How can I set a minimum window size for an app developed in app designer?

I am currently working on a app in app designer and I've been using the SizeChangedFcn call back to code for resizing the components. I want to set a minimum window size so it cannot be resized smaller than a certain size. I've been trying methods such as the one mentioned here (https://www.mathworks.com/matlabcentral/answers/361224-set-uifigure-size-limits-on-display-with-scaling-win10-r2017b) but it's not working, If someone knows how to do this, please can you help me?

Answer 1

[Adam Danz]

1. Set the minimum size as an app property named minSize defined by 1x2 vector describing the minimum [width, height] (see how to define an app property). Example: minSize = [400, 300];
2. Set the SizeChangedFcn to the two lines below. The second line assures that the App stays on the screen.

Don't forget that AutoResizeChildren needs to be set to off to use SizeChangedFcn.

        function UIFigureSizeChanged(app, event)
            app.UIFigure.Position(3:4) = max(app.UIFigure.Position(3:4), minSize);
            movegui(app.UIFigure)
        end

[Erika Yoshikawa]

Hi, thank you for your answer. This seems to resize the app back to minSize when ever it becomes smaller. I'm wondering if there's a neater way to just enable them from dragging the window size smaller than minSize.

[Adam Danz]

No, there is no way to do that. The workaround in my answer is the only alternative I can imagine.

You can set the figure's Resize property to Off which will prevent any resizing.

[Erika Yoshikawa]

No problem, thank you for your help!

[Fryderyk Kukowski]

@Adam Danz, are there any plans on adding this feature? The workaround you proposed doesn't look very good. Disabling Resize all together is also not so good option.

The main problem why it doesn't look very good is that when user resizes app to smaller size than minimal, the programatic resizing doesn't force them to let go the corner or border of app's window and it looks very glitchy.

Answer 2

[Fryderyk Kukowski]

Actually I've found a way of doing it (setting minimum window size without the glichiness (see my comment above)):

properties (Access = private)
	mouseRelease
	minWidth = 1600;
	minHeight = 700;
	lastPos
end
function startupFcn(app)
	import java.awt.*;
	import java.awt.event.*;
	rob = Robot;
	app.mouseRelease = @() rob.mouseRelease(InputEvent.BUTTON1_DOWN_MASK);
	app.lastPos = app.UIFigure.Position;
end
function UIFigureSizeChanged(app, event)
	pos = app.UIFigure.Position;
	if pos(3) < app.minWidth || pos(4) < app.minHeight
		app.mouseRelease();
		app.UIFigure.Position(1:2) = app.lastPos(1:2);
		if pos(3) < app.minWidth
			app.UIFigure.Position(3) = app.minWidth;
		end
		if pos(4) < app.minHeight
			app.UIFigure.Position(4) = app.minHeight;
		end
	else
		app.lastPos = pos;
	end
end

Your startupFcn and SizeChanged functions should look like that. You should also add mouseRelease property to your app.

Its not perfect but its better than figting with the user over the size of UIFigure.

Edit: It now works almost as well as native minimum size restriction.