[libchamplain: 43/45] Add descriptive comments.

[Jiří Techet <jiritechet src gnome org>]

commit dc5e31232a2cbf3c37b13ec0dc9491251d2b310a
Author: Marius Stanciu <stanciumarius94 gmail com>
Date:   Tue Aug 9 20:23:29 2016 +0300

    Add descriptive comments.

 champlain/champlain-path-layer.c |    6 ++++++
 champlain/champlain-view.c       |    4 ++++
 2 files changed, 10 insertions(+), 0 deletions(-)
---
diff --git a/champlain/champlain-path-layer.c b/champlain/champlain-path-layer.c
index a6699c1..0872c04 100644
--- a/champlain/champlain-path-layer.c
+++ b/champlain/champlain-path-layer.c
@@ -568,6 +568,12 @@ invalidate_canvas (ChamplainPathLayer *layer)
       champlain_view_get_viewport_origin (priv->view, &viewport_x, &viewport_y);
       champlain_view_get_viewport_anchor (priv->view, &anchor_x, &anchor_y);
 
+      /* For efficiency in terms of clipping, the path actors must have a minimal size.
+       * The right_actor renders the paths on the visible side of the original map layer
+       * (from viewport offset to end of the map).
+       * The left_actor renders the paths on the visible side of the first cloned map layer
+       * (from the leftmost point on the map, clamped by the viewport width).
+       */
       right_actor_width = MIN (map_width - (viewport_x + anchor_x), (gint)view_width);
       right_actor_height = MIN (map_height - (viewport_y + anchor_y), (gint)view_height);
       left_actor_width = MIN (view_width - right_actor_width, map_width - right_actor_width);
diff --git a/champlain/champlain-view.c b/champlain/champlain-view.c
index 62c79ee..63ac2bb 100644
--- a/champlain/champlain-view.c
+++ b/champlain/champlain-view.c
@@ -425,6 +425,10 @@ view_relocated_cb (G_GNUC_UNUSED ChamplainViewport *viewport,
   row_count = champlain_map_source_get_row_count (priv->map_source, priv->zoom_level);
   champlain_viewport_get_anchor (CHAMPLAIN_VIEWPORT (priv->viewport), &anchor_x, &anchor_y);
 
+  /* The area containing tiles in the map layer is actually column_count * tile_size wide (same
+   * for height), but the viewport anchor acts as an offset for the tile actors, causing the map
+   * layer to contain some empty space as well.
+   */
   new_width = column_count * tile_size + anchor_x;
   new_height = row_count * tile_size + anchor_y;