On Tue, 27 Oct 2009 19:44:42 +0800 ZHOU Xiao-bo <[email protected]> wrote:
| hi: | | I found that when I resize and quantize a gif such as | | "http://img1.cache.netease.com/img09/logo/logo.gif"; | | using "convert logo.gif -resize 160x46 -colors 16 out.gif", I got a | gif with bad quality. | | But if I use "convert logo.gif -resize 160x46 tmp,gif"; and then | "convert tmp.gif -colors 16 out.gif", the quality is much better. | | I think it's because the platte has been changed when resizing. | I found that platte of 'tmp.gif' is much larger than that of | logo.gif. | So, how can I get the better output image in c++ code? | thanks a lot. | ZHOU Xiaobo | Resize does not change the palette, it destroys the palette as it generate completely new colors as part of the process. The save to gif however restricted the colors to a new 256 color palette as part of the save. This may be the cause of the improved result You could try the equivalent of convert logo.gif -resize 160x46 -colors 256 -colors 16 out.gif Also you may like to try using a different dither, -dither FloydSteinberg which may produce a better result for small images. Anthony Thyssen ( System Programmer ) <[email protected]> ----------------------------------------------------------------------------- `` Well you know what they say... All Good Things... '' StarTrek, New Generations (Final Epsoide) ----------------------------------------------------------------------------- Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/ _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
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