The XY Anchor control input is present in the Flip, Lookup, Offset, Rotate, Scale, Free Ellipse, Free Rectangle, Free Polygon, and Free Gradient components and determines how the coordinate values in the component are interpreted. Its value affects coordinates of all points in the component (such as the rotation origin point in the Rotate component, or the gradient endpoints in the Free Gradient component.) XY Anchor can accept one of three values: Default (Size), Max Size and Image Bounds.
This mode makes all points in the component change their positions according to the changes of the Size slider. For example, if a Free Ellipse with XY Anchor set to Default (Size) is blended with a Perlin Noise and then the Size slider is shifted, the ellipse will 'stick' to the noise – they will scale together without any discrepancies between them as the Size value changes. In this mode, the point with the coordinates of 0, 0 refers to the upper left corner of the image, and a point with coordinates of 1, 1 refers to the lower right corner of the rectangle Size * Size pixels, where Size is the current value of the Size slider.
This mode makes point coordinates independent of the Size slider – just like the Image Bounds mode – while avoiding its inherent problem with non-equal distances along the coordinates that may arise in non-square images. In this mode, the point with the coordinates of 0, 0 refers to the upper left corner of the image, and the point with the coordinates of 1, 1 refers to the lower right corner of the rectangle MaxSize * MaxSize pixels, where MaxSize is the maximum value of the Size slider (its rightmost position).
This mode makes all points in the component independent of the Size slider. Point coordinates are interpreted as percentages of width and height of the source image loaded into Filter Forge (or of 600*600 pixels if no external image is loaded). In this mode, the point with the coordinates of 0, 0 refers to the upper left corner of the image, and a point with coordinates of 1, 1 refers to the lower right corner of the image, no matter if the image is square or rectangular.
