2

I made a GUI with TKinter that reads a scope trace from a agilent scope. I want the x axis to update when I change time/div. To update the x and y data I use set_xdata and set_ydata. Is there a similar method for updating the x limits?

Zephyr
  • 11,891
  • 53
  • 45
  • 80
Mark Mitry
  • 29
  • 1
  • 2

2 Answers2

2

You need to understand a bit of the object hierarchy. You are calling set_xdata on a Line2D object, which is an Artist which is associated with an Axes object (which handles things like log vs linear, the x/y limits, axis label, tick location and labels) which is associated with a Figure object (which groups together a bunch of axes objects, deals with the window manager (for gui), ect) and a canvas object (which actually deals with translating all of the other objects to a picture on the screen).

If you are using Tkinter, I assume that you have an axes object, (that I will call ax).

ax = fig.subplot(111) # or where ever you want to get you `Axes` object from.
my_line = ax.plot(data_x, data_y)
# whole bunch of code
#
# more other code


# update your line object
my_line.set_xdata(new_x_data)
my_line.set_ydata(new_y_data)

# update the limits of the axes object that you line is drawn on.
ax.set_xlim([top, bottom])
ax.set_ylim([left, right])

so to update the data in the line, you need to update my_line, to update the axes limits, you need to update ax.

set_xlim doc and set_ylim doc

tacaswell
  • 84,579
  • 22
  • 210
  • 199
  • my code is set up similar to this one I found on hear (answer 2). I want to update the x limits in a similar way I update the y data. http://stackoverflow.com/questions/9997869/interactive-plot-based-on-tkinter-and-matplotlib – Mark Mitry Jan 25 '13 at 19:01
  • 1
    @MarkMitry thanks are nice, up votes and accepted answers are better ;) – tacaswell Jan 25 '13 at 21:12
0

The pyplot.xlim() function changes the range of the x axis (of the current Axes).

The set_xticks() method of Axes sets the ticks. The current Axes can be obtained for instance with gca().

Eric O. Lebigot
  • 91,433
  • 48
  • 218
  • 260