content/browser/renderer_host/input/stylus_text_selector.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 "content/browser/renderer_host/input/stylus_text_selector.h"
   6
   7 #include "ui/events/event_constants.h"
   8 #include "ui/events/gesture_detection/gesture_detector.h"
   9 #include "ui/events/gesture_detection/gesture_provider_config_helper.h"
  10 #include "ui/events/gesture_detection/motion_event.h"
  11
  12 using ui::GestureDetector;
  13 using ui::MotionEvent;
  14
  15 namespace content {
  16 namespace {
  17 scoped_ptr<GestureDetector> CreateGestureDetector(
  18     ui::GestureListener* listener) {
  19   GestureDetector::Config config =
  20       ui::GetGestureProviderConfig(
  21           ui::GestureProviderConfigType::CURRENT_PLATFORM)
  22           .gesture_detector_config;
  23
  24   ui::DoubleTapListener* null_double_tap_listener = nullptr;
  25
  26   // Doubletap, showpress and longpress detection are not required, and
  27   // should be explicitly disabled for efficiency.
  28   scoped_ptr<ui::GestureDetector> detector(
  29       new ui::GestureDetector(config, listener, null_double_tap_listener));
  30   detector->set_longpress_enabled(false);
  31   detector->set_showpress_enabled(false);
  32
  33   return detector.Pass();
  34 }
  35
  36 }  // namespace
  37
  38 StylusTextSelector::StylusTextSelector(StylusTextSelectorClient* client)
  39     : client_(client),
  40       text_selection_triggered_(false),
  41       secondary_button_pressed_(false),
  42       dragging_(false),
  43       dragged_(false),
  44       anchor_x_(0.0f),
  45       anchor_y_(0.0f) {
  46   DCHECK(client);
  47 }
  48
  49 StylusTextSelector::~StylusTextSelector() {
  50 }
  51
  52 bool StylusTextSelector::OnTouchEvent(const MotionEvent& event) {
  53   // Only trigger selection on ACTION_DOWN to prevent partial touch or gesture
  54   // sequences from being forwarded.
  55   if (event.GetAction() == MotionEvent::ACTION_DOWN)
  56     text_selection_triggered_ = ShouldStartTextSelection(event);
  57
  58   if (!text_selection_triggered_)
  59     return false;
  60
  61   secondary_button_pressed_ =
  62       event.GetButtonState() == MotionEvent::BUTTON_SECONDARY;
  63
  64   switch (event.GetAction()) {
  65     case MotionEvent::ACTION_DOWN:
  66       dragging_ = false;
  67       dragged_ = false;
  68       anchor_x_ = event.GetX();
  69       anchor_y_ = event.GetY();
  70       break;
  71
  72     case MotionEvent::ACTION_MOVE:
  73       if (!secondary_button_pressed_) {
  74         dragging_ = false;
  75         anchor_x_ = event.GetX();
  76         anchor_y_ = event.GetY();
  77       }
  78       break;
  79
  80     case MotionEvent::ACTION_UP:
  81     case MotionEvent::ACTION_CANCEL:
  82       if (dragged_)
  83         client_->OnStylusSelectEnd();
  84       dragged_ = false;
  85       dragging_ = false;
  86       break;
  87
  88     case MotionEvent::ACTION_POINTER_UP:
  89     case MotionEvent::ACTION_POINTER_DOWN:
  90       break;
  91     case MotionEvent::ACTION_NONE:
  92       NOTREACHED();
  93       break;
  94   }
  95
  96   if (!gesture_detector_)
  97     gesture_detector_ = CreateGestureDetector(this);
  98
  99   gesture_detector_->OnTouchEvent(event);
 100
 101   // Always return true, even if |gesture_detector_| technically doesn't
 102   // consume the event. This prevents forwarding of a partial touch stream.
 103   return true;
 104 }
 105
 106 bool StylusTextSelector::OnSingleTapUp(const MotionEvent& e) {
 107   DCHECK(text_selection_triggered_);
 108   DCHECK(!dragging_);
 109   client_->OnStylusSelectTap(e.GetEventTime(), e.GetX(), e.GetY());
 110   return true;
 111 }
 112
 113 bool StylusTextSelector::OnScroll(const MotionEvent& e1,
 114                                   const MotionEvent& e2,
 115                                   float distance_x,
 116                                   float distance_y) {
 117   DCHECK(text_selection_triggered_);
 118
 119   // Return if Stylus button is not pressed.
 120   if (!secondary_button_pressed_)
 121     return true;
 122
 123   if (!dragging_) {
 124     dragging_ = true;
 125     dragged_ = true;
 126     client_->OnStylusSelectBegin(anchor_x_, anchor_y_, e2.GetX(), e2.GetY());
 127   } else {
 128     client_->OnStylusSelectUpdate(e2.GetX(), e2.GetY());
 129   }
 130
 131   return true;
 132 }
 133
 134 // static
 135 bool StylusTextSelector::ShouldStartTextSelection(const MotionEvent& event) {
 136   DCHECK_GT(event.GetPointerCount(), 0u);
 137   // Currently we are supporting stylus-only cases.
 138   const bool is_stylus = event.GetToolType(0) == MotionEvent::TOOL_TYPE_STYLUS;
 139   const bool is_only_secondary_button_pressed =
 140       event.GetButtonState() == MotionEvent::BUTTON_SECONDARY;
 141   return is_stylus && is_only_secondary_button_pressed;
 142 }
 143
 144 }  // namespace content