generic_image all the way (#921)

* generic_image all the way

tried to hunt down and correct the functions that were using a
non-generic_image approach to dlib’s generic images.

* generic image fix fix

Had to change a couple of const_image_view to non-const versions so array access is possible in the rest of the code

* same

same

* back to sanity

dlib/gui_widgets/base_widgets.h

@@ -410,8 +410,8 @@ namespace dlib
             auto_mutex M(m);
             assign_image_scaled(img,new_img);
             rectangle old(rect);
-            rect.set_right(rect.left()+img.nc()-1); 
-            rect.set_bottom(rect.top()+img.nr()-1);
+            rect.set_right(rect.left()+num_columns(img)-1); 
+            rect.set_bottom(rect.top()+num_rows(img)-1);
             parent.invalidate_rectangle(rect+old);
         }
 

dlib/gui_widgets/canvas_drawing.h

@@ -681,7 +681,7 @@ namespace dlib
     {
         const long x = p.x();
         const long y = p.y();
-        rectangle rect(x,y,img.nc()+x-1,img.nr()+y-1);
+        rectangle rect(x,y,num_columns(img)+x-1,num_rows(img)+y-1);
         rectangle area = c.intersect(rect).intersect(area_);
         if (area.is_empty())
             return;
@@ -709,11 +709,11 @@ namespace dlib
     )
     {
         const rectangle area = c.intersect(rect).intersect(area_);
-        if (area.is_empty() || img.size() == 0)
+        if (area.is_empty() || num_columns(img) * num_rows(img) == 0)
             return;
 
-        const matrix<long,1> x = matrix_cast<long>(round(linspace(0, img.nc()-1, rect.width())));
-        const matrix<long,1> y = matrix_cast<long>(round(linspace(0, img.nr()-1, rect.height())));
+        const matrix<long,1> x = matrix_cast<long>(round(linspace(0, num_columns(img)-1, rect.width())));
+        const matrix<long,1> y = matrix_cast<long>(round(linspace(0, num_rows(img)-1, rect.height())));
 
         for (long row = area.top(); row <= area.bottom(); ++row)
         {