From a3f9952b9ea022bf5673a4bc24a64873789fd40d Mon Sep 17 00:00:00 2001
From: Sylvie <35663410+Rangi42@users.noreply.github.com>
Date: Thu, 8 Aug 2024 13:50:51 -0400
Subject: [PATCH] Advise on how to use `-x` to make `-r` work (#1459)

---
 src/gfx/reverse.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/gfx/reverse.cpp b/src/gfx/reverse.cpp
index df525b05..a622ba4c 100644
--- a/src/gfx/reverse.cpp
+++ b/src/gfx/reverse.cpp
@@ -172,6 +172,15 @@ void reverse() {
 		options.verbosePrint(Options::VERB_INTERM, "Picked reversing width of %zu tiles\n", width);
 	}
 	if (mapSize % width != 0) {
+		if (options.trim == 0 && !tilemap) {
+			fatal(
+			    "Total number of tiles (%zu) cannot be divided by image width (%zu tiles)\n"
+			    "(To proceed anyway with this image width, try passing `-x %zu`)",
+			    mapSize,
+			    width,
+			    width - mapSize % width
+			);
+		}
 		fatal(
 		    "Total number of tiles (%zu) cannot be divided by image width (%zu tiles)",
 		    mapSize,