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  1. #1
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    Jul 2010
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    Smbian^3 QPixmap limits?

    I am having some issues with QPixmap's and QPixmapCache on Symbian^3 phones.

    I need to precache quite some QPixmaps, for speed reasons, so i set QPixmapCache size to 8MB. This works perfectly on S60v5 and things are pretty fast. The same build on S3 instead is very unstable and leads to phone reboots, app crashes, and random black areas on the screen.

    On S3 devices things improves the more i reduce the QPixmapCache size. The errors are completely gone if i use QImages instead of QPixmaps. Of course, both solutions make S3 crawl in respect to S60v5 with the QPixmapCache solution.

    What can i do? Is there a way to make QPixmaps work better on S3? Are there some known limits in QPixmapCache on S3?

  2. #2
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    Re: Smbian^3 QPixmap limits?

    Are you using some graphics parameters ?

    like this way for Open VG ,

    ‘-graphicssystem <raster|openvg|…>

    Anyway,
    Qt uses internal padding in 24bit RGB888 images. Symbian doesn't have similar padding.
    Qt requires to copy symbian bitmaps line by line to get the correct result.

    Regards,

  3. #3
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    Re: Smbian^3 QPixmap limits?

    No i am not using any graphic parameter... i dont even know how to apply them?

  4. #4
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    Re: Smbian^3 QPixmap limits?

    You told that your app works,,fine in the S^1 and not working on S^3.

    It should work, Because the version of Qt is upward compatible. If the vice-versa might there, then I will suggest you the solution.

    one suggestion is to try with low QPixmapCache size, as you described.

    Regards,

  5. #5
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    Re: Smbian^3 QPixmap limits?

    Yes, i have no issues whatsoever on S^1 and users reports of frequent crashes and even phone reboots on S^3. I tracked this down to the use of QPixmap, if i store a lot (10-20mb) of images into QPixmaps i have the crashes. If i store the same in QImages, i dont have an crashes whatsoever (but much slower operation on S^3).

    Reducing QPixmapCache helps the crashes somehow, but also decrease speed because i need to reload/rebuild the pixmaps more often. Even 2MB of QPixmapCache seems to cause random crashes, but less than 8MB or more. The current solution is to store in QImages and do a

    Code:
     painter.drawPixmap( QPixmap::fromImage( ... ) )
    Considering that i create the QImages like this:
    Code:
     QImage new_image = QImage( QPixmap( ... ).toImage() );
    This seems the fastest way witch does not leads to crashes. Still i believe this is not the intended way... Can this be related to OpenVG in some ways?

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