Qt在滚动区域中调整窗口大小以适应纵横比的问题

Question

我使用Qt创建了一个预览对象，它是一个容器，里面包含屏幕小部件。为了使它的纵横比正确，当屏幕的宽度改变时，高度也需要改变。

这会导致一个问题，因为屏幕位于滚动区域内，当其高度超过一定点时，滚动条出现。这会减小宽度，因此需要减小高度，这可能会导致滚动条不断出现和消失。

我尝试修复此问题的一种方法是取所需大小并在一些函数迭代中平均，该函数负责计算和设置大小，如果平均值与所需大小没有显著差异，则大小不会更改。这似乎已经解决了问题，但在我看来不太理想...

我想知道是否有人有解决此问题的想法？

//********************************************************************************
/// \brief Called to make the size of the preview pane the correct size
void PreviewDisplayWidget::SetSizeOfScreen()
{
  double aspect_ratio = _preview_controls->_video_settings.getVideoFormat().GetAspectRatio();

  // Calculate the new minimum size
  int minimum_size = _container->width()/aspect_ratio;

  // HACK TO FIX ISSUE WITH RESIZING:
  // The preview sets its height from the width, if the width is changed, so will the height.
  // This causes an issue with the scroll area as it can be in a situation that will cause the
  // scroll area to get thinner (due to scroll bars being added), causing the width of the widget
  // to change, therefore causing the height to change. Which can be enough to make the scroll bar go
  // away. This can loop and cause a stack overflow.
  //
  // Store the last 10 sizes.
  _previous_sizes.push_back(minimum_size);

  const int sizes_to_scan = 10;
  if (_previous_sizes.size() > sizes_to_scan)
  {
    _previous_sizes.pop_front();
  }

  int sum = 0;
  for (auto i =_previous_sizes.begin(); i != _previous_sizes.end(); i++)
  {
    sum += *i;
  }

  double average = (double) sum / (double) _previous_sizes.size();

  std::cout << "Average " << average << std::endl;

  bool change_in_average = false;
  // Significant change in average means a size change should occur
  if (average > minimum_size + 5 || average < minimum_size - 5)
  {
    change_in_average = true;
  }


  if (change_in_average || _previous_sizes.size() < sizes_to_scan - 1)
  {
    _preview_frame->setMinimumHeight(minimum_size);
    std::cout << "Preview sizes " << minimum_size << std::endl;
    _preview_frame->updateGeometry();
  }

  SetPreviewSize();
}

- robby987

Answer 1

这个能行吗？

int minimum_size;

if(scrollArea->verticalScrollBar())
minimum_size = (_container->width()+scrollArea->verticalScrollBar()->width())/aspect_ratio;
else
minimum_size = _container->width()/aspect_ratio;

- Vinod Paul