put image with translation on a canvas then crop it

[thalyric]

Hi

I'm trying for weeks now and I'm not geting anywhere.

So I have an image and I have a matrix translate string : t320.804,-254.3717s1.1201,1.1201,0,0r45,0,0


Now I want to put the image (with the translation) onto a canvas of 800 x 600.
After that I want to crop the image (from the center) to 400x200



My first attempt was to create a real image of 800 x 600, then tried to put an image with a affine translation onto it. But somehow, the whole canvas was messed up.

Then I tried with a repage, but no luck either (I think I'm not using it properly).



Any suggestion to do this?

[snibgo]

"-distort AffineProjection" takes 6 parameters: sx, rx, ry, sy, tx, ty. (See http://www.imagemagick.org/script/comma ... hp#distort .) You have 9 parameters.

"45" is a weird value for rx. Perhaps you want sin(45) = 0.7071.

Perhaps this is what you want:

Code: Select all

convert -size 150x100 gradient:red-blue sample.png

convert ^
  sample.png ^
  -virtual-pixel Black ^
  +distort AffineProjection 1.1201,0.7071,0,1.1201,320.804,-254.3717 ^
  +repage ^
  -background Blue ^
  -gravity Center ^
  -extent 800x600 ^
  -crop 400x200+0+0 +repage ^
  t1.png

[thalyric]

well ... I tried your solution,

The image does rotate and scale, but it will be centered on the canvas. And that's not what I want. I need the image to be placed on the canvas with help of the transform t (so not centered) and after that , I will crop the image (from the center). So it can be that parts of the image will fall off after the crop.

[snibgo]

Sorry, I don't understand what you want. Perhaps this is closer to what you want:

Code: Select all

convert ^
  t.png ^
  -virtual-pixel Black ^
  -distort SRT 1.1201,45 ^
  +repage ^
  -background Blue ^
  -gravity NorthWest ^
  -geometry +20.804+54.3717 ^
  -size 800x600 xc:Blue ^
  +swap -composite ^
  -crop 400x200+0+0 +repage ^
  t2.png