The gradient fill control is responsible for handling linear, radial, and center-out gradient fills. The controls, however, are the same.

Color: Specifies the color of the selected gradient stop.
Opacity: Specifies the opacity of the selected gradient stop, in percent.

The visualisation bar represents the currently selected gradient and all of its stops. The left end represents the start point of the gradient, and the right end the end point of the gradient.

To edit the color or opacity of a gradient stop, left-click on it once. You can also change the position of each gradient stop by dragging it with your left mouse button.

To remove the gradient stop, either click on it with your mouse button, or drag it off the gradient visualisation bar. To add a new gradient stop, simply left-click on where you would like it to appear on the visualisation bar.

Note that the default start and stop points are fixed, and cannot be either moved or deleted.

Linear Gradient

The linear gradient is drawn from the start point to the end point specified by the user. You can edit the position of these points by using the Gradient Tool.

Radial Gradient

Radial gradient is defined by the center and two radii. It therefore looks like a circle or an ellipse. The start point is the center, and the gradient expands until it reaches its outer radii. You can control both the center and the raiduses through the Gradient Tool.

Center-Out Gradient

This type of gradient is somewhat similar to the radial gradient in that it begins at the user-specified center. However, it has no radii, and instead expands until it reaches the outer boundary of the shape. This often produces interesting and unique-looking results. Similarly to the other gradient types, you can control the center by using the Gradient Tool.

Gradient Fill