[sixel] Small progress.

You can see images. In ~/.mailcap:
image/*; img2sixel %s; copiousoutput

src/document/document.cpp

@@ -163,6 +163,10 @@ init_document(struct cache_entry *cached, struct document_options *options)
 	init_list(document->timeouts);
 #endif
 
+#ifdef CONFIG_LIBSIXEL
+	init_list(document->images);
+#endif
+
 #ifdef CONFIG_COMBINE
 	document->comb_x = -1;
 	document->comb_y = -1;

src/document/document.h

@@ -21,6 +21,7 @@ struct ecmascript_timeout;
 struct el_form_control;
 struct frame_desc;
 struct frameset_desc;
+struct image;
 struct module;
 struct screen_char;
 
@@ -305,6 +306,9 @@ struct document {
 
 	struct el_box clipboard_box;
 	enum clipboard_status clipboard_status;
+#ifdef CONFIG_LIBSIXEL
+	LIST_OF(struct image) images;
+#endif
 };
 
 #define document_has_frames(document_) ((document_) && (document_)->frame_desc)

src/document/plain/renderer.c

@@ -5,6 +5,7 @@
 #endif
 
 #include <ctype.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -25,6 +26,7 @@
 #include "protocol/uri.h"
 #include "terminal/color.h"
 #include "terminal/draw.h"
+#include "terminal/sixel.h"
 #include "util/color.h"
 #include "util/error.h"
 #include "util/memory.h"
@@ -560,7 +562,7 @@ add_document_line(struct plain_renderer *renderer,
 
 		prev_char = line_pos > 0 ? line[line_pos - 1] : '\0';
 		next_char = (line_pos + charlen < width) ?
-		  		line[line_pos + charlen] : '\0';
+				line[line_pos + charlen] : '\0';
 
 		/* Do not expand tabs that precede back-spaces; this saves the
 		 * back-space code some trouble. */
@@ -639,10 +641,45 @@ add_document_line(struct plain_renderer *renderer,
 			if (template_->attr)
 				template_->attr |= pos->attr;
 		} else if (line_char == 27) {
-			decode_esc_color(line, &line_pos, width,
+#ifdef CONFIG_LIBSIXEL
+			if (line_pos + 1 < width && line[line_pos + 1] == 'P' && line_pos + 2 < width && line[line_pos + 2] == 'q') {
+				while (1) {
+					char *end = (char *)memchr(line + line_pos + 1, 27, width - line_pos - 1);
+
+					if (end == NULL) {
+						break;
+					}
+					if (end[1] == '\\') {
+						struct string pixels;
+
+						if (!init_string(&pixels)) {
+							break;
+						}
+						add_bytes_to_string(&pixels, line + line_pos, end + 2 - line - line_pos);
+						int ile = add_image_to_document(document, &pixels, lineno) + 1;
+
+						realloc_line(document, pos - startpos, lineno);
+
+						for (int i = 0; i < ile; i++) {
+							realloc_line(document, 0, lineno + i);
+						}
+						renderer->lineno += ile;
+						lineno += ile;
+						line_pos = end + 2 - line;
+						startpos = pos = realloc_line(document, width, lineno);
+						goto zero;
+					} else {
+						line_pos = end - line;
+					}
+				}
+			} else
+#endif
+			{
+				decode_esc_color(line, &line_pos, width,
 					 &saved_renderer_template,
 					 doc_opts->color_mode, &was_reversed);
-			*template_ = saved_renderer_template;
+				*template_ = saved_renderer_template;
+			}
 		} else {
 			int added_chars = 0;
 
@@ -700,6 +737,7 @@ add_document_line(struct plain_renderer *renderer,
 next:
 		line_pos += charlen;
 		cells += cell;
+zero:
 	}
 	mem_free(line);
 
@@ -749,11 +787,11 @@ add_document_lines(struct plain_renderer *renderer)
 		int last_space = 0;
 		int tab_spaces = 0;
 		int step = 0;
- 		int cells = 0;
+		int cells = 0;
 
