Add a "Hypertext" demo.
This commit is contained in:
Matthias Clasen
@ -21,7 +21,8 @@ demos = \
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sizegroup.c \
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stock_browser.c \
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textview.c \
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tree_store.c
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tree_store.c \
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hypertext.c
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INCLUDES = \
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-DDEMOCODEDIR="\"$(democodedir)\"" \
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315
demos/gtk-demo/hypertext.c
Normal file
315
demos/gtk-demo/hypertext.c
Normal file
@ -0,0 +1,315 @@
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/* Text Widget/Hypertext
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*
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* Usually, tags modify the appearance of text in the view, e.g. making it bold or colored or underlined.
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* But tags are not restricted to appearance. They can also affect the behavior of mouse and key presses,
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* as this demo shows.
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*/
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#include <gtk/gtk.h>
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#include <gdk/gdkkeysyms.h>
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/* Inserts a piece of text into the buffer, giving it the usual
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* appearance of a hyperlink in a web browser: blue and underlined.
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* Additionally, attaches some data on the tag, to make it recognizable
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* as a link.
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*/
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static void
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insert_link (GtkTextBuffer *buffer,
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GtkTextIter *iter,
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gchar *text,
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gint page)
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{
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GtkTextTag *tag;
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tag = gtk_text_buffer_create_tag (buffer, NULL,
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"foreground", "blue",
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"underline", PANGO_UNDERLINE_SINGLE,
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NULL);
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g_object_set_data (G_OBJECT (tag), "page", GINT_TO_POINTER (page));
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gtk_text_buffer_insert_with_tags (buffer, iter, text, -1, tag, NULL);
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}
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/* Fills the buffer with text and interspersed links. In any real
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* hypertext app, this method would parse a file to identify the links.
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*/
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static void
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show_page (GtkTextBuffer *buffer,
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gint page)
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{
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GtkTextIter iter;
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gtk_text_buffer_set_text (buffer, "", 0);
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gtk_text_buffer_get_iter_at_offset (buffer, &iter, 0);
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if (page == 1)
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{
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gtk_text_buffer_insert (buffer, &iter, "Some text to show that simple ", -1);
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insert_link (buffer, &iter, "hypertext", 3);
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gtk_text_buffer_insert (buffer, &iter, " can easily be realized with ", -1);
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insert_link (buffer, &iter, "tags", 2);
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gtk_text_buffer_insert (buffer, &iter, ".", -1);
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}
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else if (page == 2)
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{
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gtk_text_buffer_insert (buffer, &iter,
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"A tag is an attribute that can be applied to some range of text. "
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"For example, a tag might be called \"bold\" and make the text inside "
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"the tag bold. However, the tag concept is more general than that; "
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"tags don't have to affect appearance. They can instead affect the "
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"behavior of mouse and key presses, \"lock\" a range of text so the "
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"user can't edit it, or countless other things.\n", -1);
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insert_link (buffer, &iter, "Go back", 1);
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}
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else if (page == 3)
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{
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GtkTextTag *tag;
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tag = gtk_text_buffer_create_tag (buffer, NULL,
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"weight", PANGO_WEIGHT_BOLD,
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NULL);
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gtk_text_buffer_insert_with_tags (buffer, &iter, "hypertext:\n", -1, tag, NULL);
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gtk_text_buffer_insert (buffer, &iter,
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"machine-readable text that is not sequential but is organized "
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"so that related items of information are connected.\n", -1);
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insert_link (buffer, &iter, "Go back", 1);
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}
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}
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/* Looks at all tags covering the position of iter in the text view,
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* and if one of them is a link, follow it by showing the page identified
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* by the data attached to it.
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*/
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static void
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follow_if_link (GtkWidget *text_view,
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GtkTextIter *iter)
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{
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GSList *tags = NULL, *tagp = NULL;
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tags = gtk_text_iter_get_tags (iter);
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for (tagp = tags; tagp != NULL; tagp = tagp->next)
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{
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GtkTextTag *tag = tagp->data;
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gint page = GPOINTER_TO_INT (g_object_get_data (G_OBJECT (tag), "page"));
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if (page != 0)
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{
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show_page (gtk_text_view_get_buffer (GTK_TEXT_VIEW (text_view)), page);
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break;
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}
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}
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if (tags)
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g_slist_free (tags);
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}
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/* Links can be activated by pressing Enter.
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*/
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static gboolean
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key_press_event (GtkWidget *text_view,
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GdkEventKey *event)
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{
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GtkTextIter iter;
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GtkTextBuffer *buffer;
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switch (event->keyval)
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{
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case GDK_Return:
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case GDK_KP_Enter:
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buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (text_view));
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gtk_text_buffer_get_iter_at_mark (buffer, &iter,
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gtk_text_buffer_get_insert (buffer));
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follow_if_link (text_view, &iter);
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break;
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default:
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break;
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}
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return FALSE;
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}
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/* Links can also be activated by clicking.
