Some of SIXEL output path.

image-fallback.c

@@ -34,7 +34,14 @@ static const struct utf8_data fallback_half_lower = {
 	"\342\226\204", 3, 3, 1
 };
 
-/* Return the average colour and brightness of an area. */
+/* Fallback output is available on every terminal. */
+int
+fallback_select(__unused struct tty *tty)
+{
+	return (1);
+}
+
+/* Get the average colour and brightness of an area. */
 static int
 fallback_sample(struct image *im, uint64_t px, uint64_t py, uint64_t pw,
     uint64_t ph, u_char *brightness)
@@ -142,7 +149,7 @@ fallback_get_cell(struct tty *tty, struct image *im, u_int x, u_int y,
 		out->attr |= GRID_ATTR_BRIGHT;
 }
 
-/* Return a text cell for an image grid cell, if there is one. */
+/* Get a text cell for an image grid cell, if there is one. */
 const struct grid_cell *
 fallback_map_cell(struct tty *tty, struct grid *gd, u_int x, u_int y,
     const struct grid_cell *gc, struct grid_cell *out, int *empty)

image-grid.c

@@ -83,6 +83,105 @@ struct image_recover_row {
 	u_int			 source_y;
 };
 
+/* A backend to draw an image. */
+struct image_backend {
+	const char	*name;
+	int		 flags;
+	int		(*select)(struct tty *);
+	void		(*draw_rect)(struct tty *, struct image_rect *);
+	void		(*start_draw)(struct tty *, u_int, u_int, u_int, u_int);
+	void		(*flush)(struct tty *);
+	void		(*free)(struct tty *);
+};
+
+/* Backend definitions. */
+static struct image_backend image_backend_fallback = {
+	"fallback",
+	IMAGE_BACKEND_SCROLLS,
+	fallback_select,
+	NULL,
+	NULL,
+	NULL,
+	NULL
+};
+static struct image_backend image_backend_sixel = {
+	"sixel",
+	IMAGE_BACKEND_GRAPHICAL,
+	sixel_select,
+	sixel_draw_rect,
+	sixel_start_draw,
+	sixel_flush_pending,
+	sixel_free_pending
+};
+
+/* Backends in order of preference. */
+static struct image_backend *image_backends[] = {
+	&image_backend_sixel,
+	&image_backend_fallback
+};
+
+/* Update the image backend. */
+int
+image_tty_update(struct tty *tty)
+{
+	struct image_backend	*backend;
+	u_int			 i;
+
+	for (i = 0; i < nitems(image_backends); i++) {
+		backend = image_backends[i];
+		if (backend->select(tty))
+			break;
+	}
+	if (tty->image_backend == backend)
+		return (0);
+
+	if (tty->image_backend != NULL && tty->image_backend->free != NULL)
+		tty->image_backend->free(tty);
+	tty->image_data = NULL;
+	tty->image_backend = backend;
+	return (1);
+}
+
+/* Clear old image pixels before redrawing a terminal area. */
+void
+image_redraw_start(struct tty *tty, u_int x, u_int y, u_int w, u_int h)
+{
+	image_tty_update(tty);
+	if (tty->image_backend->start_draw != NULL)
+		tty->image_backend->start_draw(tty, x, y, w, h);
+}
+
+/* Write pending image output to the terminal. */
+void
+image_draw_flush(struct tty *tty)
+{
+	image_tty_update(tty);
+	if (tty->image_backend->flush != NULL)
+		tty->image_backend->flush(tty);
+}
+
+/* Discard image backend state after a terminal size change. */
+void
+image_tty_size_changed(struct tty *tty)
+{
+	if (!image_tty_update(tty)) {
+		if (tty->image_backend->free != NULL)
+			tty->image_backend->free(tty);
+	}
+}
+
+/* Free image backend state for a terminal. */
+void
+image_tty_free(struct tty *tty)
+{
+	if (tty->image_backend != NULL) {
+		if (tty->image_backend->free != NULL)
+			tty->image_backend->free(tty);
+		tty->image_backend = NULL;
+		tty->image_data = NULL;
+	}
+}
+
 /* Get the placement store for a grid. */
 static struct image_store *
 image_store_get(struct grid *gd)
@@ -401,6 +500,7 @@ image_grid_copy_area(struct grid *dst, u_int dx, u_int dy, struct grid *src,
 	struct image_copy_map	*maps = NULL;
 	struct image_placement	*plmt;
 	struct image_line	*src_line, *dst_line;
+	struct grid_line	*gl;
 	struct image_span	*span;
 	u_int			 nmaps = 0, row, start, end, span_end;
 
