| Summary: | PDF print output of Cairo has unneeded transparency with badly defined bounding boxes | ||
|---|---|---|---|
| Product: | cairo | Reporter: | Till Kamppeter <till.kamppeter> |
| Component: | pdf backend | Assignee: | Adrian Johnson <ajohnson> |
| Status: | RESOLVED FIXED | QA Contact: | cairo-bugs mailing list <cairo-bugs> |
| Severity: | major | ||
| Priority: | medium | ||
| Version: | 1.10.2 | ||
| Hardware: | All | ||
| OS: | Linux (All) | ||
| Whiteboard: | |||
| i915 platform: | i915 features: | ||
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Description
Till Kamppeter
2012-04-03 10:00:25 UTC
The page sized bounding boxes problem has been fixed in 1.12.0. The use of transparency groups for opaque objects is something that can be improved. Can you give me a patch for 1.10.2 which I could apply to the Ubuntu Precise (12.04) package? There are too many changes. To make printing also working well on mobile and generally low-performance devices it gets very important to completely do away with transparency in PDF output, at least if the document does not actually contain any transparent graphical elements. We should perhaps even make one output mode optimized for printing with no transparency at all. This would allow fast print rendering, especially also on mobile. Ghostscript developers suggest PDF/X-1 output here. Another mode could use transparency only where it is actually needed, for getting small, efficient PDF files for archiving and web download. We should raise priority for this as slow printing is a very common problem under Linux (and mostly caused by the transparency abuse in Cairo output) and Linux gets more and more used on mobile battery-driven devices. More Ubuntu bug reports showing this problem: https://bugs.launchpad.net/bugs/980616 https://bugs.launchpad.net/bugs/1159452 If I understand this correctly, this was fixed with cairo 1.12. At least Adrian claims so and no one claimed anything else. I've pushed out a fix to make transparency groups normal groups when the content is opaque. Adrian, can you post the patch or tell which commit it is, so that I can apply it to the current Poppler in Ubuntu? Apply to Poppler? This is a bug about cairo...? The commit that Adrian meant is: http://cgit.freedesktop.org/cairo/commit/?id=8addb4798c918000eaa6f6dab138e0abb0efa946 And the following two patches fix some problems with it: http://cgit.freedesktop.org/cairo/commit/?id=a6f51fed985f7db37c672bab0b5dab3f89e78282 http://cgit.freedesktop.org/cairo/commit/?id=279d5a2ed1aaa6d5dbfbeab9e4b4ffa6a66aa6f3 No idea if this can be backported sanely to older cairo versions, good luck. I have not tried it but I expect those three patches should apply to 1.12.4 or later as not much has changed since then. I would also recommend applying this patch to improve printing performance: http://cgit.freedesktop.org/cairo/commit/?id=266d6e71566ac8c5e360c0b32fb78e23e6a06168 This patch fixes the embedding of jpeg data in the pdf output. Without it the file size will be a lot larger. > I have not tried it but I expect those three patches should apply to 1.12.4
> or later
That should be 1.12.14 or later.
Thank you very much, the patches apply perfectly on Ubuntu's Cairo package (1.12.16). I have applied them to the Ubuntu package now. |
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