Left Toolbar > Compose Nodes > Mask
The Mask node modifies the transparency of the input image with a monochromatic version of the Mask Image.
The black areas of the Mask Image are 100% transparent and the white areas are 100% opaque.
On the left toolbar choose Compose Nodes > Mask. >
Drag the Mask icon into the Node Graph.
Connect the output of an image node into the Img input in the Mask node.
Connect the output of an image node into the Mask input in the Mask node.
Adjust the attributes of the Mask node to modify the output image.
The Image to which the transparency channel will be modified.
The image that defines the new transparency channel.
The modified image.
Sets the mix method.
Mix: Mixes the Input Image transparency with the monochromatic Input Mask Image.
Replace: Replaces the Input Image transparency with the monochromatic Input Mask Image.
Multiplies the transparency value.
Defines the color of the output image if the Img input image is not connected. The size and position is defined by the Mask image.