There are 2 approaches.
First, the easiest way is with the 'print' function. Call 'print' in the button callback, and it will get the current figure (which is the GUI) and print it.
For more fine-grained control over the printed image, use the following approach:
f = getframe(gcf); % Get an image of the app in pixel color values
toShow = figure('Visible','off'); % Create a new invisible figure
warning('off','images:initSize:adjustingMag') % Turn off a specific imshow warning that sometimes may appear
imshow(f.cdata); % Display the pixel data.
warning('on','images:initSize:adjustingMag') % Turn the warning back on
set(toShow,'PaperOrientation','landscape',...
'PaperUnits','normalized','PaperPosition',[0,0,1,1]); % Set some size preferences for printing
printdlg(toShow); % Open print menu
close(toShow) % Close the invisible figure
This will capture a picture of the GUI using pixel values, and print an associated figure of the GUI.
To change how the GUI appears on the paper (like the size, location, etc), you can modify some of the properties in the 'set' command. More information is below in the "Printing and Exporting" section:
