[gtksourceview] snippets: jump to iter instead of scrolling

[Christian Hergert <chergert src gnome org>]

commit 1652a12271eda38e655aece4dfa2eec45725941b
Author: Christian Hergert <chergert redhat com>
Date:   Fri May 13 19:11:51 2022 -0700

    snippets: jump to iter instead of scrolling
    
    And update the informative immediately afterwards as the visible rect
    will have changed.
    
    This doesn't use jump_to_iter because we don't care about any particular
    alignment and this seems to get the job done more correctly.

 gtksourceview/gtksourceview-snippets.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)
---
diff --git a/gtksourceview/gtksourceview-snippets.c b/gtksourceview/gtksourceview-snippets.c
index b0662093..450d2faa 100644
--- a/gtksourceview/gtksourceview-snippets.c
+++ b/gtksourceview/gtksourceview-snippets.c
@@ -28,6 +28,9 @@
 #include "gtksourcesnippetchunk-private.h"
 #include "gtksourcesnippetmanager.h"
 #include "gtksourceview-private.h"
+#include "gtksourceutils-private.h"
+
+static void gtk_source_view_snippets_update_informative (GtkSourceViewSnippets *snippets);
 
 static void
 gtk_source_view_snippets_block (GtkSourceViewSnippets *snippets)
@@ -67,11 +70,36 @@ static void
 gtk_source_view_snippets_scroll_to_insert (GtkSourceViewSnippets *snippets)
 {
        GtkTextMark *mark;
+       GtkTextIter iter;
+       GdkRectangle area;
+       GdkRectangle visible_rect;
+       double x, y;
 
        g_assert (snippets != NULL);
 
        mark = gtk_text_buffer_get_insert (GTK_TEXT_BUFFER (snippets->buffer));
-       gtk_text_view_scroll_mark_onscreen (GTK_TEXT_VIEW (snippets->view), mark);
+       gtk_text_buffer_get_iter_at_mark (GTK_TEXT_BUFFER (snippets->buffer), &iter, mark);
+       gtk_text_view_get_iter_location (GTK_TEXT_VIEW (snippets->view), &iter, &area);
+       gtk_text_view_get_visible_rect (GTK_TEXT_VIEW (snippets->view), &visible_rect);
+
+       if (area.x < visible_rect.x)
+               x = area.x;
+       else if (area.x > visible_rect.x + visible_rect.width)
+               x = area.x - visible_rect.width;
+       else
+               x = visible_rect.x;
+
+       if (area.y < visible_rect.y)
+               y = area.y;
+       else if (area.y > visible_rect.y + visible_rect.height)
+               y = area.y - visible_rect.height;
+       else
+               y = visible_rect.y;
+
+       gtk_adjustment_set_value (gtk_scrollable_get_hadjustment (GTK_SCROLLABLE (snippets->view)), x);
+       gtk_adjustment_set_value (gtk_scrollable_get_vadjustment (GTK_SCROLLABLE (snippets->view)), y);
+
+       gtk_source_view_snippets_update_informative (snippets);
 }
 
 static void