Implement stop/go button for Linux

chrome/browser/gtk/custom_button.h

 // Copyright (c) 2009 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.
 
 #ifndef CHROME_BROWSER_GTK_CUSTOM_BUTTON_H_
 #define CHROME_BROWSER_GTK_CUSTOM_BUTTON_H_
 
 #include <gtk/gtk.h>
 
 #include <string>
 
 #include "base/scoped_ptr.h"
 #include "chrome/common/owned_widget_gtk.h"
 
 class NineBox;
 
 // These classes implement two kinds of custom-drawn buttons.  They're
 // used on the toolbar and the bookmarks bar.
 
+// CustomDrawButtonBase provides the base for building a custom drawn button.
+// It handles managing the pixbufs containing all the static images used to draw
+// the button.  It also manages painting these pixbufs.
+class CustomDrawButtonBase {
+ public:
+  CustomDrawButtonBase(int normal_id,
+                       int active_id,
+                       int highlight_id,
+                       int depressed_id);
+  ~CustomDrawButtonBase();
+
+  GdkPixbuf* pixbufs(int i) const { return pixbufs_[i]; }
+
+  gboolean OnExpose(GtkWidget* widget, GdkEventExpose* e);
+
+ private:
+  // We store one GdkPixbuf* for each possible state of the button;
+  // INSENSITIVE is the last available state;
+  GdkPixbuf* pixbufs_[GTK_STATE_INSENSITIVE + 1];
+
+  DISALLOW_COPY_AND_ASSIGN(CustomDrawButtonBase);
+};
+
 // CustomDrawButton is a plain button where all its various states are drawn
 // with static images.
 class CustomDrawButton {
  public:
   // The constructor takes 4 resource ids.  If a resource doesn't exist for a
   // button, pass in 0.
   CustomDrawButton(int normal_id,
                    int active_id,
                    int highlight_id,
                    int depressed_id);
   explicit CustomDrawButton(const std::string& filename);
   ~CustomDrawButton();
 
   GtkWidget* widget() const { return widget_.get(); }
 
   // This is a convenience function for creating a widget that closes
   // a bar (find bar, download shelf, info bars). The button will be packed in
   // |hbox|.
   // The caller is responsible for destroying the returned CustomDrawButton.
   static CustomDrawButton* AddBarCloseButton(GtkWidget* hbox);
 
  private:
   // Callback for expose, used to draw the custom graphics.
-  static gboolean OnExpose(GtkWidget* widget, GdkEventExpose* e,
+  static gboolean OnExpose(GtkWidget* widget,
+                           GdkEventExpose* e,
                            CustomDrawButton* obj);
 
   // The actual button widget.
   OwnedWidgetGtk widget_;
 
-  // We store one GdkPixbuf* for each possible state of the button;
-  // INSENSITIVE is the last available state;
-  GdkPixbuf* pixbufs_[GTK_STATE_INSENSITIVE + 1];
+  CustomDrawButtonBase button_base_;
+
+  DISALLOW_COPY_AND_ASSIGN(CustomDrawButton);
 };
 
 // CustomContainerButton wraps another widget and uses a NineBox of
 // images to draw a highlight around the edges when you mouse over it.
 class CustomContainerButton {
  public:
   CustomContainerButton();
   ~CustomContainerButton();
 
   GtkWidget* widget() const { return widget_.get(); }
 
  private:
   // Callback for expose, used to draw the custom graphics.
   static gboolean OnExpose(GtkWidget* widget, GdkEventExpose* e,
                            CustomContainerButton* obj);
 
   // The button widget.
   OwnedWidgetGtk widget_;
 
   // The theme graphics for when the mouse is over the button.
   scoped_ptr<NineBox> nine_box_prelight_;
   // The theme graphics for when the button is clicked.
   scoped_ptr<NineBox> nine_box_active_;
 };
 
 #endif  // CHROME_BROWSER_GTK_CUSTOM_BUTTON_H_