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Problem with Qt 5.4.1 and TWAIN

  • I am having a problem with Qt5.4.1. I recently updated from Qt5.2.0 to Qt5.4.1. My application uses TWAIN to scan images. Since I updated to Qt5.4.1 the scan process is slower. For some reason there is about 15seconds delay before the scan starts since the update. With Qt5.2.0 the delay does not occur.

    I compiled the exact same source code with Qt5.4.1 and Qt5.2.0.

    Im am using QAbstractEventDispatcher::installNativeEventFilter() to get the TWAIN events from the event loop.

    Did something related to the event loop change between Qt5.2.0 and Qt5.4.1? Did something else change that would explain the delay while scanning?

    Kind Regards,

  • Lifetime Qt Champion

    Hi and welcome to devnet,

    Since the internals of the event loop might be in cause, you should rather bring this question to the interest mailing list. You'll find there Qt's developers/maintainers (this forum is more user oriented)

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