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-rw-r--r--ChangeLog4
-rw-r--r--demos/gtk-demo/Makefile.am1
-rw-r--r--demos/gtk-demo/textscroll.c202
-rw-r--r--docs/reference/ChangeLog5
-rw-r--r--docs/reference/gtk/question_index.sgml19
5 files changed, 223 insertions, 8 deletions
diff --git a/ChangeLog b/ChangeLog
index 9c8ca14d9e..1a95725150 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
2006-08-25 Matthias Clasen <mclasen@redhat.com>
+ * demos/gtk-demo/Makefile.am:
+ * demos/gtk-demo/textscroll.c: Add an example of automatic
+ scrolling, thanks to Yevgen Muntyan. (#351206)
+
* gtk/gtkmodules.c (find_module): Use local binding when
loading modules. (#351868)
diff --git a/demos/gtk-demo/Makefile.am b/demos/gtk-demo/Makefile.am
index e1adb57b63..f043ee0f4e 100644
--- a/demos/gtk-demo/Makefile.am
+++ b/demos/gtk-demo/Makefile.am
@@ -31,6 +31,7 @@ demos = \
sizegroup.c \
stock_browser.c \
textview.c \
+ textscroll.c \
tree_store.c \
ui_manager.c
diff --git a/demos/gtk-demo/textscroll.c b/demos/gtk-demo/textscroll.c
new file mode 100644
index 0000000000..063322141c
--- /dev/null
+++ b/demos/gtk-demo/textscroll.c
@@ -0,0 +1,202 @@
+/* Text Widget/Automatic scrolling
+ *
+ * This example demonstrates how to use the gravity of
+ * GtkTextMarks to keep a text view scrolled to the bottom
+ * while appending text.
+ */
+
+#include <gtk/gtk.h>
+#include "demo-common.h"
+
+/* Scroll to the end of the buffer.
+ */
+static gboolean
+scroll_to_end (GtkTextView *textview)
+{
+ GtkTextBuffer *buffer;
+ GtkTextIter iter;
+ GtkTextMark *mark;
+ char *spaces;
+ static int count;
+
+ buffer = gtk_text_view_get_buffer (textview);
+
+ /* Get "end" mark. It's located at the end of buffer because
+ * of right gravity
+ */
+ mark = gtk_text_buffer_get_mark (buffer, "end");
+ gtk_text_buffer_get_iter_at_mark (buffer, &iter, mark);
+
+ /* and insert some text at its position, the iter will be
+ * revalidated after insertion to point to the end of inserted text
+ */
+ spaces = g_strnfill (count++, ' ');
+ gtk_text_buffer_insert (buffer, &iter, "\n", -1);
+ gtk_text_buffer_insert (buffer, &iter, spaces, -1);
+ gtk_text_buffer_insert (buffer, &iter,
+ "Scroll to end scroll to end scroll "
+ "to end scroll to end ",
+ -1);
+ g_free (spaces);
+
+ /* Now scroll the end mark onscreen.
+ */
+ gtk_text_view_scroll_mark_onscreen (textview, mark);
+
+ /* Emulate typewriter behavior, shift to the left if we
+ * are far enough to the right.
+ */
+ if (count > 150)
+ count = 0;
+
+ return TRUE;
+}
+
+/* Scroll to the bottom of the buffer.
+ */
+static gboolean
+scroll_to_bottom (GtkTextView *textview)
+{
+ GtkTextBuffer *buffer;
+ GtkTextIter iter;
+ GtkTextMark *mark;
+ char *spaces;
+ static int count;
+
+ buffer = gtk_text_view_get_buffer (textview);
+
+ /* Get end iterator */
+ gtk_text_buffer_get_end_iter (buffer, &iter);
+
+ /* and insert some text at it, the iter will be revalidated
+ * after insertion to point to the end of inserted text
+ */
+ spaces = g_strnfill (count++, ' ');
+ gtk_text_buffer_insert (buffer, &iter, "\n", -1);
+ gtk_text_buffer_insert (buffer, &iter, spaces, -1);
+ gtk_text_buffer_insert (buffer, &iter,
+ "Scroll to bottom scroll to bottom scroll "
+ "to bottom scroll to bottom",
+ -1);
+ g_free (spaces);
+
+ /* Move the iterator to the beginning of line, so we don't scroll
+ * in horizontal direction
+ */
+ gtk_text_iter_set_line_offset (&iter, 0);
+
+ /* and place the mark at iter. the mark will stay there after we
+ * insert some text at the end because it has right gravity.
+ */
+ mark = gtk_text_buffer_get_mark (buffer, "scroll");
+ gtk_text_buffer_move_mark (buffer, mark, &iter);
+
+ /* Scroll the mark onscreen.
+ */
+ gtk_text_view_scroll_mark_onscreen (textview, mark);
+
+ /* Shift text back if we got enough to the right.
