User guide

Manipulating Images 97
Use in conjunction with the Ctrl key to transform the selection area without
constraint, creating a skewed transform (drag nodes as appropriate). The Alt
key resizes the area about its center, while the Shift key maintains the area’s
aspect ratio. It’s also possible to move the small center of rotation "handle" in the
center of the transform to produce an arc rotational movement rather than
rotating around the area’s center (by default).
Holding down the Shift key whilst rotating will cause a movement in 15
degree intervals.
Making the selection larger or smaller
If the selection you've made isn't quite the right shape, or doesn't quite include
all the necessary pixels (or perhaps includes a few too many), you can continue
to use the selection tools to add to, or subtract from, the selected region.
To add or subtract to/from the existing selection with a selection tool:
Select the tool and drag while holding down the Shift or Alt key, respectively.
The newly selected pixels don't have to adjoin the current selection—it's
possible to select two or more separate regions on the active layer.
Modifying the selection
Once you've made a selection,
several modify selection operations
can be used in combination to alter
the selection area. Feather, smooth,
contract, and expand operations
are possible from a single Modify
Selection dialog, along with the
popular Grow, Similar, and Invert
available separately. Combining
the operations in a dialog improves
efficiency, and lets you preview
your modified selection directly on
the page as you make changes.
Several preview methods are
possible.