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/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
 
@@ skipping 189 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 (!View::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)

[tdanderson, 2013/10/03 23:17:42]

If this code stays, I think the #if defined(USE_ASH) code in
TabCloseButton::GetEventHandlerForRect() can be removed.

[sky, 2013/10/04 17:05:14]

I don't like this ifdef. It implies the API should contain a bit more
information than is passed.

[tdanderson, 2013/10/07 21:35:21]

I'm also not a fan of having this ifdef where it is, but my understanding is
that we only want to include the padding if USE_ASH is true, so we have to have
the ifdef somewhere (similar to what we're already doing in
TabCloseButton::GetEventHandlerForRect()). Would moving it to a new function
such as bool TabCloseButton::IncludePadding() be better?

[sky, 2013/10/08 15:39:07]

My point is that if a view needs to know if touch is down to change the behavior
of this GetHitTestMask it implies to me the state should be passed in, eg
GetHitTestMask(HitTestSource source, path).

HitTestSource would be: touch, mouse or whatever we use.

+    // 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();
 }