scanpex.pl.preferences package

Module contents

scanpex.pl.preferences.level_cmap(color=None, grayscale=0.2, gamma=2, name=None)[source]

Create a custom linear segmented colormap transitioning from grey to a color.

This function generates a colormap that starts at a specific shade of grey and interpolates linearly to the target color.

Parameters:

  • color (tuple of float, optional) – The target RGBA color to transition to. By default None, assigning a specific purple-blue blend.

  • grayscale (float, optional) – The intensity of the starting grey color (passed to plt.cm.Greys). 0.0 is black, 1.0 is white. By default 0.2.

  • gamma (float, optional) – Gamma correction factor for the colormap. By default 2.

  • name (str, optional) – The name of the colormap. If None, generates a name based on the color. By default None.

Returns:

The generated colormap object.

Return type:

matplotlib.colors.LinearSegmentedColormap

scanpex.pl.preferences.rgba2gray(r, g, b, a)[source]

Calculate the luminance of an RGBA color weighted by its alpha channel.

Uses the standard luminance formula (0.299R + 0.587G + 0.114B) adapted to the provided weights.

Parameters:

  • r (float) – Red, Green, and Blue components (0.0 to 1.0).

  • g (float) – Red, Green, and Blue components (0.0 to 1.0).

  • b (float) – Red, Green, and Blue components (0.0 to 1.0).

  • a (float) – Alpha component (transparency).

Returns:

The weighted luminance value.

Return type:

float

scanpex.pl.preferences.textcolor(c, thresh=0.4, dark='.2', light='1')[source]

Determine whether text should be light or dark based on background brightness.

Useful for ensuring text readability on varying background colors (e.g., in heatmaps or bar plots).

Parameters:

  • c (str or tuple) – The background color. Can be a string representation of a float (e.g., “0.5” for grayscale) or an RGBA tuple.

  • thresh (float, optional) – The luminance threshold. If the calculated luminance of c is greater than this value, the background is considered “light”. By default 0.4.

  • dark (str, optional) – The color to return if the background is light. By default “.2” (dark grey).

  • light (str, optional) – The color to return if the background is dark. By default “1” (white).

Returns:

The color code for the text (dark or light).

Return type:

str