Circle Tool
From Synfig Studio :: Documentation
The circle tool is used for creating new circle layers. Click where you want the center of the circle to be, and drag to set the radius.
The circle tool can also be used to create outline layers, region layers, curve gradient layers, and plant layers, each with approximately circular BLines.
The Tool Options Panel for the Circle Tool has checkboxes for each of the 5 types of layer (circle layer plus 4 bline layers) to select which layer type(s) will be created by the tool. It also has "BLine Points" which sets the number of BLinePoints that will be used in the new BLines, and "Point Angle Offset" which determines where on the circumference of the circle the BLinePoints will be.
