Merge SIXEL branch.

Squashed commit of the following:

commit 6ebc3feb4671d9b25b3db99d3c16b2323b8e3d02
Author: topcat001 <anindya49@hotmail.com>
Date:   Sun Aug 20 16:09:51 2023 -0700

    Remove redundant {}.

commit 6f013fce39602c259a5be2d690d548c73e51cccc
Author: topcat001 <anindya49@hotmail.com>
Date:   Sun Aug 20 16:02:15 2023 -0700

    Revert "Do not defer redraw if it is just the status line (will need to do more here I"

    This reverts commit 0a15bbf3f1972dc84c5c84d5128024c1bc4c0074.

commit e6322b4196d73c975ba2e73633e6de9c46779059
Author: topcat001 <anindya49@hotmail.com>
Date:   Sun Aug 20 15:46:59 2023 -0700

    Fix placeholder label and clean up.

commit 5896ac52a1f72056a75480b3e1ada328f239df9b
Merge: ad982330 e3a8b843
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Fri Aug 18 17:00:03 2023 +0100

    Merge branch 'master' into sixel

commit ad98233066b72547aee7fa0c87838847ee7f1ece
Author: topcat001 <anindya49@hotmail.com>
Date:   Tue Aug 15 13:57:08 2023 -0700

    Better text placeholder.

commit 312d83252c27fc4d09d09d121bf7573336e3cdca
Merge: 14b8b524 3d93b0c5
Author: topcat001 <anindya49@hotmail.com>
Date:   Tue Aug 15 13:39:22 2023 -0700

    Merge remote-tracking branch 'origin/master' into sixel

commit 14b8b524523a7d5a4e42f7dfa346905c604c91e2
Merge: 4baf7642 fda39377
Author: topcat001 <anindya49@hotmail.com>
Date:   Sat Jul 22 17:29:10 2023 -0700

    Merge branch 'master' into sixel

commit 4baf76422fadb216bf27b47645b52da3379e7dea
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Wed Jun 21 07:43:53 2023 +0100

    Both files can go on one line.

commit 4c92acf6ff24dde37ad41cd168ea2d3bcefb8567
Author: topcat001 <anindya49@hotmail.com>
Date:   Sat Jun 17 17:53:01 2023 -0700

    Merge topcat001/tmux/sixel.

commit 6794facc82e98f8448c192913cf62fe6e10fde63
Merge: 7b85f5ad f41c536f
Author: topcat001 <anindya49@hotmail.com>
Date:   Sat Jun 17 17:21:02 2023 -0700

    Merge remote-tracking branch 'origin/master' into sixel

commit 7b85f5adf9a5094db580ca98e4d2231d8d5b5a4f
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Jun 8 12:55:03 2023 +0100

    Do not require passthrough for SIXEL.

commit a6ee55e0925cac35d011c188db2da0421fc09be1
Merge: 6da391f4 fe385b18
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Jun 8 12:19:55 2023 +0100

    Merge branch 'master' into sixel

commit 6da391f460414ed3dde23e5ab6ca3fe8e988ce51
Merge: 0d71e585 0eb5d254
Author: topcat001 <anindya49@hotmail.com>
Date:   Sat May 20 17:05:55 2023 -0700

    Merge branch 'master' into sixel

commit 0d71e5853ffe797f90b815ac3af25ac0ad92ab07
Merge: 64368a1a fbe6fe7f
Author: topcat001 <anindya49@hotmail.com>
Date:   Sat Apr 29 17:32:07 2023 -0700

    Merge branch 'master' into sixel

commit 64368a1a63f04fb877b57e4286c9a2e1efe966c9
Merge: c630a56a 22eb0334
Author: topcat001 <anindya49@hotmail.com>
Date:   Thu Mar 30 14:21:09 2023 -0700

    Merge branch 'master' into sixel

commit c630a56a621b9761eed558cbd566a36cb09adf8f
Merge: 34c96c4c aaa043a2
Author: topcat001 <anindya49@hotmail.com>
Date:   Thu Nov 10 18:53:01 2022 -0800

