You will probably have it happen many times that you need to place
something in an image very precisely, and find that it is not easy to do
using a mouse. Often you can get better results by using the arrow keys on
the keyboard (which move the affected object one pixel at a time, or 25
pixels if you hold down the Shift
key), but GIMP also provides you with two other aids to make positioning
easier: grids and guides.
Each image has a grid. It is always present, but by default it is not
visible until you activate it by toggling
→
in the image menu. If you want grids to be present more often than not,
you can change the default behavior by checking "Show grid" in the
Image Window Appearance
page of the Preferences dialog. (Note that there are separate settings
for Normal Mode and Fullscreen Mode.)
The default grid appearance, set up when you install GIMP, consists of
plus-shaped black crosshairs at the grid line intersections, with grid
lines spaced every 10 pixels both vertically and horizontally. You can
customize the default grid using the
Default Image Grid
page of the Preferences dialog. If you only want to change the grid
appearance for the current image, you can do so by choosing
→
from the image menu: this brings up the
Configure Grid dialog.
Not only can a grid be helpful for judging distances and spatial
relationships, it can also permit you to align things exactly with
the grid, if you toggle
→
in the image menu: this causes the pointer to "warp" perfectly to
any grid line located within a certain distance. You can
customize the snap distance threshold by setting "Snap distance"
in the Tool Options
page of the Preferences dialog, but most people seem to be happy
with the default value of 8 pixels. (Note that it is perfectly
possible to snap to the grid even if the grid is not visible. It
isn't easy to imagine why you might want to do this, though.)
