What is the default/preferred size of the hit-test area for resizing a window?

thebluetropics 1,046 Reputation points

I am trying to replace the standard window frame with a custom window frame using DWM.
It seems I need to handle the WM_NCHITTEST.

What is the default, preferred size of "window resize" hit-test area?

An illustration is shown in this image:


[Red] Left and Right
[Blue] Top and Bottom
[Green] Corners

But I have tested other applications too, it seems most of these windows uses this layout:


Is this true?

What is the preferred size of the hit-test borders and corners:

  • top, left, bottom, right
  • corners

My guess is 8px each.

I also see other apps uses this layout too:


I have an assumption that image 2 and image 3 is a matter of preference, depends of the application interface layout itself...

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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A high-level, general-purpose programming language, created as an extension of the C programming language, that has object-oriented, generic, and functional features in addition to facilities for low-level memory manipulation.
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