Difference Between saveas and print Commands

Why are image dimensions different when using saveas and print commands? Figure size is set to 560x420. Command saveas(1,'sa_01','bmp') yields image correct in size. Command print(1,'-dbmp256','pr_01.bmp') yields image incorrect in size - 576x432.

Answer 1

[Jan]

PRINT with the dbmp256 device use other coordinates than e.g. the dbmp device. Just set a breakpoint in PRINT and find the line, which changes the units to points and use the PaperPosition value as output size.

FigH = figure;
set(FigH, 'PaperUnits', 'points', 
    'PaperPosition', [18, 180, 560, 420]);
print(FigH, 'pr_01.bmp', '-dbmp256', '-r100')

This creates a 560 x 420 pixel bmp.

[Milos]

Thanks Jan! I never bothered checking _PaperUnits_ and _PaperPosition_.

Answer 2

[Walter Roberson]

"Why" is something that many of us have stopped asking with regards to saveas() and print(). No offense intended to the fine folks at Mathworks, but the challenges associated with those functions have been around a long time, and I have not seen any indication that Mathworks has made updating them to be a priority.

If you want a routine that is much more reliable and which you can customize at need, please see Oliver's contribution export_fig

[Milos]

I use export_fig regularly for saving presentation/publication quality images. I came across this saveas/print conundrum while enabling users under Unix OS to save figures to BMP format (officially not supported as saveas compatible format). Jan's solution works like a charm. Sadly, it's a workaround since MathWorks suggest returning custom value of PaperUnit to default value.