OSG with QWidget shows extra border - c++

Question

I have modified the osgViewerQt example in order to load a point cloud and visualize it in a Qt application. As you can see in the attached image, the cloud point cloud is shown but there is an extra border in the window (see the arrows).
I spent all the weekend trying to figure how to "expand" the window in order to remove that border, but it keeps showing.
Do you know what can I do to remove it? I'll post the code for the modified osgViewerQt and the piece of code where I use it.
viewer_widget.h
#ifndef VIEWER_WIDGET_H
#define VIEWER_WIDGET_H
#include "osgViewer/CompositeViewer"
#include <QTimer>
#include <QWidget>
class QGridLayout;
class QWidget;
class ViewerWidget : public QWidget, public osgViewer::CompositeViewer {
private:
std::string cloud_file;
std::string cloud_filepath;
QTimer timer_;
QWidget* widget;
QGridLayout* grid;
osg::ref_ptr<osgViewer::View> view;
private:
ViewerWidget(const ViewerWidget& V);
ViewerWidget& operator=(const ViewerWidget& V);
private:
QWidget* AddViewWidget(osg::Camera* camera,osg::Node* scene);
osg::Camera* CreateCamera(int x,int y,int w,int h,const std::string& name="",
bool windowDecoration=false
);
osg::Node* ReadOctree(const std::string& file);
public:
ViewerWidget(const std::string& filename,const std::string& filepath,bool color,
osgViewer::ViewerBase::ThreadingModel threadingModel
= osgViewer::CompositeViewer::ThreadPerCamera
);
virtual ~ViewerWidget(void){}
void AddCloud(void);
void StartFrameTimer(int msec=10) { timer_.start(msec); }
virtual void paintEvent( QPaintEvent* event ) { frame(); }
};
#endif // VIEWER_WIDGET_H
osg_viewer.cpp
#include "viewer_widget.h"
#include "osgDB/ReadFile"
#include "osgGA/TrackballManipulator"
#include "osgQt/GraphicsWindowQt"
#include "osgViewer/ViewerEventHandlers"
#include <QGridLayout>
#include <QDebug>
ViewerWidget::ViewerWidget(const std::string &filename,const std::string &filepath,
bool color, osgViewer::ViewerBase::ThreadingModel threadingModel
) :
QWidget(),
cloud_file( filename ),
cloud_filepath( filepath )
{
// this->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
connect( &(this->timer_), SIGNAL(timeout()), this, SLOT(update()) );
}
QWidget* ViewerWidget::AddViewWidget(osg::Camera *camera,osg::Node *scene) {
view = new osgViewer::View;
view->setCamera( camera );
view->setSceneData( scene );
osg::Stats* stats = this->getViewerStats();
if(stats) stats->report(std::cout);
addView( view );
view->addEventHandler( new osgViewer::StatsHandler );
view->setCameraManipulator( new osgGA::TrackballManipulator );
osgQt::GraphicsWindowQt* gw = dynamic_cast<osgQt::GraphicsWindowQt*>(
camera->getGraphicsContext()
);
return gw ? gw->getGLWidget() : 0;
}
osg::Camera* ViewerWidget::CreateCamera(int x,int y,int w,int h,const std::string &name,
bool windowDecoration
) {
osg::DisplaySettings* ds = osg::DisplaySettings::instance().get();
osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits;
traits->windowName = name;
traits->windowDecoration = windowDecoration;
traits->x = x;
traits->y = y;
qDebug() << "w:" << w << " h:" << h;
traits->width = w;
traits->height = h;
traits->doubleBuffer = true;
traits->alpha = ds->getMinimumNumAlphaBits();
traits->stencil = ds->getMinimumNumStencilBits();
traits->sampleBuffers = ds->getMultiSamples();
traits->samples = ds->getNumMultiSamples();
osg::ref_ptr<osg::Camera> camera = new osg::Camera;
camera->setGraphicsContext( new osgQt::GraphicsWindowQt(traits.get()) );
camera->setClearColor( osg::Vec4(0,0,0,1) );
camera->setViewport( new osg::Viewport(0, 0, traits->width, traits->height) );
camera->setProjectionMatrixAsPerspective(
30.0f, static_cast<double>(traits->width)/static_cast<double>(traits->height), 1.0f, 10000.0f );
return camera.release();
}
osg::Node* ViewerWidget::ReadOctree(const std::string &file) {
osg::Group* group = new osg::Group;
group->addChild( osgDB::readNodeFile(file, options) );
return group;
}
void ViewerWidget::AddCloud() {
std::cout << "Loading cloud from file:" << cloud_file.c_str() << "\n";
QWidget* widget = AddViewWidget(
CreateCamera(0,0,100,100,"cam1",true),
ReadOctree(cloud_file)
);
grid = new QGridLayout;
grid->addWidget( widget, 0, 0 );
this->setLayout( grid );
}
Now, in where this widget is used (simplified a bit to show only the relevant parts):
cloud.h
#ifndef CLOUD_H
class Cloud: public QObject {
Q_OBJECT
private:
osg::ref_ptr<ViewerWidget> osg_widget;
QDockWidget* dock;
/// MORE ATTRIBUTES
public:
Cloud(){
/// ...
dock = new QDockWidget;
osg_widget = new ViewerWidget( getFileName(), getFilePath(), has_color);
dockWidget->setAllowedAreas(Qt::RightDockWidgetArea);
dockWidget->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
dockWidget->addWidget(osg_widget);
}
/// More methods, cloud manipulators, etc.
};
#endif
When specifying the size policy, I have also tried with Minimum, MinimumExpanding and
Ignored, but with the same effect. I tried to specify the size policy directly inside the ViewerWidget (as it inherits from QWidget) and to specify it its widget attribute, too, but with no success.

Answer 1

You're using a grid layout to insert the view widget in your target window, if I understand correctly:
grid = new QGridLayout;
grid->addWidget( widget, 0, 0 );
this->setLayout( grid );
Layouts usually insert padding around their elements (called margin in the Qt docs). You can tune that using QLayout::setContentsMargin(), so here something in the spirit of this
grid->setContentsMargins(0,0,0,0);
should do the trick.