[3d] missing piece of the jigsaw: save 3d canvas as image (#5927)

src/app/3d/qgs3dmapcanvas.cpp

@@ -17,6 +17,7 @@
 
 #include <QBoxLayout>
 #include <Qt3DExtras/Qt3DWindow>
+#include <Qt3DRender/QRenderCapture>
 
 #include "qgscameracontroller.h"
 #include "qgs3dmapsettings.h"
@@ -27,6 +28,11 @@ Qgs3DMapCanvas::Qgs3DMapCanvas( QWidget *parent )
   : QWidget( parent )
 {
   mWindow3D = new Qt3DExtras::Qt3DWindow;
+
+  mCapture = new Qt3DRender::QRenderCapture;
+  mWindow3D->activeFrameGraph()->setParent( mCapture );
+  mWindow3D->setActiveFrameGraph( mCapture );
+
   mContainer = QWidget::createWindowContainer( mWindow3D );
 
   QHBoxLayout *hLayout = new QHBoxLayout( this );
@@ -89,3 +95,19 @@ void Qgs3DMapCanvas::setViewFromTop( const QgsPointXY &center, float distance, f
   float worldY = center.y() - mMap->origin().y();
   mScene->cameraController()->setViewFromTop( worldX, -worldY, distance, rotation );
 }
+
+void Qgs3DMapCanvas::saveAsImage( const QString fileName, const QString fileFormat )
+{
+  if ( !fileName.isEmpty() )
+  {
+    Qt3DRender::QRenderCaptureReply *captureReply;
+    captureReply = mCapture->requestCapture();
+    connect( captureReply, &Qt3DRender::QRenderCaptureReply::completed, this, [ = ]
+    {
+      captureReply->image().save( fileName, fileFormat.toLocal8Bit().data() );
+      emit savedAsImage( fileName );
+
+      captureReply->deleteLater();
+    } );
+  }
+}

src/app/3d/qgs3dmapcanvas.h

@@ -17,6 +17,7 @@
 #define QGS3DMAPCANVAS_H
 
 #include <QWidget>
+#include <Qt3DRender/QRenderCapture>
 
 namespace Qt3DExtras
 {
@@ -54,12 +55,22 @@ class Qgs3DMapCanvas : public QWidget
     //! Sets camera position to look down at the given point (in map coordinates) in given distance from plane with zero elevation
     void setViewFromTop( const QgsPointXY &center, float distance, float rotation = 0 );
 
+    //! Saves the current scene as an image
+    void saveAsImage( const QString fileName, const QString fileFormat );
+
+  signals:
+    //! Emitted when the 3D map canvas was successfully saved as image
+    void savedAsImage( const QString fileName );
+
   protected:
     void resizeEvent( QResizeEvent *ev ) override;
 
   private:
     //! 3D window with all the 3D magic inside
     Qt3DExtras::Qt3DWindow *mWindow3D = nullptr;
+    //! Frame graph node for render capture
+    Qt3DRender::QRenderCapture *mCapture = nullptr;
+
     //! Container QWidget that encapsulates mWindow3D so we can use it embedded in ordinary widgets app
     QWidget *mContainer = nullptr;
     //! Description of the 3D scene

src/app/3d/qgs3dmapcanvasdockwidget.cpp

@@ -30,6 +30,7 @@
 #include <QDialogButtonBox>
 #include <QProgressBar>
 #include <QToolBar>
+#include <QUrl>
 
 Qgs3DMapCanvasDockWidget::Qgs3DMapCanvasDockWidget( QWidget *parent )
   : QgsDockWidget( parent )
@@ -42,6 +43,8 @@ Qgs3DMapCanvasDockWidget::Qgs3DMapCanvasDockWidget( QWidget *parent )
   toolBar->setIconSize( QgisApp::instance()->iconSize( true ) );
   toolBar->addAction( QgsApplication::getThemeIcon( QStringLiteral( "mActionZoomFullExtent.svg" ) ),
                       tr( "Zoom Full" ), this, &Qgs3DMapCanvasDockWidget::resetView );
+  toolBar->addAction( QgsApplication::getThemeIcon( QStringLiteral( "mActionSaveMapAsImage.svg" ) ),
+                      tr( "Save as image..." ), this, &Qgs3DMapCanvasDockWidget::saveAsImage );
   toolBar->addAction( QgsApplication::getThemeIcon( QStringLiteral( "mIconProperties.svg" ) ),
                       tr( "Configure" ), this, &Qgs3DMapCanvasDockWidget::configure );
 
@@ -49,6 +52,11 @@ Qgs3DMapCanvasDockWidget::Qgs3DMapCanvasDockWidget( QWidget *parent )
   mCanvas->setMinimumSize( QSize( 200, 200 ) );
   mCanvas->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );
 
+  connect( mCanvas, &Qgs3DMapCanvas::savedAsImage, this, [ = ]( const QString fileName )
+  {
+    QgisApp::instance()->messageBar()->pushSuccess( tr( "Save as Image" ), tr( "Successfully saved the 3D map to <a href=\"%1\">%2</a>" ).arg( QUrl::fromLocalFile( QFileInfo( fileName ).path() ).toString(), fileName ) );
+  } );
+
   mLabelPendingJobs = new QLabel( this );
   mProgressPendingJobs = new QProgressBar( this );
   mProgressPendingJobs->setRange( 0, 0 );
@@ -74,6 +82,15 @@ Qgs3DMapCanvasDockWidget::Qgs3DMapCanvasDockWidget( QWidget *parent )
   onTerrainPendingJobsCountChanged();
 }
 
+void Qgs3DMapCanvasDockWidget::saveAsImage()
+{
+  QPair< QString, QString> fileNameAndFilter = QgsGuiUtils::getSaveAsImageName( this, tr( "Choose a file name to save the 3D map canvas to an image" ) );
+  if ( !fileNameAndFilter.first.isEmpty() )
+  {
+    mCanvas->saveAsImage( fileNameAndFilter.first, fileNameAndFilter.second );
+  }
+}
+
 void Qgs3DMapCanvasDockWidget::setMapSettings( Qgs3DMapSettings *map )
 {
   mCanvas->setMap( map );

src/app/3d/qgs3dmapcanvasdockwidget.h

@@ -42,6 +42,7 @@ class Qgs3DMapCanvasDockWidget : public QgsDockWidget
   private slots:
     void resetView();
     void configure();
+    void saveAsImage();
 
     void onMainCanvasLayersChanged();
     void onMainCanvasColorChanged();