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Type: Bug
Resolution: Unresolved
Priority: P3: Somewhat important
Fix Version/s: None
Affects Version/s: 5.11.3
Component/s: GUI: Painting, GUI: Printing
Labels:
None

Platform/s:

Linux/X11

Description

This is a bug with QPreviewPaintEngine.
If I use setClipPath to cut the original image, the preview data will disappear from the second page.
Comparing the generated preview QPictures , starting from page 2 , the data size starts to be different from that of page1 .
Here is my example:

QPrintPreviewDialog dialog;
connect(&dialog, &QPrintPreviewDialog::paintRequested, this, [=](QPrinter *_printer){
    QPainter p(_printer);

    QImage testImage(_printer->pageLayout().fullRectPixels(_printer->resolution()).size(), QImage::Format_ARGB32);
    testImage.fill(Qt::green);
    p.setClipRect(QRect(0, 0, 200, 200));
    for (int i = 0; i < 10; ++i) {
        if (i != 0)
            _printer->newPage();

        p.drawImage(0, 0, testImage);
    }
    for (int i = 0; i < _printer->d_func()->previewPages().count(); ++i) {
        qInfo() << "currentPage: " << i + 1 << "Pictures Data Size: " <<  _printer->d_func()->previewPages().at(i)->size();
    }
});

dialog.exec();

The following is the debug output of the program:

currentPage: 1 Pictures Data Size: 138
 currentPage: 2 Pictures Data Size: 355
 currentPage: 3 Pictures Data Size: 355
 currentPage: 4 Pictures Data Size: 355
 currentPage: 5 Pictures Data Size: 355
 currentPage: 6 Pictures Data Size: 355
 currentPage: 7 Pictures Data Size: 355
 currentPage: 8 Pictures Data Size: 355
 currentPage: 9 Pictures Data Size: 355
 currentPage: 10 Pictures Data Size: 353

Obviously, the same image is used as the raw data, but the resulting data is not the same size.Even if the setClippath function is not used, the output data size is also not the same.