From a3d8be5e2f82fa36e128171a914cd25054b40c9f Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 5 Mar 2024 10:49:47 +0530
Subject: [PATCH] icat: Nicer error when user specifies invalid screen geometry

---
 kittens/icat/main.go     | 6 ++++++
 kittens/icat/transmit.go | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/kittens/icat/main.go b/kittens/icat/main.go
index 265281c9d..85ead219b 100644
--- a/kittens/icat/main.go
+++ b/kittens/icat/main.go
@@ -182,6 +182,12 @@ func main(cmd *cli.Command, o *Options, args []string) (rc int, err error) {
 			return 1, fmt.Errorf("Invalid size specification: %s with error: %w", opts.UseWindowSize, err)
 		}
 		screen_size.Ypixel = uint16(t)
+		if screen_size.Xpixel < screen_size.Col {
+			return 1, fmt.Errorf("Invalid size specification: %s with error: The pixel width is smaller than the number of columns", opts.UseWindowSize)
+		}
+		if screen_size.Ypixel < screen_size.Row {
+			return 1, fmt.Errorf("Invalid size specification: %s with error: The pixel height is smaller than the number of rows", opts.UseWindowSize)
+		}
 	}
 
 	if opts.PrintWindowSize {
diff --git a/kittens/icat/transmit.go b/kittens/icat/transmit.go
index 7c2fde022..c847458d0 100644
--- a/kittens/icat/transmit.go
+++ b/kittens/icat/transmit.go
@@ -210,8 +210,8 @@ func calculate_in_cell_x_offset(width, cell_width int) int {
 }
 
 func place_cursor(imgd *image_data) {
-	cw := int(screen_size.Xpixel) / int(screen_size.Col)
-	ch := int(screen_size.Ypixel) / int(screen_size.Row)
+	cw := max(int(screen_size.Xpixel)/int(screen_size.Col), 1)
+	ch := max(int(screen_size.Ypixel)/int(screen_size.Row), 1)
 	imgd.cell_x_offset = calculate_in_cell_x_offset(imgd.canvas_width, cw)
 	imgd.width_cells = int(math.Ceil(float64(imgd.canvas_width) / float64(cw)))
 	imgd.height_cells = int(math.Ceil(float64(imgd.canvas_height) / float64(ch)))