src/ui/app_list/views/page_switcher.cc

   1 // Copyright (c) 2012 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/app_list/views/page_switcher.h"
   6
   7 #include <algorithm>
   8
   9 #include "third_party/skia/include/core/SkPath.h"
  10 #include "ui/app_list/app_list_constants.h"
  11 #include "ui/app_list/pagination_model.h"
  12 #include "ui/gfx/animation/throb_animation.h"
  13 #include "ui/gfx/canvas.h"
  14 #include "ui/gfx/skia_util.h"
  15 #include "ui/views/controls/button/custom_button.h"
  16 #include "ui/views/layout/box_layout.h"
  17
  18 namespace app_list {
  19
  20 namespace {
  21
  22 const int kPreferredHeight = 57;
  23
  24 const int kMaxButtonSpacing = 18;
  25 const int kMinButtonSpacing = 4;
  26 const int kMaxButtonWidth = 68;
  27 const int kMinButtonWidth = 28;
  28 const int kButtonHeight = 6;
  29 const int kButtonCornerRadius = 2;
  30 const int kButtonStripPadding = 20;
  31
  32 class PageSwitcherButton : public views::CustomButton {
  33  public:
  34   explicit PageSwitcherButton(views::ButtonListener* listener)
  35       : views::CustomButton(listener),
  36         button_width_(kMaxButtonWidth),
  37         selected_range_(0) {
  38   }
  39   virtual ~PageSwitcherButton() {}
  40
  41   void SetSelectedRange(double selected_range) {
  42     if (selected_range_ == selected_range)
  43       return;
  44
  45     selected_range_ = selected_range;
  46     SchedulePaint();
  47   }
  48
  49   void set_button_width(int button_width) { button_width_ = button_width; }
  50
  51   // Overridden from views::View:
  52   virtual gfx::Size GetPreferredSize() OVERRIDE {
  53     return gfx::Size(button_width_, kButtonHeight);
  54   }
  55
  56   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE {
  57     if (state() == STATE_HOVERED)
  58       PaintButton(canvas, kPagerHoverColor);
  59     else
  60       PaintButton(canvas, kPagerNormalColor);
  61   }
  62
  63  private:
  64   // Paints a button that has two rounded corner at bottom.
  65   void PaintButton(gfx::Canvas* canvas, SkColor base_color) {
  66     gfx::Rect rect(GetContentsBounds());
  67     rect.ClampToCenteredSize(gfx::Size(button_width_, kButtonHeight));
  68
  69     SkPath path;
  70     path.addRoundRect(gfx::RectToSkRect(rect),
  71                       SkIntToScalar(kButtonCornerRadius),
  72                       SkIntToScalar(kButtonCornerRadius));
  73
  74     SkPaint paint;
  75     paint.setAntiAlias(true);
  76     paint.setStyle(SkPaint::kFill_Style);
  77     paint.setColor(base_color);
  78     canvas->DrawPath(path, paint);
  79
  80     int selected_start_x = 0;
  81     int selected_width = 0;
  82     if (selected_range_ > 0) {
  83       selected_width = selected_range_ * rect.width();
  84     } else if (selected_range_ < 0) {
  85       selected_width =  -selected_range_ * rect.width();
  86       selected_start_x = rect.right() - selected_width;
  87     }
  88
  89     if (selected_width) {
  90       gfx::Rect selected_rect(rect);
  91       selected_rect.set_x(selected_start_x);
  92       selected_rect.set_width(selected_width);
  93
  94       SkPath selected_path;
  95       selected_path.addRoundRect(gfx::RectToSkRect(selected_rect),
  96                                  SkIntToScalar(kButtonCornerRadius),
  97                                  SkIntToScalar(kButtonCornerRadius));
  98       paint.setColor(kPagerSelectedColor);
  99       canvas->DrawPath(selected_path, paint);
 100     }
 101   }
 102
 103   int button_width_;
 104
 105   // [-1, 1] range that represents the portion of the button that should be
 106   // painted with kSelectedColor. Positive range starts from left side and
 107   // negative range starts from the right side.
 108   double selected_range_;
 109
 110   DISALLOW_COPY_AND_ASSIGN(PageSwitcherButton);
 111 };
 112
 113 // Gets PageSwitcherButton at |index| in |buttons|.
