The Circle Selection tool lets you create circular selections rather than rectangular boxes.
By default there is no keyboard shortcut for this, but you can assign one in your Application settings in the Edit menu.
Click on your canvas and drag to create a circular selection of a portion of the layer you are currently active on.
Your settings toolbar beneath your color wheel gives you a few options for your selection: Select All, Deselect, or Invert Selection.
The shortcut keys for these options in Magma are:
Select all: Ctrl+A
Invert Selection: Ctrl+Shift+I
Clear: Delete - removes the content from the selected area
Duplicate: Duplicates selection and pastes it on a new layer
You can easily switch between different selection modes to add to, subtract from, and intersect your selections. For tablet users, you can use the buttons in the settings panel. Keyboard users can use the shortcuts mentioned below:
Holding SHIFT when you drag will create a perfect circle selection.
Pressing Alt while dragging will center your selection around the point that you clicked.
To add a new area to your selection, press and hold SHIFT before you click and drag.
To subtract an area from your selection press and hold Alt before you click and drag.
You can move your selection by clicking inside the selected area and dragging it to your preferred position. This doesn't move the contents of the selection.
To deselect, simply tap or click outside the selected area.
Once you have an area selected, you can adjust the size of its contents by switching to the Transform tool.
You can also paint or erase within your selected area giving you a clean edge.
You can set something that you have drawn as your Magma avatar using the selection tools. Make your selection and then click/tap the Set as my avatar button in the Tool Settings panel.