Re: [Matplotlib-users] configuring colorbar labels on a black background

[Jim V. <Jim...@no...>]

Jae-Joon Lee wrote:
> This seems to be a bug and I recommend you to file a bug.
> This happens because Axis.set_ticklabels method only changes the
> attributes of left (or bottom) tick labels.
>
> Meanwhile, try
>
> for t in colorbar.ax.get_yticklabels():
>     t.set_color("w")
>
> -JJ
>   
Thanks for the explanation and alternative which works just fine!

As per your suggestion, I have submitted a trouble report (2957923). 
entitled: "set_yticklabels(labels, color='white') ignored"

-- jv
> On Tue, Feb 23, 2010 at 11:03 AM, Jim Vickroy <Jim...@no...> wrote:
>   
>> Hello,
>>
>> I'm (unsuccessfully) trying to generate a figure (with a labeled colorbar)
>> having a black background.
>>
>> Here is the code.
>>
>> _purpose_ = 'demonstrate capability to create PNG with black background
>> including labeled color bar'
>> _author_  = 'jim...@no...'
>>
>> import numpy      # http://numpy.scipy.org/
>> import matplotlib # http://matplotlib.sourceforge.net/index.html
>> matplotlib.use('Agg') # http://matplotlib.sourceforge.net/backends.html --
>> probably the fastest, non-GUI, rendering backend
>> import matplotlib.pyplot as plot #
>> http://matplotlib.sourceforge.net/api/pyplot_api.html#matplotlib.pyplot
>> import matplotlib.cm # color maps
>>
>> import sys
>> assert sys.version            == '2.6.4 (r264:75708, Oct 26 2009, 08:23:19)
>> [MSC v.1500 32 bit (Intel)]', sys.version
>> assert numpy.__version__      == '1.4.0',  numpy.__version__
>> assert matplotlib.__version__ == '0.99.1', matplotlib.__version__
>>
>> data_min =   0
>> data_max = 256
>> data     = numpy.random.randint(data_max, size=(512,512))
>> rows_cnt, columns_cnt = data.shape
>> shape    = rows_cnt, columns_cnt
>> x        = numpy.empty(data.shape, dtype=int)
>> y        = numpy.empty(data.shape, dtype=int)
>> x[:]     = numpy.arange(rows_cnt)
>> y[:]     = numpy.arange(columns_cnt)
>> XI, YI   = numpy.meshgrid(x[0], y[0])
>>
>> title      = 'this is the figure title'
>> plot.clf() # clear the figure
>> plot.title(title,color='white',backgroundcolor='black')
>> plot.axis('off')
>> colormap = 'gist_heat'
>> config   = dict(cmap=eval('matplotlib.cm.%s' % colormap), vmin=data_min,
>> vmax=data_max) # vmin,vmax specify a fixed (color-map) scale
>> plot.pcolormesh(XI, YI, data, **config)
>> colorbar = plot.colorbar()
>> ##############################################################################################################################################################
>> # labels   = ??? list of strings labels ???
>> labels = [str(i) for i in range(10)]
>> colorbar.ax.set_yticklabels(labels, color='white')
>> ##############################################################################################################################################################
>> plot.imshow(data, interpolation='bilinear', cmap=config['cmap'],
>> origin='upper', extent=[0,rows_cnt,0,columns_cnt])
>> # plot.show() # interactive
>> filename = 'trial-plot-with-labeled-colorbar.png'
>> plot.savefig(filename, facecolor='black')
>> plot.close()
>>
>> which generates a figure with a black background and invisible (black) color
>> bar labels.
>>
>> I'm probably going about this completely wrong.
>>
>> Questions:
>>
>> How do I get white color bar labels?
>> How do I access the generated sequence of string labels (for use as the
>> first set_yticklabels parameter) rather than artificially defining a list of
>> labels?
>>
>> Thanks,
>> -- jv
>>
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>>     
>
> ------------------------------------------------------------------------------
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> Try the new software tools for yourself. Speed compiling, find bugs
> proactively, and fine-tune applications for parallel performance.
> See why Intel Parallel Studio got high marks during beta.
> http://p.sf.net/sfu/intel-sw-dev
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