diff -r 8efa612b17e1 -r f394adb5b00e savefig.rst --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/savefig.rst Fri Sep 17 18:12:48 2010 +0530 @@ -0,0 +1,111 @@ +======= +Savefig +======= + +Hello and welcome to the tutorial. In this tutorial you will learn how +to save plots using Python. + +Start your IPython interpreter with the command :: + + ipython -pylab + +It will start your IPython interpreter with the required python +modules for plotting and saving your plots. + +{{{ Open ipython }}} + +Now let us plot something, let us plot a sine wave from minus 3 pi to +3 pi. Let us start by calculating the required points for the plot. It +can be done using linspace as, :: + + x = linspace(-3*pi,3*pi,100) + +We have stored required points in x. Now let us plot the points using +the statement :: + + plot(x,sin(x)) + +{{{ Keep the plot open }}} + +Done! we have made a very basic sine plot, now let us see how to save +the plot for future use so that you can embed the plot in your +reports. + +{{{ Switch the focus to IPython interpreter window }}} + +For saving the plot, we will use savefig function, and it has to be +done with the plot window open. The statement is, :: + + savefig('/home/fossee/sine.png') + +Notice that ``savefig`` function takes one argument which is a string +which is the filename. The last 3 characters after the ``.`` in the +filename is the extension or type of the file which determines the +format in which you want to save. + +{{{ Highlight the /home/fossee part using mouse movements }}} + +Also, note that we gave the full path or the absolute path to which we +want to save the file. + +{{{ Highlight the .png part using mouse movements }}} + +Here I have used an extension ``.png`` which means i want to save the +image as a PNG file. + +Now let us locate ``sine.png`` file saved. We saved the file to +``/home/fossee`` so let us navigate to ``/home/fossee`` using the +file browser. + +{{{ Open the browser, navigate to /home/fossee and highlight the file +sine.png }}} + +Yes, the file ``sine.png`` is here and let us check the it. + +{{{ Open the file sine.png and show it for two-three seconds and then +close it and return to IPython interpreter, make sure the plot window +is still open, also don't close the file browser window }}} + +So in-order to save a plot, we use ``savefig`` function. ``savefig`` +can save the plot in many formats, such as pdf - portable document +format, ps - post script, eps - encapsulated post script, svg - +scalable vector graphics, png - portable network graphics which +support transparency etc. + +#[slide must give the extensions for the files - Anoop] + +Let us now try to save the plot in eps format. ``eps`` stands for +encapsulated post script, and it can be embedded in your latex +documents. + +{{{ Switch focus to the already open plot window }}} + +We still have the old sine plot with us, and now let us save the plot +as ``sine.eps``. + +{{{ Switch focus to IPython interpreter }}} + +Now, We will save the plot using the function ``savefig`` :: + + savefig('/home/fossee/sine.eps') + +{{{ Switch focus to file browser window }}} + +Now let us go to ``/home/fossee`` and see the new file created. + +{{{ Highlight the file sine.eps with a single mouse click for 2 +seconds and then double click and open the file }}} + +Yes! the new file ``sine.eps`` is here. + +Now you may try saving the same in pdf, ps, svg formats. + +Let us review what we have learned in this session! We have learned to +save plots in different formats using the function ``savefig()``. + +Thank you! + +.. Author: Anoop Jacob Thomas + Reviewer 1: + Reviewer 2: + External reviewer: