New topic: Color Reduction
<http://forums.realsoftware.com/viewtopic.php?t=46566> Page 1 of 1 [ 4 posts ] Previous topic | Next topic Author Message DaveS Post subject: Color ReductionPosted: Mon Jan 14, 2013 7:01 pm Joined: Sun Aug 05, 2007 10:46 am Posts: 4412 Location: San Diego, CA Doe anyone have a straight forward (pure RealStudio, no plugins) algorithm for color reduction? Right now my app calls the QTGraphicsExporter Two problems.. 1) Not Cross Platform (plus it does things I don't want/need) 2) currently Deprecated All I need to be able to do is take a PICTURE object stored as 32bit and reduce it to what ever the user selects 256 Color 256 Gray 16 Color 16 Gray 4 colors 4 gray B&W 256 Gray is easy, I have a algrorithm for that..... and perhaps all I need to do is take each value AND it with 0xF0 to get 16 levels? then AND it with 0xC0 to get 4 gray?? but that doesn't seem right... HELP? _________________ Dave Sisemore MacPro, OSX Lion 10.7.4 RB2012r1 Note : I am not interested in any solutions that involve custom Plug-ins of any kind Top kermit Post subject: Re: Color ReductionPosted: Tue Jan 15, 2013 10:49 am Joined: Mon May 30, 2011 12:56 am Posts: 590 I struggled with this for years and ended up biting the bullet and using the dreaded plugin. There are some algorithms knocking about which use binary trees and progressive levels of averaging. Mostly expressed in C terminology. There are a few PD libraries about: notably for Windows: the imagemagik set has a function or two for quantisation. But you'll struggle to find anything easy for Mac, making a cross platform solution really messy. Plugin wasnt expensive, and boy did it make my life easier. Other than that, my previous efforts were 'map to closest of a fixed set of colors' such as the 147 Interent colors: http://www.w3schools.com/html/html_colornames.asp and the Netscape bunch: http://www.techbomb.com/websafe Top DaveS Post subject: Re: Color ReductionPosted: Tue Jan 15, 2013 11:02 am Joined: Sun Aug 05, 2007 10:46 am Posts: 4412 Location: San Diego, CA Thanks... I am seeing the same types of things.... you would think it would be easy. I have a valid way to do the GrayScale ones.... and can "cheat" for 256 colors, by saving image as a GIF and reloading it (OSX forces it to 256 colors then) so now all I need is colors 256->16 and then 16->4 _________________ Dave Sisemore MacPro, OSX Lion 10.7.4 RB2012r1 Note : I am not interested in any solutions that involve custom Plug-ins of any kind Top charonn0 Post subject: Re: Color ReductionPosted: Tue Jan 15, 2013 1:58 pm Joined: Mon Apr 02, 2007 2:08 am Posts: 1066 Location: San Francisco, CA, USA I believe the FreeImage library (open source, cross platform though you must build from source for non-Win32) can do this. There's a RB wrapper here. _________________ Boredom Software Top Display posts from previous: All posts1 day7 days2 weeks1 month3 months6 months1 year Sort by AuthorPost timeSubject AscendingDescending Page 1 of 1 [ 4 posts ] -- Over 1500 classes with 29000 functions in one REALbasic plug-in collection. The Monkeybread Software Realbasic Plugin v9.3. http://www.monkeybreadsoftware.de/realbasic/plugins.shtml [email protected]
