Implement JPEG2000 compression

This commit is contained in:
RunasSudo 2025-05-08 22:05:46 +10:00
parent 730cf23ba7
commit cf4afa44a3
Signed by: RunasSudo
GPG Key ID: 7234E476BF21C61A
4 changed files with 40 additions and 12 deletions

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@ -14,7 +14,7 @@
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
from .compression import compress_pages
from .compression import CompressionOptions, compress_pages
from .input.xcf import xcf_get_pages
from .output.pdf import pdf_write_pages
from .segmentation import segment_pages
@ -31,7 +31,7 @@ def convert_file(
output_format: Optional[str] = None,
fg_compression: str = 'jbig2',
bg_compression: str = 'jpeg',
jpeg_quality: Optional[float] = None
options: CompressionOptions = CompressionOptions()
) -> None:
# Create temporary directory
tempdir = tempfile.mkdtemp('pdf-segmented')
@ -63,7 +63,7 @@ def convert_file(
segmented_pages=segmented_pages,
fg_compression=fg_compression,
bg_compression=bg_compression,
jpeg_quality=jpeg_quality,
options=options,
tempdir=tempdir
)

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@ -15,6 +15,7 @@
# along with this program. If not, see <https://www.gnu.org/licenses/>.
from . import convert_file
from .compression import CompressionOptions
import argparse
@ -28,7 +29,9 @@ parser.add_argument('output_file')
parser.add_argument('--input-format', choices=['xcf'])
parser.add_argument('--output-format', choices=['pdf'])
parser.add_argument('--fg-compression', default='jbig2', choices=['jbig2'])
parser.add_argument('--bg-compression', default='jpeg', choices=['jpeg'])
parser.add_argument('--bg-compression', default='jpeg', choices=['jpeg', 'jp2'])
parser.add_argument('--jp2-lossless', action='store_true')
parser.add_argument('--jp2-rate', type=float)
parser.add_argument('--jpeg-quality', type=float)
args = parser.parse_args()
@ -41,5 +44,9 @@ convert_file(
output_format=args.output_format,
fg_compression=args.fg_compression,
bg_compression=args.bg_compression,
jpeg_quality=args.jpeg_quality
options=CompressionOptions(
jp2_lossless=args.jp2_lossless,
jp2_rate=args.jp2_rate,
jpeg_quality=args.jpeg_quality
)
)

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@ -22,6 +22,7 @@ class CompressedLayer:
pass
from .jbig2 import jbig2_compress_layer
from .jp2 import jp2_compress_layer
from .jpeg import jpeg_compress_layer
from ..segmentation import SegmentedPage
@ -30,6 +31,12 @@ from PIL import Image
from dataclasses import dataclass
from typing import Generator, Iterable, Optional
@dataclass
class CompressionOptions:
jp2_lossless: bool = False
jp2_rate: Optional[float] = None
jpeg_quality: Optional[float] = None
@dataclass
class CompressedPage:
fg: CompressedLayer
@ -39,7 +46,7 @@ def compress_pages(
segmented_pages: Iterable[SegmentedPage],
fg_compression: str,
bg_compression: str,
jpeg_quality: Optional[float],
options: CompressionOptions,
tempdir: str
) -> Generator[CompressedPage]:
@ -49,7 +56,7 @@ def compress_pages(
segmented_page=segmented_page,
fg_compression=fg_compression,
bg_compression=bg_compression,
jpeg_quality=jpeg_quality,
options=options,
tempdir=tempdir
)
@ -57,7 +64,7 @@ def compress_page(
segmented_page: SegmentedPage,
fg_compression: str,
bg_compression: str,
jpeg_quality: Optional[float],
options: CompressionOptions,
tempdir: str
) -> CompressedPage:
@ -66,13 +73,13 @@ def compress_page(
fg=compress_layer(
layer=segmented_page.fg,
compression=fg_compression,
jpeg_quality=jpeg_quality,
options=options,
tempdir=tempdir
),
bg=compress_layer(
layer=segmented_page.bg,
compression=bg_compression,
jpeg_quality=jpeg_quality,
options=options,
tempdir=tempdir
)
)
@ -80,14 +87,16 @@ def compress_page(
def compress_layer(
layer: Image,
compression: str,
jpeg_quality: Optional[float],
options: CompressionOptions,
tempdir: str
) -> CompressedLayer:
# Compress the given layer
if compression == 'jbig2':
return jbig2_compress_layer(layer=layer, tempdir=tempdir)
elif compression == 'jp2':
return jp2_compress_layer(layer=layer, jp2_lossless=options.jp2_lossless, jp2_rate=options.jp2_rate)
elif compression == 'jpeg':
return jpeg_compress_layer(layer=layer, jpeg_quality=jpeg_quality)
return jpeg_compress_layer(layer=layer, jpeg_quality=options.jpeg_quality)
else:
raise NotImplementedError()

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@ -16,6 +16,7 @@
from ..compression import CompressedLayer, CompressedPage
from ..compression.jbig2 import JBIG2Layer
from ..compression.jp2 import JP2Layer
from ..compression.jpeg import JPEGLayer
from ..input import InputPages
@ -78,6 +79,17 @@ def pdf_write_layer(
BitsPerComponent=1,
Mask=[1, 1] # Layer mask
)
elif isinstance(layer, JP2Layer):
pdf_write_image(
input_pages=input_pages,
pdf=pdf,
page=page,
value=layer.data,
content_instructions=content_instructions,
ColorSpace=Name.DeviceRGB,
Filter=Name.JPXDecode,
BitsPerComponent=8
)
elif isinstance(layer, JPEGLayer):
pdf_write_image(
input_pages=input_pages,