    Merge branch 'master' into sixel

commit 34c96c4c4a33f86b49c8a53dc48b2b817db24e95
Merge: 2a1e16a2 50f4e0fa
Author: topcat001 <anindya49@hotmail.com>
Date:   Sat Nov 5 18:05:36 2022 -0700

    Merge branch 'master' into sixel

commit 2a1e16a24dc75741c66f5d72fa5bf26b73507993
Merge: a82f14c7 d001a94d
Author: topcat001 <anindya49@hotmail.com>
Date:   Thu Oct 27 16:01:35 2022 -0700

    Merge branch 'master' into sixel

commit a82f14c7b23a239a2114c756ef73bba8609ebe33
Merge: 742c0634 f7b30ed3
Author: topcat001 <anindya49@hotmail.com>
Date:   Sun Aug 28 13:43:07 2022 -0700

    Merge branch 'master' into sixel

commit 742c0634734e6b2840762e58b0bf27626b5ac24b
Merge: 906c92a5 87b248f3
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Fri Apr 1 10:14:15 2022 +0100

    Merge branch 'master' into sixel

commit 906c92a5f458b8843e7abd1d6f419dc091f8063c
Merge: 6680a024 138ffc7c
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Wed Dec 8 10:37:33 2021 +0000

    Merge branch 'master' into sixel

commit 6680a024be5e173a27c10e9a0be6c9072576086d
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Oct 7 13:59:08 2021 +0100

    Fix build.

commit ebd2c585937f18045d334226d4a0cc788fe14353
Merge: 90dc0519 fed7b29c
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Oct 7 13:19:48 2021 +0100

    Merge branch 'master' into sixel

commit 90dc05191cbba8de6d9d77ee7f9726325abe844e
Merge: a282439f 4694afbe
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Feb 20 20:37:32 2020 +0000

    Merge branch 'master' into sixel

commit a282439fcb2f597927a5ba33d2c378c90eec8b42
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Jan 30 09:12:53 2020 +0000

    Add missing declarations.

commit 3a741aacd108538f99239c68bfa2cd416bf0eb46
Merge: 40ad0107 339832b9
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Jan 30 09:11:01 2020 +0000

    Merge branch 'sixel-passthrough' into sixel

commit 339832b92c298538f398754f6d3fc21d15d13326
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Jan 30 09:04:51 2020 +0000

    Bad merge.

commit 92ed9fc0b20440f2bc553757e6bfe3126fe84be4
Merge: 5bb07548 32be954b
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Jan 30 09:03:38 2020 +0000

    Merge branch 'master' into sixel-passthrough

commit 40ad01073d73a531b4e85b0138f78bf0b472b354
Merge: dd3c72f1 61b075a2
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Sun Jan 12 20:03:41 2020 +0000

    Merge branch 'master' into sixel

commit 5bb075487f5897d7402adb880e678043c0f7f3e0
Merge: 7c033a74 54efe337
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Wed Dec 18 20:24:42 2019 +0000

    Merge branch 'master' into sixel-passthrough

commit dd3c72f132c911b0ba61b56a56f46510704d3392
Merge: 1a0e5fe9 54efe337
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Wed Dec 18 20:24:26 2019 +0000

    Merge branch 'master' into sixel

commit 1a0e5fe933e89932f2f658936c52eb50644fbef4
Merge: cf071ffe 15d7e564
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Tue Dec 10 16:34:11 2019 +0000

    Merge branch 'master' into sixel

commit cf071ffecd5a0d33008fd0a8b66a22f6855c7a8d
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Mon Dec 9 15:41:56 2019 +0000

    Remove images when reflow happens.

commit 2006b7a5631787a7086c6bae364e62d0a0b5948a
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Dec 5 09:27:15 2019 +0000

    More invalidation of images.

commit b642eac4503cc89cde01103f7bacca57cc9c1a2b
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Dec 5 09:11:24 2019 +0000

    Redraw and scroll images and part of invalidating them.

