From ad98233066b72547aee7fa0c87838847ee7f1ece Mon Sep 17 00:00:00 2001
From: topcat001 <anindya49@hotmail.com>
Date: Tue, 15 Aug 2023 13:57:08 -0700
Subject: [PATCH] Better text placeholder.

---
 image.c | 37 +++++++++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/image.c b/image.c
index 7135c6a3..20ef104a 100644
--- a/image.c
+++ b/image.c
@@ -19,6 +19,7 @@
 #include <sys/types.h>
 
 #include <stdlib.h>
+#include <string.h>
 
 #include "tmux.h"
 
@@ -50,6 +51,36 @@ image_free_all(struct screen *s)
 	return (redraw);
 }
 
+/* Create text placeholder for an image. */
+static void
+image_fallback(char **ret, u_int sx, u_int sy)
+{
+	char	*buf, *label;
+	u_int	 py, size, lsize;
+
+	/* Placeholder label. */
+	lsize = xasprintf(&label, "Sixel image (%ux%u)\n", sx, sy);
+	size = (sx + 2) * sy + 1;
+	if (lsize > size)
+		size = lsize;
+
+	/* Each placeholder line has \r\n at the end. */
+	*ret = buf = xmalloc(size);
+	for (py = 0; py < sy; py++) {
+		memset(buf, '+', sx);
+		buf += sx;
+		snprintf(buf, 3, "\r\n");
+		buf += 2;
+	}
+
+	/* Print the label.*/
+	if (size == lsize)
+		memcpy(*ret, label, lsize);
+	else
+		memcpy(*ret, label, lsize - 1);
+	free(label);
+}
+
 struct image*
 image_store(struct screen *s, struct sixel_image *si)
 {
@@ -63,8 +94,7 @@ image_store(struct screen *s, struct sixel_image *si)
 	im->py = s->cy;
 	sixel_size_in_cells(si, &im->sx, &im->sy);
 
-	/* XXX Fallback mode: This can be abstracted further. */
-	xasprintf(&im->fallback, "Sixel image (%ux%u)\n", im->sx, im->sy);
+	image_fallback(&im->fallback, im->sx, im->sy);
 
 	TAILQ_INSERT_TAIL(&s->images, im, entry);
 
@@ -135,6 +165,9 @@ image_scroll_up(struct screen *s, u_int lines)
 
 		im->py = 0;
 		sixel_size_in_cells(im->data, &im->sx, &im->sy);
+
+		free(im->fallback);
+		image_fallback(&im->fallback, im->sx, im->sy);
 		redraw = 1;
 	}
 	return (redraw);