Re: Patch for issue 3882: stencils with stroke-thickness set to zero (issue 201520044 by address@hidden)

[luk . pietsch]

Reviewers: dak,

Message:
On 2015/02/25 20:25:25, dak wrote:
> That sounds like unnecessary effort in some cases.  How about
>            (cond ((not fill?) "stroke")
>                  ((positive? thickness) "gsave stroke grestore fill")
>                  (else "fill")))

You're right, that's more elegant.

> Zero thickness without fill seems a bit awkward.  It's the odd man out
after
> this change.

No-fill contours with thickness set to zero seem to be a well-defined
construct in Postscript; apparently they are supposed to be rendered as
a one-pixel hairline, so I guess we might want to continue supporting
that as an option.


Description:
Patch for issue 3882: stencils with stroke-thickness set to zero

Bring PS output in line with SVG output, so that it becomes possible
to define path stencil expressions with a filled contour but no
outline stroke. (This is necessary for consistent support of
user-defined glyphs defined as path stencils, to be used for
planned mensural notation extensions)

Please review this at https://codereview.appspot.com/201520044/

Affected files (+12, -8 lines):
  M scm/output-ps.scm


Index: scm/output-ps.scm
diff --git a/scm/output-ps.scm b/scm/output-ps.scm
index  
c4c0a4da07bb93d1547927c3a2be119a407031c6..bb4ee254603a2babfbf2f8b0c8b70ddf11cf39f6  
100644
--- a/scm/output-ps.scm
+++ b/scm/output-ps.scm
@@ -295,15 +295,19 @@
                                     (ly:warning (_ "unknown  
line-join-style: ~S")
                                                 (symbol->string join))
                                     1)))))
-    (ly:format
-     "gsave currentpoint translate
+     (ly:format
+      "gsave currentpoint translate
 ~a setlinecap ~a setlinejoin ~a setlinewidth
-~l gsave stroke grestore ~a grestore"
-     cap-numeric
-     join-numeric
-     thickness
-     (convert-path-exps exps)
-     (if fill? "fill" ""))))
+~l ~a ~a grestore"
+      cap-numeric
+      join-numeric
+      thickness
+      (convert-path-exps exps)
+      ;; print outline contour only if there is no fill or if
+      ;; contour is explicitly requested with a thickness > 0
+      (if (or (not fill?)(> thickness 0)) "gsave stroke grestore" "")
+      (if fill? "fill" ""))))
+

 (define (setscale x y)
   (ly:format "gsave ~4l scale\n"