3.2.2. Ellipse Selection Tool

The Ellipse Selection tool is designed to select circular and elliptical regions from images or layers so you can work on specific areas of an image or layer.

Activate Tool
  • The Ellipse Selection Tool can be called in the following order, from the image-menu: Tools/ Selection Tools/Ellipse Select.

  • The Tool can also be called by clicking the tool icon:

Key modifiers (Defaults)
Shortcut

The e key will change the active tool to Ellipse Select.

Ctrl

Holding Ctrl while creating an elliptical selection can do up to two things. First, the selection will be created using the pixel you started the selection on as a center. Normally, the selection is created using that pixel as a corner. Second, Ctrl will place the selection into subtraction mode (see above). If you require only one ofthe actions to take place, you can release the Ctrl key prior to releasing the mouse button. Doing so will leave the selection in subtraction mode, but without the center point constraint.

Alt

Holding Alt will allow movement of the current selection (only its frame, not its content). If the whole image is moved instead of the selection only, try Shift+Alt

Shift

Holding Shift while creating a selection will perform up to two different things. The first is to add a constraint such that the height and width of the selection will remain equal (a circle). Second, this key modifier will change the selection mode to addition (see above). If you require only one of these actions to take place, you can release the Shift key prior to releasing the mouse button. Doing so will leave the selection in addition mode, but without the height and width constraints.

Ctrl+Shift

Using Ctrl-Shift can do a variety of things. Both keys alone will do up to two things. Firstly the selection mode will be switched to intersection (or union). Secondly, the selection will have both the center point constraint discussed above and the height and width constraints (also discussed above). It is an exercise for the reader to play with the various combinations available when performing elliptical selections while holding Ctrl-Shift and releasing either both or either prior to releasing the mouse button.

Options

Overview

The available tool options for Ellipse Select can be accessed by double clicking the Ellipse Select tool icon.

Mode

Replace mode will cause any existing selection to be destroyed or replaced when the new selection is created.

Add mode will cause the new selection to be added to any existing selection regions.

Subtract mode will remove the new selection area from any existing selection regions.

Intersection mode will make a new selection from the area where the existing selection region and the new selection region overlap.

Antialiasing

This option will make your selection appear more circular by antialiasing the edge of the selection with the neighbouring pixels. Antialiasing is discussed in further detail under the glossary entry Antialiasing.

Feather Edges

The Radius slider adjusts the amount of feathering in pixels for the next selection that is created. For further information regarding feathering, see the glossary entry Feathering.

Auto Shrink Selection

The Auto Shrink Selection checkbox will make the next selection automatically shrink to the nearest elliptical shape available on the image layer if one can be detected.

If Sample Merged is also enabled, then the Auto Shrink will use the pixel information from all the layers of the image. For further information regarding Sample Merge, see the glossary entry Sample Merged.

Fixed Size

Enabling Fixed Size will allow you to manually specify a size for the selection using the Width, Height, and Unit controls.

Fixed Aspect Ratio

The Fixed Aspect Ratio option allows more controlled creation of the selection region. By setting the size to the desired amount, predetermined areas can be selected with ease. The area can also be specified as a percentage of the total layer.

Additional information
[Note] Note
When moving a selection beyond the boundaries of the image canvas, the selection will be cropped to the image area. Selections can exist on the visible canvas only. Selection movements and changes are, however, kept in the undo buffer should you need to repair an error.