run-llama/liteparse · error · std::io::Error

invalid zero-sized RGB image

Error message

invalid zero-sized RGB image: {width}x{height}

What it means

rgb_image in the oar OCR module builds an image::RgbImage from a raw RGB byte buffer plus declared width/height. Before doing so it validates the dimensions: if either width or height is 0 the image is meaningless, so it rejects the call with this InvalidInput error. This guards against empty OCR buffers reaching the image constructor.

Solutions

  1. Check the source image's dimensions before OCR and skip/error early if width or height is 0.
  2. Re-encode or re-decode the image to recover real dimensions; if the file is corrupt, replace it.
  3. Fix the upstream producer (e.g. OCR HTTP server or renderer) that reports zero-sized images.

Example fix

// before: blind OCR call with unverified dimensions
ocr.recognize_sync(&buf, width, height)?;

// after: validate first
if width == 0 || height == 0 {
    return Err(anyhow!("skipping OCR: image has zero extent"));
}
ocr.recognize_sync(&buf, width, height)?;
Defensive patterns

Strategy: validation

Validate before calling

// Rust: reject zero-dimension images before OCR
fn dims_ok(width: u32, height: u32) -> bool {
    width > 0 && height > 0
}

Type guard

fn non_zero_dims(w: u32, h: u32) -> Option<(u32, u32)> {
    (w > 0 && h > 0).then_some((w, h))
}

Prevention

When it happens

Trigger: Calling the OCR recognize path (recognize_sync) with an image buffer whose reported width or height is 0; also exercised by the rejects_non_rgb_buffers test path. Any caller that passes dimensions from a decoded image whose header claims zero extent triggers it.

Common situations: Corrupt or truncated image files whose decoded dimensions come back as 0; OCR server responses that report zero-size image metadata; passing an uninitialized/placeholder buffer to the OCR API.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

AI-assisted analysis of run-llama/liteparse@22d2dd8cd7 (2026-09-08). Data as JSON: /api/errors/a75f3588140491b5. Report an issue: GitHub.

Appendix: source

Thrown at crates/liteparse/src/ocr/oar.rs:260

}

static LANGUAGE_IGNORED_WARNING: Once = Once::new();

/// Warn once per process that this backend ignores `OcrOptions::language`.
fn warn_language_ignored_once(language: &str) {
    if language.is_empty() {
        return;
    }
    LANGUAGE_IGNORED_WARNING.call_once(|| {
        eprintln!(
            "[oar-ocr] ignoring OcrOptions::language ({language:?}); recognition language is fixed by the model and character dictionary"
        );
    });
}

fn rgb_image(image_data: &[u8], width: u32, height: u32) -> Result<image::RgbImage, io::Error> {
    if width == 0 || height == 0 {
        return Err(io::Error::new(
            io::ErrorKind::InvalidInput,
            format!("invalid zero-sized RGB image: {width}x{height}"),
        ));
    }

    let expected_len = (width as usize)
        .checked_mul(height as usize)
        .and_then(|pixels| pixels.checked_mul(3))
        .ok_or_else(|| {
            io::Error::new(
                io::ErrorKind::InvalidInput,
                format!("RGB image dimensions overflow: {width}x{height}"),
            )
        })?;

    if image_data.len() != expected_len {
        return Err(io::Error::new(
            io::ErrorKind::InvalidInput,

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