Figure 13.4. Rectangle Select icon in the Toolbox
The Rectangle Selection tool is designed to select rectangular regions of
the active layer: it is the most basic of the selection tools, but very
commonly used. For information on selections and how they are used in GIMP
for information on features common to all selection tools see
This tool is also used for rendering a rectangle on an image. To render a
filled rectangle, create a rectangular selection, and then fill it using
the Bucket Fill tool.
To create a rectangular outline, the simplest and most flexible approach
is to create a rectangular selection and then
2.2.1. Activating the tool
You can access to the Selection Tool in different ways:
See Selection Tools for
help with modifier keys that affect all these tools in the same
way. Only effects options that are specific to this tool are explained
Pressing the Ctrl key after starting
your selection, and holding it down until you are finished,
causes your starting point to be used as the center of the
selected rectangle, instead of a corner. Note that if you
press the Ctrl key before starting to
make the selection, the resulting selection will be
subtracted from the existing selection. The cursor becomes
If you press the Shift key
before starting the selection, the
resulting selection will be added to the existing one. The cursor
Pressing the Shift key after
starting your selection, toggles the Fixed
option, and holding it down until you are finished,
will constrain the selection to a square, if it is your first
selection. Later, with the default Aspect Ratio
, your selection will respect the aspect ratio of the
Pressing both keys after starting your selection
combines the two effects, giving you a square selection centered
on your starting point. Note that pressing these keys before
starting your selection intersects the resulting selection with
the existing one and the pointer change shape accordingly :
Example of Rectangle Selection.
When this tool is selected the mouse pointer is displayed like this:
as soon as it is over the image. A drag and drop allows to get a
rectangular (or square) shape. When the mouse button is relaxed, a
dotted line (“marching ants”) outlines the selection. It's
not necessary to adjust the selection with care; you can resize it
When the pointer is moving on the canvas, the pointer and selection
- outside the selection it looks like previously; this allows to design
a new selection but will erase the existing one if this isn't combined
with an action on the relevant key to add or subtract another selection
as described in the previous paragraph.
- within selection peripheral parts, the mouse pointer changes into
various shapes when overflying rectangular sensitive and clearly marked
areas. These handles allow you to resize the
selection. In selection corners the pointer changes into a shape
according to the context; for instance in the low right corner it
So, by click-and-dragging these areas, you can magnify or shrink the
selection size. Over median selection parts, lateral, low or up,
pointer is changed into appropriate shapes according to the context.
For instance, when the mouse pointer is over the median right side, the
pointer looks like:
So you can click-and-drag to magnify or to shrink the selection size by
moving the chosen boundary.
- inside selection central area the mouse pointer looks like usual for
object manipulation, i.e.:
So you can move the whole selection by a click-and-drag.
Moreover, if you have not unchecked the Highlight
option, your work will be easier because what is out the selection will be
darkest than what is in the selection, and then the selection seems
If you use moving keys you can move the selection or modify its size
by one pixel step. If you use it in combination with
Shift you can move it by a 25 pixel step.
Sensitive selection areas
After creating and modifying the selection, you will have to exit this
editing mode (and commit any changes). You can do this with a single
click inside the selection or by pressing the Enter
key. Or you can just use a non-selection tool and, for example, fill or
paint the selection.
Figure 13.7. Tool Options for the Rectangle Select tool
Normally, tool options are displayed in a window attached under the
Toolbox as soon as you activate a tool. If they are not, you can access
them from the image menu bar through
→ → which opens the option window of the selected tool.
See Selection Tools
for help with options that are common to all these tools. Only
options that are specific to this tool are explained here.
Mode; Antialiasing; Feather edges
Common select options.
If you enable this option, a slider appears. You can use this to
adjust the radius that is used to round the corners of the
Expand from center
If you enable this option, the point the selection is started by
pressing the mouse button is used as center of the selected area.
This menu allows you the option of constraining the shape of
the rectangle in different ways.
This option allows you to design and resize the selection
while keeping the aspect ratio fixed and written within the
relevant box. By default the ratio is 1:1 (so we have a
square) but it can be changed. With the two little landscape
and picture icons, you can invert this ratio.
With this choice you can fix the width of the selection.
With this choice you can fix the height of the selection.
With this choice you can fix the width and height of the
X; Y; Width; Height
These four text fields contain the current place and size of the
selection. You can use these fields to adjust size and place of
the selection by numbers.
If you enable this option, the selected area is emphasized by a
surrounding mask to make visual selection much easier.
With this menu you can select the type of guides that is shown
within the selection to make the creation of a selection easier,
respecting Photo composition rules.
No guides are shown at all.
Only center lines are shown as guides within the selected
Rule of thirds
Guides are shown along the rule of thirds while creating the
With this option, guides show up to mark the golden
Auto Shrink Selection
The Auto Shrink Selection check-box will
make your next selection automatically shrink to the nearest
rectangular shape available on the image layer. The
algorithm for finding the best rectangle to shrink to is
“intelligent”, which in this case means that it
sometimes does surprisingly sophisticated things, and sometimes
does surprisingly strange things. In any case, if the region
that you want to select has a solid-colored surround,
auto-shrinking will always pick it out correctly. Note that
the resulting selection does not need to have the
same shape as the one you sweep out.
If Sample Merged
is also enabled, then Auto Shrink will use the pixel information
from the visible display of the image, rather than just from the
active layer. For further information regarding Sample Merge, see
the glossary entry