[Inkscape-devel] SVG question, pattern references another pattern but adds a solid background.

6 Mar 2013


      EMF and WMF formats have BKMODE and BKCOLOR parameters which are 
applied to
patterns.  BKMODE is either transparent (no background) or opaque 
(BKCOLOR is drawn
first, then the pattern is drawn over it).  The tricky part for 
importing these
formats and converting them to SVG is that the values of BKMODE/BKCOLOR 
are NOT employed
when the pattern is defined, but when it is drawn.
Here is an example of a pattern without a background (transparent)
     <pattern
        id="EMFhatch0_3F7FFF"
        patternUnits="userSpaceOnUse"
        width="6"
        height="6"
        x="0"
        y="0">
       <path
          d="M 0,0 6,0"
          style="fill:none;stroke:#3f7fff"
          id="path15"
          inkscape:connector-curvature="0" />
     </pattern>
and here is the same pattern with a background (opaque)
<pattern
        id="EMFhatch0_3F7FFF_FOE0DO"
        patternUnits="userSpaceOnUse"
        width="6"
        height="6"
        x="0"
        y="0">
       <rect x="0" y="0" width="6" height="6" fill="#F0E0D0" />
       <path
          d="M 0,0 6,0"
          style="fill:none;stroke:#3f7fff"
          id="path15"
          inkscape:connector-curvature="0" />
     </pattern>
What I really need to be able to generate, when the pattern is used, 
and BKMODE and BKCOLOR are both known,
something like this (pseudocode, definitely NOT the right syntax!)
<pattern
        id="EMFhatch0_3F7FFF_FOE0DO"
        patternUnits="userSpaceOnUse"
        width="6"
        height="6"
        x="0"
        y="0">
       <rect x="0" y="0" width="6" height="6" fill="#F0E0D0" />
       xlink:href="#EMFhatch0_3F7FFF"
     </pattern>
How is that supposed to be written?  The idea is to write the solid 
background color and then the transparent
"base" pattern over it.  It doesn't look like <path> can do it by 
referencing the "base" pattern, since style="fill:" is used for the URL 
to that pattern, so it isn't available to specify the solid background 
color.  That suggests to me that it must be done within the <pattern> - 
but any technique that works would be fine.
Thank you,
David Mathog
mathog@...1176...
Manager, Sequence Analysis Facility, Biology Division, Caltech