Can I have a background and foreground axis ?

I built a GUI where I let the user select various region of interest (ROI) on a histogram plot. When the user click the plot, I have to refresh the main histogram plot (imhist) then refresh the ROI... this process is very slow as it takes 1 to 2 seconds to refresh the entire plot. I wanted to provide the option to move a ROI but due to the slow refresh, that's not even possible. What could work is having as a 'background' axis the imhist plot, and in a foreground axis, the ROIs.... the user would then only modify the foreground axis... no need then to refresh the background axis. Is that possible ?

Answer 1

[Walter Roberson]

Yes. You can have overlapping axes. Set the Color of the top axis to 'none' to be able to see the parts underneath. If you define your ROI as an image or as a patch you may need to set AlphaData properties to be able to see what should be logically underneath.

However, it sounds to me like you do not need to do this: that you should simply record the handles of the ROI and when the user moves the ROI, set() its new coordinates and drawnow() once you have adjusted all the handles you need adjusted.

[Jean Bilheux]

Sounds great. I'm gonna try this. Thanks a lot.

Answer 2

[Jan]

See the plotyy command, which creates 2 axes also: edit plotyy.

[Jean Bilheux]

I will take a look at that too. Thanks so much.