content/browser/renderer_host/input/gesture_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/gesture_text_selector.h"
   6
   7 #include "ui/events/event_constants.h"
   8 #include "ui/events/gesture_detection/gesture_event_data.h"
   9 #include "ui/events/gesture_detection/motion_event.h"
  10
  11 namespace content {
  12
  13 GestureTextSelector::GestureTextSelector(GestureTextSelectorClient* client)
  14     : client_(client),
  15       text_selection_triggered_(false),
  16       anchor_x_(0.0f),
  17       anchor_y_(0.0f) {
  18 }
  19
  20 GestureTextSelector::~GestureTextSelector() {
  21 }
  22
  23 bool GestureTextSelector::OnTouchEvent(const ui::MotionEvent& event) {
  24   if (event.GetAction() == ui::MotionEvent::ACTION_DOWN) {
  25     // Only trigger selection on ACTION_DOWN to prevent partial touch or gesture
  26     // sequences from being forwarded.
  27     text_selection_triggered_ = ShouldStartTextSelection(event);
  28   }
  29   return text_selection_triggered_;
  30 }
  31
  32 bool GestureTextSelector::OnGestureEvent(const ui::GestureEventData& gesture) {
  33   if (!text_selection_triggered_)
  34     return false;
  35
  36   switch (gesture.type()) {
  37     case ui::ET_GESTURE_TAP: {
  38       client_->LongPress(gesture.time, gesture.x, gesture.y);
  39       break;
  40     }
  41     case ui::ET_GESTURE_SCROLL_BEGIN: {
  42       client_->Unselect();
  43       anchor_x_ = gesture.x;
  44       anchor_y_ = gesture.y;
  45       break;
  46     }
  47     case ui::ET_GESTURE_SCROLL_UPDATE: {
  48       // TODO(changwan): check if we can show handles on ET_GESTURE_SCROLL_END
  49       // instead. Currently it is not possible as ShowSelectionHandles should
  50       // be called before we change the selection.
  51       client_->ShowSelectionHandlesAutomatically();
  52       client_->SelectRange(anchor_x_, anchor_y_, gesture.x, gesture.y);
  53       break;
  54     }
  55     default:
  56       // Suppress all other gestures when we are selecting text.
  57       break;
  58   }
  59   return true;
  60 }
  61
  62 // static
  63 bool GestureTextSelector::ShouldStartTextSelection(
  64     const ui::MotionEvent& event) {
  65   DCHECK_GT(event.GetPointerCount(), 0u);
  66   // Currently we are supporting stylus-only cases.
  67   const bool is_stylus =
  68       event.GetToolType(0) == ui::MotionEvent::TOOL_TYPE_STYLUS;
  69   const bool is_only_secondary_button_pressed =
  70       event.GetButtonState() == ui::MotionEvent::BUTTON_SECONDARY;
  71   return is_stylus && is_only_secondary_button_pressed;
  72 }
  73
  74 }  // namespace content