Fixes for cairo surface export

Return NULL for surface when PathLayer is not visible.
And do not try to export layers where surface is NULL.

Also honor the tile opacity.

https://bugzilla.gnome.org/show_bug.cgi?id=757350

2 files changed, 11 insertions, 3 deletions

diff --git a/champlain/champlain-path-layer.c b/champlain/champlain-path-layer.c
index 0669929..4a8c0fc 100644
--- a/champlain/champlain-path-layer.c
+++ b/champlain/champlain-path-layer.c
@@ -435,7 +435,12 @@ get_surface (ChamplainExportable *exportable)
 {
   g_return_val_if_fail (CHAMPLAIN_IS_PATH_LAYER (exportable), NULL);
 
-  return CHAMPLAIN_PATH_LAYER (exportable)->priv->surface;
+  ChamplainPathLayer *self = CHAMPLAIN_PATH_LAYER (exportable);
+
+  if (self->priv->visible)
+    return CHAMPLAIN_PATH_LAYER (exportable)->priv->surface;
+  else
+    return NULL;
 }
 
 
diff --git a/champlain/champlain-view.c b/champlain/champlain-view.c
index 85ea530..7e9718f 100644
--- a/champlain/champlain-view.c
+++ b/champlain/champlain-view.c
@@ -1775,6 +1775,8 @@ layers_to_surface (ChamplainView *view,
         continue;
 
       surface = champlain_exportable_get_surface (CHAMPLAIN_EXPORTABLE (layer));
+      if (!surface)
+        continue;
       cairo_set_source_surface (cr, surface, 0, 0);
       cairo_paint(cr);
     }
@@ -1832,7 +1834,7 @@ champlain_view_to_surface (ChamplainView *view,
       if (tile_in_tile_map (view, tile_x, tile_y))
         {
           cairo_surface_t *tile_surface;
-          double x, y;
+          double x, y, opacity;
 
           tile_surface = champlain_exportable_get_surface (CHAMPLAIN_EXPORTABLE (tile));
           if (!tile_surface)
@@ -1841,12 +1843,13 @@ champlain_view_to_surface (ChamplainView *view,
               cairo_surface_destroy (surface);
               return NULL;
             }
+          opacity = ((double) clutter_actor_get_opacity (CLUTTER_ACTOR (tile))) / 255.0;
           x = ((double) tile_x * tile_size) - priv->viewport_x;
           y = ((double) tile_y * tile_size) - priv->viewport_y;
           cairo_set_source_surface (cr,
                                     tile_surface,
                                     x, y);
-          cairo_paint(cr);
+          cairo_paint_with_alpha(cr, opacity);
         }
     }