 114 PageSwitcherButton* GetButtonByIndex(views::View* buttons, int index) {
 115   return static_cast<PageSwitcherButton*>(buttons->child_at(index));
 116 }
 117
 118 }  // namespace
 119
 120 PageSwitcher::PageSwitcher(PaginationModel* model)
 121     : model_(model),
 122       buttons_(new views::View) {
 123   AddChildView(buttons_);
 124
 125   TotalPagesChanged();
 126   SelectedPageChanged(-1, model->selected_page());
 127   model_->AddObserver(this);
 128 }
 129
 130 PageSwitcher::~PageSwitcher() {
 131   model_->RemoveObserver(this);
 132 }
 133
 134 int PageSwitcher::GetPageForPoint(const gfx::Point& point) const {
 135   if (!buttons_->bounds().Contains(point))
 136     return -1;
 137
 138   gfx::Point buttons_point(point);
 139   views::View::ConvertPointToTarget(this, buttons_, &buttons_point);
 140
 141   for (int i = 0; i < buttons_->child_count(); ++i) {
 142     const views::View* button = buttons_->child_at(i);
 143     if (button->bounds().Contains(buttons_point))
 144       return i;
 145   }
 146
 147   return -1;
 148 }
 149
 150 void PageSwitcher::UpdateUIForDragPoint(const gfx::Point& point) {
 151   int page = GetPageForPoint(point);
 152
 153   const int button_count = buttons_->child_count();
 154   if (page >= 0 && page < button_count) {
 155     PageSwitcherButton* button =
 156         static_cast<PageSwitcherButton*>(buttons_->child_at(page));
 157     button->SetState(views::CustomButton::STATE_HOVERED);
 158     return;
 159   }
 160
 161   for (int i = 0; i < button_count; ++i) {
 162     PageSwitcherButton* button =
 163         static_cast<PageSwitcherButton*>(buttons_->child_at(i));
 164     button->SetState(views::CustomButton::STATE_NORMAL);
 165   }
 166 }
 167
 168 gfx::Size PageSwitcher::GetPreferredSize() {
 169   // Always return a size with correct height so that container resize is not
 170   // needed when more pages are added.
 171   return gfx::Size(buttons_->GetPreferredSize().width(),
 172                    kPreferredHeight);
 173 }
 174
 175 void PageSwitcher::Layout() {
 176   gfx::Rect rect(GetContentsBounds());
 177
 178   CalculateButtonWidthAndSpacing(rect.width());
 179
 180   // Makes |buttons_| horizontally center and vertically fill.
 181   gfx::Size buttons_size(buttons_->GetPreferredSize());
 182   gfx::Rect buttons_bounds(rect.CenterPoint().x() - buttons_size.width() / 2,
 183                            rect.y(),
 184                            buttons_size.width(),
 185                            rect.height());
 186   buttons_->SetBoundsRect(gfx::IntersectRects(rect, buttons_bounds));
 187 }
 188
 189 void PageSwitcher::CalculateButtonWidthAndSpacing(int contents_width) {
 190   const int button_count = buttons_->child_count();
 191   if (!button_count)
 192     return;
 193
 194   contents_width -= 2 * kButtonStripPadding;
 195
 196   int button_width = kMinButtonWidth;
 197   int button_spacing = kMinButtonSpacing;
 198   if (button_count > 1) {
 199     button_spacing = (contents_width - button_width * button_count) /
 200         (button_count - 1);
 201     button_spacing = std::min(kMaxButtonSpacing,
 202                               std::max(kMinButtonSpacing, button_spacing));
 203   }
 204
 205   button_width = (contents_width - (button_count - 1) * button_spacing) /
 206       button_count;
 207   button_width = std::min(kMaxButtonWidth,
 208                           std::max(kMinButtonWidth, button_width));
 209
 210   buttons_->SetLayoutManager(new views::BoxLayout(
 211       views::BoxLayout::kHorizontal, kButtonStripPadding, 0, button_spacing));
 212   for (int i = 0; i < button_count; ++i) {
 213     PageSwitcherButton* button =
 214         static_cast<PageSwitcherButton*>(buttons_->child_at(i));
 215     button->set_button_width(button_width);
 216   }
 217 }
 218
 219 void PageSwitcher::ButtonPressed(views::Button* sender,
 220                                  const ui::Event& event) {
 221   for (int i = 0; i < buttons_->child_count(); ++i) {
 222     if (sender == static_cast<views::Button*>(buttons_->child_at(i))) {
 223       model_->SelectPage(i, true /* animate */);
 224       break;
 225     }
 226   }
 227 }
 228
 229 void PageSwitcher::TotalPagesChanged() {
 230   buttons_->RemoveAllChildViews(true);
 231   for (int i = 0; i < model_->total_pages(); ++i) {
 232     PageSwitcherButton* button = new PageSwitcherButton(this);
 233     button->SetSelectedRange(i == model_->selected_page() ? 1 : 0);
 234     buttons_->AddChildView(button);
 235   }
 236   buttons_->SetVisible(model_->total_pages() > 1);
 237   Layout();
 238 }
 239
 240 void PageSwitcher::SelectedPageChanged(int old_selected, int new_selected) {
 241   if (old_selected >= 0 && old_selected < buttons_->child_count())
 242     GetButtonByIndex(buttons_, old_selected)->SetSelectedRange(0);
 243   if (new_selected >= 0 && new_selected < buttons_->child_count())
 244     GetButtonByIndex(buttons_, new_selected)->SetSelectedRange(1);
 245 }
 246
 247 void PageSwitcher::TransitionStarted() {
 248 }
 249
 250 void PageSwitcher::TransitionChanged() {
 251   const int current_page = model_->selected_page();
 252   const int target_page = model_->transition().target_page;
 253
 254   double progress = model_->transition().progress;
 255   double remaining = progress - 1;
 256
 257   if (current_page > target_page) {
 258     remaining = -remaining;
 259     progress = -progress;
 260   }
 261
 262   GetButtonByIndex(buttons_, current_page)->SetSelectedRange(remaining);
 263   if (model_->is_valid_page(target_page))
 264     GetButtonByIndex(buttons_, target_page)->SetSelectedRange(progress);
 265 }
 266
 267 }  // namespace app_list