kovidgoyal/kitty · error

Invalid size specification: %s with error: The pixel width i

Error message

Invalid size specification: %s with error: The pixel width is smaller than the number of columns

What it means

After parsing, icat validates that pixel width is at least the column count (each cell must be >= 1 pixel wide). This error means Xpixel < Col in the --use-window-size spec.

Source

Thrown at kittens/icat/main.go:216

		var t uint64
		if t, err = strconv.ParseUint(parts[0], 10, 16); err != nil || t < 1 {
			return 1, fmt.Errorf("Invalid size specification: %s with error: %w", opts.UseWindowSize, err)
		}
		screen_size.Col = uint16(t)
		if t, err = strconv.ParseUint(parts[1], 10, 16); err != nil || t < 1 {
			return 1, fmt.Errorf("Invalid size specification: %s with error: %w", opts.UseWindowSize, err)
		}
		screen_size.Row = uint16(t)
		if t, err = strconv.ParseUint(parts[2], 10, 16); err != nil || t < 1 {
			return 1, fmt.Errorf("Invalid size specification: %s with error: %w", opts.UseWindowSize, err)
		}
		screen_size.Xpixel = uint16(t)
		if t, err = strconv.ParseUint(parts[3], 10, 16); err != nil || t < 1 {
			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 {
		fmt.Printf("%dx%d", screen_size.Xpixel, screen_size.Ypixel)
		return 0, nil
	}
	if opts.Clear {
		cc := &graphics.GraphicsCommand{}
		cc.SetAction(graphics.GRT_action_delete).SetDelete(graphics.GRT_free_visible)
		if err = cc.WriteWithPayloadTo(os.Stdout, nil); err != nil {
			return 1, err
		}
	}
	switch {

View on GitHub (pinned to 6d5d0c4406)

Solutions

1. Make pixel width >= columns (typically ~cell_width * columns)
2. Double-check field order: COLS,ROWS,XPIXEL,YPIXEL
3. If unsure of the cell size, divide pixels by columns to sanity-check >= 1

Example fix

// before
--use-window-size=1920,1080,80,24
// after
--use-window-size=80,24,1920,1080

if xpixel < cols { log.Fatal("pixel width must be >= columns") }

When it happens

Trigger: --use-window-size=80,24,64,1080 — 64 pixels wide for 80 columns is physically impossible.

Common situations: Swapping columns and pixels in the field order; using scaled-down window metrics; script computing cells from a different window than pixels.

Related errors

• Invalid size specification: %s with error: The pixel height
• Invalid size specification: %s
• Invalid size specification: %s with error: %w
• Unknown type_of_input: {type_of_input}
• Unknown keys in multicell_command:

AI-assisted analysis of kovidgoyal/kitty@6d5d0c4406 (2026-08-27). Data as JSON: /api/errors/e56a79b44963d612. Report an issue: GitHub.