VNCViewer: The screen did not resize to full screen when the client has set the scaling and text size in Windows 11 23H2

[w93163red]

Describe the bug
When launching the application in fullscreen mode, the content does not properly resize to fit the entire screen. Instead, part of the screen remains black, and the displayed content appears cropped or offset. Additionally, the mouse pointer's actual interaction position does not align with the displayed UI elements, leading to mismatches between clicks and their intended targets.

The client version I built is from commit 9da4f05
The server version is built from commit (b5225e9)

To Reproduce
Steps to reproduce the behavior:

1. Set windows resolution to 2560x1600 (I have tested two resolutions 2560x1600, 3840x2160, they both have the same issue). The scale set to 150%.
2. In the Windows accessibility tab, set the Text Size to 112%
   

Expected behavior
It should display the content as full screen

Screenshots

Client (please complete the following information):

• OS: Windows 11 23H2
• VNC client: TigerVNC
• VNC client version: 9da4f05
• Client downloaded from: self build

Server (please complete the following information):

• OS: [e.g. Windows 8.1]
• VNC server: TigerVNC
• VNC server version: b5225e9
• Server downloaded from: self-build
• Server was started using: Xvnc

Additional context
I have tested the novnc with the mouse back commit (novnc/noVNC#1919) , it works correctly

[CendioOssman]

There might be different issues at play at once here. Neither the TigerVNC client, nor the server supports scaling. But at least the client should work correctly in the backwards compatible mode.

To rule out build issues, what problems are you seeing if using the official builds on our release page?

[w93163red]

The official build is working correctly. It might be related to the process when I built the binary. The step I used is to follow the command in the https://github.com/TigerVNC/tigervnc/blob/master/.github/workflows/build.yml

And line 224 to 228 in vncviewer/DesktopWindow.cxx have been commented out since there was a build error.

D:/tigervnc/vncviewer/DesktopWindow.cxx: In constructor 'DesktopWindow::DesktopWindow(int, int, const char*, const rfb::PixelFormat&, CConn*)':
D:/tigervnc/vncviewer/DesktopWindow.cxx:225:15: error: cannot convert 'Fl_Window::maximize' from type 'void (Fl_Window::)()' to type 'bool'
  225 |   if (maximize)
      |               ^

The FLTK version is 1.4.0-1.

Not sure if it related to the code I commented out. I manually printed out the log:

Sat Dec 07 20:49:00 2024
 DesktopWindow: Requesting framebuffer resize from 1707x996 to 1322x788
 DesktopWindow: 1 screen(s)
 DesktopWindow:          15782 (0x00003da6): 1322x788+0+0 (flags 0x00000000)
 DesktopWindow:
 DesktopWindow: Resizing to 1322x788

The size is not correct here:

And it matches the scale number (1983 / 1322 = 1.5)

[w93163red]

Downgrade to FLTK 1.3.9-10 works.
Seems like it is related to the FLTK 1.4.0 update.

One interesting thing is from the CI

the FLTK version that installed from MSYS2 is 1.3.9-2

When I checked the msys2 package, they have updated to 1.4.0 already: https://packages.msys2.org/base/mingw-w64-fltk

[CendioOssman]

I'm afraid FLTK 1.4 is not backwards compatible, so you need to use FLTK 1.3 when building TigerVNC.

I've filed an issue with MSYS2 that they need to provide both: msys2/MINGW-packages#22769