[sixel] Added sixel to terminal options.

To see sixel images you must:
- build elinks with -Dlibsixel=true
- set document.plain.sixel=1
- enable sixel in terminal options
- add to mailcap:
image/*; img2sixel %s; copiousoutput
or
image/*; convert %s sixel:- ; copiousoutput

and click some images on terminal which supports sixel.

While opening dialogs or menu, sixel images are not shown.

src/bfu/dialog.c

@@ -475,6 +475,7 @@ dialog_func(struct window *win, struct term_event *ev)
 		case EVENT_RESIZE:
 		case EVENT_REDRAW:
 			redraw_dialog(dlg_data, 1);
+			win->term->sixel = 0;
 			break;
 
 		case EVENT_MOUSE:
@@ -489,6 +490,7 @@ dialog_func(struct window *win, struct term_event *ev)
 
 		case EVENT_ABORT:
 			dialog_ev_abort(dlg_data);
+			win->term->sixel = 1;
 			break;
 	}
 }

src/bfu/menu.c

@@ -1014,6 +1014,7 @@ menu_handler(struct window *win, struct term_event *ev)
 			 * menu->selected here. */
 			scroll_menu(menu, 0, 1);
 			display_menu(win->term, menu);
+			win->term->sixel = 0;
 			break;
 
 		case EVENT_MOUSE:
@@ -1027,6 +1028,7 @@ menu_handler(struct window *win, struct term_event *ev)
 			break;
 
 		case EVENT_ABORT:
+			win->term->sixel = 1;
 			free_menu_items(menu->items);
 			break;
 	}
@@ -1367,6 +1369,7 @@ mainmenu_handler(struct window *win, struct term_event *ev)
 			break;
 
 		case EVENT_ABORT:
+			win->term->sixel = 1;
 			break;
 	}
 }

src/config/options.inc

@@ -1126,7 +1126,11 @@ static union option_info config_options_info[] = {
 		"underline", OPT_ZERO, 0,
 		N_("If we should use underline or enhance the color "
 		"instead.")),
-
+#ifdef CONFIG_LIBSIXEL
+	INIT_OPT_BOOL("terminal._template_", N_("Sixel"),
+		"sixel", OPT_ZERO, 0,
+		N_("Whether terminal supports sixel graphics.")),
+#endif
 	INIT_OPT_CODEPAGE("terminal._template_", N_("Codepage"),
 		"charset", OPT_ZERO, "System",
 		N_("Codepage of charset used for displaying content on "

src/dialogs/options.c

@@ -99,7 +99,9 @@ enum termopt {
 #ifdef CONFIG_COMBINE
 	TERM_OPT_COMBINE,
 #endif
-
+#ifdef CONFIG_LIBSIXEL
+	TERM_OPT_SIXEL,
+#endif
 	TERM_OPTIONS,
 };
 
@@ -116,6 +118,9 @@ static struct option_resolver resolvers[] = {
 #ifdef CONFIG_COMBINE
 	{ TERM_OPT_COMBINE,	 "combine"	},
 #endif
+#ifdef CONFIG_LIBSIXEL
+	{ TERM_OPT_SIXEL,	 "sixel"	},
+#endif
 };
 
 static widget_handler_status_T
@@ -241,7 +246,9 @@ terminal_options(struct terminal *term, void *xxx, struct session *ses)
 #ifdef CONFIG_COMBINE
 	add_dlg_checkbox(dlg, _("Combining characters", term), &values[TERM_OPT_COMBINE].number);
 #endif
-
+#ifdef CONFIG_LIBSIXEL
+	add_dlg_checkbox(dlg, _("Sixel", term), &values[TERM_OPT_SIXEL].number);
+#endif
 	add_dlg_button(dlg, _("~OK", term), B_ENTER, push_ok_button, NULL);
 	if (!anonymous)
 		add_dlg_button(dlg, _("Sa~ve", term), B_ENTER, push_save_button, NULL);

src/terminal/screen.c

@@ -270,6 +270,10 @@ struct screen_driver_opt {
 	/* Whether use terminfo. */
 	unsigned int terminfo:1;
 #endif
+
+#ifdef CONFIG_LIBSIXEL
+	unsigned int sixel:1;
+#endif
 };
 
