[webkit-qt] progressive rendering in a QML browser

[Olivier Tilloy]

On 2013-04-11, Andras Becsi <abecsi at webkit.org> wrote:
> Hi Oliver,
>
>
> On 11 April 2013 12:11, Olivier Tilloy <olivier at tilloy.net
> <mailto:olivier at tilloy.net>> wrote:
>
>     Olivier Tilloy a écrit :
>
>         Olivier Tilloy a écrit :
>
>             […]
>
>
>                 Just quickly ran a test with MiniBrowser on my desktop
>                 and for me with a
>                 clean cache even heavy pages like nytimes.com
>                 <http://nytimes.com> <http://nytimes.com> start
>                 to render when the progress bar is at about 50%
>                 completion. Although
>                 this probably varies depending on network and HW speed.
>
>                 This is comparably similar behaviour as you would
>                 experience with Safari
>                 on Mac.
>
>
>             Thanks for the heads-up! So this means my build of QtWebKit
>             somehow is
>             to blame.
>             I’m using libqt5webkit5-qmlwebkitplugin
>             5.0.0-0ubuntu1~quantal1~test5~__withdebug~gstabs~patches (from
>             https://launchpad.net/~__canonical-qt5-edgers/+archive/__qt5-proper
>             <https://launchpad.net/~canonical-qt5-edgers/+archive/qt5-proper>)
>             in
>             Ubuntu 12.10, which according to the source package is based
>             off trunk
>             subversion revision 136242.
>
>
>         A heads-up on my ongoing investigation of the issue: packages
>         built from
>         trunk (tested on 2013-03-28) work well, i.e. pages start
>         rendering while
>         still loading, whereas packages built from the latest release branch
>         (git://gitorious.org/qt/__qtwebkit.git
>         <http://gitorious.org/qt/qtwebkit.git>, being prepared for
>         5.1.0) still
>         exhibit the issue, i.e. pages are not rendered until fully loaded.
>
>         So the problem persists in 5.0.1 and above, but has somehow been
>         fixed
>         in trunk. If I read the history of the release branch correctly, the
>         latest import from trunk was revision
>         6a4a1d32e1d779548c726c4826cba9__d69eb87601 (svn 136242), on
>         2012-11-30.
>         Which makes me think that the issue (regression?) was fixed sometime
>         between 2012-11-30 and 2013-03-28 in trunk (roughly 10000 commits).
>
>
>     It took a lot of bisecting, building and testing, but I finally
>     nailed down the commit that fixed this regression:
>     http://trac.webkit.org/__changeset/136302
>     <http://trac.webkit.org/changeset/136302>.
>
>     This commit applies cleanly on top of the current qtwebkit release
>     branch, and fixes progressive rendering (i.e. pages start to display
>     before fully loaded).
>
>
> Thank you for doing the bisecting. I was about to look into it, but got
> sidetracked.
>
>
>         Any hint where I should be looking for what possibly fixed the
>         issue?
>
>         Do others observe the same issue with 5.0.1?
>
>
>     I’m kind of puzzled that no-one else has observed that, looks like
>     an important regression to me.
>
>     Any chance commit 136302 can be backported to the release branch for
>     5.1.0 ? What would be the process for this?
>
> I just checked and could reproduce the issue with the stable branch of
> the qtwebkit module. I'm going to cherry-pick the change the stable
> branch so that it is included in 5.1.

Awesome, thanks Andras!