Reported to me by Osma Ahvenlampi <oa@spray.fi>

Problem is caused by a rounding problem in functions/gdttf.c

Here is the fix:

*** gdttf.c.old Wed May 20 14:46:54 1998
--- gdttf.c     Thu Aug  6 18:08:41 1998
***************
*** 688,695 ****
                return (char *)NULL;
  
        /* render (via cache) a bitmap for the current fractional offset */
!       bitmapkey.xoffset = ((x1+32) & 63) - 32 - (glyph->xmin & -64);
!       bitmapkey.yoffset = ((y1+32) & 63) - 32 - (glyph->ymin & -64);
        bitmapkey.glyph = glyph;
        gdCacheGet(glyph->bitmapCache, &bitmapkey);
  
--- 688,695 ----
                return (char *)NULL;
  
        /* render (via cache) a bitmap for the current fractional offset */
!       bitmapkey.xoffset = ((x1+32) & 63) - 32 - ((glyph->xmin+32) & -64);
!       bitmapkey.yoffset = ((y1+32) & 63) - 32 - ((glyph->ymin+32) & -64);
        bitmapkey.glyph = glyph;
        gdCacheGet(glyph->bitmapCache, &bitmapkey);