Support Kitty source rectangle placements

2026-08-04 06:28:35 +00:00 · 2026-08-03 12:31:11 +01:00
parent a4b8d1c822
commit cfab0590a4
4 changed files with 227 additions and 46 deletions
--- a/image-kitty.c
+++ b/image-kitty.c
@@ -75,6 +75,10 @@ struct kitty_state {
 	char	 compression;
 	u_int	 width;
 	u_int	 height;
+	u_int	 source_x;
+	u_int	 source_y;
+	u_int	 source_width;
+	u_int	 source_height;
 	u_int	 columns;
 	u_int	 rows;
 	u_int	 image_id;
@@ -232,7 +236,8 @@ kitty_upload(struct tty *tty, struct image *im)
 	struct kitty_output	*ko = kitty_get_output(tty);
 	struct kitty_image_cache	*cache;
 	char			 control[128], encoded[4097];
-	size_t			 offset, size;
+	u_char			 raw[3072];
+	size_t			 offset, size, copied, row, column, available;
 	int			 encodedlen;
 	u_int			 id;

@@ -261,9 +266,18 @@ kitty_upload(struct tty *tty, struct image *im)

 	for (offset = 0; offset < im->size; offset += size) {
 		size = im->size - offset;
-		if (size > 3072)
-			size = 3072;
-		encodedlen = b64_ntop(im->pixels + offset, size, encoded,
+		if (size > sizeof raw)
+			size = sizeof raw;
+		for (copied = 0; copied < size; copied += available) {
+			row = (offset + copied) / ((size_t)im->width * 4);
+			column = (offset + copied) % ((size_t)im->width * 4);
+			available = (size_t)im->width * 4 - column;
+			if (available > size - copied)
+				available = size - copied;
+			memcpy(raw + copied, im->pixels + row * im->stride +
+			    column, available);
+		}
+		encodedlen = b64_ntop(raw, size, encoded,
 		    sizeof encoded);
 		if (encodedlen < 0)
 			return (NULL);
@@ -418,6 +432,10 @@ kitty_control(struct kitty_state *ks, const u_char *buf, size_t len)
 		case 'f':
 		case 's':
 		case 'v':
+		case 'x':
+		case 'y':
+		case 'w':
+		case 'h':
 		case 'c':
 		case 'r':
 		case 'i':
@@ -431,6 +449,10 @@ kitty_control(struct kitty_state *ks, const u_char *buf, size_t len)
 			case 'f': ks->format = number; break;
 			case 's': ks->width = number; break;
 			case 'v': ks->height = number; break;
+			case 'x': ks->source_x = number; break;
+			case 'y': ks->source_y = number; break;
+			case 'w': ks->source_width = number; break;
+			case 'h': ks->source_height = number; break;
 			case 'c': ks->columns = number; break;
 			case 'r': ks->rows = number; break;
 			case 'i': ks->image_id = number; break;
@@ -594,9 +616,87 @@ kitty_raw(struct kitty_state *ks, u_char *data, size_t size)
 	return (pixels);
 }

