Use missing SVG from parent if -pid name starts with sub_

If the current piece-image directory's name starts with "sub_", any
pieces not found in it will be searched in the parent directory.
This allows variants that need just a few pieces of a theme changed
to get their own sub_xxx sub-directory within the directory with SVG
images, containing the deviating SVGs. This will work recursively.

diff --git a/draw.c b/draw.c
index 4ad6887..82072bf 100644 (file)
--- a/draw.c
+++ b/draw.c
@@ -351,6 +351,15 @@ LoadSVG (char *dir, int color, int piece, int retry)
 
     if(!svg && *dir) {
       svg = rsvg_handle_new_from_file(buf, &svgerror);
+      if(!svg) { // failed! If -pid name starts with "sub_" we try to load the piece from the parent directory
+       char *p = buf, *q;
+       safeStrCpy(buf, dir, MSG_SIZ);
+       while((q = strchr(p, '/'))) p = q + 1;
+       if(!strncmp(p, "sub_", 4)) {
+         if(p == buf) safeStrCpy(buf, ".", MSG_SIZ); else p[-1] = NULLCHAR; // strip last directory off path
+         return LoadSVG(buf, color, piece, retry);
+       }
+      }
       if(!svg && *appData.inscriptions) { // if there is no piece-specific SVG, but we make inscriptions, try general background
        snprintf(buf, MSG_SIZ, "%s/%sTile.svg", dir, color ? "Black" : "White");
        svg = rsvg_handle_new_from_file(buf, &svgerror);