[PATCH 6/6] win32u: Properly scale monitor work area when emulate_modeset is enabled.

[Zhiyi Zhang]

From: Zhiyi Zhang

---
 dlls/win32u/sysparams.c | 48 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/dlls/win32u/sysparams.c b/dlls/win32u/sysparams.c
index e33ff6e60e5..81b5e9a4288 100644
--- a/dlls/win32u/sysparams.c
+++ b/dlls/win32u/sysparams.c
@@ -1911,9 +1911,55 @@ static void monitor_get_info( struct monitor *monitor, MONITORINFO *info, UINT d
     UINT x, y;

info->rcMonitor = monitor_get_rect( monitor, dpi, MDT_DEFAULT );
-    info->rcWork = map_dpi_rect( monitor->rc_work, monitor_get_dpi( monitor, MDT_DEFAULT, &x, &y ), dpi );
     info->dwFlags = is_monitor_primary( monitor ) ? MONITORINFOF_PRIMARY : 0;

+    if (emulate_modeset)
+    {
+        UINT left_edge, top_edge, right_edge, bottom_edge;
+        struct source *source;
+        UINT num, den;
+        RECT rect;
+
+        if (!(source = monitor->source))
+        {
+            SetRect( &rect, 0, 0, 1024, 768 );
+            info->rcWork = map_dpi_rect( rect, monitor_get_dpi( monitor, MDT_DEFAULT, &x, &y ), dpi );
+        }
+        else if (!(source->state_flags & DISPLAY_DEVICE_ATTACHED_TO_DESKTOP))
+        {
+            SetRectEmpty( &info->rcWork );
+        }
+        else
+        {
+            /* Taskbar size at each side, always non-negative */
+            left_edge = monitor->rc_work.left - source->physical.dmPosition.x;
+            top_edge = monitor->rc_work.top - source->physical.dmPosition.y;
+            right_edge = source->physical.dmPosition.x + source->physical.dmPelsWidth - monitor->rc_work.right;
+            bottom_edge = source->physical.dmPosition.y + source->physical.dmPelsHeight - monitor->rc_work.bottom;
+
+            /* Scale down the area occupied by taskbar. For example, if the height of the taskbar
+             * is 100 on 3840x2160. Then changing to emulated 1920x1080 should report a taskbar of
+             * height 50 because the taskbar height is constant from the perspective of the host
+             * system */
+            monitor_virt_to_raw_ratio( monitor, &den, &num );
+            left_edge = muldiv( left_edge, num, den );
+            top_edge = muldiv( top_edge, num, den );
+            right_edge = muldiv( right_edge, num, den );
+            bottom_edge = muldiv( bottom_edge, num, den );
+
+            rect = monitor_get_rect( monitor, 0, MDT_EFFECTIVE_DPI );
+            rect.left += left_edge;
+            rect.top += top_edge;
+            rect.right -= right_edge;
+            rect.bottom -= bottom_edge;
+            info->rcWork = map_dpi_rect( rect, monitor_get_dpi( monitor, MDT_DEFAULT, &x, &y ), dpi );
+        }
+    }
+    else
+    {
+        info->rcWork = map_dpi_rect( monitor->rc_work, monitor_get_dpi( monitor, MDT_DEFAULT, &x, &y ), dpi );
+    }
+
     if (info->cbSize >= sizeof(MONITORINFOEXW))
     {
         char buffer[CCHDEVICENAME];