[gimp/gimp-2-10] app: in GimpProjection, avoid invalidating preview on flush while rendering

[Ell <ell src gnome org>]

commit 66d7dc76aa16c90cf8b242135b0304739344857a
Author: Ell <ell_se yahoo com>
Date:   Wed Sep 4 12:51:27 2019 +0300

    app: in GimpProjection, avoid invalidating preview on flush while rendering
    
    In GimpProjection, avoid erroneously invalidating the projectable's
    preview when flushing the projection and there's nothing to be
    flushed, if the chunk renderer is still running, and hence the
    projection is not fully rendered yet.

 app/core/gimpprojection.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/app/core/gimpprojection.c b/app/core/gimpprojection.c
index 1932d58a7e..bbca827cb0 100644
--- a/app/core/gimpprojection.c
+++ b/app/core/gimpprojection.c
@@ -676,7 +676,7 @@ gimp_projection_flush_whenever (GimpProjection *proj,
           gimp_projection_chunk_render_start (proj);
         }
     }
-  else if (! now && proj->priv->invalidate_preview)
+  else if (! now && ! proj->priv->iter && proj->priv->invalidate_preview)
     {
       /* invalidate the preview here since it is constructed from
        * the projection