gdiplus: Don't crash when a NULL format is passed to GdipDrawString.
diff --git a/dlls/gdiplus/graphics.c b/dlls/gdiplus/graphics.c
index 2be64c7..3525743 100644
--- a/dlls/gdiplus/graphics.c
+++ b/dlls/gdiplus/graphics.c
@@ -2239,7 +2239,7 @@
 
     length = j;
 
-    if (format->align == StringAlignmentNear)
+    if (!format || format->align == StringAlignmentNear)
     {
         drawbase.x = corners[0].x;
         drawbase.y = corners[0].y;