optimize guide canvasupdating

diff --git a/src/display/guideline.cpp b/src/display/guideline.cpp
index fcddbb0e6e5fd86e4f25abc8ee16fc99e7060634..32d0e0c1eaae3602679ce327eace236095f52201 100644 (file)
--- a/src/display/guideline.cpp
+++ b/src/display/guideline.cpp
@@ -141,7 +141,9 @@ static void sp_guideline_update(SPCanvasItem *item, NR::Matrix const &affine, un
     gl->point_on_line[Geom::Y] = affine[5];
 
     if (gl->normal_to_line[Geom::Y] == 1.) {
-        sp_canvas_update_bbox (item, -1000000, -1000000, 1000000, 1000000);
+        sp_canvas_update_bbox (item, -1000000, gl->point_on_line[Geom::Y], 1000000, gl->point_on_line[Geom::Y] + 1);
+    } else if (gl->normal_to_line[Geom::X] == 1.) {
+        sp_canvas_update_bbox (item, gl->point_on_line[Geom::X], -1000000, gl->point_on_line[Geom::X]+1, 1000000);
     } else {
         sp_canvas_update_bbox (item, -1000000, -1000000, 1000000, 1000000);
     }