Release 4.0

Parameters - alpha

Name: alpha

Type: real

Read/Write: readable and writeable

Context: Transformation, Iteration, Coloring

Description:

This parameter allows you to influence the transparency of the current pixel. If you simply calculate an Escapetime fractal then transparency is of no use.

But as soon as you create a "Layered Fractal", you can use this information: Each pixel has a transparency, initially set to 1 (not transparent), all pixels together form the so called alpha channel.

Now you can make the inner region of the Mandelbrot set transparent (by setting alpha to 0 in the inside coloring formula), while the outer region is still opaque.
Another layer lying behind that fractal (perhaps a Julia set) could shine through the transparent inner Mandelbrot region.
You can create lots of stunning effects playing with the alpha-channel and its transparencies.

Initially alpha is set to 1, which means: Pixel is opaque, not transparent at all. You can set alpha to any value between 0 and 1, 0 means: Pixel is transparent.

Due to its importance I've created an additional chapter (see Alpha Channel), which describes in more detail the purpose of the alpha channel feature.