Port world file generation code to layouts

python/core/layout/qgslayoutexporter.sip

@@ -174,6 +174,22 @@ Resolution to export layout at
  :rtype: bool
 %End
 
+    void computeWorldFileParameters( double &a, double &b, double &c, double &d, double &e, double &f, double dpi = -1 ) const;
+%Docstring
+ Compute world file parameters. Assumes the whole page containing the reference map item
+ will be exported.
+
+ The ``dpi`` argument can be set to the actual DPI of exported file, or left as -1 to use the layout's default DPI.
+%End
+
+    void computeWorldFileParameters( const QRectF &region, double &a, double &b, double &c, double &d, double &e, double &f, double dpi = -1 ) const;
+%Docstring
+ Computes the world file parameters for a specified ``region`` of the layout.
+
+ The ``dpi`` argument can be set to the actual DPI of exported file, or left as -1 to use the layout's default DPI.
+%End
+
+
 };
 
 

src/core/layout/qgslayoutexporter.cpp

@@ -212,9 +212,9 @@ QgsLayoutExporter::ExportResult QgsLayoutExporter::exportToImage( const QString
 
     if ( page == worldFilePageNo )
     {
-#if 0
-      georeferenceOutput( outputFilePath, nullptr, bounds, imageDlg.resolution() );
+      georeferenceOutput( outputFilePath, nullptr, bounds, settings.dpi );
 
+#if 0
       if ( settings.generateWorldFile )
       {
         // should generate world file for this page
@@ -356,6 +356,94 @@ bool QgsLayoutExporter::georeferenceOutput( const QString &file, QgsLayoutItemMa
   return true;
 }
 
+void QgsLayoutExporter::computeWorldFileParameters( double &a, double &b, double &c, double &d, double &e, double &f, double dpi ) const
+{
+  QgsLayoutItemMap *map = mLayout->referenceMap();
+  if ( !map )
+  {
+    return;
+  }
+
+  int pageNumber = map->page();
+  QgsLayoutItemPage *page = mLayout->pageCollection()->page( pageNumber );
+  double pageY = page->pos().y();
+  QSizeF pageSize = page->rect().size();
+  QRectF pageRect( 0, pageY, pageSize.width(), pageSize.height() );
+  computeWorldFileParameters( pageRect, a, b, c, d, e, f, dpi );
+}
+
+void QgsLayoutExporter::computeWorldFileParameters( const QRectF &exportRegion, double &a, double &b, double &c, double &d, double &e, double &f, double dpi ) const
+{
+  // World file parameters : affine transformation parameters from pixel coordinates to map coordinates
+  QgsLayoutItemMap *map = mLayout->referenceMap();
+  if ( !map )
+  {
+    return;
+  }
+
+  double destinationHeight = exportRegion.height();
+  double destinationWidth = exportRegion.width();
+
+  QRectF mapItemSceneRect = map->mapRectToScene( map->rect() );
+  QgsRectangle mapExtent = map->extent();
+
+  double alpha = map->mapRotation() / 180 * M_PI;
+
+  double xRatio = mapExtent.width() / mapItemSceneRect.width();
+  double yRatio = mapExtent.height() / mapItemSceneRect.height();
+
+  double xCenter = mapExtent.center().x();
+  double yCenter = mapExtent.center().y();
+
+  // get the extent (in map units) for the region
+  QPointF mapItemPos = map->pos();
+  //adjust item position so it is relative to export region
+  mapItemPos.rx() -= exportRegion.left();
+  mapItemPos.ry() -= exportRegion.top();
+
+  double xmin = mapExtent.xMinimum() - mapItemPos.x() * xRatio;
+  double ymax = mapExtent.yMaximum() + mapItemPos.y() * yRatio;
+  QgsRectangle paperExtent( xmin, ymax - destinationHeight * yRatio, xmin + destinationWidth * xRatio, ymax );
+
+  double X0 = paperExtent.xMinimum();
+  double Y0 = paperExtent.yMinimum();
+
+  if ( dpi < 0 )
+    dpi = mLayout->context().dpi();
+
+  int widthPx = static_cast< int >( dpi * destinationWidth / 25.4 );
+  int heightPx = static_cast< int >( dpi * destinationHeight / 25.4 );
+
+  double Ww = paperExtent.width() / widthPx;
+  double Hh = paperExtent.height() / heightPx;
+
+  // scaling matrix
+  double s[6];
+  s[0] = Ww;
+  s[1] = 0;
+  s[2] = X0;
+  s[3] = 0;
+  s[4] = -Hh;
+  s[5] = Y0 + paperExtent.height();
+
+  // rotation matrix
+  double r[6];
+  r[0] = std::cos( alpha );
+  r[1] = -std::sin( alpha );
+  r[2] = xCenter * ( 1 - std::cos( alpha ) ) + yCenter * std::sin( alpha );
+  r[3] = std::sin( alpha );
+  r[4] = std::cos( alpha );
+  r[5] = - xCenter * std::sin( alpha ) + yCenter * ( 1 - std::cos( alpha ) );
+
+  // result = rotation x scaling = rotation(scaling(X))
+  a = r[0] * s[0] + r[1] * s[3];
+  b = r[0] * s[1] + r[1] * s[4];
+  c = r[0] * s[2] + r[1] * s[5] + r[2];
+  d = r[3] * s[0] + r[4] * s[3];
+  e = r[3] * s[1] + r[4] * s[4];
+  f = r[3] * s[2] + r[4] * s[5] + r[5];
+}
+
 QImage QgsLayoutExporter::createImage( const QgsLayoutExporter::ImageExportSettings &settings, int page, QRectF &bounds, bool &skipPage ) const
 {
   bounds = QRectF();

src/core/layout/qgslayoutexporter.h

@@ -186,6 +186,22 @@ class CORE_EXPORT QgsLayoutExporter
     bool georeferenceOutput( const QString &file, QgsLayoutItemMap *referenceMap = nullptr,
                              const QRectF &exportRegion = QRectF(), double dpi = -1 ) const;
 
