matplotlib-users

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

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

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:

   1. How do I get white color bar labels?
   2. 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

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

[Jae-Joon L. <lee...@gm...>]

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

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
>
> ------------------------------------------------------------------------------
> Download Intel&#174; Parallel Studio Eval
> 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
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
>

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
>>
>> ------------------------------------------------------------------------------
>> Download Intel&#174; Parallel Studio Eval
>> 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
>> _______________________________________________
>> Matplotlib-users mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>>
>>
>>     
>
> ------------------------------------------------------------------------------
> Download Intel&#174; Parallel Studio Eval
> 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
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>