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  1. Qt
  2. QTBUG-96604

WebAssembly: QScrolllArea always updates with refreshing the entire viewport

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    Details

    • Platform/s:
      WebAssembly

      Description

      When moving the slider of vertical scrollbars,  the scrollview always perform fully update on the Webassembly platform.  While on Windows platform, widgets will receive paint events for the newly exposed parts。

       

      Sample Code:

      #include <QApplication>
      #include <QDebug>
      #include <QMainWindow>
      #include <QPaintEvent>
      #include <QPainter>
      #include <QScrollArea>
      
      class MyWidget : public QWidget
      {
      public:
          MyWidget() {}
      
          void paintEvent(QPaintEvent *event)
          {
              QPainter painter(this);
              painter.fillRect(event->rect(), Qt::white);
              qDebug() << event->rect();
          }
      };
      
      int main(int argc, char *argv[])
      {
          QApplication a(argc, argv);
      
          MyWidget *widget = new MyWidget();
          widget->resize(2000, 3000);
          QScrollArea *scrollArea = new QScrollArea();
          scrollArea->setWidget(widget);
      
          QMainWindow w;
          w.setCentralWidget(scrollArea);
          w.show();
          return a.exec();
      }
      

       

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            Assignee:
            lagocs Laszlo Agocs
            Reporter:
            piggestbaby lei chen
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              Dates

              Created:
              Updated:

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