Backdrop degrades when loaded

[punkyclown]

I created my own workbench backdrop but when I load it with my workbench patterns Pref the picture is degraded.  I reload it in my graphics program and it looks great.  What is going on here?  Thanks

[marcfrick2112]

Well, first of all . it helps if you give us some specifics about your Amiga: configuration, WB version, etc ....

I'd guess that you're running WB with 16, 32, or 64 colors? WB has to reduce/remap the colors of the picture... and it's not too good at it, as you have seen. Best bet is to use a graphics program to reduce the amount of colors in the picture. I use ImageFX, but other progs. like PPaint can do it too.

Marc

[lsmart]

There are indeed a lot of possible reasons, depending on your soft- and hardware.

On the classic machines (pre 1200) you had to match the colors of the Workbench to avoid crazy dithering artifacts. Check your prerferences for the screen colors to see which ones there are. You couldn't use HAM-Pictures either.

On OS4.X there is an option for the quality of the scaling algorithm in WBPattern. You may see some degrading when not running in 32Bit-Color, but this should be minor.

[Piru]

On OS4.X there is an option for the quality of the scaling algorithm in WBPattern.

This option was available for OS 3.5 already.

[punkyclown]

Sorry, I am running a 64 color pic on an A1200 with 1230 board with 32 megs of ram.
I am running OS 3.9 BB1 & BB2.  So you are saying if I reduce it to 32 colors it will not degrade?  Thanks.  Also is there someway to get a 1024X768 screen on an AGA machine?

[Karlos]

Sorry, I am running a 64 color pic on an A1200 with 1230 board with 32 megs of ram.

Do you mean the picture is 64 colours or the screen mode is 64 colours or both?

I am running OS 3.9 BB1 & BB2.  So you are saying if I reduce it to 32 colors it will not degrade?  Thanks.

The Workbench screen itself allocates several colours (usually at least four) for it's own use. So, if your screenmode uses 64 colours, it may be that only 60 of them (and probably a fair few less) are available when drawing your background image. So, if your background image contained 64 or more colours, it will be remapped when used as a background. Consider that the background, icons, workbench colours etc all have to fit into your screen's 64-colour budget, so sacrifices are made.

I used to use a carefully edited (and dithered) set of images that had 16 colours in them on a 32 colour screen. It was a decent enough compromise at the time but all that went out the window when I got my first amiga graphics card.

Also is there someway to get a 1024X768 screen on an AGA machine?

Sure, for that you'll need the HighGFX monitor driver (see aminet.net). However, it is not guaranteed that your existing monitor will support it. If you have some cash spare, I believe it's well supported by the Indivision AGA flickerfixer.

[Karlos]

Regarding HighGFX, search the gallery here and put "highgfx" in the search box.

Plenty of 1024x768 AGA fun to be had