+    /**
+     * Compute world file parameters. Assumes the whole page containing the reference map item
+     * will be exported.
+     *
+     * The \a dpi argument can be set to the actual DPI of exported file, or left as -1 to use the layout's default DPI.
+     */
+    void computeWorldFileParameters( double &a, double &b, double &c, double &d, double &e, double &f, double dpi = -1 ) const;
+
+    /**
+     * Computes the world file parameters for a specified \a region of the layout.
+     *
+     * The \a dpi argument can be set to the actual DPI of exported file, or left as -1 to use the layout's default DPI.
+     */
+    void computeWorldFileParameters( const QRectF &region, double &a, double &b, double &c, double &d, double &e, double &f, double dpi = -1 ) const;
+
+
   private:
 
     QPointer< QgsLayout > mLayout;

tests/src/core/testqgslayoutmap.cpp

@@ -27,6 +27,7 @@
 #include "qgsproject.h"
 #include "qgsmapthemecollection.h"
 #include "qgsproperty.h"
+#include "qgslayoutpagecollection.h"
 #include <QObject>
 #include "qgstest.h"
 
@@ -46,8 +47,9 @@ class TestQgsLayoutMap : public QObject
     void render();
 #if 0
     void uniqueId(); //test if map id is adapted when doing copy paste
-    void worldFileGeneration(); // test world file generation
 #endif
+    void worldFileGeneration(); // test world file generation
+
     void mapPolygonVertices(); // test mapPolygon function with no map rotation
     void dataDefinedLayers(); //test data defined layer string
     void dataDefinedStyles(); //test data defined styles
@@ -189,17 +191,31 @@ void TestQgsLayoutMap::uniqueId()
 
   QVERIFY( oldId != newId );
 }
+#endif
 
 void TestQgsLayoutMap::worldFileGeneration()
 {
-  mComposerMap->setNewExtent( QgsRectangle( 781662.375, 3339523.125, 793062.375, 3345223.125 ) );
-  mComposerMap->setMapRotation( 30.0 );
+  QgsLayout l( QgsProject::instance() );
+  l.initializeDefaults();
+  QgsLayoutItemPage *page2 = new QgsLayoutItemPage( &l );
+  page2->setPageSize( "A4", QgsLayoutItemPage::Landscape );
+  l.pageCollection()->addPage( page2 );
+
+  QgsLayoutItemMap *map = new QgsLayoutItemMap( &l );
+  map->attemptSetSceneRect( QRectF( 20, 20, 200, 100 ) );
+  map->setFrameEnabled( true );
+  map->setLayers( QList<QgsMapLayer *>() << mRasterLayer );
+  l.addLayoutItem( map );
+
+  map->setExtent( QgsRectangle( 781662.375, 3339523.125, 793062.375, 3345223.125 ) );
+  map->setMapRotation( 30.0 );
 
-  mComposition->setGenerateWorldFile( true );
-  mComposition->setReferenceMap( mComposerMap );
+  l.setReferenceMap( map );
+
+  QgsLayoutExporter exporter( &l );
 
   double a, b, c, d, e, f;
-  mComposition->computeWorldFileParameters( a, b, c, d, e, f );
+  exporter.computeWorldFileParameters( a, b, c, d, e, f );
 
   QGSCOMPARENEAR( a, 4.18048, 0.001 );
   QGSCOMPARENEAR( b, 2.41331, 0.001 );
@@ -209,8 +225,8 @@ void TestQgsLayoutMap::worldFileGeneration()
   QGSCOMPARENEAR( f, 3.34241e+06, 1e+03 );
 
   //test with map on second page. Parameters should be the same
-  mComposerMap->setItemPosition( 20, 20, QgsComposerItem::UpperLeft, 2 );
-  mComposition->computeWorldFileParameters( a, b, c, d, e, f );
+  map->attemptMove( QgsLayoutPoint( 20, 20 ), true, false, 1 );
+  exporter.computeWorldFileParameters( a, b, c, d, e, f );
 
   QGSCOMPARENEAR( a, 4.18048, 0.001 );
   QGSCOMPARENEAR( b, 2.41331, 0.001 );
@@ -220,21 +236,16 @@ void TestQgsLayoutMap::worldFileGeneration()
   QGSCOMPARENEAR( f, 3.34241e+06, 1e+03 );
 
   //test computing parameters for specific region
-  mComposerMap->setItemPosition( 20, 20, QgsComposerItem::UpperLeft, 2 );
-  mComposition->computeWorldFileParameters( QRectF( 10, 5, 260, 200 ), a, b, c, d, e, f );
+  map->attemptMove( QgsLayoutPoint( 20, 20 ), true, false, 1 );
+  exporter.computeWorldFileParameters( QRectF( 10, 5, 260, 200 ), a, b, c, d, e, f );
 
   QGSCOMPARENEAR( a, 4.18061, 0.001 );
   QGSCOMPARENEAR( b, 2.41321, 0.001 );
   QGSCOMPARENEAR( c, 773810, 1 );
   QGSCOMPARENEAR( d, 2.4137, 0.001 );
   QGSCOMPARENEAR( e, -4.1798, 0.001 );
   QGSCOMPARENEAR( f, 3.35331e+06, 1e+03 );
-
-  mComposition->setGenerateWorldFile( false );
-  mComposerMap->setMapRotation( 0.0 );
-
 }
-#endif
 
 
 void TestQgsLayoutMap::mapPolygonVertices()