CGContextRef unit conversion

Question

Some month ago I created a PDF Creator using FPDF (PHP Class). Now I was using NSData to fetch the PDF data from a URL into a UIWebView. Because I'm implementing offline functionalities into my app I want to convert the FPDF PHP Script into cocoa touch.

The unit used in my PHP script is mm. Now I want to know how I can convert mm to the unit used in CGRectMake() (I think it is pixels, am I right?).

Thanks for help, with kind regards, Julian

Answer 1

Well, simple math will get you the answer. Look up the PPI of a non-retina display, divide that by 25.4 (mm per inch) and you have your answer in pixels. However, non-retina is 1 pixel per point, so your answer in points will be the same (can be used on retina and non-retina both, retina is simply 4 pixels per point but that is taken care of for you). I'm almost sure this will be different between iPhone and iPad, so you will need to account for both.