Distortion/Ellipse
 
 

As the function's name already states, the Ellipse function is used best with ellipse mask mode. It distorts the texture within the ellipse relative to the distance of a pixel and the ellipse's center. The achieved effects range from the well-known magnifying glass (Image 2) to it's counterpart contraction (Image 3) and other distortions.

A pixel's distance to the center is used directly as Input value for the Transformation. The Output defines the distance of a second pixel to the ellipse's center, which will replace our target pixel.

The Magnifying glass effect for example utilizes the transformation type Round. This causes the pixels to concentrate at the ellipse's border and to be stretched at the center. Another example is the Sinus type, which can be used to create concentric waves (Image 4).

Usually, both dimensions are distorted by this function. However, you can limit the function to work with horizontal or vertical distortions only.

The strength of distortion is manipulated by the Amplify value. It regulates the distance of the replacement pixels to the ellipse's center.