 		/* End of line detection: We handle \r, \r\n and \n types. */
- 		for (width = 0; (width < length) &&
+		for (width = 0; (width < length) &&
- 				(cells < renderer->max_width);) {
+				(cells < renderer->max_width);) {
 			if (source[width] == ASCII_CR)
 				step++;
 			if (source[width + step] == ASCII_LF)

src/terminal/meson.build

@@ -1,6 +1,9 @@
 if conf_data.get('CONFIG_MOUSE')
 	srcs += files('mouse.c')
 endif
+if conf_data.get('CONFIG_LIBSIXEL')
+	srcs += files('sixel.c')
+endif
 if conf_data.get('CONFIG_TERMINFO')
 	srcs += files('terminfo.c')
 endif

src/terminal/screen.c

@@ -20,6 +20,7 @@
 #include "terminal/hardio.h"
 #include "terminal/kbd.h"
 #include "terminal/screen.h"
+#include "terminal/sixel.h"
 #include "terminal/terminal.h"
 #ifdef CONFIG_TERMINFO
 #include "terminal/terminfo.h"
@@ -675,7 +676,7 @@ done_screen_drivers(struct module *xxx)
 
 /** Adds the term code for positioning the cursor at @a x and @a y to
  * @a string.  The template term code is: "\033[<y>;<x>H" */
-static inline struct string *
+struct string *
 add_cursor_move_to_string(struct string *screen, int y, int x)
 {
 #ifdef CONFIG_TERMINFO
@@ -1372,6 +1373,8 @@ add_char_true(struct string *screen, struct screen_driver *driver,
 	}								\
 }
 
+#include <stdio.h>
+
 /*! Updating of the terminal screen is done by checking what needs to
  * be updated using the last screen. */
 void
@@ -1453,6 +1456,9 @@ redraw_screen(struct terminal *term)
 
 	copy_screen_chars(screen->last_image, screen->image, term->width * term->height);
 	screen->was_dirty = 0;
+#ifdef CONFIG_LIBSIXEL
+	try_to_draw_images(term);
+#endif
 }
 
 void

src/terminal/screen.h

@@ -8,6 +8,7 @@ extern "C" {
 struct bitfield;
 struct module;
 struct screen_char;
+struct string;
 struct terminal;
 
 /** The terminal's screen manages */
@@ -50,6 +51,8 @@ void erase_screen(struct terminal *term);
 /** Meeep! */
 void beep_terminal(struct terminal *term);
 
+struct string *add_cursor_move_to_string(struct string *screen, int y, int x);
+
 extern struct module terminal_screen_module;
 
 #ifdef __cplusplus

src/terminal/sixel.c

@@ -0,0 +1,110 @@
+/** Terminal sixel routines.
+ * @file */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sixel.h>
+
+#include "elinks.h"
+
+#include "document/document.h"
+#include "osdep/osdep.h"
+#include "terminal/hardio.h"
+#include "terminal/screen.h"
+#include "terminal/sixel.h"
+#include "terminal/terminal.h"
+
+/* encode settings object */
+struct sixel_decoder {
+	unsigned int ref;
+	char *input;
+	char *output;
+	sixel_allocator_t *allocator;
+};
+
+void
+try_to_draw_images(struct terminal *term)
+{
+	struct image *im;
+
+	foreach (im, term->images) {
+		struct string text;
+
+		if (!init_string(&text)) {
+			return;
+		}
+		add_cursor_move_to_string(&text, im->y + 1, im->x + 1);
+		add_string_to_string(&text, &im->sixel);
+
+		if (text.length) {
+			if (term->master) want_draw();
+			hard_write(term->fdout, text.source, text.length);
+			if (term->master) done_draw();
+		}
+		done_string(&text);
+	}
+}
+
+void
+delete_image(struct image *im)
+{
+	del_from_list(im);
+	done_string(&im->sixel);
+	mem_free(im);
+}
+
+int
+add_image_to_document(struct document *doc, struct string *pixels, int lineno)
+{
+	struct image *im = mem_calloc(1, sizeof(*im));
+
+	if (!im) {
+		return 0;
+	}
+	sixel_decoder_t *decoder = NULL;
+	SIXELSTATUS status = sixel_decoder_new(&decoder, NULL);
+
+	if (status != SIXEL_OK) {
+		return 0;
+	}
+
+	unsigned char *indexed_pixels = NULL;
+	unsigned char *palette = NULL;
+	int ncolors;
+	int width;
+	int height;
+	int ile = 0;
+
+	status = sixel_decode_raw(
+		(unsigned char *)pixels->source,
+		pixels->length,
+		&indexed_pixels,
+		&width,
+		&height,
+		&palette,
+		&ncolors,
+		decoder->allocator
+	);
+
+	if (SIXEL_FAILED(status)) {
+		goto end;
+	}
+	im->y = lineno + 1;
+	im->x = 0;
+	im->width = width;
+	im->height = height;
+	*(&im->sixel) = *pixels;
+	ile = (height + 15) / 16;
+	add_to_list(doc->images, im);
+end:
+	sixel_allocator_free(decoder->allocator, indexed_pixels);
+	sixel_allocator_free(decoder->allocator, palette);
+	sixel_decoder_unref(decoder);
+
+	return ile;
+}

