projection.Expmap

[adammaj1]

Hi,

Tx for great program Can you write more about :

• "rotates_df : If True, the derivative will be scaled but also rotated according to the mapping."
• screen pixels are defined in [0.5, 0.5]x[-0.5, 0.5]
• the xy_ratio will be udjusted ...
• h_{moy}

TIA

[GBillotey]

Hi Adam,

To understand the 'rotate df' option, maybe the best is to play with this example: https://gbillotey.github.io/Fractalshades-doc/examples/projections/P01-feigenbaum_expmap.html#sphx-glr-examples-projections-p01-feigenbaum-expmap-py See also the last examples in the movie section (recently added), as it was the main use case and reason to add this option rotates_df = False

I believe the pixel windows is now described more clearly also in the doc. In short, all pixels of an image are described by their coordinates, as measured 'on the paper'. See also the paper http://dx.doi.org/10.14236/ewic/EVA2019.74 "At the helm of the Burning ship" which uses a similar concept.

[adammaj1]

https://commons.wikimedia.org/wiki/File:Complex_exponential_function_graph_spiral_shape_yvw_dimensions.jpg

Graph of the complex exponential function in y, v, and w dimensions where v+iw = exp(x+iy) for values of x from -1.5 to 1.5 and values of y from -2π to 2π, so that shows two complete rotations of the spiral. Areas checkered with green are for positive values of x. Areas checkered with red are for negative values of x. Areas checkered with yellow are for positive values of y. Areas checkered with blue are for negative values of y.

[GBillotey]

I will close this issue for now, feel free to reopen if you still have some question.