[gtk/text-scroll-test] Add a testcase for scroll-to-mark

[Matthias Clasen <matthiasc src gnome org>]

commit db46a8dd0636750d49573ca34f89da849aaccdc1
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Dec 1 17:20:52 2021 -0500

    Add a testcase for scroll-to-mark
    
    This should help for figuring out #4325.

 tests/meson.build      |   1 +
 tests/testtextscroll.c | 193 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 194 insertions(+)
---
diff --git a/tests/meson.build b/tests/meson.build
index ede335a15e..d837b5af6d 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -93,6 +93,7 @@ gtk_tests = [
   ['testswitch'],
   ['testtreepos'],
   ['testsensitive'],
+  ['testtextscroll'],
   ['testtextview'],
   ['testtextview2'],
   ['testgmenu'],
diff --git a/tests/testtextscroll.c b/tests/testtextscroll.c
new file mode 100644
index 0000000000..d0787d5557
--- /dev/null
+++ b/tests/testtextscroll.c
@@ -0,0 +1,193 @@
+/* simple.c
+ * Copyright (C) 2017  Red Hat, Inc
+ * Author: Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <gtk/gtk.h>
+
+static GtkWidget *_margin;
+static GtkWidget *_align;
+static GtkWidget *_xalign;
+static GtkWidget *_yalign;
+
+static void
+highlight_at_mark (GtkTextBuffer *buffer,
+                   GtkTextMark   *mark,
+                   gboolean       on)
+{
+  GtkTextIter iter, iter2;
+
+  gtk_text_buffer_get_iter_at_mark (buffer, &iter, mark);
+  iter2 = iter;
+  gtk_text_iter_forward_line (&iter2);
+
+  if (on)
+    gtk_text_buffer_apply_tag_by_name (buffer, "hihi", &iter, &iter2);
+  else
+    gtk_text_buffer_remove_tag_by_name (buffer, "hihi", &iter, &iter2);
+}
+
+static void
+go_forward_or_back (GtkButton   *button,
+                    GtkTextView *tv,
+                    gboolean     forward)
+{
+  GtkTextBuffer *buffer;
+  GtkTextMark *mark;
+  GtkTextIter iter;
+  gboolean found;
+
+  buffer = gtk_text_view_get_buffer (tv);
+  mark = gtk_text_buffer_get_mark (buffer, "mimi");
+  highlight_at_mark (buffer, mark, FALSE);
+
+  gtk_text_buffer_get_iter_at_mark (buffer, &iter, mark);
+  if (forward)
+    found = gtk_text_iter_forward_search (&iter, "\n-----", 0, &iter, NULL, NULL);
+  else
+    found = gtk_text_iter_backward_search (&iter, "\n-----", 0, &iter, NULL, NULL);
+  if (found)
+    {
+      double margin;
+      gboolean use_align;
+      double xalign, yalign;
+
+      gtk_text_iter_forward_char (&iter);
+      gtk_text_buffer_move_mark (buffer, mark, &iter);
+      highlight_at_mark (buffer, mark, TRUE);
+
+      margin = gtk_spin_button_get_value (GTK_SPIN_BUTTON (_margin));
+      use_align = gtk_check_button_get_active (GTK_CHECK_BUTTON (_align));
+      xalign = gtk_spin_button_get_value (GTK_SPIN_BUTTON (_xalign));
+      yalign = gtk_spin_button_get_value (GTK_SPIN_BUTTON (_yalign));
+
+      gtk_text_view_scroll_to_mark (tv, mark, margin, use_align, xalign, yalign);
+    }
+  else
+    {
+      if (forward)
+        gtk_text_buffer_get_end_iter (buffer, &iter);
+      else
+        gtk_text_buffer_get_start_iter (buffer, &iter);
+
+      gtk_text_buffer_move_mark (buffer, mark, &iter);
+
