Why isn't my pdf shown?

[yuyu26]

I have my canvas printed as “func.png” with the code:
c1->Print("func.png");
I just installed command “eog”, and I seccessfully print a png with command:
eog func.png
however when I changed the class of the file as:
c1->Print("func.pdf");
the pop window of the canvas was shown but the canvas was blank:

and it says the pdf cannot load. What is wrong with that?

[linev]

Did you try xdg-open file.pdf