Re: Apple IIgs video modes?

[stc7@cunixb.cc.columbia.edu (Steven T Chiang)]

In article <jmk3.735971760@crux1.cit.cornell.edu> jmk3@crux3.cit.cornell.edu (Jay Krell) writes:
>>        640 mode has 4 pure colors per line, 64 per screen with
>>multiple palette and 800 using the equivalent of 3200 color mode in
>>640 mode.  That's pure colors though.
> 
>I beg to differ Steve. It is completely impractical for drawing, but you could
>give each line's palette 16 different colors. Each pixel has a choice of 4 of
>these, but all 16 could appear on the line.

	Well, this was in response to your first post.  You had stated
that 640 mode had 16 *pure* colors, which is not the case.  640 mode
has 16 dithered colors or 4 pure colors.  If you are using DPaint II
in 640 mode, you only have 4 pure colors to work with.  Other paint
programs support 640 w/ the 16 dithered colors.  You could have a 640
w/ 3200 dithered colors, but there isn't a real advantage, except your
fonts would look nicer on the screen.

	I would agree with you that mixing colors is tough in dithered
color mode...  But it is possible, because Bo Monroe does a fantastic
job with 640 mode graphics w/ dithered colors.

>repeats for each successive group of 4 pixels in a horizontal line. Thus, even
>though a given pixel can be one of 4 colors, different pixels in a line can
>take on any of the 16 colors in a palette." (IIGS Hardware Ref, 2nd ed, p. 96)

	Right, but the colors are dithered.

>  --Jay, jay.krell@cornell.edu

Steven Chiang                  Order - DreamGrafix:  The ONLY 16/256/3200
stc7@cunixb.cc.columbia.edu       color paint program for the Apple IIGS.
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Genie:  S.Chiang4              Apple IIGS Forever!