src/ui/views/view_targeter_delegate.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/views/view_targeter_delegate.h"
   6
   7 #include "ui/gfx/rect_conversions.h"
   8 #include "ui/views/rect_based_targeting_utils.h"
   9 #include "ui/views/view.h"
  10
  11 namespace {
  12
  13 // The minimum percentage of a view's area that needs to be covered by a rect
  14 // representing a touch region in order for that view to be considered by the
  15 // rect-based targeting algorithm.
  16 static const float kRectTargetOverlap = 0.6f;
  17
  18 }  // namespace
  19
  20 namespace views {
  21
  22 // TODO(tdanderson): Move the contents of rect_based_targeting_utils.(h|cc)
  23 //                   into here.
  24
  25 bool ViewTargeterDelegate::DoesIntersectRect(const View* target,
  26                                              const gfx::Rect& rect) const {
  27   return target->GetLocalBounds().Intersects(rect);
  28 }
  29
  30 View* ViewTargeterDelegate::TargetForRect(View* root, const gfx::Rect& rect) {
  31   // |rect_view| represents the current best candidate to return
  32   // if rect-based targeting (i.e., fuzzing) is used.
  33   // |rect_view_distance| is used to keep track of the distance
  34   // between the center point of |rect_view| and the center
  35   // point of |rect|.
  36   View* rect_view = NULL;
  37   int rect_view_distance = INT_MAX;
  38
  39   // |point_view| represents the view that would have been returned
  40   // from this function call if point-based targeting were used.
  41   View* point_view = NULL;
  42
  43   for (int i = root->child_count() - 1; i >= 0; --i) {
  44     View* child = root->child_at(i);
  45
  46     if (!child->CanProcessEventsWithinSubtree())
  47       continue;
  48
  49     // Ignore any children which are invisible or do not intersect |rect|.
  50     if (!child->visible())
  51       continue;
  52     gfx::RectF rect_in_child_coords_f(rect);
  53     View::ConvertRectToTarget(root, child, &rect_in_child_coords_f);
  54     gfx::Rect rect_in_child_coords = gfx::ToEnclosingRect(
  55         rect_in_child_coords_f);
  56     if (!child->HitTestRect(rect_in_child_coords))
  57       continue;
  58
  59     View* cur_view = child->GetEventHandlerForRect(rect_in_child_coords);
  60
  61     if (views::UsePointBasedTargeting(rect))
  62       return cur_view;
  63
  64     gfx::RectF cur_view_bounds_f(cur_view->GetLocalBounds());
  65     View::ConvertRectToTarget(cur_view, root, &cur_view_bounds_f);
  66     gfx::Rect cur_view_bounds = gfx::ToEnclosingRect(
  67         cur_view_bounds_f);
  68     if (views::PercentCoveredBy(cur_view_bounds, rect) >= kRectTargetOverlap) {
  69       // |cur_view| is a suitable candidate for rect-based targeting.
  70       // Check to see if it is the closest suitable candidate so far.
  71       gfx::Point touch_center(rect.CenterPoint());
  72       int cur_dist = views::DistanceSquaredFromCenterToPoint(touch_center,
  73                                                              cur_view_bounds);
  74       if (!rect_view || cur_dist < rect_view_distance) {
  75         rect_view = cur_view;
  76         rect_view_distance = cur_dist;
  77       }
  78     } else if (!rect_view && !point_view) {
  79       // Rect-based targeting has not yielded any candidates so far. Check
  80       // if point-based targeting would have selected |cur_view|.
  81       gfx::Point point_in_child_coords(rect_in_child_coords.CenterPoint());
  82       if (child->HitTestPoint(point_in_child_coords))
  83         point_view = child->GetEventHandlerForPoint(point_in_child_coords);
  84     }
  85   }
  86
  87   if (views::UsePointBasedTargeting(rect) || (!rect_view && !point_view))
  88     return root;
  89
  90   // If |root| is a suitable candidate for rect-based targeting, check to
  91   // see if it is closer than the current best suitable candidate so far.
  92   gfx::Rect local_bounds(root->GetLocalBounds());
  93   if (views::PercentCoveredBy(local_bounds, rect) >= kRectTargetOverlap) {
  94     gfx::Point touch_center(rect.CenterPoint());
  95     int cur_dist = views::DistanceSquaredFromCenterToPoint(touch_center,
  96                                                            local_bounds);
  97     if (!rect_view || cur_dist < rect_view_distance)
  98       rect_view = root;
  99   }
 100
 101   return rect_view ? rect_view : point_view;
 102 }
 103
 104 }  // namespace views