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Amiga computer related discussion => Amiga Desktop Audio and Video => Topic started by: commodorejohn on December 20, 2011, 11:01:54 PM
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So, as I'm settling in with an AGA machine, I'd like to get my own desktop background to replace the ClassicWB defaults. But I'm not 100% clear on how to go about this. For starters, I'm running Workbench in 16-color mode, but as the palette editor and the default widgets only edit 8 colors, I'm wondering if the background doesn't just use the spare 8 colors, especially as the current one doesn't seem to be affected by my palette-tweaking. Is this the standard approach? Is it possible for it to use both the eight system colors and another eight custom ones?
Also, what about image formats? I believe Photoshop can export to IFF, I presume that should work?
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What happens is that, as the image is decoded, it is mapped to the existing "locked" pens, that is, the ones Workbench is already using and the ones in the palette editor. Any colours other than those it needs are taken from the remaining unlocked pens, which are altered to suit and then locked. The precision of these mappings can be adjusted, poor precision will leave more pens free for other purposes, but doesn't look as good. I should ask here, what version of the OS are you using? Because 3.9 has much better options for the background than 3.1.
As for image formats, anything you have a datatype for you can use, but I strongly suggest IFF as it doesn't need any translation. Scaling the image to your screen resolution and pre-mapping the colours will greatly reduce the time taken to display the image. Photoshop does export IFF IIRC, but I recommend Personal Paint for these things, since it's so much better suited to dealing with indexed colours, and can remap, resize and dither easily for the best results.
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I'm using ClassicWB Full, which is 3.1-based.
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What happens is that, as the image is decoded, it is mapped to the existing "locked" pens, that is, the ones Workbench is already using and the ones in the palette editor. Any colours other than those it needs are taken from the remaining unlocked pens, which are altered to suit and then locked. The precision of these mappings can be adjusted, poor precision will leave more pens free for other purposes, but doesn't look as good. I should ask here, what version of the OS are you using? Because 3.9 has much better options for the background than 3.1.
As for image formats, anything you have a datatype for you can use, but I strongly suggest IFF as it doesn't need any translation. Scaling the image to your screen resolution and pre-mapping the colours will greatly reduce the time taken to display the image. Photoshop does export IFF IIRC, but I recommend Personal Paint for these things, since it's so much better suited to dealing with indexed colours, and can remap, resize and dither easily for the best results.
100% agree with this: I use ImageFX to scale and map to my WB palette... but even some freeware apps. can do it, iirc...
Personal Paint IS great.... but I found ImageFX easier to re-map WB pics... tho, I am running in 64 colors... dang, I SO NEED a gfx. card!!
Ohh, DON"T count on Photoshop to handle ALL ILBM's (Interleaved BitMaps, the proper term) ... EHB, Dynanic Hires, etc. may well not work...
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@commodorejohn
When WB loads background image it is remapped and dithered using full 16 colours. First 8 colours are always locked and WB can't change them but remaining spare colours may get tuned to suit better with your background image. Depending on your precision setting WB may or may not alter those last 8 colours again.
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Hmm. Well, I'm not too worried about EHB or fancy mode-twiddling, I just want to put together some Workbench backgrounds. I'll stick with Photoshop for convenience's sake unless it has trouble with the format, I think.
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I'm not familiar with Photoshop's settings for IFF (yeah, ILBM) saving, but saving as the correct bit depth will be important for loading speed and keeping some pens free. I don't think the standard OS3.1 datatype and preferences support scaling of the image, so having the exact resolution isn't that important - it will just tile or centre the image for you. Also, I don't think the standard datatype does dithering, so this would probably be best done with Photoshop or whatever beforehand...
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I'm a bit shocked nobody has mentioned this yet, but you should download FullPalette to lock the pens, then Rebol and Cammy's superb palette:
Loads of info in these threads:
http://eab.abime.net/showthread.php?t=51657
http://www.amiga.org/forums/showthread.php?t=51924&page=3
There's also some nice "already made" backdrops you can use:
http://dl.dropbox.com/u/939939/Backdrops_640x512%4016.lha
Previews: http://dl.dropbox.com/u/939939/Backdrops.png
http://dl.dropbox.com/u/939939/Backdrops-Games.png
http://dl.dropbox.com/u/939939/Backdrops-Misc.png
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Yep these backdrops were converted by me one-by-one and shared them over EAB and Amibay at some point.
Playing with 16 colors and Rebel's awesome palette, is definitely the way to go if you want a nice colorful Workbench.