Home | History | Annotate | Download | only in util 
      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 "athena/util/drag_handle.h"
      6 
      7 #include "ui/views/background.h"
      8 #include "ui/views/view.h"
      9 
     10 namespace athena {
     11 namespace {
     12 
     13 const SkColor kDragHandleColorNormal = SK_ColorGRAY;
     14 const SkColor kDragHandleColorHot = SK_ColorWHITE;
     15 
     16 // This view notifies its delegate of the touch scroll gestures performed on it.
     17 class DragHandleView : public views::View {
     18  public:
     19   DragHandleView(DragHandleScrollDirection scroll_direction,
     20                  DragHandleScrollDelegate* delegate,
     21                  int preferred_width,
     22                  int preferred_height);
     23   virtual ~DragHandleView();
     24 
     25  private:
     26   void SetColor(SkColor color);
     27 
     28   void SetIsScrolling(bool scrolling);
     29 
     30   // views::View:
     31   virtual gfx::Size GetPreferredSize() const OVERRIDE;
     32   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
     33 
     34   bool scroll_in_progress_;
     35   DragHandleScrollDelegate* delegate_;
     36   DragHandleScrollDirection scroll_direction_;
     37   SkColor color_;
     38   float scroll_start_location_;
     39   const int preferred_width_;
     40   const int preferred_height_;
     41 
     42   DISALLOW_COPY_AND_ASSIGN(DragHandleView);
     43 };
     44 
     45 DragHandleView::DragHandleView(DragHandleScrollDirection scroll_direction,
     46                                DragHandleScrollDelegate* delegate,
     47                                int preferred_width,
     48                                int preferred_height)
     49     : scroll_in_progress_(false),
     50       delegate_(delegate),
     51       scroll_direction_(scroll_direction),
     52       color_(SK_ColorTRANSPARENT),
     53       preferred_width_(preferred_width),
     54       preferred_height_(preferred_height) {
     55   SetColor(kDragHandleColorNormal);
     56 }
     57 
     58 DragHandleView::~DragHandleView() {
     59 }
     60 
     61 void DragHandleView::SetColor(SkColor color) {
     62   if (color_ == color)
     63     return;
     64   color_ = color;
     65   set_background(views::Background::CreateSolidBackground(color_));
     66   SchedulePaint();
     67 }
     68 
     69 void DragHandleView::SetIsScrolling(bool scrolling) {
     70   if (scroll_in_progress_ == scrolling)
     71     return;
     72   scroll_in_progress_ = scrolling;
     73   if (!scroll_in_progress_)
     74     scroll_start_location_ = 0;
     75 }
     76 
     77 // views::View:
     78 gfx::Size DragHandleView::GetPreferredSize() const {
     79   return gfx::Size(preferred_width_, preferred_height_);
     80 }
     81 
     82 void DragHandleView::OnGestureEvent(ui::GestureEvent* event) {
     83   SkColor change_color = SK_ColorTRANSPARENT;
     84   if (event->type() == ui::ET_GESTURE_BEGIN &&
     85       event->details().touch_points() == 1) {
     86     change_color = kDragHandleColorHot;
     87   } else if (event->type() == ui::ET_GESTURE_END &&
     88              event->details().touch_points() == 1) {
     89     change_color = kDragHandleColorNormal;
     90   }
     91 
     92   if (change_color != SK_ColorTRANSPARENT) {
     93     SetColor(change_color);
     94     event->SetHandled();
     95     return;
     96   }
     97 
     98   if (event->type() == ui::ET_GESTURE_SCROLL_BEGIN) {
     99     if (scroll_in_progress_)
    100       return;
    101     float delta;
    102     if (scroll_direction_ == DRAG_HANDLE_VERTICAL) {
    103       delta = event->details().scroll_y_hint();
    104       scroll_start_location_ = event->root_location().y();
    105     } else {
    106       delta = event->details().scroll_x_hint();
    107       scroll_start_location_ = event->root_location().x();
    108     }
    109     delegate_->HandleScrollBegin(delta);
    110     SetIsScrolling(true);
    111     event->SetHandled();
    112   } else if (event->type() == ui::ET_GESTURE_SCROLL_END ||
    113              event->type() == ui::ET_SCROLL_FLING_START) {
    114     if (!scroll_in_progress_)
    115       return;
    116     delegate_->HandleScrollEnd();
    117     SetColor(kDragHandleColorNormal);
    118     SetIsScrolling(false);
    119     event->SetHandled();
    120   } else if (event->type() == ui::ET_GESTURE_SCROLL_UPDATE) {
    121     if (!scroll_in_progress_)
    122       return;
    123     float delta = scroll_direction_ == DRAG_HANDLE_VERTICAL
    124                       ? event->root_location().y() - scroll_start_location_
    125                       : event->root_location().x() - scroll_start_location_;
    126     delegate_->HandleScrollUpdate(delta);
    127     event->SetHandled();
    128   }
    129 }
    130 
    131 }  // namespace
    132 
    133 views::View* CreateDragHandleView(DragHandleScrollDirection scroll_direction,
    134                                   DragHandleScrollDelegate* delegate,
    135                                   int preferred_width,
    136                                   int preferred_height) {
    137   views::View* view = new DragHandleView(
    138       scroll_direction, delegate, preferred_width, preferred_height);
    139   return view;
    140 }
    141 
    142 }  // namespace athena
    143