Problem writing images when GUI and Figure are open at the same time

Hi everyone,

i'm having a little trouble writing images.

I have a GUI which runs some analyzes on images. At some point i want to plot some markers into an image and save it afterwards. The code for this goes like this:

 figure_handle = figure;
 set(figure_handle,'Visible','off');
        if(cboxchecked(handles.mergecbox))
            try
                imshow(handles.mergedimg);
                title(['# cells:  ', numberOfCells]);
                hold on
                plot(centroidCoordinates(:,1), centroidCoordinates(:,2), ...
                    'go','MarkerSize',7,...
                    'MarkerEdgeColor','b',...
                    'LineWidth',2,...
                    'MarkerFaceColor','g');
            catch
                warning('No merged image available');
            end
         end
saveas(figure_handle,[savingName],'png')

So i actually don't want the figure to pop up, so i set the visibility off. But when i do, the plot and title won't be in the figure that i am saving afterwards. If i switch the visibility on i don't have this problem but still i got some issues. I only get the results i want if i slowly step through the code and make sure the figure is always in the foreground. But when i simply run it, my GUI (with the original image that was uploaded) will normally be displayed in the foreground and then the plot will only appear in the GUI. Is there something i can do to fix this? Thanks a lot!

[Walter Roberson]

Try putting a small pause() before the saveas(). Sometimes the render pipeline does not have time to finish when triggered by saveas() alone.

[Julian]

Thanks for your comment Walter, unfortunately it this didn't fix it

[Kevin Chng]

will it help? if small pause() + drawnow?

[Julian]

No, still the same problem. If the GUI is in the foreground, the plot will be displayed in there.

Answer 1

[OCDER]

Always specify which axes you are drawing to. Also, use print instead of saveas to get the desired resolution.

figure_handle = figure;
axes_handle = axes; %<=== track the axes handle
set(figure_handle,'Visible','off');
if(cboxchecked(handles.mergecbox))
    try
        imshow(handles.mergedimg, 'parent', axes_handle); %<==== specify axes handle to use
        title(['# cells:  ', numberOfCells]);
        hold on
        plot(axes_handle, centroidCoordinates(:,1), centroidCoordinates(:,2), ...  %<=== specify axes 
            'go','MarkerSize',7,...
            'MarkerEdgeColor','b',...
            'LineWidth',2,...
            'MarkerFaceColor','g');
        drawnow(); %<=== refresh image
    catch
        warning('No merged image available');
    end
end
%Make sure to setup the figure PaperPosition, Position, etc
print(figure_handle, sprintf('%s.png', savingName), '-dpng', '-r600')

[Walter Roberson]

I would go further to

figure_handle = figure;
axes_handle = axes('Parent', figure_handle); %<=== track the axes handle
set(figure_handle,'Visible','off');
if(cboxchecked(handles.mergecbox))
    try
        imshow(handles.mergedimg, 'parent', axes_handle); %<==== specify axes handle to use
        title(axes_handle, ['# cells:  ', numberOfCells]);
        hold(axes_handle, 'on')
        plot(axes_handle, centroidCoordinates(:,1), centroidCoordinates(:,2), ...  %<=== specify axes 
            'go','MarkerSize',7,...
            'MarkerEdgeColor','b',...
            'LineWidth',2,...
            'MarkerFaceColor','g');
        drawnow(); %<=== refresh image
    catch
        warning('No merged image available');
    end
end
%Make sure to setup the figure PaperPosition, Position, etc
print(figure_handle, sprintf('%s.png', savingName), '-dpng', '-r600')

[Julian]

Great, it works now, thank you guys!