MacViews: Overlay Scrollbars with Show/Hide Animations

ui/views/controls/scrollbar/native_scroll_bar_views.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/controls/scrollbar/native_scroll_bar_views.h"
 
 #include "base/logging.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/path.h"
@@ skipping 11 matching lines @@
 // Wrapper for the scroll buttons.
 class ScrollBarButton : public BaseScrollBarButton {
  public:
   enum Type {
     UP,
     DOWN,
     LEFT,
     RIGHT,
   };
 
-  ScrollBarButton(ButtonListener* listener, Type type);
+  ScrollBarButton(ButtonListener* listener,
+                  Type type,
+                  NativeScrollBarWrapper* wrapper);
   ~ScrollBarButton() override;
 
   gfx::Size GetPreferredSize() const override;
   const char* GetClassName() const override { return "ScrollBarButton"; }
 
  protected:
   void OnPaint(gfx::Canvas* canvas) override;
 
  private:
   ui::NativeTheme::ExtraParams GetNativeThemeParams() const;
   ui::NativeTheme::Part GetNativeThemePart() const;
   ui::NativeTheme::State GetNativeThemeState() const;
 
   Type type_;
+  NativeScrollBarWrapper* wrapper_;
 };
 
 // Wrapper for the scroll thumb
 class ScrollBarThumb : public BaseScrollBarThumb {
  public:
-  explicit ScrollBarThumb(BaseScrollBar* scroll_bar);
+  explicit ScrollBarThumb(BaseScrollBar* scroll_bar,

[tapted, 2016/02/08 00:31:15]

nit: explicit not needed

[spqchan, 2016/02/09 21:21:26]

Done.

+                          NativeScrollBarWrapper* wrapper);
   ~ScrollBarThumb() override;
 
   gfx::Size GetPreferredSize() const override;
   const char* GetClassName() const override { return "ScrollBarThumb"; }
 
  protected:
   void OnPaint(gfx::Canvas* canvas) override;
 
  private:
   ui::NativeTheme::ExtraParams GetNativeThemeParams() const;
   ui::NativeTheme::Part GetNativeThemePart() const;
   ui::NativeTheme::State GetNativeThemeState() const;
 
   ScrollBar* scroll_bar_;
+  NativeScrollBarWrapper* wrapper_;

[tapted, 2016/02/08 00:31:15]

hm. I wonder if ScrollBar should expose a GetNativeWrapper virtual method. Or,
does anything other than NativeScrollBarViews call the constructor? (can you
just pass a NativeScrollBar, add a NativeScrollBar::native_wrapper() accessor,
and change the type of |scroll_bar_| to NativeScrollBar?

[spqchan, 2016/02/09 21:21:26]

ScrollBar doesn't contain the native_wrapper so that wouldn't work.
Changing it to NativeScrollBar would work though
Anyway, I just removed the wrapper since we no longer need it

 };
 
 /////////////////////////////////////////////////////////////////////////////
 // ScrollBarButton
 
-ScrollBarButton::ScrollBarButton(ButtonListener* listener, Type type)
-    : BaseScrollBarButton(listener),
-      type_(type) {
+ScrollBarButton::ScrollBarButton(ButtonListener* listener,
+                                 Type type,
+                                 NativeScrollBarWrapper* wrapper)
+    : BaseScrollBarButton(listener), type_(type), wrapper_(wrapper) {
   SetFocusable(false);
   SetAccessibilityFocusable(false);
 }
 
 ScrollBarButton::~ScrollBarButton() {
 }
 
 gfx::Size ScrollBarButton::GetPreferredSize() const {
   return GetNativeTheme()->GetPartSize(GetNativeThemePart(),
                                        GetNativeThemeState(),
@@ skipping 13 matching lines @@
 
   switch (state()) {
     case CustomButton::STATE_HOVERED:
       params.scrollbar_arrow.is_hovering = true;
       break;
     default:
       params.scrollbar_arrow.is_hovering = false;
       break;
   }
 
+  params.scrollbar_arrow.overlay = wrapper_->GetOverlayParams();

[tapted, 2016/02/08 00:31:15]

check for a null |wrapper_|?

[spqchan, 2016/02/09 21:21:26]

Acknowledged.

