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Use ZIP (Deflate) instead of LZW for TIFF exports (#238) #453

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Merged
marcinz606 merged 1 commit into from
Jul 12, 2026
Merged

Use ZIP (Deflate) instead of LZW for TIFF exports (#238) #453

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3 changes: 2 additions & 1 deletion negpy/services/rendering/image_processor.py
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Original file line number Diff line number Diff line change
Expand Up @@ -361,7 +361,8 @@ def _encode_export(
img_out,
photometric="rgb" if img_out.ndim == 3 else "minisblack",
iccprofile=icc_bytes,
compression="lzw",
compression="zlib",
predictor=True,
)
return output_buf.getvalue(), "tiff"
elif fmt == ExportFormat.DNG:
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4 changes: 2 additions & 2 deletions negpy/services/scanning/writer.py
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Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,7 @@ def write_tiff_16bit(result: ScanResult, path: str) -> str:
fd, tmp_path = tempfile.mkstemp(suffix=".tif", dir=os.path.dirname(path) or ".")
os.close(fd)
try:
tifffile.imwrite(tmp_path, rgb, photometric="rgb", compression="lzw")
tifffile.imwrite(tmp_path, rgb, photometric="rgb", compression="zlib", predictor=True)
os.replace(tmp_path, path)
except Exception:
if os.path.exists(tmp_path):
Expand All @@ -51,7 +51,7 @@ def write_tiff_16bit(result: ScanResult, path: str) -> str:
fd_ir, tmp_ir = tempfile.mkstemp(suffix=".tif", dir=os.path.dirname(ir_path) or ".")
os.close(fd_ir)
try:
tifffile.imwrite(tmp_ir, ir_data, photometric="minisblack", compression="lzw")
tifffile.imwrite(tmp_ir, ir_data, photometric="minisblack", compression="zlib", predictor=True)
os.replace(tmp_ir, ir_path)
except Exception:
if os.path.exists(tmp_ir):
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2 changes: 1 addition & 1 deletion tests/metadata/test_writer.py
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@ def _make_tiff_bytes() -> bytes:
"""16-bit RGB TIFF in the shape produced by the real export pipeline."""
arr = np.random.randint(0, 65535, (16, 16, 3), dtype=np.uint16)
buf = io.BytesIO()
tifffile.imwrite(buf, arr, photometric="rgb", compression="lzw")
tifffile.imwrite(buf, arr, photometric="rgb", compression="zlib", predictor=True)
return buf.getvalue()


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3 changes: 2 additions & 1 deletion tests/test_export_service.py
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Expand Up @@ -65,7 +65,8 @@ def test_image_service_tiff_export_format() -> None:
img_16,
photometric="rgb",
iccprofile=b"fake_icc_bytes",
compression="lzw",
compression="zlib",
predictor=True,
)
res = out_buf.getvalue()
assert len(res) > 0
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