Use the canvas controls to control clearing and wiping of the image.
You can clear all strokes from the result image and output matte at the current frame or all frames.
To clear strokes from the canvas:
Select one of the following from the Clear Canvas option box:

Clear Canvas option box
The strokes are removed from the result image.
During the painting process, you can rotate the canvas, making it easier to paint on any part of your image.
To rotate the canvas:
Do one of the following:

Rotation field
You can wipe the result image when you want to apply a uniform colour at the current frame in a single brush stroke. Alternatively, you can use a source, to wipe over an image.
To wipe the result image with a colour or a source:
From the View box, select Result (F4).
Do one of the following:
To display the source as an overlay of the result image, enable Overlay (Tab). You can apply transformations to the source before you apply the wipe:
Do one of the following: