXPECT_EQ(v1, root_view->GetViewForPoint(v1_origin));
+  EXPECT_EQ(root_view, root_view->GetViewForPoint(v2_origin));
+}