Edit: This answer from MATLAB support is pasted from one of the comments below. I'm editing my initial answer to include it so that others can find it more easily:
This is the answer of MATLAB support team and it works fine.
using images.roi.Rectangle instead of drawrectangle.
function startupFcn(app)
app.UIAxes.Visible = 'on';
im = imshow('peppers.png', 'Parent', app.UIAxes);
axis(app.UIAxes, 'tight');
% Assign the ROI creating function as the callback for any button press on image object
im.ButtonDownFcn = @createROI;
function createROI(~,~)
% Create ROI object
roi = images.roi.Rectangle(app.UIAxes);
% Define an ROI start point within the image
beginDrawingFromPoint(roi,[0,0])
end
end
---- Original answer follows ----
You can pass in a DrawingArea to drawrectangle which will constrain the rectangle to the image. That keeps the drawn rectangles inside the image boundaries, although the crosshair will apear when the mouse hovers outside of the image...clicking there will initiate a rectangle inside the image:
im = imread('peppers.png')
imshow(im, 'Parent', app.UIAxes);
h = drawrectangle(app.UIAxes, 'DrawingArea', [0,0,width(im),height(im)])
Alternatively, you could use axis tight to make the axis (including the invisible part) correspond directly to the boundaries of the image.
imshow('peppers.png', 'Parent', app.UIAxes);
axis(app.UIAxes,'tight')
h = drawrectangle(app.UIAxes)
