From 8867f77f1232b2a780528194815c7681f394a09b Mon Sep 17 00:00:00 2001
From: Virgile Prevosto <virgile.prevosto@m4x.org>
Date: Thu, 10 Jan 2019 16:36:31 +0100
Subject: [PATCH] [gui] fold/unfold with appropriate scrolling
---
src/plugins/gui/design.ml | 62 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 61 insertions(+), 1 deletion(-)
diff --git a/src/plugins/gui/design.ml b/src/plugins/gui/design.ml
index 3fc6a1b8e6f..22d2aaa5079 100644
--- a/src/plugins/gui/design.ml
+++ b/src/plugins/gui/design.ml
@@ -1534,7 +1534,67 @@ class main_window () : main_window_extension_points =
self#reset ();
(* give some time for the sourceview to recompute
its height, otherwise scrolling is broken. *)
- Unix.sleep 1;
+ let has_stabilized = ref false in
+ (* According to the blog post here
+ https://picheta.me/articles/2013/08/gtk-plus--a-method-to-guarantee-scrolling.html
+ the best way to check whether we have correctly scrolled
+ is to retrieve the rectangle corresponding to the mark,
+ the rectangle effectively displayed, and see whether
+ the former is included in the latter.
+ *)
+ let check () =
+ (* not entirely accurate because of
+ the (un)fold action, but should do the trick.
+ We will do the real scroll after stabilization
+ anyway.
+ *)
+ let iter =
+ source_viewer#buffer#get_iter (`LINE line)
+ in
+ let my_rect = source_viewer#get_iter_location iter in
+ let visible_rect = source_viewer#visible_rect in
+ (* in Gdk, x,y represents the top left corner of the
+ rectangle. We just check whether the beginning of the
+ selection is visible (we only have one line of text
+ anyway). *)
+ let res =
+ Gdk.Rectangle.(
+ y my_rect >= y visible_rect &&
+ y my_rect <= y visible_rect + height visible_rect
+ )
+ in
+ Gdk.Rectangle.(Gui_parameters.debug ~dkey:dkey_scroll
+ "my rect is %d (+%d) %d (+%d)@\n\
+ vis rect is %d (+%d) %d (+%d)@\n\
+ my rect is visible: %B@."
+ (x my_rect) (width my_rect) (y my_rect) (height my_rect)
+ (x visible_rect) (width visible_rect) (y visible_rect)
+ (height visible_rect) res);
+ has_stabilized := res;
+ (* when added as an idle procedure below, check will
+ be removed whenever it returns false. *)
+ not res
+ in
+ (* in case we were lucky and have stabilized directly. *)
+ ignore (check());
+ let proc = Glib.Idle.add check in
+ (* in case we are unlucky, stop waiting after
+ 0.5 second and hope for the best. *)
+ let alarm =
+ Glib.Timeout.add
+ ~ms:500
+ ~callback:
+ (fun () ->
+ has_stabilized := true;
+ Glib.Idle.remove proc;
+ false)
+ in
+ while (not !has_stabilized) do
+ (* do one main loop step so that buffer gets
+ a chance to recompute its height. *)
+ ignore (Glib.Main.iteration false)
+ done;
+ Glib.Timeout.remove alarm;
self#view_stmt stmt;
with Not_found -> Format.printf "call not found@."
end;
--
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