408 lines
15 KiB
C
408 lines
15 KiB
C
/* Text View/Hypertext
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* #Keywords: GtkTextView, GtkTextBuffer
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*
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* Usually, tags modify the appearance of text in the view, e.g. making it
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* bold or colored or underlined. But tags are not restricted to appearance.
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* They can also affect the behavior of mouse and key presses, as this demo
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* shows.
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*
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* We also demonstrate adding other things to a text view, such as
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* clickable icons and widgets which can also replace a character
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* (try copying the ghost text).
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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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const char *text,
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int 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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/* Quick-and-dirty text-to-speech for a single word. If you don't hear
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* anything, you are missing espeak-ng on your system.
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*/
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static void
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say_word (GtkGestureClick *gesture,
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guint n_press,
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double x,
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double y,
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const char *word)
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{
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const char *argv[3];
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argv[0] = "espeak-ng";
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argv[1] = word;
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argv[2] = NULL;
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g_spawn_async (NULL, (char **)argv, NULL, G_SPAWN_SEARCH_PATH, NULL, NULL, NULL, 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 (GtkTextView *text_view,
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int page)
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{
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GtkTextBuffer *buffer;
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GtkTextIter iter, start;
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GtkTextMark *mark;
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GtkWidget *child;
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GtkTextChildAnchor *anchor;
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GtkEventController *controller;
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GtkTextTag *bold, *mono, *nobreaks;
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buffer = gtk_text_view_get_buffer (text_view);
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bold = gtk_text_buffer_create_tag (buffer, NULL,
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"weight", PANGO_WEIGHT_BOLD,
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"scale", PANGO_SCALE_X_LARGE,
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NULL);
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mono = gtk_text_buffer_create_tag (buffer, NULL,
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"family", "monospace",
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NULL);
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nobreaks = gtk_text_buffer_create_tag (buffer, NULL,
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"allow-breaks", FALSE,
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NULL);
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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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gtk_text_buffer_begin_irreversible_action (buffer);
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if (page == 1)
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{
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GtkIconPaintable *icon;
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GtkIconTheme *theme;
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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, ".\n", -1);
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gtk_text_buffer_insert (buffer, &iter, "Of course you can also embed Emoji 😋, ", -1);
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gtk_text_buffer_insert (buffer, &iter, "icons ", -1);
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theme = gtk_icon_theme_get_for_display (gtk_widget_get_display (GTK_WIDGET (text_view)));
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icon = gtk_icon_theme_lookup_icon (theme,
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"view-conceal-symbolic",
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NULL,
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16,
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1,
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GTK_TEXT_DIR_LTR,
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0);
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gtk_text_buffer_insert_paintable (buffer, &iter, GDK_PAINTABLE (icon));
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g_object_unref (icon);
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gtk_text_buffer_insert (buffer, &iter, ", or even widgets ", -1);
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anchor = gtk_text_buffer_create_child_anchor (buffer, &iter);
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child = gtk_level_bar_new_for_interval (0, 100);
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gtk_level_bar_set_value (GTK_LEVEL_BAR (child), 50);
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gtk_widget_set_size_request (child, 100, -1);
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gtk_text_view_add_child_at_anchor (text_view, child, anchor);
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gtk_text_buffer_insert (buffer, &iter, " and labels with ", -1);
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anchor = gtk_text_child_anchor_new_with_replacement ("👻");
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gtk_text_buffer_insert_child_anchor (buffer, &iter, anchor);
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child = gtk_label_new ("ghost");
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gtk_text_view_add_child_at_anchor (text_view, child, anchor);
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gtk_text_buffer_insert (buffer, &iter, " text.", -1);
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}
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else if (page == 2)
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{
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mark = gtk_text_buffer_create_mark (buffer, "mark", &iter, TRUE);
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gtk_text_buffer_insert_with_tags (buffer, &iter, "tag", -1, bold, NULL);
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gtk_text_buffer_insert (buffer, &iter, " /", -1);
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gtk_text_buffer_get_iter_at_mark (buffer, &start, mark);
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gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter);
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gtk_text_buffer_insert (buffer, &iter, " ", -1);
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gtk_text_buffer_move_mark (buffer, mark, &iter);
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gtk_text_buffer_insert_with_tags (buffer, &iter, "tag", -1, mono, NULL);
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gtk_text_buffer_insert (buffer, &iter, " /", -1);
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gtk_text_buffer_get_iter_at_mark (buffer, &start, mark);
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gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter);
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gtk_text_buffer_insert (buffer, &iter, " ", -1);
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anchor = gtk_text_buffer_create_child_anchor (buffer, &iter);
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child = gtk_image_new_from_icon_name ("audio-volume-high-symbolic");
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gtk_widget_set_cursor_from_name (child, "pointer");
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controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ());
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g_signal_connect (controller, "pressed", G_CALLBACK (say_word), (gpointer)"tag");
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gtk_widget_add_controller (child, controller);
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gtk_text_view_add_child_at_anchor (text_view, child, anchor);
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gtk_text_buffer_insert (buffer, &iter, "\n"
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"An attribute that can be applied to some range of text. For example, "
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"a tag might be called “bold” and make the text inside the tag bold.\n"
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"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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gtk_text_buffer_delete_mark (buffer, mark);
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}
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else if (page == 3)
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{
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mark = gtk_text_buffer_create_mark (buffer, "mark", &iter, TRUE);
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gtk_text_buffer_insert_with_tags (buffer, &iter, "hypertext", -1, bold, NULL);
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gtk_text_buffer_insert (buffer, &iter, " /", -1);
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gtk_text_buffer_get_iter_at_mark (buffer, &start, mark);
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gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter);
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gtk_text_buffer_insert (buffer, &iter, " ", -1);
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gtk_text_buffer_move_mark (buffer, mark, &iter);
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gtk_text_buffer_insert_with_tags (buffer, &iter, "ˈhaɪ pərˌtɛkst", -1, mono, NULL);
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gtk_text_buffer_insert (buffer, &iter, " /", -1);
