GraphicsUnit.Point, isn't converting well to PDF... GraphicsUnit.World is, but how can I convert it to Point?

Question

Hello,

I have some code in .Net to draw some text content using GDI+. I used GraphicsUnit.Point to size the text. It's working wonderfully on-screen, and even if Print it.

I've been asked to make a system that generates a PDF, and I got ComponentOne's PDF control. It has got similar interface to GDI+.

The problem is: Font sizes are not working. If I use GraphicsUnit.Point, the text is much smaller, and I am getting empty space below the text. When I use GraphicsUnit.World, the text is still small, but there's no extra empty space below the text.

I want to understand how to convert GraphicsUnit.World to GraphicsUnit.Point.

All help will be appreciated.

Thanks

Answer 1

After some Googeling and from what I know from personal experience with GDI+ and String drawing it comes down to DPI (Dots per Inch). Basically the different devices (and as far as GDI+ is concerned, PDF is probably a device) have different DPI values. Displays usually have something like 70 DPI. Printers use 72. I don't know what PDFs use, but it might be 100 (as this is a common value for device independence and would explain the smaller text).

Now, Points are defined as being 72 DPI. This is always true. What GDI+ should do, when drawing to a PDF with a different DPI is, to transform the string drawing accordingly. But this does not always work, especially with text.

The GraphicsUnit.World should (according to some googeling) be device independent and should look the same on all devices.

Answer 2

Hi yspad.. You're right, GraphicsUnit.World looks the same on print, and also on screen. My final solution was to use GraphicsUnit.World as the unit of measure, and shun points. I still don't know the conversion ratio, but I approximated the value till the look was okay.

For my purpose this was enough.