Number: 1869
Title: SVG output does not preserve alpha (transparency) color component
Submitter: Jonathan Feinberg
Date: Fri Jan 29 12:56:16 2010
Subsys: Output
Version: 2.27.20100108.0545 (20100108.0545)
System: x86-Windows-XP Pro
Severity: major
Problem: The SVG renderer ignores the alpha component of an edge's color. It should be respected and emitted as an "opacity" attribute in the resulting SVG.
Input: 
graph G {apple -- banana [penwidth=5, color="#00000050"];}
Comments:
[Ole-Morten Duesund] I have a fix for bug #1869, my first priority is to get it in to Debian, but obviously it'd be nice so have it in Graphviz proper as well.

This is the bug-report I submitted to the debian BTS.

- Ole-Morten Duesund 


-------- Original Message --------
Subject: graphviz: core SVG output does not preserve alpha (transparency) color component
Date: Fri, 27 Aug 2010 10:29:54 +0200
From: Ole-Morten Duesund <olemd@glemt.net>
To: Debian Bug Tracking System <submit@bugs.debian.org>


Package: graphviz
Version: 2.20.2-3
Severity: normal




As already reported upstream in in
http://www.graphviz.org/bugs/b1869.html the core SVG renderer for
graphviz ignores the alpha component in RGBA colors (Not only for edges,
but also for fills)


The attached patch turns on support for RGBA in both cases by using
stroke- or fill-opacity as apropriate.


See also attached example input and output with and w/o the patch.


- Ole-Morten Duesund




-- System Information:
Debian Release: 5.0.5
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: i386 (i686)


Kernel: Linux 2.6.26-2-xen-686 (SMP w/1 CPU core)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash


Versions of packages graphviz depends on:
ii  libc6           2.7-18lenny4             GNU C Library: Shared libraries
ii  libexpat1       2.0.1-4+lenny3           XML parsing C library - runtime li
ii  libgd2-xpm      2.0.36~rc1~dfsg-3+lenny1 GD Graphics Library version 2
ii  libgraphviz4    2.20.2-3                 rich set of graph drawing tools
ii  libx11-6        2:1.1.5-2                X11 client-side library
ii  libxaw7         2:1.0.4-2                X11 Athena Widget library
ii  libxmu6         2:1.0.4-1                X11 miscellaneous utility library
ii  libxt6          1:1.0.5-3                X11 toolkit intrinsics library


Versions of packages graphviz recommends:
ii  ttf-liberation                1.04.93-1  Free fonts with the same metrics a


Versions of packages graphviz suggests:
pn  graphviz-doc  <none>                     (no description available)
ii  gsfonts       1:8.11+urwcyr1.0.7~pre44-3 Fonts for the Ghostscript interpre


-- no debconf information

Fix: 

diff --git a/plugin/core/gvrender_core_svg.c b/plugin/core/gvrender_core_svg.c
index 91786e1..3dbfe75 100644
--- a/plugin/core/gvrender_core_svg.c
+++ b/plugin/core/gvrender_core_svg.c
@@ -95,8 +95,11 @@ static void svg_grstyle(GVJ_t * job, int filled)
     obj_state_t *obj = job->obj;


     gvputs(job, " fill="");
-    if (filled)
+    if (filled) {
 	svg_print_color(job, obj->fillcolor);
+	if (obj->fillcolor.type == RGBA_BYTE && obj->fillcolor.u.rgba[3] > 0 && obj->fillcolor.u.rgba[3] < 255 )
+	    gvprintf(job, "" fill-opacity="%f", ((float)obj->fillcolor.u.rgba[3]/255.0));
+    }
     else
 	gvputs(job, "none");
     gvputs(job, "" stroke="");
@@ -108,6 +111,8 @@ static void svg_grstyle(GVJ_t * job, int filled)
     } else if (obj->pen == PEN_DOTTED) {
 	gvprintf(job, "" stroke-dasharray="%s", sdotarray);
     }
+    if (obj->pencolor.type == RGBA_BYTE && obj->pencolor.u.rgba[3] > 0 && obj->pencolor.u.rgba[3] < 255)
+	gvprintf(job, "" stroke-opacity="%f", ((float)obj->fillcolor.u.rgba[3]/255.0));
     gvputs(job, """);
 }

Owner: erg
Status: Fixed (27 Aug 2010)