Check pixels and paper seams before handing over visual outputs

Begin with the receiving workflow

A game renderer reads sprite rectangles, a designer composites transparent pixels, and a printer places PDF content on physical paper. Their acceptance questions differ even when each result is an image on screen. Keep the report beside the downloadable material and choose a check that the recipient can repeat.

Coordinates matter beside the atlas image

The overall atlas may look correct while one rectangle is offset by a gutter or extrusion width. Metadata should identify the sprite’s own pixels, and spacing should stay outside that rectangle. Compare a small sprite at actual pixels and make the receiving renderer use the recorded coordinates rather than estimating them from a screenshot.

Transparent PNG pixels can contain hidden RGB values. Exact raw PNG handling preserves those values where the supported format allows it. A general canvas conversion can have different premultiplication behaviour, so the tool states which decoder was used instead of treating every image path as byte equivalent.

An enclosed region changes a mask decision

Imagine a black frame around a white centre on a white background. Removing all matching white pixels also clears the centre. A border-connected mask keeps it when no matching path connects it to an image edge. Choose the mode by the desired object, then check the downloaded result against the decoded original.

Tolerance measures the maximum RGB channel difference from the chosen color. It does not infer an object, repair anti-aliasing or guarantee a clean mask against a textured background. Review the transition pixels at the size where the image will be used.

Paper size is part of the output

Poster assembly depends on both source geometry and printable paper dimensions. A page CropBox or rotation can alter the visible source area, while margins reduce the area available on each sheet. The assembly drawing describes where sheets belong; the real output PDF preview shows the content actually printed.

Fit-to-page can resize an otherwise correct tiled PDF. Print one sheet at actual size, measure a known feature and inspect an overlap before committing to the full poster. Keep enough overlap for alignment and account for hardware margins in the layout controls.

Give the recipient a repeatable check

• Supply coordinate or assembly JSON with the final file.
• Identify the intended mask mode and decoded-original comparison.
• Record the physical paper dimensions and print scale.
• Keep source files for a revised gutter, tolerance or margin.
• Verify the result in the renderer, compositor or PDF reader that will consume it.

Tools used in this article