在QRubberband上实现调整大小的句柄? QSizeGrip相关吗? [英] Implementing resize handles on QRubberband? Is QSizeGrip relevant?

问题描述

我想让我的QRubberband实例用户可调整大小.我已经在此处看到了这个问题，但是没有解决方案.

I'd like to make my QRubberband instance user resizeable. I've seen this question here but there isn't a solution.

用例是用户可以在照片上拖出一个选框，然后通过拖动QRubberband边距进行精细调整以更改几何形状，或者通过拖动选区来重新定位现有几何.我已经实现了重新定位，但是我想知道用于改变QRubberband几何形状的调整手柄大小.

The use case is that the user can drag out a selection marquee over a photo and then make fine adjustments by dragging on the QRubberband margins to change geometry, or reposition existing geometry by dragging the selection. I have the repositioning implemented but I am wondering about resize handles for changing the geometry of the QRubberband.

在这里可以使用QSizeGrip吗?除此以外，是否有标准的方法可以检查Qt中的空白处"鼠标事件或其他实现此方法的方法?这是针对不需要此功能或无需为此付出很多努力的研究应用程序，但是拥有它会很好.

Is it possible to use QSizeGrip here? Barring that, is there a standard way of checking for mouse-within-margin type events within Qt or some other way to implement this? This is for a research app that doesn't need or warrant lots of effort on this feature but it would be good to have.

推荐答案

是的，有可能.这是实现:

Yes, it's possible. Here is the implementation:

标题:

class Resizable_rubber_band : public QWidget {
public:
  Resizable_rubber_band(QWidget* parent = 0);

private:
  QRubberBand* rubberband;
  void resizeEvent(QResizeEvent *);

};

来源:

Resizable_rubber_band::Resizable_rubber_band(QWidget *parent) : QWidget(parent) {
  //tell QSizeGrip to resize this widget instead of top-level window
  setWindowFlags(Qt::SubWindow);
  QHBoxLayout* layout = new QHBoxLayout(this);
  layout->setContentsMargins(0, 0, 0, 0);
  QSizeGrip* grip1 = new QSizeGrip(this);
  QSizeGrip* grip2 = new QSizeGrip(this);
  layout->addWidget(grip1, 0, Qt::AlignLeft | Qt::AlignTop);
  layout->addWidget(grip2, 0, Qt::AlignRight | Qt::AlignBottom);
  rubberband = new QRubberBand(QRubberBand::Rectangle, this);
  rubberband->move(0, 0);
  rubberband->show();
  show();
}

void Resizable_rubber_band::resizeEvent(QResizeEvent *) {
  rubberband->resize(size());
}

用法:(ui->label是用于显示要裁剪的图像的标签)

Usage: (ui->label is the label used for displaying the image to be cropped)

Resizable_rubber_band* band = new Resizable_rubber_band(ui->label);
band->move(100, 100);
band->resize(50, 50);
band->setMinimumSize(30, 30);

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