How scoring works

Every judge and compare run produces four things worth reading.

• pixel_match — mean per-channel agreement (0–100) after compositing both images over white.
• ssim — an in-house mean-SSIM index (Wang et al. 2004) over a Gaussian window, implemented in pure Rust to keep the license permissive and the scores deterministic.
• combined — a weighted blend of the two; the single number to optimize.
• regions — the frame is tiled, per-block error is measured, and contiguous high-error blocks are merged into ranked bounding boxes in reference-pixel coordinates.

Interpreting the scores

• High pixel match + low SSIM usually means structural or edge misalignment — check --blend.
• Low pixel match + high SSIM means the shapes are right but the colors are off — re-run colors.