Cleaned up the list_box's objects code by making it use the scrollable_region widget.

Also gave the list_box a user settable style.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%402598

dlib/gui_widgets/style.h

@@ -577,6 +577,139 @@ namespace dlib
 
     };
 
+// ----------------------------------------------------------------------------------------
+// ----------------------------------------------------------------------------------------
+    // list_box styles  
+// ----------------------------------------------------------------------------------------
+// ----------------------------------------------------------------------------------------
+
+    class list_box_style
+    {
+    public:
+
+        virtual ~list_box_style() {}
+
+        virtual void draw_list_box_background (
+            const canvas& c,
+            const rectangle& display_rect,
+            const bool enabled
+        ) const = 0;
+
+        virtual void draw_list_box_item (
+            const canvas& c,
+            const rectangle& rect,
+            const rectangle& display_rect,
+            const bool enabled,
+            const font& mfont,
+            const std::string& text,
+            const bool is_selected
+        ) const = 0;
+
+        virtual void draw_list_box_item (
+            const canvas& c,
+            const rectangle& rect,
+            const rectangle& display_rect,
+            const bool enabled,
+            const font& mfont,
+            const std::wstring& text,
+            const bool is_selected
+        ) const = 0;
+
+        virtual void draw_list_box_item (
+            const canvas& c,
+            const rectangle& rect,
+            const rectangle& display_rect,
+            const bool enabled,
+            const font& mfont,
+            const ustring& text,
+            const bool is_selected
+        ) const = 0;
+
+    };
+
+// ----------------------------------------------------------------------------------------
+
+    class list_box_style_default : public list_box_style
+    {
+    public:
+        scrollable_region_style_default get_scrollable_region_style (
+        ) const { return scrollable_region_style_default(); }
+
+        virtual void draw_list_box_item (
+            const canvas& c,
+            const rectangle& rect,
+            const rectangle& display_rect,
+            const bool enabled,
+            const font& mfont,
+            const std::string& text,
+            const bool is_selected
+        ) const { draw_list_box_item_template(c,rect,display_rect, enabled, mfont, text, is_selected); }
+
+        virtual void draw_list_box_item (
+            const canvas& c,
+            const rectangle& rect,
+            const rectangle& display_rect,
+            const bool enabled,
+            const font& mfont,
+            const std::wstring& text,
+            const bool is_selected
+        ) const { draw_list_box_item_template(c,rect,display_rect, enabled, mfont, text, is_selected); }
+
+        virtual void draw_list_box_item (
+            const canvas& c,
+            const rectangle& rect,
+            const rectangle& display_rect,
+            const bool enabled,
+            const font& mfont,
+            const ustring& text,
+            const bool is_selected
+        ) const { draw_list_box_item_template(c,rect,display_rect, enabled, mfont, text, is_selected); }
+
+        template <typename string_type>
+        void draw_list_box_item_template (
+            const canvas& c,
+            const rectangle& rect,
+            const rectangle& display_rect,
+            const bool enabled,
+            const font& mfont,
+            const string_type& text,
+            const bool is_selected
+        ) const
+        {
+            if (is_selected)
+            {
+                if (enabled)
+                    fill_rect_with_vertical_gradient(c,rect,rgb_pixel(110,160,255),  rgb_pixel(100,130,250),display_rect);
+                else
+                    fill_rect_with_vertical_gradient(c,rect,rgb_pixel(140,190,255),  rgb_pixel(130,160,250),display_rect);
+            }
+
+            if (enabled)
+                mfont.draw_string(c,rect,text,rgb_pixel(0,0,0),0,std::string::npos,display_rect);
+            else
+                mfont.draw_string(c,rect,text,rgb_pixel(128,128,128),0,std::string::npos,display_rect);
+        }
+
+        virtual void draw_list_box_background (
+            const canvas& c,
+            const rectangle& display_rect,
+            const bool enabled
+        ) const
+        {
+            if (enabled)
+            {
+                // first fill our area with white
+                fill_rect(c, display_rect,rgb_pixel(255,255,255));
+            }
+            else
+            {
+                // first fill our area with gray 
+                fill_rect(c, display_rect,rgb_pixel(212,208,200));
+            }
+        }
+
+    };
+
 // ----------------------------------------------------------------------------------------
 
 }

dlib/gui_widgets/style_abstract.h

@@ -499,6 +499,110 @@ namespace dlib
         !*/
     };
 
