/* Text View/Hypertext * #Keywords: GtkTextView, GtkTextBuffer * * Usually, tags modify the appearance of text in the view, e.g. making it * bold or colored or underlined. But tags are not restricted to appearance. * They can also affect the behavior of mouse and key presses, as this demo * shows. * * We also demonstrate adding other things to a text view, such as * clickable icons and widgets which can also replace a character * (try copying the ghost text). */ #include #include /* Inserts a piece of text into the buffer, giving it the usual * appearance of a hyperlink in a web browser: blue and underlined. * Additionally, attaches some data on the tag, to make it recognizable * as a link. */ static void insert_link (GtkTextBuffer *buffer, GtkTextIter *iter, const char *text, int page) { GtkTextTag *tag; tag = gtk_text_buffer_create_tag (buffer, NULL, "foreground", "blue", "underline", PANGO_UNDERLINE_SINGLE, NULL); g_object_set_data (G_OBJECT (tag), "page", GINT_TO_POINTER (page)); gtk_text_buffer_insert_with_tags (buffer, iter, text, -1, tag, NULL); } /* Quick-and-dirty text-to-speech for a single word. If you don't hear * anything, you are missing espeak-ng on your system. */ static void say_word (GtkGestureClick *gesture, guint n_press, double x, double y, const char *word) { const char *argv[3]; argv[0] = "espeak-ng"; argv[1] = word; argv[2] = NULL; g_spawn_async (NULL, (char **)argv, NULL, G_SPAWN_SEARCH_PATH, NULL, NULL, NULL, NULL); } /* Fills the buffer with text and interspersed links. In any real * hypertext app, this method would parse a file to identify the links. */ static void show_page (GtkTextView *text_view, int page) { GtkTextBuffer *buffer; GtkTextIter iter, start; GtkTextMark *mark; GtkWidget *child; GtkTextChildAnchor *anchor; GtkEventController *controller; GtkTextTag *bold, *mono, *nobreaks; buffer = gtk_text_view_get_buffer (text_view); bold = gtk_text_buffer_create_tag (buffer, NULL, "weight", PANGO_WEIGHT_BOLD, "scale", PANGO_SCALE_X_LARGE, NULL); mono = gtk_text_buffer_create_tag (buffer, NULL, "family", "monospace", NULL); nobreaks = gtk_text_buffer_create_tag (buffer, NULL, "allow-breaks", FALSE, NULL); gtk_text_buffer_set_text (buffer, "", 0); gtk_text_buffer_get_iter_at_offset (buffer, &iter, 0); gtk_text_buffer_begin_irreversible_action (buffer); if (page == 1) { GtkIconPaintable *icon; GtkIconTheme *theme; gtk_text_buffer_insert (buffer, &iter, "Some text to show that simple ", -1); insert_link (buffer, &iter, "hypertext", 3); gtk_text_buffer_insert (buffer, &iter, " can easily be realized with ", -1); insert_link (buffer, &iter, "tags", 2); gtk_text_buffer_insert (buffer, &iter, ".\n", -1); gtk_text_buffer_insert (buffer, &iter, "Of course you can also embed Emoji 😋, ", -1); gtk_text_buffer_insert (buffer, &iter, "icons ", -1); theme = gtk_icon_theme_get_for_display (gtk_widget_get_display (GTK_WIDGET (text_view))); icon = gtk_icon_theme_lookup_icon (theme, "eye-not-looking-symbolic", NULL, 16, 1, GTK_TEXT_DIR_LTR, 0); gtk_text_buffer_insert_paintable (buffer, &iter, GDK_PAINTABLE (icon)); g_object_unref (icon); gtk_text_buffer_insert (buffer, &iter, ", or even widgets ", -1); anchor = gtk_text_buffer_create_child_anchor (buffer, &iter); child = gtk_level_bar_new_for_interval (0, 100); gtk_level_bar_set_value (GTK_LEVEL_BAR (child), 50); gtk_widget_set_size_request (child, 100, -1); gtk_text_view_add_child_at_anchor (text_view, child, anchor); gtk_text_buffer_insert (buffer, &iter, " and labels with ", -1); anchor = gtk_text_child_anchor_new_with_replacement ("👻"); gtk_text_buffer_insert_child_anchor (buffer, &iter, anchor); child = gtk_label_new ("ghost"); gtk_text_view_add_child_at_anchor (text_view, child, anchor); gtk_text_buffer_insert (buffer, &iter, " text.", -1); } else if (page == 2) { mark = gtk_text_buffer_create_mark (buffer, "mark", &iter, TRUE); gtk_text_buffer_insert_with_tags (buffer, &iter, "tag", -1, bold, NULL); gtk_text_buffer_insert (buffer, &iter, " /", -1); gtk_text_buffer_get_iter_at_mark (buffer, &start, mark); gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter); gtk_text_buffer_insert (buffer, &iter, " ", -1); gtk_text_buffer_move_mark (buffer, mark, &iter); gtk_text_buffer_insert_with_tags (buffer, &iter, "tag", -1, mono, NULL); gtk_text_buffer_insert (buffer, &iter, " /", -1); gtk_text_buffer_get_iter_at_mark (buffer, &start, mark); gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter); gtk_text_buffer_insert (buffer, &iter, " ", -1); anchor = gtk_text_buffer_create_child_anchor (buffer, &iter); child = gtk_image_new_from_icon_name ("audio-volume-high-symbolic"); gtk_widget_set_cursor_from_name (child, "pointer"); controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ()); g_signal_connect (controller, "pressed", G_CALLBACK (say_word), (gpointer)"tag"); gtk_widget_add_controller (child, controller); gtk_text_view_add_child_at_anchor (text_view, child, anchor); gtk_text_buffer_insert (buffer, &iter, "\n" "An attribute that can be applied to some range of text. For example, " "a tag might be called “bold” and make the text inside the tag bold.\n" "However, the tag concept is more general than that; " "tags don't have to affect appearance. They can instead affect the " "behavior of mouse and key presses, “lock” a range of text so the " "user can't edit it, or countless other things.\n", -1); insert_link (buffer, &iter, "Go back", 1); gtk_text_buffer_delete_mark (buffer, mark); } else if (page == 3) { mark = gtk_text_buffer_create_mark (buffer, "mark", &iter, TRUE); gtk_text_buffer_insert_with_tags (buffer, &iter, "hypertext", -1, bold, NULL); gtk_text_buffer_insert (buffer, &iter, " /", -1); gtk_text_buffer_get_iter_at_mark (buffer, &start, mark); gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter); gtk_text_buffer_insert (buffer, &iter, " ", -1); gtk_text_buffer_move_mark (buffer, mark, &iter); gtk_text_buffer_insert_with_tags (buffer, &iter, "ˈhaɪ pərˌtɛkst", -1, mono, NULL); gtk_text_buffer_insert (buffer, &iter, " /", -1); gtk_text_buffer_get_iter_at_mark (buffer, &start, mark); gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter); gtk_text_buffer_insert (buffer, &iter, " ", -1); anchor = gtk_text_buffer_create_child_anchor (buffer, &iter); child = gtk_image_new_from_icon_name ("audio-volume-high-symbolic"); gtk_widget_set_cursor_from_name (child, "pointer"); controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ()); g_signal_connect (controller, "pressed", G_CALLBACK (say_word), (gpointer)"hypertext"); gtk_widget_add_controller (child, controller); gtk_text_view_add_child_at_anchor (text_view, child, anchor); gtk_text_buffer_insert (buffer, &iter, "\n" "Machine-readable text that is not sequential but is organized " "so that related items of information are connected.\n", -1); insert_link (buffer, &iter, "Go back", 1); gtk_text_buffer_delete_mark (buffer, mark); } gtk_text_buffer_end_irreversible_action (buffer); } /* Looks at all tags covering the position of iter in the text view, * and if one of them is a link, follow it by showing the page identified * by the data attached to it. */ static void follow_if_link (GtkWidget *text_view, GtkTextIter *iter) { GSList *tags = NULL, *tagp = NULL; tags = gtk_text_iter_get_tags (iter); for (tagp = tags; tagp != NULL; tagp = tagp->next) { GtkTextTag *tag = tagp->data; int page = GPOINTER_TO_INT (g_object_get_data (G_OBJECT (tag), "page")); if (page != 0) { show_page (GTK_TEXT_VIEW (text_view), page); break; } } if (tags) g_slist_free (tags); } /* Links can be activated by pressing Enter. */ static gboolean key_pressed (GtkEventController *controller, guint keyval, guint keycode, GdkModifierType modifiers, GtkWidget *text_view) { GtkTextIter iter; GtkTextBuffer *buffer; switch (keyval) { case GDK_KEY_Return: case GDK_KEY_KP_Enter: buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (text_view)); gtk_text_buffer_get_iter_at_mark (buffer, &iter, gtk_text_buffer_get_insert (buffer)); follow_if_link (text_view, &iter); break; default: break; } return GDK_EVENT_PROPAGATE; } static void set_cursor_if_appropriate (GtkTextView *text_view, int x, int y); static void released_cb (GtkGestureClick *gesture, guint n_press, double x, double y, GtkWidget *text_view) { GtkTextIter start, end, iter; GtkTextBuffer *buffer; int tx, ty; if (gtk_gesture_single_get_button (GTK_GESTURE_SINGLE (gesture)) > 1) return; gtk_text_view_window_to_buffer_coords (GTK_TEXT_VIEW (text_view), GTK_TEXT_WINDOW_WIDGET, x, y, &tx, &ty); buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (text_view)); /* we shouldn't follow a link if the user has selected something */ gtk_text_buffer_get_selection_bounds (buffer, &start, &end); if (gtk_text_iter_get_offset (&start) != gtk_text_iter_get_offset (&end)) return; if (gtk_text_view_get_iter_at_location (GTK_TEXT_VIEW (text_view), &iter, tx, ty)) follow_if_link (text_view, &iter); } static void motion_cb (GtkEventControllerMotion *controller, double x, double y, GtkTextView *text_view) { int tx, ty; gtk_text_view_window_to_buffer_coords (text_view, GTK_TEXT_WINDOW_WIDGET, x, y, &tx, &ty); set_cursor_if_appropriate (text_view, tx, ty); } static gboolean hovering_over_link = FALSE; /* Looks at all tags covering the position (x, y) in the text view, * and if one of them is a link, change the cursor to the "hands" cursor * typically used by web browsers. */ static void set_cursor_if_appropriate (GtkTextView *text_view, int x, int y) { GSList *tags = NULL, *tagp = NULL; GtkTextIter iter; gboolean hovering = FALSE; if (gtk_text_view_get_iter_at_location (text_view, &iter, x, y)) { tags = gtk_text_iter_get_tags (&iter); for (tagp = tags; tagp != NULL; tagp = tagp->next) { GtkTextTag *tag = tagp->data; int page = GPOINTER_TO_INT (g_object_get_data (G_OBJECT (tag), "page")); if (page != 0) { hovering = TRUE; break; } } } if (hovering != hovering_over_link) { hovering_over_link = hovering; if (hovering_over_link) gtk_widget_set_cursor_from_name (GTK_WIDGET (text_view), "pointer"); else gtk_widget_set_cursor_from_name (GTK_WIDGET (text_view), "text"); } if (tags) g_slist_free (tags); } GtkWidget * do_hypertext (GtkWidget *do_widget) { static GtkWidget *window = NULL; if (!window) { GtkWidget *view; GtkWidget *sw; GtkTextBuffer *buffer; GtkEventController *controller; window = gtk_window_new (); gtk_window_set_title (GTK_WINDOW (window), "Hypertext"); gtk_window_set_display (GTK_WINDOW (window), gtk_widget_get_display (do_widget)); gtk_window_set_default_size (GTK_WINDOW (window), 330, 330); gtk_window_set_resizable (GTK_WINDOW (window), FALSE); g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window); view = gtk_text_view_new (); gtk_text_view_set_wrap_mode (GTK_TEXT_VIEW (view), GTK_WRAP_WORD); gtk_text_view_set_top_margin (GTK_TEXT_VIEW (view), 20); gtk_text_view_set_bottom_margin (GTK_TEXT_VIEW (view), 20); gtk_text_view_set_left_margin (GTK_TEXT_VIEW (view), 20); gtk_text_view_set_right_margin (GTK_TEXT_VIEW (view), 20); gtk_text_view_set_pixels_below_lines (GTK_TEXT_VIEW (view), 10); controller = gtk_event_controller_key_new (); g_signal_connect (controller, "key-pressed", G_CALLBACK (key_pressed), view); gtk_widget_add_controller (view, controller); controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ()); g_signal_connect (controller, "released", G_CALLBACK (released_cb), view); gtk_widget_add_controller (view, controller); controller = gtk_event_controller_motion_new (); g_signal_connect (controller, "motion", G_CALLBACK (motion_cb), view); gtk_widget_add_controller (view, controller); buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view)); gtk_text_buffer_set_enable_undo (buffer, TRUE); sw = gtk_scrolled_window_new (); gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw), GTK_POLICY_NEVER, GTK_POLICY_AUTOMATIC); gtk_window_set_child (GTK_WINDOW (window), sw); gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (sw), view); show_page (GTK_TEXT_VIEW (view), 1); } if (!gtk_widget_get_visible (window)) gtk_widget_show (window); else gtk_window_destroy (GTK_WINDOW (window)); return window; }