commit 7566e37a461bf245bd2e54e1d522e919071e9c44
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Dec 5 08:51:24 2019 +0000

    Call sixel_scale with the right number of arguments.

commit 62c0280b23cf67fc43f691392a8eca5cd7ff0727
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Dec 5 08:48:58 2019 +0000

    Correctly remove when not visible.

commit 86c5098a887f2cd09b828e051ccf0fab21bf4f6a
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Dec 5 08:32:25 2019 +0000

    Add helpers to scroll image up and a flag to copy the colours.

commit 49f2f0a8f1e72389f4128aa38119ed124cdc31c5
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Dec 5 00:02:55 2019 +0000

    Store images, currently at most 10.

commit 3aebcc67099ccbc5964c744fc1435931c1a78583
Merge: 146ee3f6 92ecd611
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Wed Dec 4 19:27:16 2019 +0000

    Merge branch 'master' into sixel

commit 7c033a74e25957d333217cb71a7658b860583501
Merge: 0a15bbf3 92ecd611
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Wed Dec 4 12:41:09 2019 +0000

    Merge branch 'master' into sixel-passthrough

commit 146ee3f6f8ee2629c6a88b6900a71f3e6fd14e4d
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Sat Nov 30 09:47:53 2019 +0000

    Don't write image as text yet.

commit 0a15bbf3f1972dc84c5c84d5128024c1bc4c0074
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Sat Nov 30 09:15:35 2019 +0000

    Do not defer redraw if it is just the status line (will need to do more here I
    think).

commit a5b1e209417b7d3f5b0099642dd317c312f79377
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Nov 28 14:20:22 2019 +0000

    Add a flag to disable blocking while sending a SIXEL image (turned off when the
    buffer hits 0 size).

commit 968382aa6a4b9c71fbc221aa4f0e899f6a83a260
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Nov 28 12:35:18 2019 +0000

    Pass through SIXEL DCS sequences (treat similarly to the passthrough escape
    sequence) if it appears the terminal outside supports them.

commit b1904c9b8db514133d3372aac13b2ff0b2093cc3
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Sat Nov 30 09:17:18 2019 +0000

    Store SIXELs as a box for the moment.

commit 5d8dbcdf3d76d0e69b8f2d21eff48f819dcec199
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Sat Nov 30 09:15:35 2019 +0000

    Do not defer redraw if it is just the status line (will need to do more here I
    think).

commit 0c999a402ece7b40e6ae84547893421b52d508ff
Merge: 28961dd5 866b053f
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Fri Nov 29 18:54:09 2019 +0000

    Merge branch 'master' into sixel

commit 28961dd5a38dd5a7b703ed0e6625fa9a65556d35
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Nov 28 14:24:57 2019 +0000

    Add an image.

commit d2e3f3c1cca5410570c5392340d14e96ae7a354c
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Nov 28 14:20:22 2019 +0000

    Add a flag to disable blocking while sending a SIXEL image (turned off when the
    buffer hits 0 size).

commit e01df67ca106e57f5c689e75f313f8cda6f8b805
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Nov 28 13:21:40 2019 +0000

    Crop and scale images as needed when drawing them.

commit e24acc0b5c3ac19dcacebdea243dcc7784215ffa
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Nov 28 12:38:02 2019 +0000

    Simple SIXEL parse and modify API.

commit b34111b3da1e4b1769a976cd40486144f7b4f5a2
Author: Nicholas Marriott <nicholas.marriott@gmail.com>
Date:   Thu Nov 28 12:35:18 2019 +0000

    Pass through SIXEL DCS sequences (treat similarly to the passthrough escape
    sequence) if it appears the terminal outside supports them.

