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Compress image in an hourglass format

Posted: 2007-01-21T14:58:33-07:00
by portscanner
First - please excuse me if I dont use the correct terms. I do not do much graphics work, so I will probably not use the correct names for things.

I looked all over (including Anthony Thyssen's pages which I found were fantastic) but I could find what I was looking for. I want to use "convert" to compress the center of an image by about 15-20%, leaving the top and the bottom thirds of the image alone. Sort of change the image into an hourglass type of shape.

Does anyone know how to do that?

Thank you!

Posted: 2007-01-21T21:16:07-07:00
by anthony
Not at this time. though you could create distortion maps to do that using some maths.

the perspective transform (DIY currently) can do a 'tie' shape with a zero crossover point, but not an hourglass figure.

If you really want and I get time, I could try to create a simple one dimension X distortion map for you, but I perform you to have a go and pass me back the results.

Posted: 2007-01-22T05:39:14-07:00
by portscanner
Thank you. I think you pointed me in a direction where I can get my own solution!

Posted: 2007-01-22T16:58:28-07:00
by anthony
Last night I worked out a one dimensional solution for you.
http://www.cit.gu.edu.au/~anthony/graph ... _hourglass

Posted: 2007-01-22T20:14:32-07:00
by portscanner
That's it!!!!!

Thank you!