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Font rendering bug on some Android devices!?

  • Hi, I have some weird font rendering bug with Qt 5.2.1 on Android, until now only one user reported that bug but I cannot reproduce it on any of my Android devices. It looks like this (he send me a "screenshot":http://i.imgur.com/wqGijgi.png):
    !http://i.imgur.com/wqGijgi.png(font bug)!

    how it should look like (on my devices): http://i.imgur.com/20zOYJP.png

    As you can see some Text elements are missing letters or the text is cut off in the middle of a letter, on other text elements it works just fine, so not all element have rendering issues, very weird.

    The bug was reported from an Sony Xperia T (LT30p) device, but I have some other users with Sony devices that work just fine, so I have no idea how I can fix that bug.

    Maybe that is some OpenGL bug with the QML renderer? I only use a default Text element with the default font (nothing set as font.family) so I assume it uses the Roboto font on Android.

    Any ideas maybe? :)

  • What about android versions. Are they the same on the both phones?

  • Hi, the user didn't provide the android version.. I might ask him, but as far as I can see it should be Android 4.0.3+
    Anyway I don't think that should matter much, since Qt should run on all android version from 2.3+.
    What I can see form the screenshot that he is using a non default Android launcher, but many device manufacturers provide custom Android launchers, I have no way of testing that myself because I don't have access to all the different devices.

    In another thread here I described problems with 3rd party virtual keyboards and Qt input, so there are some problems with non default android widgets I guess?

  • I still have some users complaining about this bug, I hope this gets fixed with Qt 5.3. :/

    Another screenshot from a user using Samsung Galaxy 3 running CM11:
    !http://i.imgur.com/GIzIYFZ.png(font bug)!

    Same thing reported from a user running Samsung Galaxy 3 on Android version 4.3.

    I don't know if that is only happening only samsung devices, but i know some users have no problems on samsung devices and I still can't reproduce this bug.. :(
    From what I can see mostly bold text is affected, very weird, I have one screenshot in landscape mode where normal text is affected too so it's not only bold text but if you look at there screens here it's happening with bold font.

    Anyone have any idea or can maybe test the app on their device? Here is the Google play link: https://play.google.com/store/apps/details?id=ws.aggregator.critiq

  • I also just got a bugreport from a user with a Sony Xperia TS running Android 4.3 that fonts are broken. At the moment I'm using a plain Text element with font.family set to Roboto and shipping the Roboto font with the app to workaround a HTC rendering bug.

    There have been a lot of fixes for text rendering on Android recently and I hope that one is among them :/

    I'm getting more and more reports of people with broken font rendering (so far various Huawei (P2, P6) devices, Sony Xperia TS, HTC One S (however I cannot reproduce it on that device)...

  • Hi, yeah I know the worst is we can't reproduce the bug ourselves and test possible fixes for it. :/

    Another user send me a possible workaround, I have set the QML environment variable QML_USE_GLYPHCACHE_WORKAROUND to 1, that should work for some devices, but again I can't test it myself so it's hard to say.

    qputenv("QML_USE_GLYPHCACHE_WORKAROUND", QByteArray("1"));

    that workaround was described here: https://bugreports.qt-project.org/browse/QTBUG-34984

    I think most rendering bugs are due to corrupt device drivers for OpenGL, but there is nothing we can do about it I guess.

  • I just got feedback from a user that Qt 5.3 fixes the issue for him on his Sony Xperia T, I hope it will work on Huawei and the others too. Stay tuned :)

  • Great, I am waiting fort the stable release of Qt 5.3, but if that fixes the font problems that would be nice. :)

  • Greetings,

    i have a font rendering bug under windows which doesn't exist on android-devices... strange QML. :)

  • I usually use native font "Droid Sans" when building Android application. It is so far so good.

  • For my app I did not specify any font explicitly, so it should use the default device font I think ( Roboto on Android?). It looked good on my devices so I thought it would be best not to set any font family at all.
    [quote author="jiangcaiyang" date="1399629141"]I usually use native font "Droid Sans" when building Android application. It is so far so good.[/quote]

  • Hi
    how can i set the QML environment variable QML_USE_GLYPHCACHE_WORKAROUND to 1?

  • Moderators

    @mehrdad Using qputenv. Call this before loading the QML.

  • thanks, it work for huawei p6 but not for textfiled element...

  • Moderators

    @mehrdad Well the bug report https://bugreports.qt-project.org/browse/QTBUG-34984 (posted by @Xander84 here) says it is fixed. Which Qt version are you using ?

  • 5.4.1
    i use textEdit for create my own textField and it work!

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