1 files changed, 153 insertions, 3 deletions

diff --git a/screen-write.c b/screen-write.c
index ee3a31a1..d51f4c4d 100644
--- a/screen-write.c
+++ b/screen-write.c
@@ -1011,6 +1011,11 @@ screen_write_alignmenttest(struct screen_write_ctx *ctx)
 	memcpy(&gc, &grid_default_cell, sizeof gc);
 	utf8_set(&gc.data, 'E');
 
+#ifdef ENABLE_SIXEL
+	if (image_free_all(s) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	for (yy = 0; yy < screen_size_y(s); yy++) {
 		for (xx = 0; xx < screen_size_x(s); xx++)
 			grid_view_set_cell(s->grid, xx, yy, &gc);
@@ -1045,6 +1050,11 @@ screen_write_insertcharacter(struct screen_write_ctx *ctx, u_int nx, u_int bg)
 	if (s->cx > screen_size_x(s) - 1)
 		return;
 
+#ifdef ENABLE_SIXEL
+	if (image_check_line(s, s->cy, 1) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	screen_write_initctx(ctx, &ttyctx, 0);
 	ttyctx.bg = bg;
 
@@ -1073,6 +1083,11 @@ screen_write_deletecharacter(struct screen_write_ctx *ctx, u_int nx, u_int bg)
 	if (s->cx > screen_size_x(s) - 1)
 		return;
 
+#ifdef ENABLE_SIXEL
+	if (image_check_line(s, s->cy, 1) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	screen_write_initctx(ctx, &ttyctx, 0);
 	ttyctx.bg = bg;
 
@@ -1101,6 +1116,11 @@ screen_write_clearcharacter(struct screen_write_ctx *ctx, u_int nx, u_int bg)
 	if (s->cx > screen_size_x(s) - 1)
 		return;
 
+#ifdef ENABLE_SIXEL
+	if (image_check_line(s, s->cy, 1) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	screen_write_initctx(ctx, &ttyctx, 0);
 	ttyctx.bg = bg;
 
@@ -1119,9 +1139,18 @@ screen_write_insertline(struct screen_write_ctx *ctx, u_int ny, u_int bg)
 	struct grid	*gd = s->grid;
 	struct tty_ctx	 ttyctx;
 
+#ifdef ENABLE_SIXEL
+	u_int		 sy = screen_size_y(s);
+#endif
+
 	if (ny == 0)
 		ny = 1;
 
+#ifdef ENABLE_SIXEL
+	if (image_check_line(s, s->cy, sy - s->cy) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	if (s->cy < s->rupper || s->cy > s->rlower) {
 		if (ny > screen_size_y(s) - s->cy)
 			ny = screen_size_y(s) - s->cy;
@@ -1165,13 +1194,19 @@ screen_write_deleteline(struct screen_write_ctx *ctx, u_int ny, u_int bg)
 	struct screen	*s = ctx->s;
 	struct grid	*gd = s->grid;
 	struct tty_ctx	 ttyctx;
+	u_int		 sy = screen_size_y(s);
 
 	if (ny == 0)
 		ny = 1;
 
+#ifdef ENABLE_SIXEL
+	if (image_check_line(s, s->cy, sy - s->cy) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	if (s->cy < s->rupper || s->cy > s->rlower) {
-		if (ny > screen_size_y(s) - s->cy)
-			ny = screen_size_y(s) - s->cy;
+		if (ny > sy - s->cy)
+			ny = sy - s->cy;
 		if (ny == 0)
 			return;
 
@@ -1217,6 +1252,11 @@ screen_write_clearline(struct screen_write_ctx *ctx, u_int bg)
 	if (gl->cellsize == 0 && COLOUR_DEFAULT(bg))
 		return;
 
+#ifdef ENABLE_SIXEL
+	if (image_check_line(s, s->cy, 1) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	grid_view_clear(s->grid, 0, s->cy, sx, 1, bg);
 
 	screen_write_collect_clear(ctx, s->cy, 1);
@@ -1246,6 +1286,11 @@ screen_write_clearendofline(struct screen_write_ctx *ctx, u_int bg)
 	if (s->cx > sx - 1 || (s->cx >= gl->cellsize && COLOUR_DEFAULT(bg)))
 		return;
 
