Hello Anthony, > convert image1.png image2.png \ > mask.png -compose Src -composite \ > result.png
First experiments are showing that with some minor adjustments this seems to work: First I made a black background image for image2 ($black) the same size as $extraction_mask (white hexagon on black background) and $img->Composite(image=>$black, mask=>$extraction_mask, compose=>'Src', gravity=>'Center'); delivers first the opposite from from what I want: extracted was the region outside the white hexagon not inside. So I negate the $extraction_mask (black hexagon on white background) and now the intended region inside the hexagon is extracted. Thank you very much for your help!! Guenter Anthony Thyssen schrieb: > =?ISO-8859-1?Q?G=FCnter_Bachelier?= on wrote... > | Hello, > | > | I want to extract specific hexagonal regions with freestanding > | structures from images (p3m1 tiles and patterns) like > | > | > http://www.vi-anec.de/Trance-Art/IM-examples/p3m1_extraction/extraction_type_1.jpg > | > http://www.vi-anec.de/Trance-Art/IM-examples/p3m1_extraction/extraction_type_2.jpg > | > | I have tried to make this by drawing an extraction mask > | (with matte=>'false') and use compose=>'CopyOpacity' > | but the image remains unchanged after the operation. > | See PerlMagick code in > | > | > http://www.vi-anec.de/Trance-Art/IM-examples/p3m1_extraction/Test_p3m1_extraction.PLX > | > | I would appreciate any help because I need such an extraction > | method also for some other symmetry group tiles and patterns. > | Thank you very much! > | > | > Sorry fro the late reply but I didn't think of an aswer until late last > night. > > Are you trying to JUST extract the masked region, or will you overlay > that extraction over another image! > > Either way the 3 imae Alpha Composite Masking should NOT have the > alpha channel limitation of CopyOpacity, and can be used to either extract > or blend two images. > > convert image1.png image2.png \ > mask.png -compose Src -composite \ > result.png > > This should do a bleaned overlay of image2.png (Src) with image1 (dest) > according to the mask image. > > See Using a Mask to Limit Composed Area > http://www.imagemagick.org/Usage/compose/#mask > Also see Masked Alpha Composition > http://www.imagemagick.org/Usage/channels/#masked_compose > > No alpha channel is needed for this thpe of operation. > > If one of the images (say images2.png) is an empty (null:) image > and the -compose method is 'Clear' then you can use the mask to > 'clear' or make transparent areas of the first image (assuming it has > an alpha channel). > > For example > convert image.png null: -compose Clear -composite result.png > > The second image in this case does not matter at all, it is nor > referenced by the 'Clear' Duff-Porter composition method. > However the first image MUST have an alpha/matte channel our you will > get black instead of transparent. > > Ways of converting a greyscale mask image into a shaped mask image > with transparency (for duff-porter style operations) is given in > http://www.imagemagick.org/Usage/channels/#shapes > > The simplest way is actually to -combine the gray-scale image using > a -channel A the other color connels will then default to the > background color, though that does not matter if you only plan to use a > shape mask as a 'cookie cutter'. > > NOTE: I would also read the Dst_In and Dst_Out composition operators > and how these to operators are designed so that you 'blend' or 'plus' > (addition) the resulting images together to get a seamless result. > > See http://www.imagemagick.org/Usage/compose/#dstin > which uses one cookie cutter image, to get the 'in' and 'out' parts > of another image, then 'Plus' re-joins the images back into the original > image. An internal test of IM checks that this result is seamless. > > That is the alpha channel comes out to perfect opacity, no > semi-transparency, or extra overlay (super-opacity), just as you would > get for a perfect blend of two cookie-cut images. > > > Anthony Thyssen ( System Programmer ) <[EMAIL PROTECTED]> > ----------------------------------------------------------------------------- > You're traveling through another dimension -- a dimension not only of sight > and > sound but of mind. A journey into a wonderous land whose boundaries are that > of > imagination. That's a signpost up ahead: your next stop: the Twilight Zone! > ----------------------------------------------------------------------------- > 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
