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maskUse

Image mask usage. Specifies how the mask or alpha channel of the image is used for operations on the image (for example, colorize=). When specified in an effect layer, it allows applying the effect to the background area of parent layer or to the entire parent layer rectangle.
maskUse=norm|invert|off
The following table illustrates the effect of maskUse= depending on availability and type of the mask (alpha channel) associated with the layer image.
Value No mask Unassociated alpha (or separate mask image) Associated (pre-multiplied) alpha
off
Opaque image rectangle
Opaque image rectangle
Foreground area of image over rectangle filled with solid black
norm
Opaque image rectangle
Foreground area of image
Foreground area of image or layer
invert
Hidden layer
Background area of image
Background area of image or layer filled with solid black

Properties

Image or layer attribute. Applies to layer 0 if layer=comp . If specified in an effect layer, the command modifies the mask inherited from the parent layer.
The behavior of maskUse= is undefined and unsupported when specified with text or solid color layers when no image mask is applicable (specified with mask= or catalog::Mask ).

Default

maskUse=norm

Example

Colorize the background area of an image; the image foreground is defined by a separate mask image. This is achieved by layering the colorized image background on top if the unmodified image:
http://server/myRootId/myImageId?layer=1&src=myImageId&mask=myImgMask&maskUse=invert&colorize=0x306090

See also