why color maps become blank or invisible, and how to fix it

hi all,

i have a GUI-based program that generates many kinds of plots sequentially.

at some point during runtime, color scale ceases from being plotted. this means that CData is not graphically represented (plot disappear), although the data is there in the plot, like if all the dots became white, on a white background.

if you look for the current axes children- the plot and it's CData is there.

when this happens, any color map i try to plot from now on, either by scatter plot or image (etc...), becomes blanc.

• recently noticed : if I close internet browser (Firefox, in my case), and restart Matlab, while browser is still closed, the problem would disappear. If I open Firefox again, it might happen again after sometime.

might it be some compatibility issue of color mapping with some graphic-related modules (Flash plugin, or OpenGL/ ActiveX, or whatever. I don’t really know…), that is effected by the usage of the browser graphics?

attached are examples of figures generated in this sequence, before and after colorscale (of scatter plot) becomes blank. (i can provide also image plot alike, if needed)

could anyone tell what was the problem, and how to avoid it?

thanks in advance!

[Guillaume]

Have you got some code that can reliably reproduce this issue? If so, attach it.

Matlab does not rely on the browser for its graphics, but it's possible that the two together somehow corrupts the graphics stack. Matlab doesn't use flash or activex, but it does use opengl.

Have a look at Resolving Low-Level Graphics Issues. Make sure that your graphics drivers are up to date.

[Sharon Aharon]

dear Guillaume, thanks for your response!

the code i use is a large tool that uses for various data analysis and plotting. i don't think i can share it, due to IP constraints.

anyway, the issue occures sporadically, and i couldn't find the triger for it. i can use it for plotting of 100 plots, and then on the #101 plot (and on), it will become blanc. once this happens, the following simple code generates a blanc plot as well:

A= 1:1:100;
B= A;
C= rand(1,100);
figure
scatter(A,B,30,C,'filled')

actually, this is the case in this very moment. if we can take it offline for live sharing (we can update forum on the issue later), and you can generously further assist, pls contact me on: [e-mail]

thanks!

[Guillaume]

I'm afraid that if you want this kind of support, you'll have to contact mathworks support.

I was certainly not asking for complex code. Just a recipe to reproduce the problem. If the problem is intermitent it's most likely a low-level graphics issue so have a look at the link I gave you. Try switching to software opengl (but this will obviously slow down the graphics generation).

[Sharon Aharon]

indeed, Guillaume

i intended to contact mathworks support, as the next step.

i forgot to say, that i do get a "low-level graphics issue" warning ocationally, so i already tried to solve it by the suggested solutions. didn't work for me so far.

anyway, thank you very much for your good will!

best regards,

Sharon

[Image Analyst]

If your code is too big to upload or proprietary, try to whittle it down to just some simple code with random data that will demonstrate the problem. If we don't have any code to reproduce the problem then about all we can say is "It's just you, Sharon", because I've never encountered that.

1. Does the problem happen randomly at the same place in the program? Like on the call to colormap() or plot() on the same line number?
2. Does the appearance change on its own, after your program has finished up everything and is just sitting there idle as you interact with other programs? Or it is only exhibited as the program runs?
3. Does it only happen if you leave your app and MATLAB and switch focus to another app?

[Sharon Aharon]

thanks for your response, #Image Analyst!

your point is well understood. i think i have partial (or un-determined) answers to your Qs, so i will try to get to a clear unswers, and follow up with you once ready.