(C#) How to get the point to pixel relationship for my screen?

Question

Hello. From what I've understood the relationship point to pixel will depend on the screen resolution. So how can I calcule it at run-time in c#?

Thanks

Answer 1

It is all in Screen object

    int bpp = System.Windows.Forms.Screen.PrimaryScreen.BitsPerPixel;
    int wid = Screen.PrimaryScreen.WorkingArea.Width;
    int ht = Screen.PrimaryScreen.WorkingArea.Height;

On my machine it gives:

bpp=32
width=1280
height=740

Answer 2

If you're trying to get the DPI of the screen it's a bit trickier. You'll have to create a real Graphics object and query that.

For example, in the Load event of your main form:

using( Graphics g = CreateGraphics() )
{
    _dpiX = g.DpiX;
    _dpiY = g.DpiY; // In practice usually == dpiX
    _points = _dpiX / 72.0f; // There are 72 points per inch
}

Of course most monitors lie about the actual DPI and always return 72 or 96, or when large fonts are enabled 120. If you actually want to map a physical inch to a the screen you'll have to actually calibrate it with the user's help - having them pick a line that they measure to be 1 inch.