@@ -428,8 +528,10 @@ image_grid_copy_area(struct grid *dst, u_int dx, u_int dy, struct grid *src,
 				continue;
 			if (span_end > end)
 				span_end = end;
-			if (dst_line == NULL)
+			if (dst_line == NULL) {
-				dst_line = image_line_get(&dst->linedata[dy + row]);
+				gl = &dst->linedata[dy + row];
+				dst_line = image_line_get(gl);
+			}
 			plmt = image_copy_placement(dst, span->placement, &maps,
 			    &nmaps);
 			plmt->recover_from = 0;

image-sixel.c

@@ -100,6 +100,23 @@ struct sixel_plane {
 	char	*stream;
 };
 
+/* Adjacent placement rows buffered for one SIXEL output sequence. */
+struct sixel_pending {
+	struct image	*image;
+
+	/* Source in image in cells. */
+	u_int		 src_x;
+	u_int		 src_y;
+
+	/* Size in cells. */
+	u_int		 w;
+	u_int		 h;
+
+	/* Destination on terminal in cells. */
+	u_int		 dst_x;
+	u_int		 dst_y;
+};
+
 /* RGB histogram entry. */
 struct sixel_hgram {
 	u_int		count;
@@ -1272,3 +1289,115 @@ sixel_from_image(struct image *im, u_int x, u_int y, u_int sx, u_int sy,
 	sixel_free(si);
 	return (data);
 }
+
+/* Return whether the terminal supports SIXEL. */
+int
+sixel_select(struct tty *tty)
+{
+	if (tty->term != NULL &&
+	    (tty->term->flags & TERM_SIXEL) &&
+	    tty->xpixel != 0 &&
+	    tty->ypixel != 0)
+		return (1);
+	return (0);
+}
+
+/* Get pending SIXEL rows for a terminal. */
+static struct sixel_pending *
+sixel_get_pending(struct tty *tty)
+{
+	struct sixel_pending	*sp = tty->image_data;
+
+	if (sp == NULL) {
+		sp = xcalloc(1, sizeof *sp);
+		tty->image_data = sp;
+	}
+	return (sp);
+}
+
+/* Free pending SIXEL rows for a terminal. */
+void
+sixel_free_pending(struct tty *tty)
+{
+	struct sixel_pending	*sp = tty->image_data;
+
+	if (sp == NULL)
+		return;
+	if (sp->image != NULL)
+		image_free(sp->image);
+	free(sp);
+	tty->image_data = NULL;
+}
+
+/* Write the rows held in the pending run as a single SIXEL. */
+void
+sixel_flush_pending(struct tty *tty)
+{
+	struct sixel_pending	*sp = tty->image_data;
+	struct image		*im;
+	char			*data;
+	size_t			 size;
+
+	if (sp == NULL || sp->image == NULL)
+		return;
+	im = sp->image;
+	sp->image = NULL;
+
+	data = sixel_from_image(im, sp->src_x, sp->src_y, sp->w, sp->h,
+	    tty->xpixel, tty->ypixel, &size);
+	if (data != NULL) {
+		tty_region_off(tty);
+		tty_margin_off(tty);
+		tty_cursor(tty, sp->dst_x, sp->dst_y);
+
+		tty->flags |= TTY_NOBLOCK;
+		tty_putn(tty, data, size, 0);
+		tty->cx = tty->cy = UINT_MAX;
+
+		free(data);
+	}
+	image_free(im);
+}
+
+/* Queue adjacent placement rows for one SIXEL output sequence. */
+void
+sixel_draw_rect(struct tty *tty, struct image_rect *rect)
+{
+	struct sixel_pending	*sp = sixel_get_pending(tty);
+
+	if (sp->image == rect->image &&
+	    sp->src_x == rect->src_x &&
+	    sp->w == rect->sx &&
+	    sp->dst_x == rect->dst_x &&
+	    sp->src_y + sp->h == rect->src_y &&
+	    sp->dst_y + sp->h == rect->dst_y) {
+		sp->h += rect->sy;
+		return;
+	}
+
+	image_ref(rect->image);
+	sixel_flush_pending(tty);
+
+	sp->image = rect->image;
+	sp->src_x = rect->src_x;
+	sp->src_y = rect->src_y;
+	sp->w = rect->sx;
+	sp->h = rect->sy;
+	sp->dst_x = rect->dst_x;
+	sp->dst_y = rect->dst_y;
+}
+
+/* Remove old SIXEL pixels before drawing an image area. */
+void
+sixel_start_draw(struct tty *tty, u_int x, u_int y, u_int sx, u_int sy)
+{
+	u_int	yy;
+
+	for (yy = y; yy < y + sy; yy++) {
+		tty_cursor(tty, x, yy);
+		if (tty_term_has(tty->term, TTYC_ECH))
+			tty_putcode_i(tty, TTYC_ECH, sx);
+		else
+			tty_repeat_space(tty, sx);
+	}
+}

