[gnome-builder/wip/file-marks] gtk: add more util helpers for gtk

[Christian Hergert <chergert src gnome org>]

commit fd7a515f788df519fe41b8ac5f2668aa01ba2436
Author: Christian Hergert <christian hergert me>
Date:   Wed Oct 8 16:05:03 2014 -0700

    gtk: add more util helpers for gtk
    
    These helpers add some convenience functions for things we've been doing
    all over the place manually.
    
    It also adds a workaround for the inability to scroll to the right offset
    until textlayouts have been processed enough to know where our offset is.

 src/gnome-builder.mk |    2 +
 src/util/gb-gtk.c    |  131 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/util/gb-gtk.h    |   40 +++++++++++++++
 3 files changed, 173 insertions(+), 0 deletions(-)
---
diff --git a/src/gnome-builder.mk b/src/gnome-builder.mk
index bafc215..405e02e 100644
--- a/src/gnome-builder.mk
+++ b/src/gnome-builder.mk
@@ -109,6 +109,8 @@ libgnome_builder_la_SOURCES = \
        src/trie/trie.h \
        src/util/gb-cairo.c \
        src/util/gb-cairo.h \
+       src/util/gb-gtk.c \
+       src/util/gb-gtk.h \
        src/util/gb-rgba.c \
        src/util/gb-rgba.h \
        src/util/gb-string.h \
diff --git a/src/util/gb-gtk.c b/src/util/gb-gtk.c
new file mode 100644
index 0000000..5ed0bcb
--- /dev/null
+++ b/src/util/gb-gtk.c
@@ -0,0 +1,131 @@
+/* gb-gtk.c
+ *
+ * Copyright (C) 2014 Christian Hergert <christian hergert me>
+ *
+ * This file is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This file 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "gb-gtk.h"
+
+struct ScrollState
+{
+  GtkTextView *view;
+  guint        line;
+  guint        line_offset;
+  gboolean     within_margin;
+  gboolean     use_align;
+  gdouble      xalign;
+  gdouble      yalign;
+};
+
+void
+gb_gtk_text_buffer_get_iter_at_line_and_offset (GtkTextBuffer *buffer,
+                                                GtkTextIter   *iter,
+                                                guint          line,
+                                                guint          line_offset)
+{
+  g_return_if_fail (GTK_IS_TEXT_BUFFER (buffer));
+  g_return_if_fail (iter);
+
+  gtk_text_buffer_get_iter_at_line (buffer, iter, line);
+
+  if (gtk_text_iter_get_line (iter) == line)
+    {
+      for (; line_offset; line_offset--)
+        {
+          if (gtk_text_iter_ends_line (iter))
+            break;
+          if (!gtk_text_iter_forward_char (iter))
+            {
+              gtk_text_buffer_get_end_iter (buffer, iter);
+              break;
+            }
+        }
+    }
+}
+
+static gboolean
+gb_gtk_text_view_scroll_to_iter_cb (gpointer data)
+{
+  struct ScrollState *state = data;
+  GtkTextBuffer *buffer;
+  GtkTextIter iter;
+
+  g_assert (state);
+  g_assert (GTK_IS_TEXT_VIEW (state->view));
+
+  buffer = gtk_text_view_get_buffer (state->view);
+
+  gb_gtk_text_buffer_get_iter_at_line_and_offset (buffer, &iter, state->line,
+                                                  state->line_offset);
+
+  gb_gtk_text_view_scroll_to_iter (state->view, &iter, state->within_margin,
+                                   state->use_align, state->xalign,
+                                   state->yalign);
+
+  g_object_unref (state->view);
+  g_free (state);
+
+  return G_SOURCE_REMOVE;
+}
+
+/**
+ * gb_gtk_text_view_scroll_to_iter:
+ * 
+ * This function is a wrapper function for gb_gtk_text_view_scroll_to_iter()
+ * that will check to see if the text_view has calculated enough of it's
+ * internal sizing to be able to scroll to the given iter.
+ *
+ * If not, an idle timeout is added that will check again until we can
+ * reach the target location.
+ */
+void
+gb_gtk_text_view_scroll_to_iter (GtkTextView *text_view,
+                                 GtkTextIter *iter,
+                                 gboolean     within_margin,
+                                 gboolean     use_align,
+                                 gdouble      xalign,
+                                 gdouble      yalign)
+{
+  GdkRectangle rect;
+  GtkTextIter y_iter;
+  struct ScrollState *state;
+  gint line_top;
+
+  g_return_if_fail (GTK_IS_TEXT_VIEW (text_view));
+  g_return_if_fail (iter);
+
+  gtk_text_view_get_iter_location (text_view, iter, &rect);
+
+  gtk_text_view_get_line_at_y (text_view, &y_iter, rect.y + (rect.height / 2),
+                               &line_top);
+
+  if (gtk_text_iter_get_line (&y_iter) == gtk_text_iter_get_line (iter))
+    {
+      gtk_text_view_scroll_to_iter (text_view, iter, within_margin, use_align,
+                                    xalign, yalign);
+      return;
+    }
+
+  state = g_new0 (struct ScrollState, 1);
+  state->view = g_object_ref (text_view);
+  state->line = gtk_text_iter_get_line (iter);
+  state->line_offset = gtk_text_iter_get_line_offset (iter);
+  state->within_margin = within_margin;
+  state->use_align = use_align;
+  state->xalign = xalign;
+  state->yalign = yalign;
+
+  g_timeout_add (50, gb_gtk_text_view_scroll_to_iter_cb, state);
+}
diff --git a/src/util/gb-gtk.h b/src/util/gb-gtk.h
new file mode 100644
index 0000000..807d31a
--- /dev/null
+++ b/src/util/gb-gtk.h
@@ -0,0 +1,40 @@
+/* gb-gtk.h
+ *
+ * Copyright (C) 2014 Christian Hergert <christian hergert me>
+ *
+ * This file is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This file 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GB_GTK_H
+#define GB_GTK_H
+
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+void gb_gtk_text_buffer_get_iter_at_line_and_offset (GtkTextBuffer *buffer,
+                                                     GtkTextIter   *iter,
+                                                     guint          line,
+                                                     guint          line_offset);
+
+void gb_gtk_text_view_scroll_to_iter (GtkTextView *text_view,
+                                      GtkTextIter *iter,
+                                      gboolean     within_margin,
+                                      gboolean     use_align,
+                                      gdouble      xalign,
+                                      gdouble      yalign);
+
+G_END_DECLS
+
+#endif /* GB_GTK_H */