Total newbie to Gimp needs a bit of help....

Software GIMP
1

I have 104 PNG files that I need to do one simple thing to… enlarge the canvas by 200 pixels on each of the four sides.

These are floor plans of the buildings on a campus. The person who originally scanned the blueprints used some kind of automated process that cropped the margins… and stored
them in a folder with the building number, building name, and then inside the folder there is a PNG file for each floor… example:

Directory: 172-(name)
Files:
172-1-Basement
172-2-1st
172-3-2nd
…
172-7-6th
172-8-Penthouse-(elevator equipment)
172-9-Roof

I have 40 directories with 104 files in them.

Now I an using the floorplans in a software package that needs the margins.

All I want to do is to add 200 pixels to all four sides of each floor plan file.

Does GIMP have a macro function that will do this?
Or am I destined to waste many hours manually adding the same white space margins to each file?

Thanks in advance

Mike

2

Hey @YetAnotherMike welcome

While gimp is an excellent program I think you should use imagemagick:

convert input.jpg -gravity center -background white -extent 200x200 output.jpg

2 Likes
3

Don’t know about Gimp, but ImageMagick will do it easily.

Haven’t tested it, but this command should work:

convert -bordercolor white -border 200 input.jpg output.jpg

If you’re on Windows, the FOR command will make it easy to loop over all the files.

https://ss64.com/nt/for_r.html
https://ss64.com/nt/syntax-args.html

Untested (!) example if you want to run it from the command line directly:

For /R C:\temp\ %G IN (*.png) do convert -bordercolor white -border 200 "%G" "border_%G"

To run it from a batch file, you need to double the %'s. So %%G instead of %G.

1 Like
4

You both were faster then me, as I was just trying to create a command myself.

@Donatzsky your command works.
@paperdigits your’s sadly does not - it just crops to 200x200. Which is weird because the manual on first sight says it should do that.

@YetAnotherMike if you want to run such a command on all images in a folder you can use mogrify:

mogrify -bordercolor white -border 200 *.png

Beware that this will overwrite the original files, so only use it on a copy of the files.

5

The FOR command I posted will recursively loop through all the folders and files, creating a copy called border_ORGFILE.png.

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6

If the commandline is not your friend, here is another idea.

In darktable you can use the framing tool to add a border by percentage of the image.

That won’t give you an exact margin of 200 pixels, but if you want a quick and convenient solution to add some margin to the files this can do very nicely.

7

…Well, using Gimp, there is a batch plugin BIMP that gives you a GUI rather than command line.

Add folders of files.
Add ‘other gimp procedure’ and the script-fu-border filter (In Gimp this is Filters → Decor → Border)
Set the destination and keep the folder structure. Looks like this:

https://i.imgur.com/gF4YRVZ.jpg

There are options to change the export format and rename if required.
edit: Really helps if you give version of Gimp and OS (Win / linux / MacOS)

8

ImageMagick -extent 200x200 will set the final size of the image to those dimensions, by adding or removing pixels. See ImageMagick – Command-line Options

The required task is different; we want to add 200 pixels on each of the four sides. “-border 200x200” does that.

IM can process all the files in a directory (using “magick mogrify”), but can’t recurse into subdirectories. Use a shell facility for that.

If your IM is v7 (ie not more than a couple of years old) I suggest using magick instead of convert.

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