Makes IntersectRect more efficient

git-svn-id: trunk@16226 -

rtl/objpas/types.pp

@@ -345,31 +345,31 @@ end;
 
 function IntersectRect(var Rect : TRect;const R1,R2 : TRect) : Boolean;
 var
-  lR1, lR2: TRect;
+  lRect: TRect;
 begin
-  // We copy the parameter to a local variables to avoid problems
+  lRect := R1;
+  if R2.Left > R1.Left then
+    lRect.Left := R2.Left;
+  if R2.Top > R1.Top then
+    lRect.Top := R2.Top;
+  if R2.Right < R1.Right then
+    lRect.Right := R2.Right;
+  if R2.Bottom < R1.Bottom then
+    lRect.Bottom := R2.Bottom;
+
+  // The var parameter is only assigned in the end to avoid problems
   // when passing the same rectangle in the var and const parameters.
   // See http://bugs.freepascal.org/view.php?id=17722
-  lR1 := R1;
-  lR2 := R2;
-
-  Rect := lR1;
-  if lR2.Left > lR1.Left then
-    Rect.Left := lR2.Left;
-  if lR2.Top > R1.Top then
-    Rect.Top := lR2.Top;
-  if lR2.Right < R1.Right then
-    Rect.Right := lR2.Right;
-  if lR2.Bottom < R1.Bottom then
-    Rect.Bottom := lR2.Bottom;
-
-  if IsRectEmpty(Rect) then
+  if IsRectEmpty(lRect) then
   begin
     FillChar(Rect,SizeOf(Rect),0);
     IntersectRect:=false;
   end
   else
+  begin
     IntersectRect:=true;
+    Rect := lRect;
+  end;	
 end;
 
 function UnionRect(var Rect : TRect;const R1,R2 : TRect) : Boolean;