The Rectangle Selection tool is designed to select rectangular
regions of an image: it is the most basic of the selection tools,
but very commonly used. For information on selections and how
they are used in GIMP see Selections; for information on
features common to all selection tools see Selection Tools.
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 stroke it.
If you want to round the edges of a rectangular selection, the
easiest method is using
Select → Rounded Rectangle
from the image menu.
2.2.1. How to Activate
You can access to the Selection Tool in different ways:
From the image menu bar
Tools → Selection Tools → Rect Select;
By clicking on the tool icon
in the ToolBox,
By using the keyboard shortcut R.
2.2.2. Key modifiers
Note
See Selection Tools for
help with modifier keys that affect all these tools in the same
way. Only effects that are specific to the Rectangle Select
tool are explained here.
Ctrl: 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.
Shift: Pressing the Shift key after starting
your selection, and holding it down until you are finished,
constrains the selection to be square. Note that if you
press the Shift key before starting to
make the selection, the resulting selection will be
added to the existing selection.
Ctrl-Shift: Pressing both keys combines the two effects,
giving you a square selection centered on your starting
point.
2.2.3. Tool Options
Figure 8.3.
Tool Options for the Rectangle Select tool
Note
See Selection Tools for
help with options that are common to all these tools. Only
options that are specific to the Rectangle Select
tool are explained here.
Antialiasing
This option performs no function for this tool and is present to
unify the user interface between the various selection types.
Auto Shrink Selection
The Auto Shrink Selection checkbox 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 Sample
Merge.
Size Constraints
Figure 8.4.
Size Constraint Option Menu for the Rectangle Select tool
This menu allows you the option of constraining the shape of
the rectangle in three different ways.
Free Select.
This option places no constraint on the rectangle.
Fixed Size.
This will allow you to manually specify a size for the
selection using the Width, Height, and Unit controls.
Fixed Aspect Ratio.
This option allows you to resize the selection while
keeping the aspect ratio fixed according to the two numbers
entered in the Width and Height controls.
![[Note]](../images/note.png)
