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layout: default
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---
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+If you want the **TL;DR** version, you can skip to the [summary](#summary)
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+and [recommendations](#recommendations).
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+
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+## History
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+
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+According to the git history, [Jakob Truelsen] started this project the day
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+after [Qt 4.4 introduced QtWebKit]. The [initial commit] seems more a demo,
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+but soon grew to have a lot of new features. Although Qt 4.5 enhanced the
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+QtWebKit API, the focus wasn't on the HTML to PDF conversion use case, so
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+the [first Qt patch] got introduced. As an example of how far ahead of the
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+curve this was, the equivalent support was added for [Chrome 64 in 2017]
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+-- more than 8 years later!
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+
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+During the early years, the focus of both Google and Apple was the web
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+platform -- printing (_especially to PDF_) simply wasn't a focus area.
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+So although there were attempts to [upstream the API changes], there
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+wasn't much interest in getting them merged. At the same time, the only
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+other capable tool at that time (_which is still going strong_) was
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+[PrinceXML], but it was commercial and had steep license fees so the
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+popularity of wkhtmltopdf kept on exploding.
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+
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+> Fun fact: [Ariya Hidayat], who did an initial review of the API changes
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+> was then working at Nokia (_which had acquired Qt in 2008_) and would go
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+> on to develop [PhantomJS], which too was based on QtWebKit and enabled
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+> a whole class of other tools to be developed.
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+
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+Even as the upstreaming work stalled, Jakob and other contributors kept
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+developing new features and extending the Qt patches. Once Qt 5.0 was
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+released in 2012, due to a quirk in the way C++ libraries are developed
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+meant that no new APIs could be introduced in the Qt 5.x lifecycle.
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+
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+During the 2012-2014 timeframe, the project was stagnant -- the number
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+of users kept on increasing but the number of developers didn't. This
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+resulted in a lot of issues being created in the tracker. In most
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+open-source projects, some of the users eventually step up and become
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+contributors -- which didn't happen as the project was an intersection
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+between Qt and WebKit (_both written in C++_) while most users were just
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+familiar with HTML, CSS and JS.
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+
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+Meanwhile, interesting things were happening in the wider world. Google
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+decided to [fork WebKit into Blink] in April 2013, and Qt decided to
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+follow with it by announcing [Qt WebEngine] within 6 months. Although
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+their plan was to keep developing both, it didn't work out and QtWebKit
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+was eventually deprecated in 2015 and removed in 2016. It had been on
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+life support for years ever since it was [removed from WebKit] within
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+a month of the Qt WebEngine announcement.
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+
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+Back in wkhtmltopdf-land, a shiny new [0.12.0 release] happened in
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+early 2014. [Ashish Kulkarni] became the maintainer after that and
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+all further releases in the 0.12.x series were made by him (_in case
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+it isn't obvious, he's the author of this long **and** boring essay_ 😁).
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+However, things weren't rosy: the 0.12.0 release was based on Qt 4.8.5
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+but Qt 5.0 had been already released just under 2 years ago -- so there
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+was an urgent need to update the underlying engine.
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+
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+Initially, [QtWebKit 2.3] seemed promising but it turned out to be a
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+red herring: it was supported mostly by Linux distributions and not
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+officially by Qt. Although there were some contributions to both [Qt4]
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+and [Qt5Base]/[Qt5WebKit] in this time period -- it was a small fraction
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+of the patches that needed to be upstreamed. Less than a year later
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+in 2015, QtWebKit would be deprecated and there was effectively
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+**no upstream to contribute to**.
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+
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+History tends to repeat itself, and the same thing happened in 2015-2016:
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+too many users, too few developers and not enough clarity on what was to
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+be done to take things forward. At the same time, there was growing
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+awareness about the sorry [state of WebKit security] (_for those who read
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+it, wkhtmltopdf depends on the WebKit1 in-process API_). It looked like
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+things would improve with a [revamped QtWebKit fork] which would be
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+accepted by most Linux distributions, but that turned out to be a mirage.
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+
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+Regardless, an [initial plan for 0.13] major release was drawn and work
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+started. But work on the [revamped QtWebKit] stalled after 5.212 alpha2
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+in 2017 and so did the motivation to continue on 0.13 😞. Although the
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+revamped QtWebKit has revived again in 2019, received funding via
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+Patreon/GitHub and [annulen] has made great progress, the status shown
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+by GitHub (_as of 2020-06-10_) shows how much it has to catch up:
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+
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+> This branch is 2947 commits ahead, **9266** commits behind WebKit:master.
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+
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+Plus Qt 6.0 is going to ship this November, and there's uncertainity
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+over [the future of Qt] itself. Meanwhile, Chrome has made great
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+strides since 2016 when they started making Printing/PDF a focus --
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+this same fact led to a significant [maintainer stepping down] for
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+PhantomJS. Also, if you see the [puppeteer page.pdf] API, it looks
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+eerily similar to the options used by wkhtmltopdf -- which is a good
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+thing, as it's well supported and has a much more modern browser engine 🎉
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+
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+But this has led to a Blink monoculture -- almost everyone uses the
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+same browser engine, which doesn't feel healthy for someone who lived
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+through the IE 6 days, I personally had to support that monstrosity
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+even as late as 2014 (_in a very conservative banking context_). Even
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+though Google is unlikely to do that, things can change in the future
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+so more competition is always good. _Note that these are the personal
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+views of [Ashish Kulkarni], not of anyone else_.
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+
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+## Summary
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+
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+* Qt 4 (_which wkhtmltopdf uses_) hasn't been supported since 2015, the
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+ WebKit in it hasn't been updated since 2012.
