How to check rounded corner?

DangDKhanh-2637 941 Reputation points
2024-02-05T19:27:18.3733333+00:00

Hi, I'm using the following code to check rounded on win11.

DWM_WINDOW_CORNER_PREFERENCE preference ; 
DwmGetWindowAttribute(hwnd,WINDOW_CORNER_PREFERENCE, ref preference , sizeof(uint));

However it doesn't work as expected. I used window + left arrow to align it, clearly its state at this time is perpendicular. However preference always returns 2. Is there any other way to fix it? Thanks you! User's image

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Microsoft Technologies based on the .NET software framework.
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Windows API - Win32
Windows API - Win32
A core set of Windows application programming interfaces (APIs) for desktop and server applications. Previously known as Win32 API.
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  1. RLWA32 38,856 Reputation points
    2024-02-05T19:57:36.2233333+00:00

    According to Apply rounded corners in desktop apps for Windows 11 "By design, apps are not rounded when maximized, snapped, running in a Virtual Machine (VM), running on a Windows Virtual Desktop (WVD), or running as a Windows Defender Application Guard (WDAG) window." That would explain why your snapped window does not have rounded corners.

    1 person found this answer helpful.

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  1. Michael Taylor 43,976 Reputation points
    2024-02-05T19:43:37.27+00:00

    The call returns the preference, not whether it actually is or not. As discussed in the docs for having rounded corners here a snapped window doesn't have rounded corners whether its preference was to have them or not. There are quite a few other situations where rounding isn't supported even if the preference is to have it.

    AFAIK there isn't a way to determine if the corners are actually rounded on a window or not. I guess you could brute force a solution but since it is part of the chrome then I'm not sure it'll work. Windows still sees it as a rectangle. You might be able to look at the window styles but I think you'd need to run Spy++ to see if there is a difference. I've never looked.

    1 person found this answer helpful.