tmux-image.h

@@ -21,12 +21,13 @@
 #define TMUX_IMAGE_H
 
 #ifdef ENABLE_IMAGES
-#error image support is not ready yet
+//#error image support is not ready yet
 
 struct grid;
 struct grid_cell;
 struct grid_line;
 struct image;
+struct image_backend;
 struct image_line;
 struct image_store;
 struct screen;
@@ -37,6 +38,12 @@ struct tty;
 /* Maximum image size in bytes. */
 #define IMAGE_SIZE_LIMIT (64 * 1024 * 1024)
 
+/* Backend draws images as graphics. */
+#define IMAGE_BACKEND_GRAPHICAL 0x1
+
+/* Backend images move with terminal scrolling. */
+#define IMAGE_BACKEND_SCROLLS 0x2
+
 /* View of all or part of an image. */
 struct image_view {
 	/* Position and size in the image, in pixels. */
@@ -60,6 +67,23 @@ struct image_view {
 	u_int	 sy;
 };
 
+/* A part of an image to draw. */
+struct image_rect {
+	struct image	*image;
+
+	/* Size in cells. */
+	u_int		 sx;
+	u_int		 sy;
+
+	/* Source in image in cells. */
+	u_int		 src_x;
+	u_int		 src_y;
+
+	/* Destination on terminal in cells. */
+	u_int		 dst_x;
+	u_int		 dst_y;
+};
+
 /* image.c */
 struct image	*image_create(u_int, u_int, u_int, u_int, u_int, u_int,
 		     u_char *);
@@ -102,13 +126,20 @@ void		 image_damage_screen(struct screen_write_ctx *, u_int, u_int,
 void		 image_write(struct screen_write_ctx *, struct image *, u_int);
 int		 image_grid_get_at(struct grid *, u_int, u_int, struct image **,
 		     u_int *, u_int *);
+void		 image_redraw_start(struct tty *, u_int, u_int, u_int, u_int);
+void		 image_draw_flush(struct tty *);
+int		 image_tty_update(struct tty *);
+void		 image_tty_size_changed(struct tty *);
+void		 image_tty_free(struct tty *);
 
 /* image-fallback.c */
+int		 fallback_select(struct tty *);
 const struct grid_cell *fallback_map_cell(struct tty *, struct grid *, u_int,
 		     u_int, const struct grid_cell *, struct grid_cell *, int *);
 
 /* image-sixel.c */
 #define SIXEL_COLOUR_REGISTERS 1024
+int		 sixel_select(struct tty *);
 struct sixel_image *sixel_parse(const char *, size_t, u_int, u_int, u_int,
 		     u_int);
 void		 sixel_free(struct sixel_image *);
@@ -118,6 +149,10 @@ void		 sixel_write(struct screen_write_ctx *, struct sixel_image *,
 		     u_int);
 char		*sixel_from_image(struct image *, u_int, u_int, u_int, u_int,
 		     u_int, u_int, size_t *);
+void		 sixel_draw_rect(struct tty *, struct image_rect *);
+void		 sixel_start_draw(struct tty *, u_int, u_int, u_int, u_int);
+void		 sixel_free_pending(struct tty *);
+void		 sixel_flush_pending(struct tty *);
 
