Alpha Tool
Manipulates the Alpha Channel.

Alpha Remove | Alpha Fade | Brightness Mask
Linear Mask | Circle Mask | Angle Mask
Frame I | Frame II |

Attention: If your application doesn't support the alpha channel,
this plugin won't produce any result.

Intensity Slider | Lets you adjust the alpha mask.
Invert Check Box | Inverts the alpha mask effect.
Color Box | Only works for Alpha Remove. Defines the color which will be made transparent. Shift clicking on the color box will activate a color picker for selecting a color from the preview.
Preview Coordinate | Only works for Linear, Circle and Angle Mask. Right click on the preview to set a coordinate.