+static struct image *
+kitty_place_image(struct image *source, struct kitty_state *ks, u_int xpixel,
+    u_int ypixel)
+{
+	uint64_t	 numerator, denominator, value;
+	u_int		 x, y, width, height, sx, sy, canvas_width;
+	u_int		 canvas_height, cell_width, cell_height;
+
+	x = ks->source_x;
+	y = ks->source_y;
+	if (x >= source->width || y >= source->height)
+		return (NULL);
+	width = ks->source_width;
+	if (width == 0 || width > source->width - x)
+		width = source->width - x;
+	height = ks->source_height;
+	if (height == 0 || height > source->height - y)
+		height = source->height - y;
+
+	cell_width = (xpixel == 0 ? 8 : xpixel);
+	cell_height = (ypixel == 0 ? 16 : ypixel);
+	if (ks->columns == 0 && ks->rows == 0) {
+		image_size_in_cells(width, height, cell_width, cell_height,
+		    &sx, &sy);
+		value = (uint64_t)sx * cell_width;
+		if (value > UINT_MAX)
+			return (NULL);
+		canvas_width = value;
+		value = (uint64_t)sy * cell_height;
+		if (value > UINT_MAX)
+			return (NULL);
+		canvas_height = value;
+	} else if (ks->columns != 0 && ks->rows != 0) {
+		sx = ks->columns;
+		sy = ks->rows;
+		canvas_width = width;
+		canvas_height = height;
+	} else if (ks->columns != 0) {
+		sx = ks->columns;
+		numerator = (uint64_t)height * sx * cell_width;
+		denominator = (uint64_t)width * cell_height;
+		value = (numerator + denominator - 1) / denominator;
+		if (value == 0 || value > UINT_MAX)
+			return (NULL);
+		sy = value;
+		canvas_width = width;
+		numerator = (uint64_t)sy * cell_height * width;
+		denominator = (uint64_t)sx * cell_width;
+		value = (numerator + denominator - 1) / denominator;
+		if (value < height)
+			value = height;
+		if (value > UINT_MAX)
+			return (NULL);
+		canvas_height = value;
+	} else {
+		sy = ks->rows;
+		numerator = (uint64_t)width * sy * cell_height;
+		denominator = (uint64_t)height * cell_width;
+		value = (numerator + denominator - 1) / denominator;
+		if (value == 0 || value > UINT_MAX)
+			return (NULL);
+		sx = value;
+		canvas_height = height;
+		numerator = (uint64_t)sx * cell_width * height;
+		denominator = (uint64_t)sy * cell_height;
+		value = (numerator + denominator - 1) / denominator;
+		if (value < width)
+			value = width;
+		if (value > UINT_MAX)
+			return (NULL);
+		canvas_width = value;
+	}
+
+	return (image_create_view(source, x, y, width, height, canvas_width,
+	    canvas_height, sx, sy));
+}
+
 /*
 * Parse one Kitty graphics APC body (without the leading G). Only direct
- * static images are accepted. The returned image owns decoded RGBA pixels.
+ * static images are accepted. The returned image retains immutable RGBA
+ * pixels for the lifetime of its placement.
 */
 struct image *
 kitty_parse_image(void **state, const u_char *buf, size_t len, u_int xpixel,
@@ -609,8 +709,9 @@ kitty_parse_image(void **state, const u_char *buf, size_t len, u_int xpixel,
 	u_char			*uncompressed;
 	size_t			 controllen, payloadlen, decodedlen;
 	uLongf			 uncompressedlen;
-	u_int			 sx, sy;
-	struct image		*im;
+	u_int			 sx, sy, cell_width, cell_height;
+	uint64_t		 canvas_width, canvas_height;
+	struct image		*im = NULL, *source;

 	if (kc == NULL) {
 		kc = xcalloc(1, sizeof *kc);
@@ -650,9 +751,16 @@ kitty_parse_image(void **state, const u_char *buf, size_t len, u_int xpixel,
 	}
 	kc->transfer = NULL;
 	if (ks->action == 'p') {
-		im = kitty_source_get(kc, ks->image_id);
-		*status = (im == NULL ? KITTY_PARSE_MISSING :
-		    KITTY_PARSE_OK);
+		source = kitty_source_get(kc, ks->image_id);
+		if (source == NULL) {
+			*status = KITTY_PARSE_MISSING;
+			im = NULL;
+		} else {
+			im = kitty_place_image(source, ks, xpixel, ypixel);
+			image_free(source->id);
+			if (im != NULL)
+				*status = KITTY_PARSE_OK;
+		}
 		kitty_state_free(ks);
 		return (im);
 	}
@@ -717,21 +825,30 @@ kitty_parse_image(void **state, const u_char *buf, size_t len, u_int xpixel,
 	if (pixels == NULL)
 		goto fail;