+// ----------------------------------------------------------------------------------------
+// ----------------------------------------------------------------------------------------
+    // list_box styles  
+// ----------------------------------------------------------------------------------------
+// ----------------------------------------------------------------------------------------
+
+    class list_box_style
+    {
+        /*!
+            WHAT THIS OBJECT REPRESENTS
+                This is an abstract class that defines the interface a
+                list_box style object must implement.
+
+                Note that derived classes must be copyable via
+                their copy constructors.
+        !*/
+    public:
+
+        virtual ~list_box_style() {}
+
+        virtual void draw_list_box_background (
+            const canvas& c,
+            const rectangle& display_rect,
+            const bool enabled
+        ) const = 0;
+        /*!
+            requires
+                - the mutex drawable::m is locked
+                - c == the canvas to draw on
+                - display_rect == the display_rect for the list_box.  This is the area
+                  in which list box items are drawn (see display_rect in the scrollable_region
+                  widget for more info)
+                - enabled == true if the list box is enabled
+            ensures
+                - draws the background of a list box on the canvas c at the location given 
+                  by display_rect.  
+        !*/
+
+        scrollable_region_style_type get_scrollable_region_style (
+        ) const;
+        /*!
+            ensures
+                - returns the style of scrollable_region to use for the 
+                  list_box.
+        !*/
+
+        virtual void draw_list_box_item (
+            const canvas& c,
+            const rectangle& rect,
+            const rectangle& display_rect,
+            const bool enabled,
+            const font& mfont,
+            const std::string& text,
+            const bool is_selected
+        ) const = 0;
+        /*!
+            requires
+                - the mutex drawable::m is locked
+                - c == the canvas to draw on
+                - rect == the rectangle that defines where on the screen this list box item is.
+                - display_rect == the display_rect for the list_box.  This is the area
+                  in which list box items are drawn (see display_rect in the scrollable_region
+                  widget for more info)
+                - mfont == the font to use to draw the list box item
+                - text == the text of the list box item to be drawn
+                - enabled == true if the list box is enabled
+                - is_selected == true if the item is to be drawn in a selected state
+            ensures
+                - draws the list box item on the canvas c at the location given by rect.  
+        !*/
+
+        // wide character overloads
+        virtual void draw_list_box_item (
+            const canvas& c,
+            const rectangle& rect,
+            const rectangle& display_rect,
+            const bool enabled,
+            const font& mfont,
+            const std::wstring& text,
+            const bool is_selected
+        ) const = 0;
+
+        virtual void draw_list_box_item (
+            const canvas& c,
+            const rectangle& rect,
+            const rectangle& display_rect,
+            const bool enabled,
+            const font& mfont,
+            const ustring& text,
+            const bool is_selected
+        ) const = 0;
+
+    };
+
+// ----------------------------------------------------------------------------------------
+
+    class list_box_style_default : public list_box_style
+    {
+    public:
+        /*!
+            This is the default style for list_box objects.  
+        !*/
+    };
+
 // ----------------------------------------------------------------------------------------
 
 }

dlib/gui_widgets/widgets.h

@@ -1105,34 +1105,24 @@ namespace dlib
 
     namespace list_box_helper{
     template <typename S = std::string>
-    class list_box : public drawable, 
+    class list_box : public scrollable_region, 
                      public enumerable<const S>
     {
         /*!
             INITIAL VALUE
                 - ms_enabled == false
                 - items.size() == 0
-                - pos == 0
-                - text_start = 0
                 - last_selected = 0
 
             CONVENTION
                 - size() == items.size()
                 - (*this)[i] == items[i].name
                 - is_selected(i) == items[i].is_selected
+                - ms_enabled == multiple_select_enabled()
 
                 - items[i].width == the width of items[i].name as given by font::compute_size() 
                 - items[i].height == the height of items[i].name as given by font::compute_size() 
 
-                - items[pos] == the item currently being displayed at the top of the list box
-                - sbv == our vertical scroll bar
-                - sbh == our horizontal scroll bar
-                - text_area == the area that is free to be used for text display (e.g. not occluded 
-                  by scroll bars or anything)
-                - text_start == the amount of pixels the text should be shifted to the left (but the
-                  part outside this widget should be clipped).  This is used by the horizontal 
-                  scroll bar.
-                - pos == the first line that is shown in the list box
                 - last_selected == the last item the user selected
         !*/
 