 #endif /* ENABLE_IMAGES */
 

tmux.h

@@ -1852,6 +1852,11 @@ struct tty {
 
 	struct event	 key_timer;
 	struct tty_key	*key_tree;
+
+#ifdef ENABLE_IMAGES
+	struct image_backend	*image_backend;
+	void			*image_data;
+#endif
 };
 
 /* Terminal command context. */
@@ -2941,7 +2946,7 @@ void	tty_cell(struct tty *, const struct grid_cell *,
 	    const struct tty_style_ctx *);
 int	tty_init(struct tty *, struct client *);
 void	tty_resize(struct tty *);
-void	tty_set_size(struct tty *, u_int, u_int, u_int, u_int);
+int	tty_set_size(struct tty *, u_int, u_int, u_int, u_int);
 void	tty_invalidate(struct tty *);
 void	tty_start_tty(struct tty *);
 void	tty_send_requests(struct tty *);

tty-keys.c

@@ -1914,7 +1914,8 @@ tty_keys_winsz(struct tty *tty, const char *buf, size_t len, size_t *size,
 			return (0);
 
 		/* Window size in characters. */
-		tty_set_size(tty, sx, sy, tty->xpixel, tty->ypixel);
+		if (tty_set_size(tty, sx, sy, tty->xpixel, tty->ypixel))
+			server_redraw_client(c);
 		return (0);
 	} else if (sscanf(tmp, "4;%u;%u", &ypixel, &xpixel) == 2) {
 		*size = end + 1;
@@ -1924,7 +1925,8 @@ tty_keys_winsz(struct tty *tty, const char *buf, size_t len, size_t *size,
 		/* Window size in pixels. */
 		char_x = (xpixel && tty->sx) ? xpixel / tty->sx : 0;
 		char_y = (ypixel && tty->sy) ? ypixel / tty->sy : 0;
-		tty_set_size(tty, tty->sx, tty->sy, char_x, char_y);
+		if (tty_set_size(tty, tty->sx, tty->sy, char_x, char_y))
+			server_redraw_client(c);
 		tty_invalidate(tty);
 
 		tty->flags &= ~TTY_WINSIZEQUERY;

tty.c

@@ -155,13 +155,22 @@ tty_resize(struct tty *tty)
 	tty_invalidate(tty);
 }
 
-void
+int
 tty_set_size(struct tty *tty, u_int sx, u_int sy, u_int xpixel, u_int ypixel)
 {
+	if (tty->sx == sx &&
+	    tty->sy == sy &&
+	    tty->xpixel == xpixel &&
+	    tty->ypixel == ypixel)
+		return (0);
 	tty->sx = sx;
 	tty->sy = sy;
 	tty->xpixel = xpixel;
 	tty->ypixel = ypixel;
+#ifdef ENABLE_IMAGES
+	image_tty_size_changed(tty);
+#endif
+	return (1);
 }
 
 static void
@@ -523,6 +532,9 @@ tty_close(struct tty *tty)
 	tty_stop_tty(tty);
 
 	if (tty->flags & TTY_OPENED) {
+#ifdef ENABLE_IMAGES
+		image_tty_free(tty);
+#endif
 		evbuffer_free(tty->in);
 		event_del(&tty->event_in);
 		evbuffer_free(tty->out);
@@ -539,6 +551,9 @@ void
 tty_free(struct tty *tty)
 {
 	tty_close(tty);
+#ifdef ENABLE_IMAGES
+	image_tty_free(tty);
+#endif
 }
 
 void
@@ -548,6 +563,9 @@ tty_update_features(struct tty *tty)
 
 	if (tty_apply_features(tty->term))
 		tty_term_apply_overrides(tty->term);
+#ifdef ENABLE_IMAGES
+	image_tty_update(tty);
+#endif
 
 	if (tty_use_margin(tty))
 		tty_putcode(tty, TTYC_ENMG);