Zhiyi Zhang : win32u: Don't enumerate mirrored monitor clones for GetSystemMetrics(SM_CMONITORS).

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 793e4640e49d367906c4a9e7f35c46bf3df6a5b9
URL:    https://gitlab.winehq.org/wine/wine/-/commit/793e4640e49d367906c4a9e7f35c46b...

Author: Zhiyi Zhang 
Date:   Fri Mar 15 10:50:40 2024 +0800

win32u: Don't enumerate mirrored monitor clones for GetSystemMetrics(SM_CMONITORS).

Only one monitor in a mirrored monitor set contributes to the result of GetSystemMetrics(SM_CMONITORS).
Tested manually on Win7 and Win10.

---

dlls/win32u/sysparams.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/dlls/win32u/sysparams.c b/dlls/win32u/sysparams.c
index d2f7396971b..6e638922629 100644
--- a/dlls/win32u/sysparams.c
+++ b/dlls/win32u/sysparams.c
@@ -3348,15 +3348,15 @@ struct monitor_enum_info
     RECT rect;
 };

-static unsigned int active_monitor_count(void)
+static unsigned int active_unique_monitor_count(void)
 {
     struct monitor *monitor;
     unsigned int count = 0;

LIST_FOR_EACH_ENTRY(monitor, &monitors, struct monitor, entry)
     {
-        if (!is_monitor_active( monitor )) continue;
-        count++;
+        if (is_monitor_active( monitor ) && !monitor->is_clone)
+            count++;
     }
     return count;
 }
@@ -5941,7 +5941,7 @@ int get_system_metrics( int index )
         return rect.bottom - rect.top;
     case SM_CMONITORS:
         if (!lock_display_devices()) return FALSE;
-        ret = active_monitor_count();
+        ret = active_unique_monitor_count();
         unlock_display_devices();
         return ret;
     case SM_SAMEDISPLAYFORMAT: