Use proj6 for custom projections dialog

Author: nyalldawson

src/app/qgscustomprojectiondialog.cpp

@@ -38,14 +38,12 @@
 #include <sqlite3.h>
 
 //proj4 includes
-extern "C"
-{
-#ifndef ACCEPT_USE_OF_DEPRECATED_PROJ_API_H
-#define ACCEPT_USE_OF_DEPRECATED_PROJ_API_H
-#endif
+#if PROJ_VERSION_MAJOR>=6
+#include "qgsprojutils.h"
+#include <proj.h>
+#else
 #include <proj_api.h>
-}
-
+#endif
 
 QgsCustomProjectionDialog::QgsCustomProjectionDialog( QWidget *parent, Qt::WindowFlags fl )
   : QDialog( parent, fl )
@@ -446,38 +444,51 @@ void QgsCustomProjectionDialog::updateListFromCurrentItem()
 void QgsCustomProjectionDialog::pbnCalculate_clicked()
 {
   // We must check the prj def is valid!
+#if PROJ_VERSION_MAJOR>=6
+  PJ_CONTEXT *pContext = QgsProjContext::get();
+  const QString projDef = teParameters->toPlainText();
+  QgsDebugMsg( QStringLiteral( "Proj: %1" ).arg( projDef ) );
+#else
   projCtx pContext = pj_ctx_alloc();
   projPJ proj = pj_init_plus_ctx( pContext, teParameters->toPlainText().toLocal8Bit().data() );
-
   QgsDebugMsg( QStringLiteral( "Proj: %1" ).arg( teParameters->toPlainText() ) );
 
   if ( !proj )
   {
     QMessageBox::information( this, tr( "QGIS Custom Projection" ),
-                              tr( "This proj4 projection definition is not valid." ) );
+                              tr( "This proj projection definition is not valid." ) );
     projectedX->clear();
     projectedY->clear();
     pj_free( proj );
     pj_ctx_free( pContext );
     return;
 
   }
+#endif
   // Get the WGS84 coordinates
   bool okN, okE;
-  double northing = northWGS84->text().toDouble( &okN ) * DEG_TO_RAD;
-  double easting = eastWGS84->text().toDouble( &okE )  * DEG_TO_RAD;
+  double northing = northWGS84->text().toDouble( &okN );
+  double easting = eastWGS84->text().toDouble( &okE );
+
+#if PROJ_VERSION_MAJOR<6
+  northing *= DEG_TO_RAD;
+  easting * = DEG_TO_RAD;
+#endif
 
   if ( !okN || !okE )
   {
     QMessageBox::information( this, tr( "QGIS Custom Projection" ),
-                              tr( "Northing and Easthing must be in decimal form." ) );
+                              tr( "Northing and Easting must be in decimal form." ) );
     projectedX->clear();
     projectedY->clear();
+#if PROJ_VERSION_MAJOR<6
     pj_free( proj );
     pj_ctx_free( pContext );
+#endif
     return;
   }
 
+#if PROJ_VERSION_MAJOR < 6
   projPJ wgs84Proj = pj_init_plus_ctx( pContext, GEOPROJ4.toLocal8Bit().data() ); //defined in qgis.h
 
   if ( !wgs84Proj )
@@ -490,38 +501,65 @@ void QgsCustomProjectionDialog::pbnCalculate_clicked()
     pj_ctx_free( pContext );
     return;
   }
+#endif
 
-  double z = 0.0;
+#if PROJ_VERSION_MAJOR>=6
+  QgsProjUtils::proj_pj_unique_ptr res( proj_create_crs_to_crs( pContext, "EPSG:4326", projDef.toUtf8(), nullptr ) );
+  if ( !res )
+  {
+    QMessageBox::information( this, tr( "QGIS Custom Projection" ),
+                              tr( "This proj projection definition is not valid." ) );
+    projectedX->clear();
+    projectedY->clear();
+    return;
+  }
 
+  proj_trans_generic( res.get(), PJ_FWD,
+                      &easting, sizeof( double ), 1,
+                      &northing, sizeof( double ), 1,
+                      nullptr, sizeof( double ), 0,
+                      nullptr, sizeof( double ), 0 );
+  int projResult = proj_errno( res.get() );
+#else
+  double z = 0.0;
   int projResult = pj_transform( wgs84Proj, proj, 1, 0, &easting, &northing, &z );
+#endif
   if ( projResult != 0 )
   {
     projectedX->setText( tr( "Error" ) );
     projectedY->setText( tr( "Error" ) );
+#if PROJ_VERSION_MAJOR>=6
+    QgsDebugMsg( proj_errno_string( projResult ) );
+#else
     QgsDebugMsg( pj_strerrno( projResult ) );
+#endif
   }
   else
   {
     QString tmp;
 
-    int precision = 4;
+    int precision = 7;
 
+#if PROJ_VERSION_MAJOR<6
     if ( pj_is_latlong( proj ) )
     {
       northing *= RAD_TO_DEG;
       easting *= RAD_TO_DEG;
       precision = 7;
     }
+#endif
 
     tmp = QLocale().toString( northing, 'f', precision );
     projectedX->setText( tmp );
     tmp = QLocale().toString( easting, 'f', precision );
     projectedY->setText( tmp );
   }
 
+#if PROJ_VERSION_MAJOR<6
   pj_free( proj );
   pj_free( wgs84Proj );
   pj_ctx_free( pContext );
+#endif
 }
 
 void QgsCustomProjectionDialog::showHelp()