Connected Image Flood Fill

How to use Connected Image Flood Fill

Replace the connected color region around an explicit source pixel and download a real PNG with region-bound evidence. Choose a seed coordinate, a fixed-source RGBA tolerance and four- or eight-neighbor connectivity. Only the reachable region is replaced, so separate regions with the same color stay distinct instead of becoming a global color replacement.

1. Provide static source image, seed x coordinate, zero-based, seed y coordinate, zero-based, maximum seed rgba difference per channel, replacement #rrggbbaa.
2. Choose the supported mode and run the tool. Review its assumptions and any reported errors.
3. Copy the result or download a separate output; reset to clear the current form.

Good to know

• One static PNG, baseline JPEG or simple VP8/VP8L WebP: at most 8 MiB, 1,000,000 decoded pixels and 2,048 per side. Existing structure/CRC/dimension preflight precedes decoding; APNG, progressive JPEG, extended/animated WebP, compressed PNG metadata, SVG/GIF and native/header orientation disagreement are refused.
• Coordinates and tolerance use exact plain nonnegative integer digits, with no fractions, exponents or lossy near-integer acceptance. Seed coordinates must lie in the actual decoded image. Enter coordinates explicitly; this page does not infer a clicked position.
• Every candidate compares its original R, G, B and A channels with the fixed original seed. Each difference must be at most tolerance. This does not accumulate neighbor-to-neighbor color drift or use a perceptual color space.
• Four neighbors share an edge; eight also includes diagonals. A bounded visited array and queue find the reachable component. Source membership is independent of replacement color, so filling with the same color still terminates and preserves correct counts.
• Replacement is exactly eight hex digits #RRGGBBAA. The report includes the decoded seed, selected pixel count and source bounds. No semantic background detection, antialiasing, fuzzy edge recovery or desktop-editor parity is claimed.
• The output keeps source dimensions and is a separate PNG. One visited byte, one four-byte queue index and one four-byte result per source pixel bound core memory, in addition to native and transfer buffers.
• Native decode waits at most 10 seconds and PNG encoding at most 5 seconds, but native codec work cannot be forcibly aborted. Late bitmaps are closed and all bitmap/canvas resources are released on success/failure. The PNG is at most 8 MiB; browser color conversion, premultiplication and re-encoding can change source metadata or hidden transparent samples.
• A same-origin pixel module prepares within 10 seconds before ready; a separate 2-second computation deadline applies. The input buffer is copied before transfer so the original source is not detached. Processing is local, with no user code execution, external URL loading, upload or automatic persistence.
• Structured text output is limited to 500,000 characters. Reduce the supplied source when that separate output budget is exceeded.
• Inputs are processed on this device and are not automatically saved or uploaded.