Simplified the add_overlay() interface for image_window.

dlib/gui_widgets/widgets.h

@@ -3479,10 +3479,22 @@ namespace dlib
             const overlay_rect& overlay
         );
 
+        template <typename pixel_type>
+        void add_overlay(const rectangle& r, pixel_type p) 
+        { add_overlay(image_display::overlay_rect(r,p)); }
+
+        template <typename pixel_type>
+        void add_overlay(const rectangle& r, pixel_type p, const std::string& l) 
+        { add_overlay(image_display::overlay_rect(r,p,l)); }
+
         void add_overlay (
             const overlay_line& overlay
         );
 
+        template <typename pixel_type>
+        void add_overlay(const point& p1, const point& p2, pixel_type p) 
+        { add_overlay(image_display::overlay_line(p1,p2,p)); }
+
         void add_overlay (
             const std::vector<overlay_rect>& overlay
         );

dlib/gui_widgets/widgets_abstract.h

@@ -2701,6 +2701,27 @@ namespace dlib
                   that it will be displayed. 
         !*/
 
+        template <typename pixel_type>
+        void add_overlay(
+            const rectangle& r, 
+            pixel_type p
+        );
+        /*!
+            ensures
+                - performs: add_overlay(overlay_rect(r,p));
+        !*/
+
+        template <typename pixel_type>
+        void add_overlay(
+            const rectangle& r, 
+            pixel_type p, 
+            const std::string& l
+        );
+        /*!
+            ensures
+                - performs: add_overlay(overlay_rect(r,p,l));
+        !*/
+
         void add_overlay (
             const overlay_line& overlay
         );
@@ -2710,6 +2731,17 @@ namespace dlib
                   that it will be displayed. 
         !*/
 
+        template <typename pixel_type>
+        void add_overlay(
+            const point& p1,
+            const point& p2,
+            pixel_type p
+        );
+        /*!
+            ensures
+                - performs: add_overlay(overlay_line(p1,p2,p));
+        !*/
+
         void add_overlay (
             const std::vector<overlay_rect>& overlay
         );