Matlab figure to pdf: measuring accuracy

Question

I am generating a PDF by saving a figure generated from the following Matlab code. When x=4, it generated a square whose measure is exactly 4 inch, using a PDF meas

Answer 1

According to last comment you can try this code:

clear all,close all   
x=5;
PaperSize=[8.5 11];
if x<min(PaperSize)
    plot([0 x  x 0], [0 0 x x]), axis tight
    %\\ Set the figure dimensions to US letter and change the background
    set(gcf,'units','inches','Position',[0.1 0.1 PaperSize],'color','w')
    %\\ Set axis position to the center
    set(gca, 'Units','inches', 'Position',[(PaperSize-[x x])./2 x x])
    export_fig('Foo','-pdf','-nocrop')

else
    disp('Axes too wide, man')
end

EDIT: I have updated the code so it is error-free.

For my setup (Win7 Enterprise 32bit, Matlab 2011b, GhostSript) the resulting pdf is as follows:

You can see that axes position is in the centre of 8.5" x 11" paper.

However, the paper height is limitted to 9.94" which is fishily close to height of my screen. For heights below 9.9" it works without any problem.

EDIT 2

As answered here, older versions of Matlab (2014 and below) have figure size limited to screen resolution (RES=get(0,'ScreenSize'); measured in pixels) and with known pixel density (PPI=get(0,'ScreenPixelsPerInch')) we can calculate limits in inches (Limits=RES(2:3)./PPI).

So I tried to sacrify the resolution:

clear all,close all   
x=5;
PaperSize=[8.5 20];  %\\ Paper Height set to 20" for example
PPI_def=get(0,'ScreenPixelPerInch');
Scr=get(0,'ScreenSize');
Scr_H_px=Scr(4);     %\\ Read the screen height in pixels
PPI_new=floor(Scr_H_px/PaperSize(2)); %\ Count new resolution
if PPI_new>PPI_def   %\\ Chech if we do not need to change the resolution
  PPI_new=PPI_def;
end
%%\\ Set root (0) resolution from default 96 to lower
set(0,'ScreenPixelPerInch',PPI_new)
if x<min(PaperSize)
  plot([0 x  x 0], [0 0 x x]), axis tight
  %\\ Set the figure dimensions to US letter and change the background
  set(gcf,'units','inches','Position',[0.1 0.1 PaperSize],'color','w')
  %\\ Set axis position to the center
  set(gca, 'Units','inches', 'Position',[(PaperSize-[x x])./2 x x])
  export_fig('Foo','-pdf','-nocrop')
else
  disp('Axes too wide, man')
end
%%\\ reset the resolution back
set(0,'ScreenPixelPerInch',PPi_def)