The Gradient tool lets you create great gradient effects across the whole or a part of the image.
The Gradient tool creates gradient effect from the background to the foreground colors. To use the tool, click on the image in the editing window, hold your left mouse button and draw a line to another part of the window, releasing the mouse button. The longer the line, the more gradually the colors will merge one into another.
You can create gradients in any direction - everything depends on where you place the starting point and where - the finishing point.
You can also apply transparency to your gradient using the Opacity option in the options window. You can create multi-layered, beautiful gradient backgrounds by overlaying semi-transparent gradients one on another.
Note that the Gradient tool applies to selected regions. By default the whole image is selected. When you select an area of the image, the tool apply changes to the selected area only.