On 8/20/07, D. Zimmer <[EMAIL PROTECTED]> wrote: > Just a thought... If speed is a big concern, then you could render the image > into an OpenGL widget as a single textured quad, taking advantage of hardware > acceleration to do the resampling for you. The quality would probably be the > same as the linear resample, and the code to manage setting up the texture > would be fiddly, but I expect the speed would be remarkable.
Thanks for the idea but most LTSP servers have really weak (non 3D accelerated) video cards. Plus I have no experience with OpenGL. > > The ImageMagick output does look noticeably smoother, I am not sure what > method it uses... possibly bi-cubic as opposed to bi-linear, which does > require some initial setup for cubic splines, and would be a bit slower. But > this could be sped up for successive resamples by retaining the spline info. Hmm, reusing spline info. Yes I can see how one could take advantage of multiple successive resizes from the same 1024x768 -> 300x225. However, I'm not that talented a programmer. I have no experience in image processing. I think I'll just call convert and add ImageMagick as a dependency. This is a nice page I found for anyone who is interested in explanations of ImageMagicks options http://www.imagemagick.org/Usage/resize/ I tried using -scale instead of -resize and that seems to have made a 25% speed increase and the image still looks good. Thanks for all your help. BTW ImageMagick convert has a -sample switch which produced output that was almost identical to your resampled image. -- Robert Arkiletian Eric Hamber Secondary, Vancouver, Canada Fl_TeacherTool http://www3.telus.net/public/robark/Fl_TeacherTool/ C++ GUI tutorial http://www3.telus.net/public/robark/ _______________________________________________ fltk mailing list [email protected] http://lists.easysw.com/mailman/listinfo/fltk