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*/
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static gboolean
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event_after (GtkWidget *text_view,
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GdkEvent *ev)
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{
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GtkTextIter start, end, iter;
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GtkTextBuffer *buffer;
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GdkEventButton *event;
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gint x, y;
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if (ev->type != GDK_BUTTON_RELEASE)
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return FALSE;
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event = (GdkEventButton *)ev;
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if (event->button != 1)
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return FALSE;
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buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (text_view));
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/* we shouldn't follow a link if the user has selected something */
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gtk_text_buffer_get_selection_bounds (buffer, &start, &end);
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if (gtk_text_iter_get_offset (&start) != gtk_text_iter_get_offset (&end))
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return FALSE;
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gtk_text_view_window_to_buffer_coords (GTK_TEXT_VIEW (text_view),
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GTK_TEXT_WINDOW_WIDGET,
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event->x, event->y, &x, &y);
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gtk_text_view_get_iter_at_location (GTK_TEXT_VIEW (text_view), &iter, x, y);
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follow_if_link (text_view, &iter);
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return FALSE;
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}
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gboolean hovering_over_link = FALSE;
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GdkCursor *hand_cursor = NULL;
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GdkCursor *regular_cursor = NULL;
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/* Looks at all tags covering the position (x, y) in the text view,
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* and if one of them is a link, change the cursor to the "hands" cursor
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* typically used by web browsers.
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*/
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static void
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set_cursor_if_appropriate (GtkTextView *text_view,
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gint x,
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gint y)
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{
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GSList *tags = NULL, *tagp = NULL;
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GtkTextBuffer *buffer;
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GtkTextIter iter;
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gboolean hovering = FALSE;
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buffer = gtk_text_view_get_buffer (text_view);
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gtk_text_view_get_iter_at_location (text_view, &iter, x, y);
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tags = gtk_text_iter_get_tags (&iter);
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for (tagp = tags; tagp != NULL; tagp = tagp->next)
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{
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GtkTextTag *tag = tagp->data;
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gint page = GPOINTER_TO_INT (g_object_get_data (G_OBJECT (tag), "page"));
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if (page != 0)
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{
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hovering = TRUE;
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break;
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}
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}
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if (hovering != hovering_over_link)
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{
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hovering_over_link = hovering;
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if (hovering_over_link)
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gdk_window_set_cursor (gtk_text_view_get_window (text_view, GTK_TEXT_WINDOW_TEXT), hand_cursor);
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else
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gdk_window_set_cursor (gtk_text_view_get_window (text_view, GTK_TEXT_WINDOW_TEXT), regular_cursor);
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}
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if (tags)
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g_slist_free (tags);
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}
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/* Update the cursor image if the pointer moved.
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*/
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static gboolean
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motion_notify_event (GtkWidget *text_view,
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GdkEventMotion *event)
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{
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gint x, y;
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gtk_text_view_window_to_buffer_coords (GTK_TEXT_VIEW (text_view),
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GTK_TEXT_WINDOW_WIDGET,
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event->x, event->y, &x, &y);
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set_cursor_if_appropriate (GTK_TEXT_VIEW (text_view), x, y);
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gdk_window_get_pointer (text_view->window, NULL, NULL, NULL);
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return FALSE;
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}
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/* Also update the cursor image if the window becomes visible
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* (e.g. when a window covering it got iconified).
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*/
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static gboolean
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visibility_notify_event (GtkWidget *text_view,
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GdkEventVisibility *event)
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{
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gint wx, wy, bx, by;
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gdk_window_get_pointer (text_view->window, &wx, &wy, NULL);
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gtk_text_view_window_to_buffer_coords (GTK_TEXT_VIEW (text_view),
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GTK_TEXT_WINDOW_WIDGET,
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wx, wy, &bx, &by);
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set_cursor_if_appropriate (GTK_TEXT_VIEW (text_view), bx, by);
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return FALSE;
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}
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GtkWidget *
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do_hypertext (void)
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{
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static GtkWidget *window = NULL;
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if (!window)
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{
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GtkWidget *view;
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GtkWidget *sw;
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GtkTextBuffer *buffer;
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hand_cursor = gdk_cursor_new (GDK_HAND2);
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regular_cursor = gdk_cursor_new (GDK_XTERM);
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window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
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gtk_window_set_default_size (GTK_WINDOW (window),
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450, 450);
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g_signal_connect (window, "destroy",
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G_CALLBACK (gtk_widget_destroyed), &window);
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gtk_window_set_title (GTK_WINDOW (window), "Hypertext");
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gtk_container_set_border_width (GTK_CONTAINER (window), 0);
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view = gtk_text_view_new ();
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gtk_text_view_set_wrap_mode (GTK_TEXT_VIEW (view), GTK_WRAP_WORD);
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g_signal_connect (G_OBJECT (view), "key-press-event",
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G_CALLBACK (key_press_event), NULL);
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g_signal_connect (G_OBJECT (view), "event-after",
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G_CALLBACK (event_after), NULL);
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g_signal_connect (G_OBJECT (view), "motion-notify-event",
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G_CALLBACK (motion_notify_event), NULL);
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g_signal_connect (G_OBJECT (view), "visibility-notify-event",
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G_CALLBACK (visibility_notify_event), NULL);
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buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));
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sw = gtk_scrolled_window_new (NULL, NULL);
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gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
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GTK_POLICY_AUTOMATIC,
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GTK_POLICY_AUTOMATIC);
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gtk_container_add (GTK_CONTAINER (window), sw);
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gtk_container_add (GTK_CONTAINER (sw), view);
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show_page (buffer, 1);
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gtk_widget_show_all (sw);
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}
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if (!GTK_WIDGET_VISIBLE (window))
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{
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gtk_widget_show (window);
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}
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else
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{
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gtk_widget_destroy (window);
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window = NULL;
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}
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return window;
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}
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@ -1,4 +1,4 @@
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/* Text Widget
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/* Text Widget/Multiple Views
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*
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* The GtkTextView widget displays a GtkTextBuffer. One GtkTextBuffer
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* can be displayed by multiple GtkTextViews. This demo has two views
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