Re: [Gimp-user] crop to content

[Gary Aitken <gimp dreamchaser org>]

On 1/30/20 1:44 PM, Liam Quin wrote:
> On Thu, 2020-01-30 at 20:44 +0100, geop wrote:
> > I have scanned photographs which have a white border. I try "Crop to
> > content"
> Crop to content removes outside borders of picels which all have
> exactly the same value but your border, although whiteish, is not like
> that.
>
> Rotate the image -- the easiest and fastest way is to use tool options,
> turn on reverse/corrective mode, and turn on a grid "number of lines",
> and change the number of lines until one lines up with the a vertical
> edge in the border; drag the lines to rotate them a little and get the
> grid line to match as well as possible, and then in case the image
> isn't actually perfectly square, repeat for the top and bottom inner
> border edges, then finally press Enter to do the rotation.
>
> Then crop the iamge with the crop tool to get rid of the border, if
> that's what you want, or to keep it, image->flatten image, then use
> rectangle select to select the inner pictiure, select->invert to change
> it to select the border, select->feather by 5px or so to make the edge
> soft, and drag the white swatch from the toolbox into the selection (if
> you don't have the default black and white, press d or click the
> black/white icon that's near the swatch).
>
> slave
>
> PS: clean the prints with a microfibre cloth, and the top of the
> scanner with that and eyeglass cleaner )spray onto the cloth of course,
> notthe scanner, and not the same cloth you use for prints; you can also
> use a special Japanese roller that was made for cleaning gramaphone
> records, https://amzn.to/2U9jN3R - but i worry that it may lift the
> surface of the print.

This is probably too simple a solution, but...
If the images are all the same size, and have roughly the same border,
can't you specify a rectangle select of a size slightly smaller to
eliminate the border, position it at the proper offset, and crop?
Or if the images are different sizes, compute a rectangle for e.g. 98%?

Gary