Resize image batch with a minimum of 10px transparency border

[Bad Pie]

I'm writing a script to take all of the images in a folder and resize them so that the longest side is 290 pixels. Then it places this image onto a new transparent image that is 300x300 and saves it as a png.

At least that's what it's supposed to do. So far, all it does is the first part of resizing the image so that its longest length is 290 px. I don't get any errors when I run the script so I can't figure out why it's not working. Can anyone see what I've done wrong here?



(define (batch-resize pattern)
(let*
(
;Create a 300x300 image with a transparent background

(filelist (cadr (file-glob pattern 1)))
(finalImageWidth 300)
(finalImageHeight 300)
(finalImage)
(finalImage
(car
(gimp-image-new
finalImageWidth
finalImageHeight
RGBA
)
)
)
(layer
(car (gimp-layer-new theImage finalImageWidth finalImageHeight RGBA "layer 1" 0 NORMAL))
)


)

(while (not (null? filelist))

;Resize all of the image files in the folder and add them as a layer to the 300x300 tranparent image
;with 10 pixels of padding on the longest side to show the transparency underneath

(let*
(
(filename (car filelist))
(image (car (gimp-file-load RUN-NONINTERACTIVE filename filename)))
(drawable1 (car (gimp-image-get-active-layer image)))
(theWidth (car (gimp-drawable-width drawable1)))
(theHeight (car (gimp-drawable-height drawable1)))
)

(if (> theHeight theWidth)
(gimp-image-scale-full image (+ theWidth (- 290 theHeight)) 290 INTERPOLATION-CUBIC)
(gimp-image-scale-full image 290 (+ theHeight (- 290 theWidth)) INTERPOLATION-CUBIC)

)
(let*
(
(new-layer (car (gimp-image-get-layers image)))
(gimp-image-add-layer theImage new-layer -1)
(drawable2 (car (gimp-image-flatten theImage)))
)


(file-png-save2 RUN-NONINTERACTIVE theImage drawable2 new.png new.png 0 0 0 0 0 0 0 0 1)
(gimp-image-delete image)
)
)
(set! filelist (cdr filelist))
)
)
)

[Bad Pie]

(Sep 28, 2011 06:27)paynekj Wrote:  I think your problem is that you're not creating a new transparent layer:

I think that the following line is where you think you should be creating the new layer

Code:

(new-layer (car (gimp-image-get-layers image)))

But I think you need a call to gimp-layer-new instead:

Code:

(new-layer (car (gimp-layer-new image finalImageWidth finalImageHeight RGBA-IMAGE "New Layer" 0 NORMAL-MODE)))

I switched out that line as you suggested but it didn't change anything. I noticed that where I was saving the file (file-png-save2), I was saving the drawable from the wrong image. But even after fixing THAT my result was the same (just resizing the original image to 290 px. I came to the conclusion that my script would have to be picked apart piece by piece to figure out what is wrong so I went with the previous suggestion to use ImageMagick. But thank you for your help anyway.

[Bad Pie]

Replied to wrong comment. Guess I can't delete...

[Bad Pie]

(Sep 27, 2011 23:10)ofnuts Wrote:  Why don't you look at ImageMagick for that. You would of course have to figure out a handful of parameters, but that would still be a lot simpler (and likely execute much faster) than using Gimp.

60 lines of code that didn't work to this using imagemagick:
mogrify -path formatted -format png images/*.jpg -resize 290x290 -background transparent -gravity center -extent 300x300 images/*.jpg

Works like a charm. Thanks for the suggestion.