+
   return params;
 }
 
 ui::NativeTheme::Part
     ScrollBarButton::GetNativeThemePart() const {
   switch (type_) {
     case UP:
       return ui::NativeTheme::kScrollbarUpArrow;
     case DOWN:
       return ui::NativeTheme::kScrollbarDownArrow;
@@ skipping 22 matching lines @@
       break;
   }
 
   NOTREACHED();
   return ui::NativeTheme::kNormal;
 }
 
 /////////////////////////////////////////////////////////////////////////////
 // ScrollBarThumb
 
-ScrollBarThumb::ScrollBarThumb(BaseScrollBar* scroll_bar)
+ScrollBarThumb::ScrollBarThumb(BaseScrollBar* scroll_bar,
+                               NativeScrollBarWrapper* wrapper)
     : BaseScrollBarThumb(scroll_bar),
-      scroll_bar_(scroll_bar) {
+      scroll_bar_(scroll_bar),
+      wrapper_(wrapper) {
   SetFocusable(false);
   SetAccessibilityFocusable(false);
 }
 
 ScrollBarThumb::~ScrollBarThumb() {
 }
 
 gfx::Size ScrollBarThumb::GetPreferredSize() const {
   return GetNativeTheme()->GetPartSize(GetNativeThemePart(),
                                        GetNativeThemeState(),
@@ skipping 14 matching lines @@
       ui::NativeTheme::kScrollbarVerticalGripper;
   GetNativeTheme()->Paint(canvas->sk_canvas(), gripper_part, theme_state,
                           local_bounds, extra_params);
 }
 
 ui::NativeTheme::ExtraParams ScrollBarThumb::GetNativeThemeParams() const {
   // This gives the behavior we want.
   ui::NativeTheme::ExtraParams params;
   params.scrollbar_thumb.is_hovering =
       (GetState() != CustomButton::STATE_HOVERED);
+  params.scrollbar_thumb.overlay = wrapper_->GetOverlayParams();

[tapted, 2016/02/08 00:31:15]

null check?

[spqchan, 2016/02/09 21:21:26]

Acknowledged.

   return params;
 }
 
 ui::NativeTheme::Part ScrollBarThumb::GetNativeThemePart() const {
   if (scroll_bar_->IsHorizontal())
     return ui::NativeTheme::kScrollbarHorizontalThumb;
   return ui::NativeTheme::kScrollbarVerticalThumb;
 }
 
 ui::NativeTheme::State ScrollBarThumb::GetNativeThemeState() const {
@@ skipping 15 matching lines @@
 }
 
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 // NativeScrollBarViews, public:
 
 const char NativeScrollBarViews::kViewClassName[] = "NativeScrollBarViews";
 
 NativeScrollBarViews::NativeScrollBarViews(NativeScrollBar* scroll_bar)
-    : BaseScrollBar(scroll_bar->IsHorizontal(),
-                    new ScrollBarThumb(this)),
+    : BaseScrollBar(scroll_bar->IsHorizontal(), new ScrollBarThumb(this, this)),
       native_scroll_bar_(scroll_bar) {
   set_controller(native_scroll_bar_->controller());
 
   if (native_scroll_bar_->IsHorizontal()) {
-    prev_button_ = new ScrollBarButton(this, ScrollBarButton::LEFT);
-    next_button_ = new ScrollBarButton(this, ScrollBarButton::RIGHT);
+    prev_button_ = new ScrollBarButton(this, ScrollBarButton::LEFT, this);
+    next_button_ = new ScrollBarButton(this, ScrollBarButton::RIGHT, this);
 
     part_ = ui::NativeTheme::kScrollbarHorizontalTrack;
   } else {
-    prev_button_ = new ScrollBarButton(this, ScrollBarButton::UP);
-    next_button_ = new ScrollBarButton(this, ScrollBarButton::DOWN);
+    prev_button_ = new ScrollBarButton(this, ScrollBarButton::UP, this);
+    next_button_ = new ScrollBarButton(this, ScrollBarButton::DOWN, this);
 
     part_ = ui::NativeTheme::kScrollbarVerticalTrack;
   }
 
   state_ = ui::NativeTheme::kNormal;
 
   AddChildView(prev_button_);
   AddChildView(next_button_);
 
   prev_button_->set_context_menu_controller(this);
@@ skipping 154 matching lines @@
   ui::NativeTheme::ExtraParams thumb_params;
   thumb_params.scrollbar_thumb.is_hovering = false;
   gfx::Size track_size = theme->GetPartSize(
       ui::NativeTheme::kScrollbarVerticalThumb,
       ui::NativeTheme::kNormal,
       thumb_params);
 
   return std::max(track_size.width(), button_size.width());
 }
 
+ui::NativeTheme::OverlayParams NativeScrollBarWrapper::GetOverlayParams() {
+  ui::NativeTheme::OverlayParams params;
+  params.is_overlay = false;
+  params.alpha = 1.0;
+  return params;
+}
+
 }  // namespace views