Hi everyone, for a QtQuick application I try to implement an asynchronous image provider. As suggested in the documentation of QQuickImageResponse I use QRunnable as base class and disabled automatic deletion in the constructor.
I have a private QThreadPool member in my QQuickAsyncImageProvider. My requestImageResponse function creates a new ImageResponse, calling the ThreadPool´s start function for the ImageResponse and returns the ImageResponse. The run method of the ImageResponse renders a pdf page with poppler, sets the QQuickTextureFactory and emits finished. To display the pdf pages I use a ListModel with all pages displayed as Images in a PathView. To display different pdf´s i use a StackView. If I push a pdf view on the StackView I can see the construction, run, finished, textureFactory and destruction calls of the ImageResponse. In the ImageResponse I added qDebug() prints for all public functions. The pages get displayed correctly in my pdf view. If I pop the pdf view from the StackView before all pages have been rendered the application crashes. I can see a call to cancel and destructor of the pages that have not signaled finished. To eliminate side effects, I replaced the pdf rendering in run with a sleep of 1 second. Here is the output of a 7 page pdf view (the second column is the requested id (fileName:pageNumber), stored in a private member of ImageRequest): QML debugging is enabled. Only use this in a safe environment. constructor: "test.pdf:4" constructor: "test.pdf:5" run: "test.pdf:4" constructor: "test.pdf:6" run: "test.pdf:5" constructor: "test.pdf:3" constructor: "test.pdf:2" constructor: "test.pdf:1" run: "test.pdf:3" constructor: "test.pdf:0" run: "test.pdf:6" run finished: "test.pdf:4" run: "test.pdf:2" run finished: "test.pdf:5" textureFactory: "test.pdf:4" run: "test.pdf:1" textureFactory: "test.pdf:5" destructor: "test.pdf:4" run finished: "test.pdf:3" run: "test.pdf:0" destructor: "test.pdf:5" textureFactory: "test.pdf:3" destructor: "test.pdf:3" run finished: "test.pdf:6" textureFactory: "test.pdf:6" destructor: "test.pdf:6" cancle: "test.pdf:0" destructor: "test.pdf:0" cancle: "test.pdf:1" cancle: "test.pdf:2" destructor: "test.pdf:1" destructor: "test.pdf:2" run finished: "test.pdf:2" run finished: "test.pdf:1" bash: line 1: 14884 Segmentation fault DISPLAY=':0.0' QT_QPA_EGLFS_PHYSICAL_HEIGHT='268.11' QT_QPA_EGLFS_PHYSICAL_WIDTH='476.64' /home/pi/test/test The only thing I can spot is the destruction of ImageRequests that have been started but not finished (the last 4 lines before the segmentation fault). Do I miss something or is this a bug? Regards Stefan HEKATRON Technik GmbH Bruehlmatten 3a - 9 D-79295 Sulzburg Reg.-Ger. Freiburg HRB 300243 Geschaeftsfuehrer: Michael Roth, Armin Berchtold Telefon +49 7634 500-0 Telefax +49 7634 500-316 _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
