Archimedean Spiral

[MJW]

 

This plugin transforms a rectangular region into an Archimedean spiral. It's in the Distort menu.

 

Plugin DLL (Version 1.0.0): Archimedean Spiral.zip

 

The description from the Help menu:
 

Archimedean Spiral transforms a rectangular region from an image into an Archimedean spiral.

The controls are:

Transform Clipboard Image: Specifies that the image to transform should come from clipboard instead of the canvas. This option is disabled if the clipboard does not contain an image.

Center Transformation at Center of Clipboard Objects: Specifies that when the image is from the clipboard, the transformation should be centered at the center of the clipboard objects rather than the center of the clipboard image. (Objects are non-transparent regions on a transparent background.)

Clipboard Blending Mode: Selects the method for blending the transformed clipboard image with the canvas image.

Clipboard Opacity: Adjusts the opacity of the transformed clipboard image.

Canvas Transformation Center: Specifies the center of the transformation when the image to transform comes from the canvas.

Transformation Scale: Increases or decreases the size of the transformed region.

Transformation Height Scale: Increases or decreases the height of the transformed region without changing the width.

Spiral Location: Specifies the location of the spiral's center on the canvas.

Spiral Scale: Increases or decreases the size of the spiral, changing both the distance between spiral loops and the size of the transformed region.

Distance From Spiral Center to Transformed Region: Specifies the distance from the spiral's center to the transformed region.

Spiral Loop Spacing: Specifies the distance between spiral loops. The transformed region is not rescaled. This is the number of pixels between loops when Spiral Scale is 1. It is also the height of the rectangular region to transform when Transformation Scale and Transformation Height Scale are both 1.

Spiral Rotation: Specifies the angle to rotate the spiral.

Spiral Direction: Selects the direction for the transformed region to spiral. The region can spiral clockwise or counterclockwise, and inward or outward.

Slant Adjustment: Adjusts the slant of the transformed region relative to the direction of the spiral loops.

Antialias: Specifies that antialiasing should be used.
Antialias Quality: Specifies the number of samples in each direction per pixel.

 

The user interface:

 

This is a release version of a plugin previously published as a beta version. The most significant changes are the option of using the clipboard image (suggested by @Red ochre)  and the "Slant Adjustment" control. When the slant value is 0, vertical lines in the transformed image are (nearly) perpendicular to the direction of the spiral. @Reptillian suggested that feature, which was both challenging and interesting to implement.