Canop/broot · error

Zlib encoder error

Error message

Zlib encoder error

What it means

Error produced in the kitty image renderer's compress step when creating the Zlib encoder (ZlibEncoder::new) fails or reports an invalid parameter. The throw site wraps the flate2 encoder construction; failure means the terminal image payload cannot be compressed for transmission, typically due to an invalid compression level or an internal encoder error.

Solutions

1. Verify the flate2/zlib dependency version is intact and compatible
2. Use a valid Compression level constant (e.g. Compression::default()) instead of a custom level
3. If the error persists, disable image preview (kitty graphics protocol) and fall back to another preview mode

When it happens

Trigger: Thrown at src/kitty/image_renderer.rs:249 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Canop/broot@17204794d7 (2026-09-08). Data as JSON: /api/errors/d80babd33d7d5b7c. Report an issue: GitHub.

Appendix: source

Thrown at src/kitty/image_renderer.rs:249

            w.queue(cursor::MoveTo(self.area.left, self.area.top + y))?;
            write!(w, "{}", id_str)?;
            if id_msb_str.is_empty() {
                write!(w, "{}{}", PLACHOLDER, DIACRITICS[y as usize])?;
            } else {
                write!(
                    w,
                    "{}{}{}{}",
                    PLACHOLDER, DIACRITICS[y as usize], DIACRITICS[0], id_msb_str
                )?;
            }
            write!(w, "{}", PLACHOLDER.repeat(self.area.width as usize - 1),)?;
            write!(w, "\u{1b}[39m")?;
        }
        Ok(())
    }
    fn compress(data: &[u8]) -> Result<Vec<u8>, ProgramError> {
        let mut encoder = ZlibEncoder::new(Vec::new(), Compression::default());
        encoder.write_all(data).expect("Zlib encoder error");
        Ok(encoder.finish().expect("Zlib encoder error"))
    }
    /// Render the image by sending multiple kitty escape sequences, each
    /// one with part of the image raw data (encoded as base64)
    fn print_with_chunks(
        &self,
        w: &mut W,
    ) -> Result<(), ProgramError> {
        let esc = get_esc_seq(self.tmux_nest_count);
        let tmux_header = self
            .is_tmux
            .then_some(get_tmux_header(self.tmux_nest_count));
        let tmux_tail = self.is_tmux.then_some(get_tmux_tail(self.tmux_nest_count));
        let display_tag = match self.display {
            KittyGraphicsDisplay::Unicode => "q=2,U=1,",
            _ => "",
        };
        let mut png_buf = Vec::new();

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