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+* Qt 5 is supported, but removed QtWebkit in 2016 (Qt 5.6), development
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+ stopped after 2012 but minor fixes continued till 2015.
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+* QtWebKit 5.212 by [annulen] uses a version more than 4 years old, but
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+ is packaged by major Linux distributions.
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+* [qtwebkit-dev-wip] uses a version of WebKit almost 1.5 years old, and
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+ isn't ready for release yet -- packaging by distributions comes later!
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+
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+**Where do you contribute to upstream the patches**? It makes sense to only
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+do the effort if it's going to be maintained -- browsers have a fast
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+release candence exactly for this, to address security issues. If you
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+wish to donate money, please [sponsor QtWebKit instead] ... that'll help
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+more projects than just this one and will ensure that there **is** a future.
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+
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+## Future Plans
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+
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+* After the 0.12.6 release, I'll do a final 0.12.7 release by Aug 2020
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+ which fixes any 0.12.6 regressions and review/merge already [submitted
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+ PRs] by a lot of people (_ignored till now due to personal reasons_ 🙈)
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+* Work on [rebaselining the patches] to QtWebKit 5.212 -- although
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+ outdated, it'll be a practice run to see if it's possible at all.
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+* If the above point is successful, submit them to the Qt and QtWebKit
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+ projects and get them merged after review, changing wkhtmltopdf as
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+ required.
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+
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+There is no deadline by when the last two points will happen, or even
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+that they will be done at all -- it all depends on the time available
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+to the maintainer and if volunteers step up to take up some tasks. So,
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+please stop asking about that 🙏
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+
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+## Recommendations
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+
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+* **Do not use wkhtmltopdf with any untrusted HTML** -- be sure to
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+sanitize any user-supplied HTML/JS, otherwise it can lead to
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+complete takeover of the server it is running on!
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+* If you're using it for report generation (i.e. with HTML you control),
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+ also consider using [WeasyPrint] or the [commercial tool Prince] --
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+ note that I'm not affiliated with either project, and do your diligence.
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+* If you're using it to convert a site which uses dynamic JS, consider
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+ using [puppeteer] or one of the many wrappers it has.
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+
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+[Jakob Truelsen]: https://github.com/antialize
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+[Qt 4.4 introduced QtWebKit]: https://doc.qt.io/archives/qtextended4.4/qt4-4-intro.html#qt-webkit-integration
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+[initial commit]: https://github.com/wkhtmltopdf/wkhtmltopdf/commit/1e55e71dab
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+[first Qt patch]: https://github.com/wkhtmltopdf/wkhtmltopdf/commit/881535f0f7
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+[Chrome 64 in 2017]: https://chromium.googlesource.com/chromium/src/+/a2e8edb82a%5E%21/
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+[PrinceXML]: https://www.princexml.com/releases/#p60r8
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+[upstream the API changes]: https://bugs.webkit.org/show_bug.cgi?id=26584
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+[Ariya Hidayat]: https://github.com/ariya
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+[PhantomJS]: https://en.wikipedia.org/wiki/PhantomJS
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+[fork WebKit into Blink]: https://en.wikipedia.org/wiki/Blink_(browser_engine)
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+[Qt WebEngine]: https://www.qt.io/blog/2013/09/12/introducing-the-qt-webengine
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+[removed from WebKit]: https://lists.webkit.org/pipermail/webkit-dev/2013-October/025609.html
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+[0.12.0 release]: https://groups.google.com/forum/m/#!msg/wkhtmltopdf-general/v7nB6wDDIHg/89oigeuZWZoJ
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+[Ashish Kulkarni]: https://github.com/ashkulz
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+[QtWebKit 2.3]: https://blogs.kde.org/2012/11/14/introducing-qtwebkit-23
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+[Qt4]: https://github.com/qt/qt/commits?author=ashkulz
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+[Qt5Base]: https://github.com/qt/qtbase/commits?author=ashkulz
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+[Qt5WebKit]: https://github.com/qt/qtwebkit/commits?author=ashkulz
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+[state of WebKit security]: https://blogs.gnome.org/mcatanzaro/2016/02/01/on-webkit-security-updates/
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+[revamped QtWebKit fork]: https://blogs.gnome.org/mcatanzaro/2017/08/06/endgame-for-webkit-woes/
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+[initial plan for 0.13]: https://github.com/wkhtmltopdf/wkhtmltopdf/tree/0.13#release-plan
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+[revamped QtWebKit]: https://github.com/qtwebkit/qtwebkit/releases
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+[annulen]: https://github.com/annulen
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+[qtwebkit-dev-wip]: https://github.com/qtwebkit/qtwebkit
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+[the future of Qt]: https://lwn.net/Articles/817129/
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+[puppeteer page.pdf]: https://github.com/puppeteer/puppeteer/blob/master/docs/api.md#pagepdfoptions
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+[maintainer stepping down]: https://groups.google.com/forum/m/#!topic/phantomjs/9aI5d-LDuNE
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+[submitted PRs]: https://github.com/wkhtmltopdf/wkhtmltopdf/pulls
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+[rebaselining the patches]: https://github.com/wkhtmltopdf/wkhtmltopdf/issues/3217
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+[sponsor QtWebKit instead]: https://github.com/qtwebkit/qtwebkit
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+[WeasyPrint]: https://weasyprint.org
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+[commercial tool Prince]: https://www.princexml.com
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+[puppeteer]: https://pptr.dev
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Ashish Kulkarni