-	image_size_in_cells(ks->width, ks->height, xpixel, ypixel, &sx, &sy);
-	if (ks->columns != 0)
-		sx = ks->columns;
-	if (ks->rows != 0)
-		sy = ks->rows;
-	im = image_create(ks->width, ks->height, sx, sy, pixels);
-	if (im == NULL)
-		free(pixels);
+	cell_width = (xpixel == 0 ? 8 : xpixel);
+	cell_height = (ypixel == 0 ? 16 : ypixel);
+	image_size_in_cells(ks->width, ks->height, cell_width, cell_height,
+	    &sx, &sy);
+	canvas_width = (uint64_t)sx * cell_width;
+	canvas_height = (uint64_t)sy * cell_height;
+	if (canvas_width > UINT_MAX || canvas_height > UINT_MAX)
+		source = NULL;
 	else
+		source = image_create(ks->width, ks->height, canvas_width,
+		    canvas_height, sx, sy, pixels);
+	if (source == NULL)
+		free(pixels);
+	else {
 		*status = KITTY_PARSE_OK;
-	if (im != NULL && ks->action != 'q')
-		kitty_source_set(kc, ks->image_id, im);
-	if (im != NULL && (ks->action == 'q' || ks->action == 't')) {
-		image_free(im->id);
-		im = NULL;
+		if (ks->action != 'q')
+			kitty_source_set(kc, ks->image_id, source);
+		if (ks->action == 'T') {
+			im = kitty_place_image(source, ks, xpixel, ypixel);
+			if (im == NULL)
+				*status = KITTY_PARSE_ERROR;
+		} else
+			im = NULL;
+		image_free(source->id);
 	}
 	kitty_state_free(ks);
 	return (im);
--- a/image.c
+++ b/image.c
@@ -209,6 +209,38 @@ image_find(u_int id)
 	return (RB_FIND(images, &images, &find));
 }

+static struct image *
+image_create1(u_int width, u_int height, u_int canvas_width,
+    u_int canvas_height, u_int sx, u_int sy, size_t stride, u_char *pixels)
+{
+	struct image	*im;
+
+	im = xcalloc(1, sizeof *im);
+	do {
+		if (++image_next_id == 0)
+			image_next_id++;
+		im->id = image_next_id;
+	} while (image_find(im->id) != NULL);
+
+	im->references = 1;
+	im->source_id = im->id;
+	im->width = width;
+	im->height = height;
+	im->canvas_width = canvas_width;
+	im->canvas_height = canvas_height;
+	im->sx = sx;
+	im->sy = sy;
+	im->stride = stride;
+	im->size = (size_t)width * height * 4;
+	im->pixels = pixels;
+
+	RB_INSERT(images, &images, im);
+	log_debug("%s: image %u is %ux%u pixels on %ux%u canvas, "
+	    "%ux%u cells", __func__, im->id, width, height, canvas_width,
+	    canvas_height, sx, sy);
+	return (im);
+}
+
 struct image *
 image_create(u_int width, u_int height, u_int canvas_width,
    u_int canvas_height, u_int sx, u_int sy, u_char *pixels)
@@ -222,29 +254,32 @@ image_create(u_int width, u_int height, u_int canvas_width,
 		return (NULL);
 	if ((uint64_t)sx * sy > SIZE_MAX / sizeof *im->cells)
 		return (NULL);
+	im = image_create1(width, height, canvas_width, canvas_height, sx, sy,
+	    (size_t)width * 4, pixels);
+	return (im);
+}

-	im = xcalloc(1, sizeof *im);
-	do {
-		if (++image_next_id == 0)
-			image_next_id++;
-		im->id = image_next_id;
-	} while (image_find(im->id) != NULL);
+/* Create an immutable rectangular view without copying its source pixels. */
+struct image *
+image_create_view(struct image *source, u_int x, u_int y, u_int width,
+    u_int height, u_int canvas_width, u_int canvas_height, u_int sx, u_int sy)
+{
+	struct image	*im;

-	im->references = 1;
-	im->width = width;
-	im->height = height;
-	im->canvas_width = canvas_width;
-	im->canvas_height = canvas_height;
-	im->sx = sx;
-	im->sy = sy;
-	im->stride = (size_t)width * 4;
-	im->size = im->stride * height;
-	im->pixels = pixels;
+	if (source == NULL || x >= source->width || y >= source->height ||
+	    width == 0 || width > source->width - x || height == 0 ||
+	    height > source->height - y || canvas_width < width ||
+	    canvas_height < height || sx == 0 || sy == 0)
+		return (NULL);
+	if ((uint64_t)sx * sy > SIZE_MAX / sizeof *im->cells)
+		return (NULL);

