Cleaned up the interface to draw_line()

dlib/image_transforms/draw.h

@@ -5,6 +5,7 @@
 
 #include "draw_abstract.h"
 #include "../algs.h"
+#include "../pixel.h"
 #include <cmath>
 
 namespace dlib
@@ -13,7 +14,8 @@ namespace dlib
 // ----------------------------------------------------------------------------------------
 
     template <
-        typename image_type
+        typename image_type,
+        typename pixel_type
         >
     void draw_line (
         long x1,
@@ -21,7 +23,7 @@ namespace dlib
         long x2,
         long y2,
         image_type& c,
-        typename image_type::type val
+        const pixel_type& val
     ) 
     {
         if (x1 == x2)
@@ -37,7 +39,7 @@ namespace dlib
                 if (y < 0 || y >= c.nr())
                     continue;
 
-                c[y][x1] = val;
+                assign_pixel(c[y][x1], val);
             }
         }
         else if (y1 == y2)
@@ -54,7 +56,7 @@ namespace dlib
                 if (x < 0 || x >= c.nc())
                     continue;
 
-                c[y1][x] = val;
+                assign_pixel(c[y1][x] , val);
             }
         }
         else
@@ -97,7 +99,7 @@ namespace dlib
                         continue;
 
 
-                    c[y][x] = val;
+                    assign_pixel(c[y][x] , val);
                 }         
             }
             else
@@ -136,13 +138,29 @@ namespace dlib
                     if (y < 0 || y >= c.nr())
                         continue;
 
-                    c[y][x] = val;
+                    assign_pixel(c[y][x] , val);
                 } 
             }
         }
 
     }
 
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename image_type,
+        typename pixel_type
+        >
+    void draw_line (
+        image_type& c,
+        const point& p1,
+        const point& p2,
+        const pixel_type& val
+    ) 
+    {
+        draw_line(p1.x(),p1.y(),p2.x(),p2.y(),c,val);
+    }
+
 // ----------------------------------------------------------------------------------------
 
     template <

dlib/image_transforms/draw_abstract.h

@@ -10,7 +10,32 @@ namespace dlib
 // ----------------------------------------------------------------------------------------
 
     template <
-        typename image_type
+        typename image_type,
+        typename pixel_type
+        >
+    void draw_line (
+        image_type& c,
+        const point& p1,
+        const point& p2,
+        const pixel_type& val
+    );
+    /*!
+        requires
+            - image_type == is an implementation of array2d/array2d_kernel_abstract.h
+            - pixel_traits<pixel_type> is defined
+        ensures
+            - #img.nr() == img.nr() && #img.nc() == img.nc()
+              (i.e. the dimensions of the input image are not changed)
+            - for all valid r and c that are on the line between point p1 and p2:
+                - performs assign_pixel(img[r][c], val)
+                  (i.e. it draws the line from p1 to p2 onto the image)
+    !*/
+
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename image_type,
+        typename pixel_type
         >
     void draw_line (
         long x1,
@@ -18,18 +43,14 @@ namespace dlib
         long x2,
         long y2,
         image_type& img,
-        typename image_type::type val
+        const pixel_type& val
     );
     /*!
         requires
             - image_type == is an implementation of array2d/array2d_kernel_abstract.h
+            - pixel_traits<pixel_type> is defined
         ensures
-            - #img.nr() == img.nr() && #img.nc() == img.nc()
-              (i.e. the dimensions of the input image are not chanaged)
-            - for all valid r and c that are on the line between point (x1,y1)
-              and point (x2,y2):
-                - performs img[r][c] = val
-                  (i.e. it draws the line from (x1,y1) to (x2,y2) onto the image)
+            - performs draw_line(img, point(x1,y1), point(x2,y2), val)
     !*/
 
 // ----------------------------------------------------------------------------------------
@@ -50,8 +71,6 @@ namespace dlib
             - fills the area defined by rect in the given image with the given pixel value.
     !*/
 
-}
-
 // ----------------------------------------------------------------------------------------
 
 }