Improved the image_window a bit.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%402967

dlib/gui_widgets/widgets.h

@@ -3159,6 +3159,11 @@ namespace dlib
         image_window(
         ); 
 
+        template < typename image_type >
+        image_window(
+            const image_type& img
+        ) : gui_img(*this) { set_image(img); show(); }
+
         ~image_window(
         );
 
@@ -3167,11 +3172,12 @@ namespace dlib
             const image_type& img
         ) 
         { 
+            const unsigned long padding = scrollable_region_style_default().get_border_size();
             auto_mutex M(wm);
             gui_img.set_image(img); 
 
             // set the size of this window to match the size of the input image
-            set_size(img.nc(),img.nr());
+            set_size(img.nc()+padding*2,img.nr()+padding*2);
 
             // call this to make sure everything else is setup properly
             on_window_resized();

dlib/gui_widgets/widgets_abstract.h

@@ -2234,6 +2234,19 @@ namespace dlib
                 - this object is properly initialized
         !*/
 
+        template <typename image_type>
+        image_window(
+            const image_type& img
+        ); 
+        /*!
+            requires
+                - image_type == an implementation of array2d/array2d_kernel_abstract.h
+                - pixel_traits<typename image_type::type> must be defined 
+            ensures
+                - this object is properly initialized 
+                - #*this window is now displaying the given image img.
+        !*/
+
         ~image_window(
         );
         /*!
@@ -2241,7 +2254,7 @@ namespace dlib
                 - any resources associated with this object have been released
         !*/
 
-        template < typename image_type >
+        template <typename image_type>
         void set_image (
             const image_type& img
         );
@@ -2250,7 +2263,7 @@ namespace dlib
                 - image_type == an implementation of array2d/array2d_kernel_abstract.h
                 - pixel_traits<typename image_type::type> must be defined 
             ensures
-                - #*this window is now displaying the given image new_img.
+                - #*this window is now displaying the given image img.
         !*/
 
         void add_overlay (