+ */
+ if (count > 40)
+ count = 0;
+
+ return TRUE;
+}
+
+static guint
+setup_scroll (GtkTextView *textview,
+ gboolean to_end)
+{
+ GtkTextBuffer *buffer;
+ GtkTextIter iter;
+ GtkTextMark *mark;
+
+ buffer = gtk_text_view_get_buffer (textview);
+ gtk_text_buffer_get_end_iter (buffer, &iter);
+
+ if (to_end)
+ {
+ /* If we want to scroll to the end, including horizontal scrolling,
+ * then we just create a mark with right gravity at the end of the
+ * buffer. It will stay at the end unless explicitely moved with
+ * gtk_text_buffer_move_mark.
+ */
+ gtk_text_buffer_create_mark (buffer, "end", &iter, FALSE);
+
+ /* Add scrolling timeout. */
+ return g_timeout_add (50, (GSourceFunc) scroll_to_end, textview);
+ }
+ else
+ {
+ /* If we want to scroll to the bottom, but not scroll horizontally,
+ * then an end mark won't do the job. Just create a mark so we can
+ * use it with gtk_text_view_scroll_mark_onscreen, we'll position it
+ * explicitely when needed. Use left gravity so the mark stays where
+ * we put it after inserting new text.
+ */
+ gtk_text_buffer_create_mark (buffer, "scroll", &iter, TRUE);
+
+ /* Add scrolling timeout. */
+ return g_timeout_add (100, (GSourceFunc) scroll_to_bottom, textview);
+ }
+}
+
+static void
+remove_timeout (GtkWidget *window,
+ gpointer timeout)
+{
+ g_source_remove (GPOINTER_TO_UINT (timeout));
+}
+
+static void
+create_text_view (GtkWidget *hbox,
+ gboolean to_end)
+{
+ GtkWidget *swindow;
+ GtkWidget *textview;
+ guint timeout;
+
+ swindow = gtk_scrolled_window_new (NULL, NULL);
+ gtk_box_pack_start_defaults (GTK_BOX (hbox), swindow);
+ textview = gtk_text_view_new ();
+ gtk_container_add (GTK_CONTAINER (swindow), textview);
+
+ timeout = setup_scroll (GTK_TEXT_VIEW (textview), to_end);
+
+ /* Remove the timeout in destroy handler, so we don't try to
+ * scroll destroyed widget.
+ */
+ g_signal_connect (textview, "destroy",
+ G_CALLBACK (remove_timeout),
+ GUINT_TO_POINTER (timeout));
+}
+
+GtkWidget *
+do_textscroll (GtkWidget *do_widget)
+{
+ static GtkWidget *window = NULL;
+
+ if (!window)
+ {
+ GtkWidget *hbox;
+ GtkWidget *swindow;
+
+ window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+ g_signal_connect (window, "destroy",
+ G_CALLBACK (gtk_widget_destroyed), &window);
+ gtk_window_set_default_size (GTK_WINDOW (window), 600, 400);
+
+ hbox = gtk_hbox_new (TRUE, 6);
+ gtk_container_add (GTK_CONTAINER (window), hbox);
+
+ create_text_view (hbox, TRUE);
+ create_text_view (hbox, FALSE);
+ }
+
+ if (!GTK_WIDGET_VISIBLE (window))
+ gtk_widget_show_all (window);
+ else
+ gtk_widget_destroy (window);
+
+ return window;
+}
diff --git a/docs/reference/ChangeLog b/docs/reference/ChangeLog
index 045b49170e..0a9adf6075 100644
--- a/docs/reference/ChangeLog
+++ b/docs/reference/ChangeLog
@@ -1,3 +1,8 @@
+2006-08-25 Matthias Clasen <mclasen@redhat.com>
+
+ * gtk/question_index.sgml: Rewrite the answer for
+ automatic scrolling.
+
2006-08-17 Matthias Clasen <mclasen@redhat.com>
* === Released 2.10.2 ===
diff --git a/docs/reference/gtk/question_index.sgml b/docs/reference/gtk/question_index.sgml
index 441def5a5a..6c1f32fff3 100644
--- a/docs/reference/gtk/question_index.sgml
+++ b/docs/reference/gtk/question_index.sgml
@@ -757,18 +757,21 @@ How do I make a text view scroll to the end of the buffer automatically ?
<answer>
<para>
-The "insert" <link linkend="GtkTextMark">mark</link> marks the insertion point
-where gtk_text_buffer_insert() inserts new text into the buffer. The text is inserted
-<emphasis>before</emphasis> the "insert" mark, so that it generally stays
-at the end of the buffer. If it gets explicitly moved to some other position,
-e.g. when the user selects some text, use gtk_text_buffer_move_mark() to set it to
-the desired location before inserting more text. The "insert" mark of a buffer can be
-obtained with gtk_text_buffer_get_insert().
+A good way to keep a text buffer scrolled to the end is to place a
+<link linkend="GtkTextMark">mark</link> at the end of the buffer, and
+give it right gravity. The gravity has the effect that text inserted
+at the mark gets inserted <emphasis>before</emphasis>, keeping the mark
+at the end.
</para>
<para>
To ensure that the end of the buffer remains visible, use
-gtk_text_view_scroll_to_mark() to scroll to the "insert" mark after inserting new text.
+gtk_text_view_scroll_to_mark() to scroll to the mark after
+inserting new text.
+</para>
+
+<para>
+The gtk-demo application contains an example of this technique.
</para>
</answer>
</qandaentry>
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