+#ifdef ENABLE_SIXEL
+	if (image_check_line(s, s->cy, 1) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	grid_view_clear(s->grid, s->cx, s->cy, sx - s->cx, 1, bg);
 
  	before = screen_write_collect_trim(ctx, s->cy, s->cx, sx - s->cx, NULL);
@@ -1273,6 +1318,11 @@ screen_write_clearstartofline(struct screen_write_ctx *ctx, u_int bg)
 		return;
 	}
 
+#ifdef ENABLE_SIXEL
+	if (image_check_line(s, s->cy, 1) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	if (s->cx > sx - 1)
 		grid_view_clear(s->grid, 0, s->cy, sx, 1, bg);
 	else
@@ -1320,6 +1370,11 @@ screen_write_reverseindex(struct screen_write_ctx *ctx, u_int bg)
 	struct screen	*s = ctx->s;
 	struct tty_ctx	 ttyctx;
 
+#ifdef ENABLE_SIXEL
+	if (image_free_all(s) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	if (s->cy == s->rupper) {
 		grid_view_scroll_region_down(s->grid, s->rupper, s->rlower, bg);
 		screen_write_collect_flush(ctx, 0, __func__);
@@ -1363,13 +1418,15 @@ screen_write_linefeed(struct screen_write_ctx *ctx, int wrapped, u_int bg)
 	struct screen		*s = ctx->s;
 	struct grid		*gd = s->grid;
 	struct grid_line	*gl;
+	int			 redraw = 0;
+	u_int			 rupper = s->rupper, rlower = s->rlower;
 
 	gl = grid_get_line(gd, gd->hsize + s->cy);
 	if (wrapped)
 		gl->flags |= GRID_LINE_WRAPPED;
 
 	log_debug("%s: at %u,%u (region %u-%u)", __func__, s->cx, s->cy,
-	    s->rupper, s->rlower);
+	    rupper, rlower);
 
 	if (bg != ctx->bg) {
 		screen_write_collect_flush(ctx, 1, __func__);
@@ -1377,6 +1434,14 @@ screen_write_linefeed(struct screen_write_ctx *ctx, int wrapped, u_int bg)
 	}
 
 	if (s->cy == s->rlower) {
+#ifdef ENABLE_SIXEL
+		if (rlower == screen_size_y(s) - 1)
+			redraw = image_scroll_up(s, 1);
+		else
+			redraw = image_check_line(s, rupper, rlower - rupper);
+		if (redraw && ctx->wp != NULL)
+			ctx->wp->flags |= PANE_REDRAW;
+#endif
 		grid_view_scroll_region_up(gd, s->rupper, s->rlower, bg);
 		screen_write_collect_scroll(ctx, bg);
 		ctx->scrolled++;
@@ -1402,6 +1467,11 @@ screen_write_scrollup(struct screen_write_ctx *ctx, u_int lines, u_int bg)
 		ctx->bg = bg;
 	}
 
+#ifdef ENABLE_SIXEL
+	if (image_scroll_up(s, lines) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	for (i = 0; i < lines; i++) {
 		grid_view_scroll_region_up(gd, s->rupper, s->rlower, bg);
 		screen_write_collect_scroll(ctx, bg);
@@ -1426,6 +1496,11 @@ screen_write_scrolldown(struct screen_write_ctx *ctx, u_int lines, u_int bg)
 	else if (lines > s->rlower - s->rupper + 1)
 		lines = s->rlower - s->rupper + 1;
 
+#ifdef ENABLE_SIXEL
+	if (image_free_all(s) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	for (i = 0; i < lines; i++)
 		grid_view_scroll_region_down(gd, s->rupper, s->rlower, bg);
 
@@ -1450,6 +1525,11 @@ screen_write_clearendofscreen(struct screen_write_ctx *ctx, u_int bg)
 	struct tty_ctx	 ttyctx;
 	u_int		 sx = screen_size_x(s), sy = screen_size_y(s);
 
+#ifdef ENABLE_SIXEL
+	if (image_check_line(s, s->cy, sy - s->cy) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	screen_write_initctx(ctx, &ttyctx, 1);
 	ttyctx.bg = bg;
 
