Pixel Art Edge Enlarger

How to use Pixel Art Edge Enlarger

Use the Scale2x neighborhood relation to choose each enlarged quadrant from categorical source colors. The rule follows adjacent equal colors only when the opposite neighbors differ; 4× repeats the same relation twice.

1. Choose your own supported small pixel graphic and select the 2× or 4× factor.
2. Run the bounded neighborhood operation and compare the enlarged edges with the original.
3. Inspect changed-quadrant counts and dimensions, then download the separate PNG or reset.

Good to know

• One nonempty static raster up to 4 MiB, with structural preflight before native decoding: checked PNG chunks/CRC, one baseline JPEG frame or simple WebP. SVG, GIF, APNG, progressive JPEG, extended/animated WebP and compressed PNG metadata are refused. Header and decoded dimensions must agree; a JPEG whose native orientation changes its declared width/height is refused.
• Native preparation/export and Worker preparation each have a 10-second deadline; isolated pixel computation has a 2-second deadline. Reset/page exit aborts the local operation. PNG output is capped at 12 MiB. Original metadata is not copied. Native decoding/Canvas can change color-space and partially transparent samples; this is a derived raster, not archival sample preservation.
• Files and pixel buffers stay on this device. No upload, input persistence, remote lookup or user code execution. Browser module Workers, ImageBitmap and Canvas are required.
• At most 2,000,000 output pixels and 4,096 output pixels per side, checked before native source decode. This limits source pixels to 500,000 at 2× or 125,000 at 4×. Working algorithm images are bounded by three million packed/RGBA pixels; no unbounded enlargement.
• Equality compares all four browser-decoded RGBA bytes. Fully-transparent source RGB is normalized to black first; partially transparent samples are copied categorically. Borders reuse the nearest source pixel. New output colors are copied from normalized source samples; no blur, photographic detail recovery, AI synthesis, OCR or metadata/hidden-RGB preservation.