@@ -1145,16 +1135,6 @@ namespace dlib
         ~list_box(
         );
 
-        void set_size (
-            unsigned long width_,
-            unsigned long height_
-        );
-
-        void set_pos (
-            long x,
-            long y
-        );
-
         bool is_selected (
             unsigned long index
         ) const;
@@ -1167,6 +1147,19 @@ namespace dlib
             unsigned long index 
         );
 
+        template <
+            typename style_type
+            >
+        void set_style (
+            const style_type& style_
+        )
+        {
+            auto_mutex M(m);
+            style.reset(new style_type(style_));
+            scrollable_region::set_style(style_.get_scrollable_region_style());
+            parent.invalidate_rectangle(rect);
+        }
+
         template <typename T>
         void get_selected (
             T& list
@@ -1195,15 +1188,22 @@ namespace dlib
             items.set_max_size(list.size());
             items.set_size(list.size());
             list.reset();
+            unsigned long max_width = 0;
+            unsigned long total_height = 0;
             while (list.move_next())
             {
                 items[i].is_selected = false;
                 items[i].name = list.element();
                 mfont->compute_size(items[i].name,items[i].width, items[i].height);
+
+                if (items[i].width > max_width)
+                    max_width = items[i].width;
+                total_height += items[i].height;
+
                 ++i;
             }
-            pos = 0;
-            adjust_sliders();
+            set_total_rect_size(max_width, total_height);
+
             parent.invalidate_rectangle(rect);
             last_selected = 0;
         }
@@ -1258,22 +1258,6 @@ namespace dlib
         unsigned long size (
         ) const;
 
-        void show(
-        );
-
-        void hide (
-        );
-
-        void enable (
-        );
-
-        void disable (
-        );
-
-        void set_z_order (
-            long order
-        );
-
         unsigned long get_selected (
         ) const;
 
@@ -1283,29 +1267,6 @@ namespace dlib
 
     private:
 
-        void sbv_handler (
-        );
-
-        void sbh_handler (
-        );
-
-        void adjust_sliders (
-        );
-        /*!
-            requires
-                - m is locked
-            ensures
-                - adjusts the scroll bars so that they are properly displayed
-        !*/
-
-        void on_wheel_up (
-            unsigned long state
-        );
-
-        void on_wheel_down (
-            unsigned long state
-        );
-
         void on_mouse_down (
             unsigned long btn,
             unsigned long state,
@@ -1327,19 +1288,13 @@ namespace dlib
             unsigned long height;
         };
 
-        const static long pad = 2;
-
         bool ms_enabled;
         typename array<data<S> >::kernel_2a_c items;
         member_function_pointer<unsigned long>::kernel_1a event_handler;
         member_function_pointer<unsigned long>::kernel_1a single_click_event_handler;
-        unsigned long pos;
-        unsigned long text_start;
         unsigned long last_selected;
-        scroll_bar sbv;
-        scroll_bar sbh;
-        rectangle text_area;
 
+        scoped_ptr<list_box_style> style;
 
         // restricted functions
         list_box(list_box&);        // copy constructor

dlib/gui_widgets/widgets_abstract.h

@@ -956,7 +956,7 @@ namespace dlib
 // ----------------------------------------------------------------------------------------
 // ----------------------------------------------------------------------------------------
 
-    class list_box : public drawable, 
+    class list_box : public scrollable_region, 
                      public enumerable<const std::string>
     {
         /*!
@@ -996,6 +996,19 @@ namespace dlib
                 - all resources associated with *this have been released
         !*/
 
+        template <
+            typename style_type
+            >
+        void set_style (
+            const style_type& style
+        );
+        /*!
+            requires
+                - style_type == a type that inherits from list_box_style 
+            ensures
+                - this list_box object will draw itself using the given style
+        !*/
+
         void set_size (
             unsigned long width_,
             unsigned long height_
@@ -1165,13 +1178,13 @@ namespace dlib
         list_box& operator=(list_box&);    // assignment operator
     };
 
-    class wlist_box : public drawable, 
+    class wlist_box : public scrollable_region, 
     public enumerable<const std::wstring>;
     /*!
         same as list_box except for std::wstring instead of std::string
     !*/
 
-    class ulist_box : public drawable, 
+    class ulist_box : public scrollable_region, 
     public enumerable<const dlib::ustring>;
     /*!
         same as list_box except for dlib::ustring instead of std::string