@@ -1479,6 +1559,11 @@ screen_write_clearstartofscreen(struct screen_write_ctx *ctx, u_int bg)
 	struct tty_ctx	 ttyctx;
 	u_int		 sx = screen_size_x(s);
 
+#ifdef ENABLE_SIXEL
+	if (image_check_line(s, 0, s->cy - 1) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	screen_write_initctx(ctx, &ttyctx, 1);
 	ttyctx.bg = bg;
 
@@ -1502,6 +1587,11 @@ screen_write_clearscreen(struct screen_write_ctx *ctx, u_int bg)
 	struct tty_ctx	 ttyctx;
 	u_int		 sx = screen_size_x(s), sy = screen_size_y(s);
 
+#ifdef ENABLE_SIXEL
+	if (image_free_all(s) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	screen_write_initctx(ctx, &ttyctx, 1);
 	ttyctx.bg = bg;
 
@@ -1770,6 +1860,11 @@ screen_write_collect_end(struct screen_write_ctx *ctx)
 		}
 	}
 
+#ifdef ENABLE_SIXEL
+	if (image_check_area(s, s->cx, s->cy, ci->used, 1) && ctx->wp != NULL)
+		ctx->wp->flags |= PANE_REDRAW;
+#endif
+
 	grid_view_set_cells(s->grid, s->cx, s->cy, &ci->gc, cl->data + ci->x,
 	    ci->used);
 	screen_write_set_cursor(ctx, s->cx + ci->used, -1);
@@ -2157,6 +2252,61 @@ screen_write_rawstring(struct screen_write_ctx *ctx, u_char *str, u_int len,
 	tty_write(tty_cmd_rawstring, &ttyctx);
 }
 
+#ifdef ENABLE_SIXEL
+/* Write a SIXEL image. */
+void
+screen_write_sixelimage(struct screen_write_ctx *ctx, struct sixel_image *si,
+    u_int bg)
+{
+	struct screen		*s = ctx->s;
+	struct grid		*gd = s->grid;
+	struct tty_ctx		 ttyctx;
+	u_int			 x, y, sx, sy, cx = s->cx, cy = s->cy, i, lines;
+	struct sixel_image	*new;
+
+	sixel_size_in_cells(si, &x, &y);
+	if (x > screen_size_x(s) || y > screen_size_y(s)) {
+		if (x > screen_size_x(s) - cx)
+			sx = screen_size_x(s) - cx;
+		else
+			sx = x;
+		if (y > screen_size_y(s) - 1)
+			sy = screen_size_y(s) - 1;
+		else
+			sy = y;
+		new = sixel_scale(si, 0, 0, 0, y - sy, sx, sy, 1);
+		sixel_free(si);
+		si = new;
+		sixel_size_in_cells(si, &x, &y);
+	}
+
+	sy = screen_size_y(s) - cy;
+	if (sy < y) {
+		lines = y - sy + 1;
+		if (image_scroll_up(s, lines) && ctx->wp != NULL)
+			ctx->wp->flags |= PANE_REDRAW;
+		for (i = 0; i < lines; i++) {
+			grid_view_scroll_region_up(gd, 0, screen_size_y(s) - 1,
+			    bg);
+			screen_write_collect_scroll(ctx, bg);
+		}
+		ctx->scrolled += lines;
+		if (lines > cy)
+			screen_write_cursormove(ctx, -1, 0, 0);
+		else
+			screen_write_cursormove(ctx, -1, cy - lines, 0);
+	}
+	screen_write_collect_flush(ctx, 0, __func__);
+
+	screen_write_initctx(ctx, &ttyctx, 0);
+	ttyctx.ptr = image_store(s, si);
+
+	tty_write(tty_cmd_sixelimage, &ttyctx);
+
+	screen_write_cursormove(ctx, 0, cy + y, 0);
+}
+#endif
+
 /* Turn alternate screen on. */
 void
 screen_write_alternateon(struct screen_write_ctx *ctx, struct grid_cell *gc,