screensave bug

*screensave (with a graphics viewport defined) sometimes produces new format sprites containing lefthand wastage which then cause (different) mayhem with !Paint, Artworks PhotoDesk etc. This is on an Iyonix with RISC OS 5.16 and 5.20.

New format sprites must not contain lefthand wastage (PRM 5a-118) but 16bpp sprites are created with ‘first bit’ =16 vice 0 and ‘last bit’ =31 vice 16. That is with left hand wastage.

Indeed – I think I spotted (but evidently never fixed) this problem a while ago when testing some of the new sprite formats. The code looks like it’ll need rewriting to use a temporary buffer so that it can shift each row left by the appropriate number of bits before saving it out to disc.

Should be fixed in today’s ROMs.

Many thanks. My work around was to use C16M (24bpp) vice C32k (16bpp).