[PATCH v2 6/6] win32u: Properly scale monitor work area when emulate_modeset is enabled.

[Zhiyi Zhang]

From: Zhiyi Zhang

---
 dlls/win32u/sysparams.c | 132 ++++++++++++++++++++++++++--------------
 1 file changed, 86 insertions(+), 46 deletions(-)

diff --git a/dlls/win32u/sysparams.c b/dlls/win32u/sysparams.c
index e33ff6e60e5..9bcd9d58720 100644
--- a/dlls/win32u/sysparams.c
+++ b/dlls/win32u/sysparams.c
@@ -1880,6 +1880,52 @@ static UINT monitor_get_dpi( struct monitor *monitor, MONITOR_DPI_TYPE type, UIN
     return min( *dpi_x, *dpi_y );
 }

+/* display_lock must be held */
+static RECT map_monitor_rect( struct monitor *monitor, RECT rect, UINT dpi_from, MONITOR_DPI_TYPE type_from,
+                              UINT dpi_to, MONITOR_DPI_TYPE type_to )
+{
+    UINT x, y;
+
+    assert( type_from != type_to );
+
+    if (monitor->source)
+    {
+        DEVMODEW current_mode = {.dmSize = sizeof(DEVMODEW)}, *mode_from, *mode_to;
+        UINT num, den, dpi;
+
+        source_get_current_settings( monitor->source, &current_mode );
+
+        dpi = monitor_get_dpi( monitor, MDT_DEFAULT, &x, &y );
+        if (!dpi_from) dpi_from = dpi;
+        if (!dpi_to) dpi_to = dpi;
+
+        if (type_from == MDT_RAW_DPI)
+        {
+            monitor_virt_to_raw_ratio( monitor, &den, &num );
+            mode_from = &monitor->source->physical;
+            mode_to = &current_mode;
+        }
+        else
+        {
+            monitor_virt_to_raw_ratio( monitor, &num, &den );
+            mode_from = &current_mode;
+            mode_to = &monitor->source->physical;
+        }
+
+        rect = map_dpi_rect( rect, dpi_from, dpi * 2 );
+        OffsetRect( &rect, -mode_from->dmPosition.x * 2 - mode_from->dmPelsWidth,
+                    -mode_from->dmPosition.y * 2 - mode_from->dmPelsHeight );
+        rect = map_dpi_rect( rect, den, num );
+        OffsetRect( &rect, mode_to->dmPosition.x * 2 + mode_to->dmPelsWidth,
+                    mode_to->dmPosition.y * 2 + mode_to->dmPelsHeight );
+        return map_dpi_rect( rect, dpi * 2, dpi_to );
+    }
+
+    if (!dpi_from) dpi_from = monitor_get_dpi( monitor, type_from, &x, &y );
+    if (!dpi_to) dpi_to = monitor_get_dpi( monitor, type_to, &x, &y );
+    return map_dpi_rect( rect, dpi_from, dpi_to );
+}
+
 /* display_lock must be held */
 static RECT monitor_get_rect( struct monitor *monitor, UINT dpi, MONITOR_DPI_TYPE type )
 {
@@ -1911,9 +1957,48 @@ 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)
+    {
+        struct source *source;
+        RECT rect, taskbar;
+
+        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
+        {
+            /* Store the task bar size (non-negative) at each side in a RECT for scaling */
+            taskbar.left = monitor->rc_work.left - source->physical.dmPosition.x;
+            taskbar.top = monitor->rc_work.top - source->physical.dmPosition.y;
+            taskbar.right = source->physical.dmPosition.x + source->physical.dmPelsWidth - monitor->rc_work.right;
+            taskbar.bottom = 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 */
+            taskbar = map_monitor_rect( monitor, taskbar, 0, MDT_RAW_DPI, dpi, MDT_DEFAULT );
+
+            rect = monitor_get_rect( monitor, 0, MDT_DEFAULT );
+            rect.left += taskbar.left;
+            rect.top += taskbar.top;
+            rect.right -= taskbar.right;
+            rect.bottom -= taskbar.bottom;
+            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];
@@ -2526,51 +2611,6 @@ static RECT monitors_get_union_rect( UINT dpi, MONITOR_DPI_TYPE type )
     return rect;
 }

-static RECT map_monitor_rect( struct monitor *monitor, RECT rect, UINT dpi_from, MONITOR_DPI_TYPE type_from,
-                              UINT dpi_to, MONITOR_DPI_TYPE type_to )
-{
-    UINT x, y;
-
-    assert( type_from != type_to );
-
-    if (monitor->source)
-    {
-        DEVMODEW current_mode = {.dmSize = sizeof(DEVMODEW)}, *mode_from, *mode_to;
-        UINT num, den, dpi;
-
-        source_get_current_settings( monitor->source, &current_mode );
-
-        dpi = monitor_get_dpi( monitor, MDT_DEFAULT, &x, &y );
-        if (!dpi_from) dpi_from = dpi;
-        if (!dpi_to) dpi_to = dpi;
-
-        if (type_from == MDT_RAW_DPI)
-        {
-            monitor_virt_to_raw_ratio( monitor, &den, &num );
-            mode_from = &monitor->source->physical;
-            mode_to = &current_mode;
-        }
-        else
-        {
-            monitor_virt_to_raw_ratio( monitor, &num, &den );
-            mode_from = &current_mode;
-            mode_to = &monitor->source->physical;
-        }
-
-        rect = map_dpi_rect( rect, dpi_from, dpi * 2 );
-        OffsetRect( &rect, -mode_from->dmPosition.x * 2 - mode_from->dmPelsWidth,
-                    -mode_from->dmPosition.y * 2 - mode_from->dmPelsHeight );
-        rect = map_dpi_rect( rect, den, num );
-        OffsetRect( &rect, mode_to->dmPosition.x * 2 + mode_to->dmPelsWidth,
-                    mode_to->dmPosition.y * 2 + mode_to->dmPelsHeight );
-        return map_dpi_rect( rect, dpi * 2, dpi_to );
-    }
-
-    if (!dpi_from) dpi_from = monitor_get_dpi( monitor, type_from, &x, &y );
-    if (!dpi_to) dpi_to = monitor_get_dpi( monitor, type_to, &x, &y );
-    return map_dpi_rect( rect, dpi_from, dpi_to );
-}
-
 /* map a monitor rect from MDT_RAW_DPI to MDT_DEFAULT coordinates */
 RECT map_rect_raw_to_virt( RECT rect, UINT dpi_to )
 {