determine axis limits *before* plotting..?

14 Ansichten (letzte 30 Tage)
Bradley Stiritz
Bradley Stiritz am 9 Sep. 2012
Hi everyone,
I need to determine the y-axis limits "before" rendering my plot, b/c the elements are rendered in a loop, one at a time. xlim() isn't any use in this case. Will I have to reverse-engineer MATLAB's algorithm, or is there another approach?
Thanks, Brad
  3 Kommentare
Bradley Stiritz
Bradley Stiritz am 9 Sep. 2012
Hi Oleg,
Thanks for your question. Let me clarify: within the rendering loop, MATLAB is forced to reset the y-axis limits & re-render the whole plot each time a new figure element is drawn which exceeds the current limits. Doing this hundreds of times for a single plot is significantly time-consuming.
Therefore, as I said, I want to determine & set the y-axis limits via ylim() "before" the rendering loop. Does this make sense?
Thanks, Brad
Oleg Komarov
Oleg Komarov am 9 Sep. 2012
I think we might help you if you posted the code.

Melden Sie sich an, um zu kommentieren.

Akzeptierte Antwort

Jan
Jan am 9 Sep. 2012
Bearbeitet: Jan am 10 Sep. 2012
Yair has explained some tricks to http://undocumentedmatlab.com/blog/plot-performance/. You can set the XLimMode of the current axes to 'fixed' and let Matlab determine the limits at the end only by resetting it to 'auto'.
[EDITED, link fixed, thanks Yair]
  3 Kommentare
Bradley Stiritz
Bradley Stiritz am 10 Sep. 2012
Yair, thanks for the very helpful blog postings. Your work is greatly appreciated, as always!

Melden Sie sich an, um zu kommentieren.

Weitere Antworten (1)

Image Analyst
Image Analyst am 9 Sep. 2012
You can save the y and x limits for the current axes at any time by using the ylim and xlim functions:
% Save initial limits.
initial_ylim_values = ylim();
initial_xlim_values = xlim();
% Now plot something that will change the ylimits
plot(x, y); % Some y that will change the y limits.
after_ylim_values = ylim();
after_xlim_values = xlim();
  2 Kommentare
Bradley Stiritz
Bradley Stiritz am 9 Sep. 2012
Hi, thanks for your comment. I'm not sure you're seeing my situation? Please see my response to Oleg, above..
Image Analyst
Image Analyst am 9 Sep. 2012
Then you need to set "hold on" and MATLAB will "lock down" all those settings and not allow subsequent plots to change them.

Melden Sie sich an, um zu kommentieren.

Kategorien

Mehr zu Environment and Settings finden Sie in Help Center und File Exchange

Produkte

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by