I have a 6" Kindle. I often read technical PDF files, but the problem is that they don't get converted very well to Kindle's native format (for example, code blocks get messed up, etc). When looking at the PDF page, it's too small to read easily. I can rotate the screen to a horizontal position in order to see it better, but my page gets divided.
Some documents would be easy to read in vertical position if I had the chance to enlarge the font size in an external PDf editor.
Is there a way to change the font size in a PDF file?