How to save figure in pdf without margins?

Let us suppose I have a figure with definite pixel size:

set(gcf,'unit','pixel','position',[0 0 figure_width figure_height])

I would like to save it as a pdf. I know the aspect ratio, but how to set the size? I don't want unnecessary margins. I want to use something like this

    set(gcf,'PaperPositionMode','auto','papersize',[a*figure_width a*figure_height]);
    %print(gcf,'Fig','-dpdf','-r0')

But how to choose the value of 'a' ?

Answer 1

[Jan]

The value of a depends on the wanted size of the PDF. You can choose it freely to what you need. To remove the border use:

print(gcf, 'Fig.pdf', '-dpdf', '-fillpage')

[André de Castro]

According to this, -fillpage still leaves a 0.25 inch page margin. If I'm printing to pdf to use it in an academic paper as a 3.5" x 2.2" figure, these margins make up 34% of its total area. Is there an option which leaves no margin?

What I get is this:

____

What I want is this, with only as much margin as needed to keep a centralized plot:

____

Or even without having the plot centralized, with no margins at all:

____

[Jan]

Did you try the -loose flag in the print command?

'-loose' — Use a loose bounding box. EPS and PS files only.

[André de Castro]

Using -loose did improve the results. It worked for PDF, EPS and PS files. I also had to:

• not use -fillpage;
• set the Position property before printing, as below.

width = 3.5;
height = 2.2;
figure_handle.Units = 'inches';
figure_position = figure_handle.Position;
figure_handle.Position = [figure_position(1),figure_position(2), width, height];

It seems strange that I had to set the figure Position though, as I had already set PaperUnits and PaperSize appropriately.

Combining -loose and the above code with the solution suggested here, in the Expand Axes to Fill Figure section, gave even better results, cropping as close as possible to the drawn area. Said solution was not effective when I had tried it before because I was using -fillpage.