pict: rectangle: Consider the stroke width when computing dimensions.

* pict.scm (rectangle): Use half of the line width as an edge offset.

1 files changed, 16 insertions, 15 deletions

diff --git a/pict.scm b/pict.scm
index 27f8fdd..4e30f6b 100644
--- a/pict.scm
+++ b/pict.scm
@@ -737,21 +737,22 @@ BORDER-COLOR (a string) and BORDER-WIDTH (a number) are accepted to
 override the line color and line thickness, respectively.  The keys RX
 and RY can be provided to round off the corners."
   (make-pict
-   `(svg (@ (width ,w)
-            (height ,h)
-            (x 0)
-            (y 0))
-         (rect (@ (style ,(style-list->string
-                           `(("fill" "none")
-                             ("stroke" ,border-color)
-                             ("stroke-width"
-                              ,(number->string border-width)))))
-                  (x 0)
-                  (y 0)
-                  (width ,w)
-                  (height ,h)
-                  (rx ,rx)
-                  (ry ,ry))))))
+   (let ((half-line-width (exact->inexact (/ border-width 2))))
+       `(svg (@ (width ,w)
+                (height ,h)
+                (x 0)
+                (y 0))
+             (rect (@ (style ,(style-list->string
+                               `(("fill" "none")
+                                 ("stroke" ,border-color)
+                                 ("stroke-width"
+                                  ,(number->string border-width)))))
+                      (x ,half-line-width)
+                      (y ,half-line-width)
+                      (width ,(- w border-width))
+                      (height ,(- h border-width))
+                      (rx ,rx)
+                      (ry ,ry)))))))
 
 (define* (filled-rectangle w h #:key
                            (color "black")