When you set the axes Position to [0 0 1 1] so that it fills the entire figure, the aspect ratio is not preserved when you print because MATLAB® printing software adjusts the figure size when printing according to the figure's PaperPosition property. To preserve the image aspect ratio when printing, set the figure's PaperPositionMode to 'auto' from the command line.
When PaperPositionMode is set to 'auto', the width and height of the printed figure are determined by the figure's dimensions on the screen, and the figure position is adjusted to center the figure on the page. If you want the default value of PaperPositionMode to be 'auto', enter this line in your startup.m file.
Printed images may not always be the same size as they are on your monitor. The size depends on accurately specifying the numbers of pixels per inch that you monitor is displaying.
To specify the pixels-per-inch on your display, do the following (in Microsoft® Windows®):
Until you do this, neither Windows software nor any other can determine how big images on the screen are, and printed images cannot match the size.
On the Macintosh platform, pixels per inch is hard-coded to 72.