 /** Used in @c add_char*() and @c redraw_screen() to reduce the logic.
@@ -312,6 +316,9 @@ static const struct screen_driver_opt dumb_screen_driver_opt = {
 #ifdef CONFIG_TERMINFO
 	/* terminfo */		0,
 #endif
+#ifdef CONFIG_LIBSIXEL
+	/* sixel */		0,
+#endif
 };
 
 /** Default options for ::TERM_VT100.  */
@@ -335,6 +342,9 @@ static const struct screen_driver_opt vt100_screen_driver_opt = {
 #ifdef CONFIG_TERMINFO
 	/* terminfo */		0,
 #endif
+#ifdef CONFIG_LIBSIXEL
+	/* sixel */		0,
+#endif
 };
 
 /** Default options for ::TERM_LINUX.  */
@@ -358,6 +368,9 @@ static const struct screen_driver_opt linux_screen_driver_opt = {
 #ifdef CONFIG_TERMINFO
 	/* terminfo */		0,
 #endif
+#ifdef CONFIG_LIBSIXEL
+	/* sixel */		0,
+#endif
 };
 
 /** Default options for ::TERM_KOI8.  */
@@ -381,6 +394,9 @@ static const struct screen_driver_opt koi8_screen_driver_opt = {
 #ifdef CONFIG_TERMINFO
 	/* terminfo */		0,
 #endif
+#ifdef CONFIG_LIBSIXEL
+	/* sixel */		0,
+#endif
 };
 
 /** Default options for ::TERM_FREEBSD.  */
@@ -404,6 +420,9 @@ static const struct screen_driver_opt freebsd_screen_driver_opt = {
 #ifdef CONFIG_TERMINFO
 	/* terminfo */		0,
 #endif
+#ifdef CONFIG_LIBSIXEL
+	/* sixel */		0,
+#endif
 };
 
 /** Default options for ::TERM_FBTERM.  */
@@ -427,6 +446,9 @@ static const struct screen_driver_opt fbterm_screen_driver_opt = {
 #ifdef CONFIG_TERMINFO
 	/* terminfo */		0,
 #endif
+#ifdef CONFIG_LIBSIXEL
+	/* sixel */		0,
+#endif
 };
 
 /** Default options for all the different types of terminals.
@@ -473,6 +495,11 @@ set_screen_driver_opt(struct screen_driver *driver, struct option *term_spec)
 #ifdef CONFIG_COMBINE
 	driver->opt.combine = get_opt_bool_tree(term_spec, "combine", NULL);
 #endif /* CONFIG_COMBINE */
+
+#ifdef CONFIG_LIBSIXEL
+	driver->opt.sixel = get_opt_bool_tree(term_spec, "sixel", NULL);
+#endif /* CONFIG_LIBSIXEL */
+
 #ifdef CONFIG_UTF8
 	/* Force UTF-8 I/O if the UTF-8 charset is selected.  Various
 	 * places assume that the terminal's charset is unibyte if
@@ -1394,7 +1421,9 @@ redraw_screen(struct terminal *term)
 	if (!init_string(&image)) return;
 
 #ifdef CONFIG_LIBSIXEL
-	try_to_draw_images(term);
+	if (driver->opt.sixel) {
+		try_to_draw_images(term);
+	}
 #endif
 	switch (driver->opt.color_mode) {
 	default:

src/terminal/sixel.c

@@ -759,6 +759,10 @@ try_to_draw_images(struct terminal *term)
 {
 	struct image *im;
 
+	if (!term->sixel) {
+		return;
+	}
+
 	foreach (im, term->images) {
 		struct string text;
 

src/terminal/terminal.cpp

@@ -120,6 +120,7 @@ init_term(int fdin, int fdout)
 
 #ifdef CONFIG_LIBSIXEL
 	init_list(term->images);
+	term->sixel = 1;
 #endif
 	term->fdin = fdin;
 	term->fdout = fdout;

src/terminal/terminal.h

@@ -151,6 +151,9 @@ struct terminal {
 	unsigned int utf8_io:1;
 #endif /* CONFIG_UTF8 */
 
+#ifdef CONFIG_LIBSIXEL
+	unsigned int sixel:1;
+#endif
 	/** The current tab number. */
 	int current_tab;