Using Masks and Layers—Painting, Filling, and Color Tools - GIMP 2.6 for Photographers: Image Editing with Open Source Software - page 251

3.11.4 The Paths Dialog
Paths created in the image window will also appear in the Paths dialog. Either
call it up from the registers of the dock window or choose Windows > Dockable
Dialogs > Paths in the image window. Here you can manage several paths in
one image, and by clicking, you can activate them. Active paths appear blue
in the dialog and are visible in the image (eye icon). Nonactive paths are not
displayed or shown in the image, but they exist nevertheless. You can save
paths in an image if you save the image in the XCF file format.
When you create the first new path, it will appear as an Unnamed path.
Subsequent new paths will be named New Path , New Path #1 , New Path #2 , etc.
To rename the path, click on the text field next to the preview thumbnail and
enter a name. (It is wise to choose a descriptive name so that you can easily
find it if you want to copy or modify it for use in another image.)
The Paths dialog works similar to the Layers dialog. You can click the eye
icon to make a path visible or click the chain icon to link a path to other paths
in the image so that you can manipulate them together.
To complete the exercise, you'll need to use the buttons at the bottom
of the dialog. From left to right, these buttons are New path , Raise path (move
upward in the palette), Lower path (move downward in the palette), Duplicate
path , Path to selection , Selection to path , Paint along the path (create a contour),
and Delete path .
3.11.5 Transforming Paths—the Shear Tool
Now you'll continue working on your image. In the Paths dialog, click the
Duplicate path button and enter a name for the new path, such as wine glass
shadow . Activate the wine glass shadow path and click the Path to selection
button. You'll know the object has been selected when you can see the
“marching ants” around it. Access the Select > Feather menu item to define a
border feathering of 3 px.
Choose Edit > Copy and make a copy of the wine glass. Check the Layers
dialog to make certain that the layer that you're copying from is active. Then
choose Edit > Paste and insert the copied object as a new layer into the image.
A floating selection will appear in the Layers dialog (the inserted new layer),
but it won't be visible on your image. To see the selection in the image, you
must first change it from a floating selection to a new layer. Simply right-click
on the Layers dialog and select New Layer .
You can now check the quality of your work more precisely by making the
background layer invisible. Just click on the eye icon in the layer.
Make wine glass shadow your active path. You'll be using the Shear tool
from the Toolbox to tilt the glass. In the tool options, the Transform > Path
button should be selected to ensure that the tool affects the path.