Legacy ImageMagick Discussions Archive

I am attempting to do 2d 2nd order polynomial warping of an image with a collection of control points.

I need the borders between two color regions to not be interpolated at all. If the source image goes from #00FF00 to #FF0000, then I want the warped image to also have that same transition (though at a different pixel location. I'm also using virtual-pixel Black to ensure that the edges of the warped image stay black.
However, the output of this shows interpolated boundaries with various colors between the two present in the source image at the border. I have also tried -interpolate Integer, and -filter Point, with the exact same effects I am seeing from the above command, where interpolated values are being added to the borders.


How do I apply a distortion without any interpolation, and retain 'hard' edges of the same color boundary in the source image?

I think "-distort" uses "-filter", not "-interpolate". See http://www.imagemagick.org/script/comma ... hp#distort

Try "-filter box" or "-filter point".

As you guessed.. add "-filter point" then distort will use fast 'point interpolation' for color determination.
EG:
-filter point -interpolate nearest

Many examples of doing this is in IM examples distortion
http://www.imagemagick.org/Usage/distor ... nterpolate

Thanks for the help. I have tried:

-filter Point
Same results as -interpolate NearestNeighbor

-filter Box
ALMOST what I'm looking for. There is only a single interpolated value instead of a smooth gradient along the borders.

try -filter point -interpolate nearestneighbor

I believe that -filter point turns off EWA resampling and then allows -interpolate to work.

fmw42 wrote:try -filter point -interpolate nearestneighbor

I believe that -filter point turns off EWA resampling and then allows -interpolate to work.

That did it. Thanks a million!

FYI, that was not intuitive based on the documentation

see
http://www.imagemagick.org/Usage/distorts/#lookup