Skip to content

Instantly share code, notes, and snippets.

@rth
Forked from dmeliza/scalebars.py
Created June 13, 2013 09:56
Show Gist options
  • Save rth/5772583 to your computer and use it in GitHub Desktop.
Save rth/5772583 to your computer and use it in GitHub Desktop.
# -*- coding: utf-8 -*-
# -*- mode: python -*-
# Adapted from mpl_toolkits.axes_grid2
# LICENSE: Python Software Foundation (http://docs.python.org/license.html)
from matplotlib.offsetbox import AnchoredOffsetbox
class AnchoredScaleBar(AnchoredOffsetbox):
def __init__(self, transform, sizex=0, sizey=0, labelx=None, labely=None, loc=4,
pad=0.1, borderpad=0.1, sep=2, prop=None, **kwargs):
"""
Draw a horizontal and/or vertical bar with the size in data coordinate
of the give axes. A label will be drawn underneath (center-aligned).
- transform : the coordinate frame (typically axes.transData)
- sizex,sizey : width of x,y bar, in data units. 0 to omit
- labelx,labely : labels for x,y bars; None to omit
- loc : position in containing axes
- pad, borderpad : padding, in fraction of the legend font size (or prop)
- sep : separation between labels and bars in points.
- **kwargs : additional arguments passed to base class constructor
"""
from matplotlib.patches import Rectangle
from matplotlib.offsetbox import AuxTransformBox, VPacker, HPacker, TextArea, DrawingArea
bars = AuxTransformBox(transform)
if sizex:
bars.add_artist(Rectangle((0,0), sizex, 0, fc="none"))
if sizey:
bars.add_artist(Rectangle((0,0), 0, sizey, fc="none"))
if sizex and labelx:
bars = VPacker(children=[bars, TextArea(labelx, minimumdescent=False)],
align="center", pad=0, sep=sep)
if sizey and labely:
bars = HPacker(children=[TextArea(labely), bars],
align="center", pad=0, sep=sep)
AnchoredOffsetbox.__init__(self, loc, pad=pad, borderpad=borderpad,
child=bars, prop=prop, frameon=False, **kwargs)
def add_scalebar(ax, matchx=True, matchy=True, hidex=True, hidey=True, **kwargs):
""" Add scalebars to axes
Adds a set of scale bars to *ax*, matching the size to the ticks of the plot
and optionally hiding the x and y axes
- ax : the axis to attach ticks to
- matchx,matchy : if True, set size of scale bars to spacing between ticks
if False, size should be set using sizex and sizey params
- hidex,hidey : if True, hide x-axis and y-axis of parent
- **kwargs : additional arguments passed to AnchoredScaleBars
Returns created scalebar object
"""
def f(axis):
l = axis.get_majorticklocs()
return len(l)>1 and (l[1] - l[0])
if matchx:
kwargs['sizex'] = f(ax.xaxis)
kwargs['labelx'] = str(kwargs['sizex'])
if matchy:
kwargs['sizey'] = f(ax.yaxis)
kwargs['labely'] = str(kwargs['sizey'])
sb = AnchoredScaleBar(ax.transData, **kwargs)
ax.add_artist(sb)
if hidex : ax.xaxis.set_visible(False)
if hidey : ax.yaxis.set_visible(False)
return sb
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment