I think nvg's mail server is on crack... yesterday it responded to an unsubscribe command that I'd sent on April 4*. Thanks Frode, if it was you who kicked it. :-)
On Fri, Apr 13, 2012 at 02:54:05PM +0100, Simon Owen wrote: > Thanks for that Ian -- it does sound very similar to what I was aiming > for. Though the standard screen$ capabilities seem very limited, with > maybe just 1 change per line? (plus flash) Sam BASIC's handling of this is tied to line interrupts (i.e., same as when you type PALETTE LINE). The advantage of that is the machine keeps working while the screen is up; the disadvantage is that you can't do much work during the interrupt (and the code isn't written for speed). I think the limit is about 2 before the changes start showing on screen. I've tried this program on a few random images but With 2 changes per line the difference between allowing changes and having no changes is only minimally visible (unless I'm just not using colourful enough images to start with). The other problem it has is that with FS dithering sometimes the error values build up to the extent that when a palette change occurs it might select too much of the new colour just to get rid of the errors - this produces either a visible horizontal line in the output or occasionally a sudden change in shade. The program's "-s" flag tries to fix this by using a random number to inhibit selection of a colour on the line where it's new, but either that doesn't work very well or I didn't get the randomness quite right. imc * Needed to slightly change the format of my email address so it would let me post.
