fsleyes_widgets.utils.colourbarbitmap

This module provides a single function, colourBarBitmap(), which uses matplotlib to plot a colour bar. The colour bar is rendered off-screen and returned as an RGBA bitmap.

fsleyes_widgets.utils.colourbarbitmap.colourBarBitmap(cmap, width, height, cmapResolution=256, negCmap=None, invert=False, gamma=1, ticks=None, ticklabels=None, tickalign=None, label=None, orientation='vertical', labelside='top', alpha=1.0, fontsize=10, bgColour=None, textColour='#ffffff', scale=1.0)[source]

Plots a colour bar using matplotlib.

The rendered colour bar is returned as a RGBA bitmap within a numpy.uint8 array of size \(w \times h \times 4\), with the top-left pixel located at index [0, 0, :].

A rendered colour bar will look something like this:

_images/colourbarbitmap.png
Parameters

  • cmap – Name of a registered matplotlib colour map.

  • width – Colour bar width in pixels.

  • height – Colour bar height in pixels.

  • cmapResolution – Colour map resolution (number of distinct colours).

  • negCmap – If provided, two colour maps are drawn, centered at 0.

  • invert – If True, the colour map is inverted.

  • gamma – Gamma correction factor - exponentially weights the colour map scale towards one end.

  • ticks – Locations of tick labels. Ignored if ticklabels is None.

  • ticklabels – Tick labels.

  • tickalign – Tick alignment (one for each tick, either 'left', 'right', or 'center').

  • label – Text label to show next to the colour bar.

  • orientation – Either vertical or horizontal.

  • labelside – Side of the colour bar to put the label - top, bottom, left or right. If orientation='vertical', then top/bottom are interpreted as left/right (and vice-versa when orientation='horizontal').

  • alpha – Colour bar transparency, in the range [0.0 - 1.0].

  • fontsize – Label font size in points.

  • bgColour – Background colour - can be any colour specification that is accepted by matplotlib.

  • textColour – Label colour - can be any colour specification that is accepted by matplotlib.

  • scale – DPI scaling factor.

fsleyes_widgets.utils.colourbarbitmap.genColours(cmap, cmapResolution, invert, alpha, gamma=1)[source]

Generate an array containing cmapResolution colours from the given colour map object/function.