Add cellophane.

1 files changed, 15 insertions, 0 deletions

diff --git a/pict.scm b/pict.scm
index 21fac99..dfa854a 100644
--- a/pict.scm
+++ b/pict.scm
@@ -44,6 +44,7 @@
             shrink
             rotate
             blur
+            cellophane
 
             frame
 
@@ -408,6 +409,20 @@ strings that are built from the list of attributes LST."
                                                        2))))
              (pict-sxml pict))))))
 
+(define (cellophane pict opacity)
+  "Set the opacity of PICT to OPACITY, a numeric value between 0 (for
+full transparency) and 1 (for full opacity)."
+  (make-pict
+   `(svg (@ (height ,(pict-height pict))
+            (width ,(pict-width pict))
+            (class "opacity")
+            (x 0)
+            (y 0))
+         ,((attribute-modifier 'opacity (const opacity))
+           `(g (@ (class "opacity")
+                  (opacity ,opacity))
+               ,(pict-sxml pict))))))
+
 (define* (frame pict #:key (color "black") (stroke-width 1))
   "Draw a box around PICT."
   (cc-superimpose pict