The abstract base class for all effect implementations.
An effect is a graphical algorithm that produces an image, typically
as a modification of a source image.
An effect can be associated with a scene graph
Node by setting
Some effects change the color properties of the source pixels
(such as ColorAdjust),
others combine multiple images together (such as Blend),
while still others warp or move the pixels of the source image around
(such as DisplacementMap or PerspectiveTransform).
All effects have at least one input defined and the input can be set
to another effect to chain the effects together and combine their
results, or it can be left unspecified in which case the effect will
operate on a graphical rendering of the node it is attached to.
Note: this is a conditional feature. See ConditionalFeature.EFFECT for more information.
Profile: common conditional effect