FormattedText and pixelsPerDip if Application is scaled independently of DPI

Question

I have a WPF application, that doesn't care of device DPI, but instead is autmatically scaled to fill the screen (but keeping its aspect ratio).

I scale it by changing the ScaleX and ScaleY properties of the transform of the outer most WPF container.

In this case, do I still have to get the monitor’s DPI or can I just use "1.0" as "pixelsPerDip" in the function call of FormattedText?

The reason I ask is, that I try to remove all warnings from my code, and I get a warning, that the override without "pixelsPerDip" is obsolete.

Answer 1

I ran into this same issue. You can get the DpiScale like this:

var dpiInfo = VisualTreeHelper.GetDpi(visual);

In this case you could pass in your root element as the visual.

Now you can call FormattedText, etc., and pass in dpiInfo.PixelsPerDip.

I hope this helps.