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GIMP Rectangle Select Tool

A Look at the Rectangle Select Tool in GIMP


GIMP's rectangle select tool

The Rectangle Select Tool has a range of options

© Ian Pullen

The Rectangle Select Tool in GIMP is perhaps the simplest of all the selection tools on offer. It can be used to select simple rectangular areas of pixels or can be combined with other selections to produce more complex selections of pixels.

Using the Rectangle Select Tool, as with all the other selection tools, allows you to edit and affect specific pixels without changing surrounding pixels; for example, allowing you to change the color of part of an image while leaving the rest unaffected.

There are a number of options that allow users to fine tune how the Rectangle Select Tool works.


By default, this tool is set to Replace the current selection, which means that every time you draw a new selection, any existing selection is canceled. However by using the Add to the current selection, Subtract from the current selection and Intersect with the current selection, you can produce far more intricate selections than you would first believe.

Feather Edges

Simply allows you to soften the edge of the selection; for example, if you intend to fill a selection with a solid color but want it to fade out at the edges. When you select this option, a slider is displayed allowing you to increase or decrease the amount of feathering.

Rounded Corners

Changes the squared off corners of the selection to softer corners. When selected, a slider is displayed to allow you to fine tune the roundness.

Expand from Center

Sometimes you need to place a selection that must be centered on a specific point, so this option allows you to start drawing the rectangle selection at that point.


When checked, the Rectangle Select Tool is constrained in one of four ways.

  • Aspect Ratio – allows users to specify the proportions of the selection; for example, 1:2 will produce a rectangle selection twice as high as it is wide
  • Width – the selection will always be the width specified in the field below the Fixed checkbox, but the height can be set freely
  • Height – works the same as Width, but the height will always be the same and the width can vary
  • Size – the exact size of a selection can be specified before starting to draw it


While drawing a selection, you can use this option to fine tune the position of a selection by changing the value in the two position fields, rather than dragging your rectangle selection.


Works much the same as the Position option but changes the size of the selection.


This grays out all of the image that is being worked upon, except for the current selection that is being made. If two or more selections have been combined, only the current selection is highlighted.


This allows you to specify guidelines that will appear within the current selection. These can be useful for helping to accurately place a rectangle selection in GIMP and can be useful for users who like to use the Rectangle Select Tool to crop images.

Auto Shrink

Will reduce the size of a rectangle selection so that there are no transparent or background colored pixels between the boundary of the selection and any colored pixels within the original selection. The Shrink merged checkbox takes into all layers rather than just the active layer, when Auto Shrink is used.

It's very easy to treat the Rectangle Select Tool as a very simple tool and overlook the power and flexibility that is available with the Tool Options dialog. By experimenting with the various options, you will find that you can achieve some surprising results. This can be a very quick tool to use when drawing complex shapes that consist wholly of right-angles.

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