figure(figsize=(6,4))
plot(blah, blah)
savefig('myfile', dpi=75)
See ttf fonts for more information.
"""
),
('SHOW',
"What's up with 'show'? Do I have to use it?",
"""\
The use of show is probably the biggest source of confusion and
vexation among new users of matplotlib. First of all, you do not
need this function with the image backends (Paint, GD, PS) but you do
need it with the GUI (GTK, WX) backends (unless you are running
matplotlib in interactive mode). The GUIs have 'mainloops' which need to be entered to do event handling. Unless you have threading enabled ala gui_thread (on the TODO list), entering the mainloop is the last command you execute. Because it is expensive to draw, I want to avoid redrawing the figure many times in a batch script such as the following
plot([1,2,3]) # draw here ?
xlabel('time') # and here ?
ylabel('volts') # and here ?
title(''a simple plot') # and here ?
show()
It is possible to force matplotlib to draw after every command, which
is what you want in interactive mode, but
in a script you want to defer all drawing until the script has
executed. This is especially important for complex figures that take
some time to draw. 'show' is designed to tell matplotlib that you're
all done issuing commands and you want to draw the figure now. """),
('PSGUI',
'Can I save PS/EPS from a GUI backend?',
"""\
Yep. Just choose a filename that contains ps in the extension, eg
somefile.ps or somefile.eps and matplotlib will try
and do the right thing. That is, if it's an eps file, it will include
a bounding box, if it's a ps file it will output plain postscript. It
is recommended you use matplotlib-0.50 or later for this feature to
work properly."""),
('TEXTOVERLAP',
'My title or ticklabel or whatever is overlapping some other figure element, what should I do?',
"""
The default subplots take up a lot of room. If you need extra space
for particularly large labels and titles, consider using custom axes, eg, axes([0.3, 0.3, 0.6,
0.6]) gives you more room to the left and at the bottom than the
standard axes.
Other things to consider. With multiple subplots, eg, multiple rows,
turn off the xticklabels for all but the lowest subplot if they are
the same in all subplots set(gca(), 'xticklabels', []). You
can make the fontsizes smaller, as in xlabel('time (s)',
fontsize=8) or, for the tick labels
t = gca().get_xticklabels() set(t, 'fontsize', 8)"""), ('DYNAMIC', 'Can matplotlib do dynamic plots, like digital oscilloscopes or animations?', """\ Absolutely. See for example, anim.py and system_monitor.py"""), ('PERFORMANCE', 'Is matplotlib fast enough for very large data sets?', """\ The answer, of course, is "it depends". I've worked hard to make matplotlib work well with very large data sets (100s of MB), because these are the kinds of data I need to handle at work. It is very good at handling data sets where the x axis is contiguous (eg, time) and only a small portion of data in displayed in the viewport; see for example stock_demo.py where you can scroll through 2 months of minute-by-minute stock quote data. The performance with higher dimensional data, eg, pseudocolor plots with x, y, and intensity parameters, leaves sometime to be desired. I'm looking into ways to improve these cases. Several people with high bandwidth requirements have reported being happy with matplotlib's performance. If you find areas that need improvement, let me know. """), ('IMAGES', 'Can matplotlib handle image data?', """\ Not currently, except as pcolor data. It's in the works; stay tuned."""), ('ROTATETICKS', 'How do I make vertical xticklabels', """\ You can set the rotation of any text instance to vertical
from matplotlib.matlab import *
plot([1,2,3,4], [1,4,9,16])
set(gca(), 'xticks', [1,2,3,4])
labels = set(gca(), 'xticklabels', ['Frogs', 'Hogs', 'Bogs', 'Slogs'])
set(labels, 'rotation', 'vertical')
show()
"""),
('WINFONTS',
"On windows with GTK, I'm getting lots of messages about not finding the Times font",
"""\
Apparently GTK changed the default pango font file, because this is a new problem. You can set font aliases in C:\GTK\etc\pango\pango.aliases. Add a line liketimes = "times new roman,angsana new,mingliu,simsun,gulimche,ms gothic,latha,mangal,code2000"""" ), ('FONTCACHE', "On windows with GD/Agg/Paint, the first time I ran my script I got a bunch or error messages but don't anymore", """\ These modules use FontTools and TTFQuery to find freetype fonts. The first time you import one of these backends, a font registry created in site-packages/ttfquery/font.cache. As you system is scanned for fonts, some errors may be caught if a font file is not readable, etc. Generally, this is not a major problem, as long as most system fonts are found. In subsequent runs, the font.cache is already built so you won't see the messages again. If you want to see the error messages, remove font.cache and rerun your script, capturing them to a file. """ ), ) @header@
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