+      gtk_widget_error_bell (GTK_WIDGET (button));
+    }
+}
+
+static void
+go_forward (GtkButton   *button,
+            GtkTextView *tv)
+{
+  go_forward_or_back (button, tv, TRUE);
+}
+
+static void
+go_back (GtkButton   *button,
+         GtkTextView *tv)
+{
+  go_forward_or_back (button, tv, FALSE);
+}
+
+int
+main (int argc, char *argv[])
+{
+  GtkWidget *window, *box;
+  GtkWidget *sw, *tv;
+  GtkWidget *button, *box2;
+  GtkTextBuffer *buffer;
+  GtkTextIter iter;
+  GtkTextTag *tag;
+  GdkRGBA bg;
+
+  gtk_init ();
+
+  window = gtk_window_new ();
+  gtk_window_set_default_size (GTK_WINDOW (window), 400, 600);
+
+  box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 10);
+
+  tv = gtk_text_view_new ();
+  gtk_text_view_set_left_margin (GTK_TEXT_VIEW (tv), 10);
+  gtk_text_view_set_right_margin (GTK_TEXT_VIEW (tv), 10);
+  gtk_text_view_set_top_margin (GTK_TEXT_VIEW (tv), 10);
+  gtk_text_view_set_bottom_margin (GTK_TEXT_VIEW (tv), 10);
+
+  buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (tv));
+
+  if (argc > 1)
+    {
+      char *contents;
+      gsize size;
+
+      if (g_file_get_contents (argv[1], &contents, &size, NULL))
+        gtk_text_buffer_set_text (buffer, contents, size);
+    }
+
+  gtk_text_buffer_get_start_iter (buffer, &iter);
+  gtk_text_buffer_create_mark (buffer, "mimi", &iter, TRUE);
+
+  tag = gtk_text_tag_new ("hihi");
+  bg.red = 0;
+  bg.green = 0;
+  bg.blue = 1;
+  bg.alpha = 0.3;
+  g_object_set (tag, "background-rgba", &bg, NULL);
+  gtk_text_tag_table_add (gtk_text_buffer_get_tag_table (buffer), tag);
+
+  sw = gtk_scrolled_window_new ();
+  gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (sw), tv);
+
+  gtk_widget_set_hexpand (sw, TRUE);
+  gtk_widget_set_vexpand (sw, TRUE);
+  gtk_box_append (GTK_BOX (box), sw);
+
+  box2 = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 10);
+  gtk_box_append (GTK_BOX (box), box2);
+
+  button = gtk_button_new_with_label ("Forward");
+  g_signal_connect (button, "clicked", G_CALLBACK (go_forward), tv);
+  gtk_box_append (GTK_BOX (box2), button);
+
+  button = gtk_button_new_with_label ("Back");
+  g_signal_connect (button, "clicked", G_CALLBACK (go_back), tv);
+  gtk_box_append (GTK_BOX (box2), button);
+
+  box2 = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 10);
+  gtk_box_append (GTK_BOX (box), box2);
+  gtk_box_append (GTK_BOX (box2), gtk_label_new ("Margin:"));
+  _margin = gtk_spin_button_new_with_range (0, 0.5, 0.1);
+  gtk_box_append (GTK_BOX (box2), _margin);
+
+  box2 = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 10);
+  gtk_box_append (GTK_BOX (box), box2);
+  gtk_box_append (GTK_BOX (box2), gtk_label_new ("Align:"));
+  _align = gtk_check_button_new ();
+  gtk_box_append (GTK_BOX (box2), _align);
+  _xalign = gtk_spin_button_new_with_range (0, 1, 0.1);
+  gtk_box_append (GTK_BOX (box2), _xalign);
+  _yalign = gtk_spin_button_new_with_range (0, 1, 0.1);
+  gtk_box_append (GTK_BOX (box2), _yalign);
+
+  gtk_window_set_child (GTK_WINDOW (window), box);
+
+  gtk_widget_show (window);
+
+  while (1)
+    g_main_context_iteration (NULL, TRUE);
+
+  return 0;
+}