Re: [Gimp-user] Stitching Photos

[Steve Kinney <admin pilobilus net>]

On 05/03/2017 10:11 PM, DERoss wrote:
> I have two JPEG files, each with a photo.  I want to creat a single file
> that has the photos stitched together side-by-side.  While I know how to
> export an image from GIMP into a JPEG file, I cannot figure out how to
> stitch two images together.  How do I do this?  Better, where in the
> user documentation is this described?

There are automated tools to facilitate this, but I have not used them.

The manual process is not terribly complicated.

First, open one of the photos in the GIMP, then import the second photo
as a layer.  Drag and drop the second image to the image canvas, quick &
easy.

Next, do Image > Canvas size, and make the 'workspace' available big
enough to accommodate both photos side by side, with some room left over
to move them around.

Then align the photos so their edges fit together accurately.  How to do
this depends on the individual photos; some rotation and scaling (in
that order) of the layer you are moving around may be required to make
them match, and maybe a little tweaking with the Perspective tool, which
enables one to arbitrarily stretch a layer by repositioning its corners.

Note that when using the Rotate tool, you can move the center of
rotation by dragging the cross hair icon in the middle of the grid to
wherever you want it.  Making one detail near the top or bottom edge of
your upper layer match the lower one exactly, and putting the center of
rotation there, will save a lot of time and effort.

Adjusting the transparency of the upper layer to about 50% will greatly
assist in lining it up with the base layer.  When your alignment,
rotation, scaling etc. are

Once the two photos / layers are aligned and look right, "save" your
work as XCF, then save it again with a new name, i.e. add "-1" or
something to the name.  This is so you can go back and tweak your first
effort if and as needed.

To make a seamless transition from one image to another, it may be
helpful to add a layer mask to the upper image and use a very soft edged
brush (or the gradient tool) on the mask to fade the edge of the upper
image out a little.

Finally, crop the aligned photos to square up their edges, make any
necessary color, light, etc. adjustments, save that result as XCF and
export the image to your format of choice as a finished product.

Functions you may want to look up, if any are unfamiliar:  The Move
tool, Scale tool, Rotate tool, Perspective tool, layer opacity
adjustment, Crop tool.

I have made panoramas this way, and it worked out quite nicely.  I
cheated, though, by taking the original pictures with a camera on a
tripod, which make the assembly /way/ easier than hand held results permit.

:o)