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I'm trying to take a screenshot of the this.location.x&y and this.Size.Width&Height of a Windows Form.

The problem is that on other laptops the screenshot is taken in the wrong location on HiDPI monitors (no problem with size).

search.Dispose();
search = new Bitmap(this.Size.Width, this.Size.Height);
Graphics gr = Graphics.FromImage(search);
gr.CopyFromScreen(this.Location.X, this.Location.Y, 0, 0, search.Size);

I want to take location of 819,184 is actually taken from the location of 538,122....

Felix An
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eater Sun
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    Lookes like you ignored high dpi settings somewhere. Either you designed the form with 100% desktop zoom and now run it on 150% or vice versa. At least the ratio between those two location you mentioned is exactly 1.5. – Ralf Mar 15 '23 at 16:24
  • Look up PointToClient (https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.control.pointtoclient) and PointToScreen (https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.control.pointtoscreen). I've given up trying to figure out which one is needed when. I just try one, then the other to see what works – Flydog57 Mar 15 '23 at 16:26
  • from the way you are describing the problem is with this.Location. how is this variable set? – Molbac Mar 15 '23 at 16:40
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    Look at `Form.PointToScreen` and `Form.PointToClient` to convert from desktop coordinates to form coordinates and back. – John Alexiou Mar 15 '23 at 16:53
  • @Molbac - `.Location` is a property defined by winforms and not a variable the user has any control over, other than you can override the system defaults after a form is created. – John Alexiou Mar 15 '23 at 16:54

1 Answers1

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This problem arises due to differences in the DPI of the monitors you are trying to run the program on. Most fancier laptops nowadays have HiDPI monitors (Apple refers to them as "Retina" monitors). This causes the coordinates to be in the wrong place, as by default, the display output image of non-DPI-aware apps is simply stretched to match the DPI of the HiDPI monitor you are trying to run it on.

A simple workaround to this problem would be to change the display scale on the computers you want to use the program on to 100%. On HiDPI monitors, this will result in everything being smaller than usual. On Windows 11, go to Settings -> Display -> Scale, and change it to 100% in the drop-down menu. However, this has the side effect of making EVERYTHING on the computer small.

You can also try using the compatibility settings. Right-click your .exe -> Properties -> Compatibility tab -> Change high DPI settings -> Check "Override high DPI scaling behaviour. Scaling performed by:" and select Application in the drop-down menu.

Another method would be to make your WinForms app DPI aware. This will fix the blurriness that results from the stretching of the window contents when it is run on HiDPI monitors. Follow the steps in this other SO answer.

This problem is actually common in a lot of old apps from before the days of everyone using fancy HiDPI monitors. Back in the days of Windows XP, the display scale was kept at the default setting on most computers. Even CRT monitors were still being used.

Felix An
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