Add support for rect-based event targeting in views

chrome/browser/ui/views/tabs/tab.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/tabs/tab.h"
 
 #include <limits>
 
 #include "base/command_line.h"
 #include "base/debug/alias.h"
@@ skipping 21 matching lines @@
 #include "ui/base/theme_provider.h"
 #include "ui/gfx/animation/animation_container.h"
 #include "ui/gfx/animation/multi_animation.h"
 #include "ui/gfx/animation/throb_animation.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/color_analysis.h"
 #include "ui/gfx/favicon_size.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/image/image_skia_operations.h"
 #include "ui/gfx/path.h"
+#include "ui/gfx/rect_conversions.h"
+#include "ui/gfx/skia_util.h"
 #include "ui/gfx/text_elider.h"
 #include "ui/views/controls/button/image_button.h"
+#include "ui/views/rect_based_targeting_utils.h"
 #include "ui/views/widget/tooltip_manager.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/window/non_client_view.h"
 
 #if defined(OS_WIN)
 #include "win8/util/win8_util.h"
 #endif
 
 #if defined(USE_ASH)
 #include "ui/aura/env.h"
@@ skipping 187 matching lines @@
 
 // Number of steps in the immersive mode loading animation.
 const int kImmersiveLoadingStepCount = 32;
 
 // Scale to resize the current favicon by when projecting.
 const double kProjectingFaviconResizeScale = 0.75;
 
 // Scale to resize the projection sheet glow by.
 const double kProjectingGlowResizeScale = 2.0;
 
+const char kTabCloseButtonName[] = "TabCloseButton";
+
 void DrawIconAtLocation(gfx::Canvas* canvas,
                         const gfx::ImageSkia& image,
                         int image_offset,
                         int dst_x,
                         int dst_y,
                         int icon_width,
                         int icon_height,
                         bool filter,
                         const SkPaint& paint) {
   // NOTE: the clipping is a work around for 69528, it shouldn't be necessary.
@@ skipping 89 matching lines @@
 // TabCloseButton
 //
 //  This is a Button subclass that causes middle clicks to be forwarded to the
 //  parent View by explicitly not handling them in OnMousePressed.
 class Tab::TabCloseButton : public views::ImageButton {
  public:
   explicit TabCloseButton(Tab* tab) : views::ImageButton(tab), tab_(tab) {}
   virtual ~TabCloseButton() {}
 
   // Overridden from views::View.
-  virtual View* GetEventHandlerForPoint(const gfx::Point& point) OVERRIDE {
+  virtual View* GetEventHandlerForRect(const gfx::Rect& rect) OVERRIDE {
+    if (!views::UsePointBasedTargeting(rect))
+      return View::GetEventHandlerForRect(rect);
+
     // Ignore the padding set on the button.
-    gfx::Rect rect = GetContentsBounds();
-    rect.set_x(GetMirroredXForRect(rect));
+    gfx::Rect contents_bounds = GetContentsBounds();
+    contents_bounds.set_x(GetMirroredXForRect(contents_bounds));
 
 #if defined(USE_ASH)
     // Include the padding in hit-test for touch events.
     if (aura::Env::GetInstance()->is_touch_down())
-      rect = GetLocalBounds();
+      contents_bounds = GetLocalBounds();
 #elif defined(OS_WIN)
     // TODO(sky): Use local-bounds if a touch-point is active.
     // http://crbug.com/145258
 #endif
 
-    return rect.Contains(point) ? this : parent();
+    return contents_bounds.Intersects(rect) ? this : parent();
   }
 
   // Overridden from views::View.
   virtual View* GetTooltipHandlerForPoint(const gfx::Point& point) OVERRIDE {
     // Tab close button has no children, so tooltip handler should be the same
     // as the event handler.
     // In addition, a hit test has to be performed for the point (as
     // GetTooltipHandlerForPoint() is responsible for it).
     if (!HitTestPoint(point))
       return NULL;
@@ skipping 22 matching lines @@
     CustomButton::OnMouseReleased(event);
   }
 
   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE {
     // Consume all gesture events here so that the parent (Tab) does not
     // start consuming gestures.
     ImageButton::OnGestureEvent(event);
     event->SetHandled();
   }
 
+  virtual bool HasHitTestMask() const OVERRIDE {
+    return true;
+  }
+
+  virtual void GetHitTestMask(gfx::Path* path) const OVERRIDE {
+    // Use the button's contents bounds (which does not include padding)
+    // and the hit test mask of our parent |tab_| to determine if the
+    // button is completely hidden behind another tab.
+    gfx::Path tab_mask;
+    tab_->GetHitTestMask(&tab_mask);
+
+    gfx::Rect button_bounds(GetContentsBounds());
+    gfx::Rect tab_bounds(
+        gfx::ToEnclosingRect(gfx::SkRectToRectF(tab_mask.getBounds())));
+    views::View::ConvertRectToTarget(tab_, this, &tab_bounds);
+
+    // If the button is completely hidden behind another tab, the hit test
+    // mask is empty. Otherwise set the hit test mask to be the contents bounds.
+    path->reset();
+    if (tab_bounds.Contains(button_bounds)) {
+#if defined(USE_ASH)
+    // Include the padding in the hit test mask for touch events.
+    if (aura::Env::GetInstance()->is_touch_down())
+      button_bounds = GetLocalBounds();
+#endif
+      path->addRect(RectToSkRect(button_bounds));
+    }
+  }
+
+  virtual const char* GetClassName() const OVERRIDE {
+    return kTabCloseButtonName;
+  }
+
  private:
   Tab* tab_;
 
   DISALLOW_COPY_AND_ASSIGN(TabCloseButton);
 };
 
 ////////////////////////////////////////////////////////////////////////////////
 // ImageCacheEntry
 
 Tab::ImageCacheEntry::ImageCacheEntry()
@@ skipping 448 matching lines @@
 }
 
 void Tab::GetHitTestMask(gfx::Path* path) const {
   // When the window is maximized we don't want to shave off the edges or top
   // shadow of the tab, such that the user can click anywhere along the top
   // edge of the screen to select a tab. Ditto for immersive fullscreen.
   const views::Widget* widget = GetWidget();
   bool include_top_shadow =
       widget && (widget->IsMaximized() || widget->IsFullscreen());
   TabResources::GetHitTestMask(width(), height(), include_top_shadow, path);
+
+  // It is possible for a portion of the tab to be occluded if tabs are
+  // stacked, so modify the hit test mask to only include the visible
+  // region of the tab.
+  if (controller()) {
+    gfx::Rect clip;
+    controller()->ShouldPaintTab(this, &clip);
+    if (clip.size().GetArea()) {
+      SkRect intersection(path->getBounds());
+      intersection.intersect(RectToSkRect(clip));
+      path->reset();
+      path->addRect(intersection);
+    }
+  }
 }
 
 bool Tab::GetTooltipText(const gfx::Point& p, string16* tooltip) const {
   if (data_.title.empty())
     return false;
 
   // Only show the tooltip if the title is truncated.
   if (font_->GetStringWidth(data_.title) > GetTitleBounds().width()) {
     *tooltip = data_.title;
     return true;
@@ skipping 979 matching lines @@
                          const gfx::ImageSkia& image) {
   DCHECK_NE(scale_factor, ui::SCALE_FACTOR_NONE);
   ImageCacheEntry entry;
   entry.resource_id = resource_id;
   entry.scale_factor = scale_factor;
   entry.image = image;
   image_cache_->push_front(entry);
   if (image_cache_->size() > kMaxImageCacheSize)
     image_cache_->pop_back();
 }