diagonal line of 2.3 mm width

Please tell me how to draw a line of 2.3mm width on a printer? If i want to use the glLineWidth then i can specify the width in terms of number of pixels.

But how can i find the exact number of pixels that are equal to 2.3mm??. Because the resolution of the printer is different in X and Y directions and i am not sure which resolution should i take to calculate the number of pixels that are equal to 2.3 mm??

Please help. I thank you in advance.


I also want to mention that i can find the dots per inch for the printer. But there are APIs for finds dots per inch in both X and Y direction. So, i do not know how to calculate dots per inch for a diagonal line!

Hmmm?? Please describe the software path between OpenGL and your printer. This is probably not an OpenGL question.