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Tilman Hausherr edited comment on PDFBOX-4184 at 5/11/18 7:50 PM: ------------------------------------------------------------------ I forgot to mention, we're planning a release soon, I prefer to wait until after the release before deciding to commit to 2.0. was (Author: tilman): I forgot to mention, we're planning a release soon, I prefer to wait until after the release. > [PATCH]: Support simple lossless compression of 16 bit RGB images > ----------------------------------------------------------------- > > Key: PDFBOX-4184 > URL: https://issues.apache.org/jira/browse/PDFBOX-4184 > Project: PDFBox > Issue Type: Improvement > Components: Writing > Affects Versions: 2.0.9 > Reporter: Emmeran Seehuber > Priority: Minor > Fix For: 2.0.10, 3.0.0 PDFBox > > Attachments: LoadGovdocs.java, > lossless_predictor_based_imageencoding.patch, > pdfbox_support_16bit_image_write.patch, png16-arrow-bad-no-smask.pdf, > png16-arrow-bad.pdf, png16-arrow-good-no-mask.pdf, png16-arrow-good.pdf > > > The attached patch add support to write 16 bit per component images > correctly. I've integrated a test for this here: > [https://github.com/rototor/pdfbox-graphics2d/commit/8bf089cb74945bd4f0f15054754f51dd5b361fe9] > It only supports 16-Bit TYPE_CUSTOM with DataType == USHORT images - but this > is what you usually get when you read a 16 bit PNG file. > This would also fix [https://github.com/danfickle/openhtmltopdf/issues/173]. > The patch is against 2.0.9, but should apply to 3.0.0 too. > There is still some room for improvements when writing lossless images, as > the images are currently not efficiently encoded. I.e. you could use PNG > encodings to get a better compression. (By adding a COSName.DECODE_PARMS with > a COSName.PREDICTOR == 15 and encoding the images as PNG). But this is > something for a later patch. It would also need another API, as there is a > tradeoff speed vs compression ratio. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@pdfbox.apache.org For additional commands, e-mail: dev-h...@pdfbox.apache.org