[PATCH 2/6] user32: Optimize getting primary monitor rectangle with GetSystemMetrics().

[Zhiyi Zhang]

This saves calls to GetMonitorInfo() and return from EnumDisplayMonitors() immediately
after the primary monitor is found.

Signed-off-by: Zhiyi Zhang 
---
 dlls/user32/sysparams.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/dlls/user32/sysparams.c b/dlls/user32/sysparams.c
index 7dc2a8df645..ab1c5af0c1b 100644
--- a/dlls/user32/sysparams.c
+++ b/dlls/user32/sysparams.c
@@ -371,6 +371,27 @@ RECT get_virtual_screen_rect(void)
     return info.virtual_rect;
 }

+static BOOL CALLBACK get_primary_monitor_proc( HMONITOR monitor, HDC hdc, LPRECT rect, LPARAM lp )
+{
+    RECT *primary_rect = (RECT *)lp;
+
+    if (!rect->top && !rect->left && rect->right && rect->bottom)
+    {
+        *primary_rect = *rect;
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+static RECT get_primary_monitor_rect(void)
+{
+    RECT rect = {0};
+
+    EnumDisplayMonitors( 0, NULL, get_primary_monitor_proc, (LPARAM)&rect );
+    return rect;
+}
+
 static BOOL CALLBACK get_monitor_count_proc( HMONITOR monitor, HDC hdc, LPRECT rect, LPARAM lp )
 {
     INT *count = (INT *)lp;
@@ -2510,6 +2531,7 @@ INT WINAPI GetSystemMetrics( INT index )
     NONCLIENTMETRICSW ncm;
     MINIMIZEDMETRICS mm;
     ICONMETRICSW im;
+    RECT rect;
     UINT ret;
     HDC hdc;

@@ -2715,11 +2737,11 @@ INT WINAPI GetSystemMetrics( INT index )
     case SM_MOUSEWHEELPRESENT:
         return 1;
     case SM_CXSCREEN:
-        get_monitors_info( &info );
-        return info.primary_rect.right - info.primary_rect.left;
+        rect = get_primary_monitor_rect();
+        return rect.right - rect.left;
     case SM_CYSCREEN:
-        get_monitors_info( &info );
-        return info.primary_rect.bottom - info.primary_rect.top;
+        rect = get_primary_monitor_rect();
+        return rect.bottom - rect.top;
     case SM_XVIRTUALSCREEN:
         get_monitors_info( &info );
         return info.virtual_rect.left;