On Wed, 25 Feb 2009 22:44:10 +0800 Jiang Miao <[email protected]> wrote:
| According C API ResizeImage | http://www.imagemagick.org/api/resize.php | There is a parameter blur,(the blur factor where > 1 is blurry, < 1 is | sharp. Typically set this to 1.0.) | how can I do that through command line 'convert' ? | if use sharpen or blur, when the value of blur of ResizeImage is 0.8, | what's the value should be set on -sharpen? | That is an old and even miss-named setting!!!! See the updated notes in IM Examples, Resize, Filters http://www.imagemagick.org/Usage/resize/#filters Also see the specific notes on the 'blur' expert setting that is really only useful to control gaussian like filters... http://www.imagemagick.org/Usage/resize/#filter_blur This documentation not only tells you how to use the setting but exactly what the setting does in terms of the re-sampling filter. I also recommend you read the section before filters on Resize Artifacts http://www.imagemagick.org/Usage/resize/#artifacts before hand so that you get a better idea of the terms and what filters are attempting to do. For a cleaner gaussian-like filter, that does not have the 'support cut-off' use a 'Quadratic' or 'Cubic' filters. See http://www.imagemagick.org/Usage/resize/#filter_support for details. of this. Basically if you need to use expert settings, then you are probably not doing things right! Or attempting to do something special. Most people use a normal resize then use a unsharp filter or adaptive sharpening for improving edge sharpening. ASIDE: Before v6.3.6-3, IM made the grave mistake of actually using the sinc windowing function directly as a filter weighting function. This in turn caused all these filters to produce rather badly aliased images, when used for resizing. As a consequence the filters were often mis-understood or rarely used. This has now been fixed. Anthony Thyssen ( System Programmer ) <[email protected]> ----------------------------------------------------------------------------- Beware the kite eating trees! -- Charlie Brown ----------------------------------------------------------------------------- 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
