I could try to compile it here if you give me the source code.
Well, we already tried that, and after an uphill battle even succeeded, and the resulting binary is even on the CVP server, as public_html/index/fen2.cgi . But it appears we ran into a problem with the server refusing to execute the resulting CGI file when accessed from the web; see the discussion here.
Do Interactive Diagrams have any way of their own to indicate different images for black and white pieces besides a different prefix?
No, they use the files that start with the blackPrefix for black. It is up to the set designer what image these contain.
As far as I know, the SVG pieces on this site are all white (outline) pieces. So, showpiece.php just loads a w*.svg file when given a b*.svg file name for the image parameter.
Well, the XBoard set has b*.svg for all pieces, and Magnetic and Motif has b*.svg for the orthodox pieces. The unorthodox pieces in the latter two are basically just cut & paste jobs on pairs of orthodox pieces, but I never got to do those jobs on the black pieces. In theory these could be easily done, though, if there would be any use for those.
As it is, showpiece.php would never allow you to use the black XBoard pieces, which seems a pity. Perhaps it could be made to use b*.svg instead of a*.svg, when it is present, and the requested color is very dark (e.g. all colors < 0x10)?
Well, we already tried that, and after an uphill battle even succeeded, and the resulting binary is even on the CVP server, as public_html/index/fen2.cgi . But it appears we ran into a problem with the server refusing to execute the resulting CGI file when accessed from the web; see the discussion here.
No, they use the files that start with the blackPrefix for black. It is up to the set designer what image these contain.
Well, the XBoard set has b*.svg for all pieces, and Magnetic and Motif has b*.svg for the orthodox pieces. The unorthodox pieces in the latter two are basically just cut & paste jobs on pairs of orthodox pieces, but I never got to do those jobs on the black pieces. In theory these could be easily done, though, if there would be any use for those.
As it is, showpiece.php would never allow you to use the black XBoard pieces, which seems a pity. Perhaps it could be made to use b*.svg instead of a*.svg, when it is present, and the requested color is very dark (e.g. all colors < 0x10)?