src/terminal/sixel.h

@@ -0,0 +1,38 @@
+#ifndef EL__TERMINAL_SIXEL_H
+#define EL__TERMINAL_SIXEL_H
+
+#include "util/lists.h"
+#include "util/string.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef CONFIG_LIBSIXEL
+struct document;
+struct terminal;
+
+struct image {
+	LIST_HEAD(struct image);
+	struct string sixel;
+	int x;
+	int y;
+	int width;
+	int height;
+};
+
+void delete_image(struct image *im);
+
+void try_to_draw_images(struct terminal *term);
+
+/* return height of image in terminal rows */
+int add_image_to_document(struct document *doc, struct string *pixels, int lineno);
+
+
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* EL__TERMINAL_SIXEL_H */

src/terminal/terminal.cpp

@@ -35,6 +35,7 @@
 #include "terminal/hardio.h"
 #include "terminal/kbd.h"
 #include "terminal/screen.h"
+#include "terminal/sixel.h"
 #include "terminal/terminal.h"
 #ifdef CONFIG_TERMINFO
 #include "terminal/terminfo.h"
@@ -117,6 +118,9 @@ init_term(int fdin, int fdout)
 #endif
 	init_list(term->windows);
 
+#ifdef CONFIG_LIBSIXEL
+	init_list(term->images);
+#endif
 	term->fdin = fdin;
 	term->fdout = fdout;
 	term->master = (term->fdout == get_output_handle());
@@ -184,6 +188,11 @@ destroy_terminal(struct terminal *term)
 	while (!list_empty(term->windows))
 		delete_window((struct window *)term->windows.next);
 
+#ifdef CONFIG_LIBSIXEL
+	while (!list_empty(term->images)) {
+		delete_image((struct image *)term->images.next);
+	}
+#endif
 	/* mem_free_if(term->cwd); */
 	mem_free_if(term->title);
 	if (term->screen) done_screen(term->screen);

src/terminal/terminal.h

@@ -172,6 +172,10 @@ struct terminal {
 	void *textarea_data;
 
 	struct term_event_mouse prev_mouse_event;
+
+#ifdef CONFIG_LIBSIXEL
+	LIST_OF(struct image) images;
+#endif
 };
 
 #define do_not_ignore_next_mouse_event(term) \

src/viewer/text/draw.c

@@ -5,6 +5,7 @@
 #include "config.h"
 #endif
 
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #ifdef HAVE_UNISTD_H
@@ -29,6 +30,7 @@
 #include "session/location.h"
 #include "session/session.h"
 #include "terminal/draw.h"
+#include "terminal/sixel.h"
 #include "terminal/tab.h"
 #include "terminal/terminal.h"
 #include "util/error.h"
@@ -458,6 +460,32 @@ draw_doc(struct session *ses, struct document_view *doc_view, int active)
 		if (vs->current_link == -1)
 			vs->current_link = 0;
 	}
+#ifdef CONFIG_LIBSIXEL
+	while (!list_empty(term->images)) {
+		delete_image((struct image *)term->images.next);
+	}
+
+	if (list_empty(term->images)) {
+		struct image *im;
+
+		foreach (im, doc_view->document->images) {
+			if (im) {
+				struct image *im_copy = mem_calloc(1, sizeof(*im_copy));
+
+				if (im_copy) {
+					if (init_string(&im_copy->sixel)) {
+						add_string_to_string(&im_copy->sixel, &im->sixel);
+						im_copy->x = im->x;
+						im_copy->y = im->y;
+						im_copy->width = im->width;
+						im_copy->height = im->height;
+						add_to_list(term->images, im_copy);
+					}
+				}
+			}
+		}
+	}
+#endif
 }
 
 static void