ash/wm/gestures/overview_gesture_handler.cc

   1 // Copyright 2013 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 "ash/wm/gestures/overview_gesture_handler.h"
   6
   7 #include "ash/metrics/user_metrics_recorder.h"
   8 #include "ash/shell.h"
   9 #include "ash/wm/overview/window_selector_controller.h"
  10 #include "ui/aura/window.h"
  11 #include "ui/events/event.h"
  12 #include "ui/events/event_constants.h"
  13 #include "ui/gfx/rect.h"
  14 #include "ui/gfx/screen.h"
  15 #include "ui/wm/core/coordinate_conversion.h"
  16
  17 namespace ash {
  18 namespace {
  19
  20 // The number of pixels from the top of the screen (a virtual bezel) to allow
  21 // the overview swipe down gesture to begin within. Note this does not actually
  22 // prevent handling of the touches so a fullscreen page which consumes these can
  23 // prevent entering overview with a swipe down.
  24 const int kTopBezelExtraPixels = 5;
  25
  26 // The threshold before engaging overview on a three finger swipe on the
  27 // touchpad.
  28 const float kSwipeThresholdPixels = 300;
  29
  30 }  // namespace;
  31
  32 OverviewGestureHandler::OverviewGestureHandler()
  33     : in_top_bezel_gesture_(false),
  34       scroll_x_(0),
  35       scroll_y_(0) {
  36 }
  37
  38 OverviewGestureHandler::~OverviewGestureHandler() {
  39 }
  40
  41 bool OverviewGestureHandler::ProcessScrollEvent(const ui::ScrollEvent& event) {
  42   if (event.type() == ui::ET_SCROLL_FLING_START ||
  43       event.type() == ui::ET_SCROLL_FLING_CANCEL ||
  44       event.finger_count() != 3) {
  45     scroll_x_ = scroll_y_ = 0;
  46     return false;
  47   }
  48
  49   scroll_x_ += event.x_offset();
  50   scroll_y_ += event.y_offset();
  51
  52   // Horizontal swiping is ignored.
  53   if (std::fabs(scroll_x_) >= std::fabs(scroll_y_)) {
  54     scroll_x_ = scroll_y_ = 0;
  55     return false;
  56   }
  57
  58   // Only allow swipe up to enter overview, down to exit. Ignore extra swiping
  59   // in the wrong direction.
  60   Shell* shell = Shell::GetInstance();
  61   if (shell->window_selector_controller()->IsSelecting()) {
  62     if (scroll_y_ < 0)
  63       scroll_x_ = scroll_y_ = 0;
  64     if (scroll_y_ < kSwipeThresholdPixels)
  65       return false;
  66   } else {
  67     if (scroll_y_ > 0)
  68       scroll_x_ = scroll_y_ = 0;
  69     if (scroll_y_ > -kSwipeThresholdPixels)
  70       return false;
  71   }
  72
  73   // Reset scroll amount on toggling.
  74   scroll_x_ = scroll_y_ = 0;
  75   shell->metrics()->RecordUserMetricsAction(UMA_TOUCHPAD_GESTURE_OVERVIEW);
  76   shell->window_selector_controller()->ToggleOverview();
  77   return true;
  78 }
  79
  80 bool OverviewGestureHandler::ProcessGestureEvent(
  81     const ui::GestureEvent& event) {
  82   // Detect at the beginning of any gesture whether it begins on the top bezel.
  83   if (event.type() == ui::ET_GESTURE_BEGIN &&
  84       event.details().touch_points() == 1) {
  85     gfx::Point point_in_screen(event.location());
  86     aura::Window* target = static_cast<aura::Window*>(event.target());
  87     ::wm::ConvertPointToScreen(target, &point_in_screen);
  88     in_top_bezel_gesture_ = !Shell::GetScreen()->GetDisplayNearestPoint(
  89         point_in_screen).bounds().y() + kTopBezelExtraPixels >
  90             point_in_screen.y();
  91     return false;
  92   }
  93
  94   if (!in_top_bezel_gesture_ ||
  95       event.type() != ui::ET_GESTURE_SWIPE ||
  96       !event.details().swipe_down() ||
  97       event.details().touch_points() != 3) {
  98     return false;
  99   }
 100
 101   Shell* shell = Shell::GetInstance();
 102   shell->metrics()->RecordUserMetricsAction(UMA_GESTURE_OVERVIEW);
 103   shell->window_selector_controller()->ToggleOverview();
 104   return true;
 105 }
 106
 107 }  // namespace ash