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/* Text View/Automatic Scrolling
* #Keywords: GtkTextView, GtkScrolledWindow
*
* 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>
/* Scroll to the end of the buffer.
*/
static gboolean
scroll_to_end (GtkTextView *textview)
{
GtkTextBuffer *buffer;
GtkTextIter iter;
GtkTextMark *mark;
char *spaces;
char *text;
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);
text = g_strdup_printf ("Scroll to end scroll to end scroll "
"to end scroll to end %d", count);
gtk_text_buffer_insert (buffer, &iter, text, -1);
g_free (spaces);
g_free (text);
/* 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 G_SOURCE_CONTINUE;
}
/* Scroll to the bottom of the buffer.
*/
static gboolean
scroll_to_bottom (GtkTextView *textview)
{
GtkTextBuffer *buffer;
GtkTextIter iter;
GtkTextMark *mark;
char *spaces;
char *text;
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);
text = g_strdup_printf ("Scroll to bottom scroll to bottom scroll "
"to bottom scroll to bottom %d", count);
gtk_text_buffer_insert (buffer, &iter, text, -1);
g_free (spaces);
g_free (text);
/* 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 left 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 G_SOURCE_CONTINUE;
}
static guint
setup_scroll (GtkTextView *textview,
gboolean to_end)
{
GtkTextBuffer *buffer;
GtkTextIter iter;
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 explicitly 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
* explicitly 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 ();
gtk_box_append (GTK_BOX (hbox), swindow);
textview = gtk_text_view_new ();
gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (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;
window = gtk_window_new ();
gtk_window_set_title (GTK_WINDOW (window), "Automatic Scrolling");
g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
gtk_window_set_default_size (GTK_WINDOW (window), 600, 400);
hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 6);
gtk_box_set_homogeneous (GTK_BOX (hbox), TRUE);
gtk_window_set_child (GTK_WINDOW (window), hbox);
create_text_view (hbox, TRUE);
create_text_view (hbox, FALSE);
}
if (!gtk_widget_get_visible (window))
gtk_widget_set_visible (window, TRUE);
else
gtk_window_destroy (GTK_WINDOW (window));
return window;
}
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