Apple IIgs dithered backgrounds

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Punkyclown's picture
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Apple IIgs dithered backgrounds

Hi  All,  I have noticed that all the IIgs backgrounds and Disk drives and scroll windows are all

dithered, and they look awful.  Is ther someway I can turn off the dithering or put smooth 

backgrounds on the OS?

 

Thanks,

 

Brad Hansen

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Punkyclown wrote:Hi  All,  I

Hi  All,  I have noticed that all the IIgs backgrounds and Disk drives and scroll windows are all

dithered, and they look awful.  Is ther someway I can turn off the dithering or put smooth 

backgrounds on the OS?

The IIgs color monitor did not show these 'aweful' dithered backgrounds as you see them on emulators or most Viedo converters. colors were mixed by the hardware in an analog fassion and resulted in semi-solid colors. There are some interesting quirks in this whole process (as even and odd pixels do not seem to be identical in width). Sadly, it makes most emulated IIgs software at 640x200 resolution very ugly. 'Nichida Radio' had added a smothing option to their IIgs -> DVI adapter that had good but not perfect results. I don't know if a solution is available for emulators. Blach&white backgrounds are solid and not dithered. This dithering trick is pretty cool on original hardware but it is ugly on modern emulators. The uneven width of the pixels does result in an aditional effect: b-w dithered lines for example appear in different intensity depending on which column white or black is (even/odd). This can be seen on original monitors in the hard-drive icon (a lighter gray line).


The 640x200 mode has only 4 solid colors. With the trick to assign 4 different colors in even and odd pixels, yYou can display 15 dithered colors. The palette of the IIgs desktop is fixed in this dithered mode with only black and white being thared between the 2 palettes. the other 2 available colors are different. As  result only b&w backbround-images can be displayed 'correctly'.

-Jonas

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Dithered backgrounds

Mr Jones,

Thanks so much for replying and letting me know.  I am not running in emulation.

I am using my IIgs, first with a Apple Scan 15AV monitor with an upscaller 15 to 31 mhz.

Then with a flat screen with the same upscaler.  Running a standard 300 x 240 16 color

screen.  Both with a pretty ugly result.  So you'er saying if I have a regular IIgs monitor

than the ugliness will go away?  When using  DPaint I was able to turn dithering off in the

color palette and got very nice looking smooth colors.  Also I have seen a YouTube video

where someone had a picture as a background and it was completely smooth.  How do I add

those kinds of pics to my background?

Again, appreciate your feedback.

Brad Hansen

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