the size of plot using "print"

Hi everyone~

I have a question about saving plot as pictures. I heard of the Oliver Woodford code but still want to check with you guys about this question.

I use >>set(gcf,'Position',[100 100 900 400]); %define the size of the plot.

>>print(gcf,'-dtiffn','-r300', 'xxx'); %save the picture.

The saved picture has a different size than the size defined by the command. If I manually drag the plot window to change the size, the saved picture still doesn't record that change.

Using things like >> axis equal can change the size of the saved picture.

Anyone knows what's the problem here? Thank you~