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| author | TazyFoundSoup <gardendistrict0x0@outlook.com> | 2026-01-31 13:04:34 +1100 |
|---|---|---|
| committer | TazyFoundSoup <gardendistrict0x0@outlook.com> | 2026-01-31 13:04:34 +1100 |
| commit | 7c56468903540fefc8029f67395665436f5d26b3 (patch) | |
| tree | f288373e87429ea0a91ded82de20f2d10663ef8b | |
| parent | 40dbca72e7cfbb01e716d747262c4f28b6cdc638 (diff) | |
fix(png): Implement Paeth predictor in ff_png_data_handler for scanline filtering
| -rw-r--r-- | src/format/image/png.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/src/format/image/png.c b/src/format/image/png.c index 1d4109d..162d5ee 100644 --- a/src/format/image/png.c +++ b/src/format/image/png.c @@ -218,7 +218,19 @@ ff_result ff_png_data_handler(uint8_t *buf, size_t len, ff_png_ctx *ctx) reconstructed_buf[x] = raw[x] + ((left + above) / 2); break; case 4: // Paeth Predictor - // TODO: Get a Paeth predictor function + { + int p = left + above - diagonal; + int pa = abs(p - left); + int pb = abs(p - above); + int pc = abs(p - diagonal); + + if (pa <= pb && pa <= pc) + reconstructed_buf[x] = raw[x] + left; + else if (pb <= pc) + reconstructed_buf[x] = raw[x] + above; + else + reconstructed_buf[x] = raw[x] + diagonal; + } break; default: // Unknown ff_dprintf("png: unsupported scanline filter method '%d'", filter_type); |