-	RB_INSERT(images, &images, im);
-	log_debug("%s: image %u is %ux%u pixels on %ux%u canvas, "
-	    "%ux%u cells", __func__, im->id, width, height, canvas_width,
-	    canvas_height, sx, sy);
+	im = image_create1(width, height, canvas_width, canvas_height, sx, sy,
+	    source->stride, source->pixels + (size_t)y * source->stride +
+	    (size_t)x * 4);
+	im->parent_id = source->id;
+	im->source_id = source->source_id;
+	image_ref(source->id);
 	return (im);
 }

@@ -272,7 +307,10 @@ image_free(u_int id)

 	log_debug("%s: freeing image %u", __func__, id);
 	RB_REMOVE(images, &images, im);
-	free(im->pixels);
+	if (im->parent_id == 0)
+		free(im->pixels);
+	else
+		image_free(im->parent_id);
 	free(im->cells);
 	free(im);
 }
@@ -413,13 +451,17 @@ image_clear(struct screen_write_ctx *ctx, u_int id)
 	struct screen		*s = ctx->s;
 	struct grid		*gd = s->grid;
 	struct grid_cell	 gc;
+	struct image		*im;
 	u_int			 x, y;

 	for (y = 0; y < gd->hsize + gd->sy; y++) {
 		for (x = 0; x < gd->sx; x++) {
 			grid_get_cell(gd, x, y, &gc);
-			if ((gc.flags & GRID_FLAG_IMAGE) &&
-			    (id == 0 || gc.image_id == id)) {
+			im = NULL;
+			if (gc.flags & GRID_FLAG_IMAGE)
+				im = image_find(gc.image_id);
+			if (im != NULL && (id == 0 || gc.image_id == id ||
+			    im->source_id == id)) {
 				if (y >= gd->hsize)
 					image_damage_area(ctx, x, y - gd->hsize,
 					    1, 1);
--- a/regress/image-support.sh
+++ b/regress/image-support.sh
@@ -96,4 +96,22 @@ sleep 1
 $TMUX capture-pane -pS0 -E0 >$TMP || exit 1
 grep -q '^#=' $TMP || exit 1

+# A retained Kitty image may be placed repeatedly using source rectangles.
+# Crop the green and white right column from a red/green/blue/white image.
+$TMUX kill-server 2>/dev/null
+$TMUX2 kill-server 2>/dev/null
+$TMUX2 new-session -d -x 10 -y 4 "
+	printf '\033_Ga=t,q=2,f=32,s=2,v=2,i=10;/wAA/wD/AP8AAP///////w==\033\\'
+	printf '\033_Ga=p,q=2,i=10,x=1,y=0,w=1,h=2,c=1,r=2\033\\'
+	sleep 10" || exit 1
+$TMUX2 set -g status off || exit 1
+$TMUX new-session -d -x 10 -y 4 || exit 1
+$TMUX set -g status off || exit 1
+$TMUX send-keys -l "$TMUX2 attach-session" || exit 1
+$TMUX send-keys Enter || exit 1
+sleep 1
+$TMUX capture-pane -pS0 -E1 >$TMP || exit 1
+[ "$(sed -n 1p $TMP)" = "*" ] || exit 1
+[ "$(sed -n 2p $TMP)" = "@" ] || exit 1
+
 exit 0
--- a/tmux.h
+++ b/tmux.h
@@ -1059,6 +1059,8 @@ struct image_cell {
 struct image {
 	u_int			 id;
 	u_int			 references;
+	u_int			 parent_id;
+	u_int			 source_id;
 	u_int			 width;
 	u_int			 height;
 	u_int			 canvas_width;
@@ -4259,6 +4261,8 @@ char		*regsub(const char *, const char *, const char *, int);
 /* image.c */
 struct image	*image_create(u_int, u_int, u_int, u_int, u_int, u_int,
 		     u_char *);
+struct image	*image_create_view(struct image *, u_int, u_int, u_int,
+		     u_int, u_int, u_int, u_int, u_int);
 struct image	*image_find(u_int);
 void		 image_ref(u_int);
 void		 image_free(u_int);