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gtk_text_buffer_get_iter_at_mark (buffer, &start, mark);
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gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter);
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gtk_text_buffer_insert (buffer, &iter, " ", -1);
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anchor = gtk_text_buffer_create_child_anchor (buffer, &iter);
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child = gtk_image_new_from_icon_name ("audio-volume-high-symbolic");
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gtk_widget_set_cursor_from_name (child, "pointer");
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controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ());
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g_signal_connect (controller, "pressed", G_CALLBACK (say_word), (gpointer)"hypertext");
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gtk_widget_add_controller (child, controller);
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gtk_text_view_add_child_at_anchor (text_view, child, anchor);
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gtk_text_buffer_insert (buffer, &iter, "\n"
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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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gtk_text_buffer_delete_mark (buffer, mark);
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}
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gtk_text_buffer_end_irreversible_action (buffer);
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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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int 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 (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_pressed (GtkEventController *controller,
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guint keyval,
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guint keycode,
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GdkModifierType modifiers,
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GtkWidget *text_view)
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{
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GtkTextIter iter;
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GtkTextBuffer *buffer;
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switch (keyval)
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{
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case GDK_KEY_Return:
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case GDK_KEY_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 GDK_EVENT_PROPAGATE;
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}
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static void set_cursor_if_appropriate (GtkTextView *text_view,
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int x,
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int y);
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static void
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released_cb (GtkGestureClick *gesture,
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guint n_press,
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double x,
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double y,
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GtkWidget *text_view)
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{
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GtkTextIter start, end, iter;
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GtkTextBuffer *buffer;
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int tx, ty;
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if (gtk_gesture_single_get_button (GTK_GESTURE_SINGLE (gesture)) > 1)
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return;
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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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x, y, &tx, &ty);
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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;
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if (gtk_text_view_get_iter_at_location (GTK_TEXT_VIEW (text_view), &iter, tx, ty))
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follow_if_link (text_view, &iter);
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}
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static void
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motion_cb (GtkEventControllerMotion *controller,
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double x,
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double y,
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GtkTextView *text_view)
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{
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int tx, ty;
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gtk_text_view_window_to_buffer_coords (text_view,
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GTK_TEXT_WINDOW_WIDGET,
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x, y, &tx, &ty);
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set_cursor_if_appropriate (text_view, tx, ty);
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}
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static gboolean hovering_over_link = FALSE;
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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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int x,
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int y)
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{
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GSList *tags = NULL, *tagp = NULL;
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GtkTextIter iter;
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gboolean hovering = FALSE;
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if (gtk_text_view_get_iter_at_location (text_view, &iter, x, y))
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{
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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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int 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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}
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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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gtk_widget_set_cursor_from_name (GTK_WIDGET (text_view), "pointer");
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else
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gtk_widget_set_cursor_from_name (GTK_WIDGET (text_view), "text");
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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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GtkWidget *
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do_hypertext (GtkWidget *do_widget)
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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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GtkEventController *controller;
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window = gtk_window_new ();
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gtk_window_set_title (GTK_WINDOW (window), "Hypertext");
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gtk_window_set_display (GTK_WINDOW (window),
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gtk_widget_get_display (do_widget));
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gtk_window_set_default_size (GTK_WINDOW (window), 330, 330);
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gtk_window_set_resizable (GTK_WINDOW (window), FALSE);
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g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
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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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gtk_text_view_set_top_margin (GTK_TEXT_VIEW (view), 20);
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gtk_text_view_set_bottom_margin (GTK_TEXT_VIEW (view), 20);
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gtk_text_view_set_left_margin (GTK_TEXT_VIEW (view), 20);
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gtk_text_view_set_right_margin (GTK_TEXT_VIEW (view), 20);
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gtk_text_view_set_pixels_below_lines (GTK_TEXT_VIEW (view), 10);
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controller = gtk_event_controller_key_new ();
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g_signal_connect (controller, "key-pressed", G_CALLBACK (key_pressed), view);
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gtk_widget_add_controller (view, controller);
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controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ());
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g_signal_connect (controller, "released",
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G_CALLBACK (released_cb), view);
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gtk_widget_add_controller (view, controller);
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controller = gtk_event_controller_motion_new ();
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g_signal_connect (controller, "motion",
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G_CALLBACK (motion_cb), view);
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gtk_widget_add_controller (view, controller);
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buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));
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gtk_text_buffer_set_enable_undo (buffer, TRUE);
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sw = gtk_scrolled_window_new ();
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gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
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GTK_POLICY_NEVER,
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GTK_POLICY_AUTOMATIC);
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gtk_window_set_child (GTK_WINDOW (window), sw);
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gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (sw), view);
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show_page (GTK_TEXT_VIEW (view), 1);
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}
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if (!gtk_widget_get_visible (window))
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gtk_widget_set_visible (window, TRUE);
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else
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gtk_window_destroy (GTK_WINDOW (window));
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return window;
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}
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