override sizeHint in osgQOpenGLWidget

[gramnation]

Default value of QWidget::rect is 0,0,640,480. This SD aspect ratio agrees with OSG when widget is shown by itself. However, once widget is put into a layout it has to return a valid sizeHint in order to preserve this aspect ratio and size.
https://doc.qt.io/qt-5/qwidget.html#size-hints-and-size-policies

[mathieu]

thanks for the PR @gramnation !

[forsnowlove]

I did like this and it worked! Thank you !
setp one:override sizeHint
class MosgQOpenGLWidget : public osgQOpenGLWidget
{
public:
MosgQOpenGLWidget();
QSize sizeHint() const override;
private:
};
QSize MosgQOpenGLWidget::sizeHint() const
{
//return QSize(640,480);
//qDebug()<<"hint"<width()<<" "<height();
return QSize(this->width(),this->height());
}
setp two:camera->setProjectionMatrixAsPerspective()
pOsgW = new MosgQOpenGLWidget;
pViewer = pOsgW->getOsgViewer();
QSize size = pOsgW->sizeHint();
float aspectRatio = static_cast( size.width()) / static_cast( size.height() );
pViewer->getCamera()->setProjectionMatrixAsPerspective( 30.f, aspectRatio, 1.f, 1000.f );

[shaozhihua]

if only this function is a pure virtual function,then we will know the usage..
anyway.thank you @gramnation

[HorrZzz]

我确实喜欢这个，它奏效了！谢谢！ setp one：override sizeHint 类 MosgQOpenGLWidget ： public osgQOpenGLWidget { public： MosgQOpenGLWidget（）;QSsize sizeHint（） const 覆盖;私人： }; QSize MosgQOpenGLWidget：：sizeHint（） const { //return QSize（640,480）; //qDebug（）<<“hint”<width（）<<“ ”<height（）;返回QSize（this->width（），this->height（））; } setp two：camera->setProjectionMatrixAsPerspective（） pOsgW = new MosgQOpenGLWidget; pViewer = pOsgW->getOsgViewer（）; QSize 大小 = pOsgW->sizeHint（）; float aspectRatio = static_cast（ size.width（）） / static_cast（ size.height（） ）; pViewer->getCamera（）->setProjectionMatrixAsPerspective（ 30.f， aspectRatio， 1.f， 1000.f ）;

It's effective. Thank you very much.