Add method to retrieve grid details from a proj string

qgis · Jun 3, 2019 · fe4ea33 · fe4ea33
1 parent 56c265f
commit fe4ea33
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Showing 3 changed files with 57 additions and 0 deletions.
diff --git a/src/core/qgsprojutils.cpp b/src/core/qgsprojutils.cpp
@@ -18,6 +18,7 @@
 #include "qgis.h"
 #include <QString>
 #include <QSet>
+#include <QRegularExpression>
 
 #if PROJ_VERSION_MAJOR>=6
 #include <proj.h>
@@ -191,6 +192,40 @@ bool QgsProjUtils::coordinateOperationIsAvailable( const QString &projDef )
   return static_cast< bool >( proj_coordoperation_is_instantiable( context, coordinateOperation.get() ) );
 }
 
+QList<QgsDatumTransform::GridDetails> QgsProjUtils::gridsUsed( const QString &proj )
+{
+  static QRegularExpression sRegex( QStringLiteral( "\\+(?:nad)?grids=(.*?)\\s" ) );
+
+  QList< QgsDatumTransform::GridDetails > grids;
+  QRegularExpressionMatchIterator matches = sRegex.globalMatch( proj );
+  while ( matches.hasNext() )
+  {
+    const QRegularExpressionMatch match = matches.next();
+    const QString gridName = match.captured( 1 );
+    QgsDatumTransform::GridDetails grid;
+    grid.shortName = gridName;
+#if PROJ_VERSION_MAJOR >= 6
+#if PROJ_VERSION_MINOR >= 2
+    const char *fullName = nullptr;
+    const char *packageName = nullptr;
+    const char *url = nullptr;
+    int directDownload = 0;
+    int openLicense = 0;
+    int available = 0;
+    proj_grid_get_info_from_database( QgsProjContext::get(), gridName.toUtf8().constData(), &fullName, &packageName, &url, &directDownload, &openLicense, &available );
+    grid.fullName = QString( fullName );
+    grid.packageName = QString( packageName );
+    grid.url = QString( url );
+    grid.directDownload = directDownload;
+    grid.openLicense = openLicense;
+    grid.isAvailable = available;
+#endif
+#endif
+    grids.append( grid );
+  }
+  return grids;
+}
+
 #if 0
 QStringList QgsProjUtils::nonAvailableGrids( const QString &projDef )
 {

diff --git a/src/core/qgsprojutils.h b/src/core/qgsprojutils.h
@@ -21,6 +21,7 @@
 
 #include "qgis_core.h"
 #include "qgsconfig.h"
+#include "qgsdatumtransform.h"
 #include <memory>
 #include <QStringList>
 
@@ -107,6 +108,12 @@ class CORE_EXPORT QgsProjUtils
      */
     static bool coordinateOperationIsAvailable( const QString &projDef );
 
+    /**
+     * Returns a list of grids used by the given \a proj string.
+     */
+    static QList< QgsDatumTransform::GridDetails > gridsUsed( const QString &proj );
+
+
 #if 0 // not possible in current Proj 6 API
 
     /**

diff --git a/tests/src/core/testqgsprojutils.cpp b/tests/src/core/testqgsprojutils.cpp
@@ -36,6 +36,7 @@ class TestQgsProjUtils: public QObject
     void usesAngularUnits();
     void axisOrderIsSwapped();
     void searchPath();
+    void gridsUsed();
 
 };
 
@@ -107,5 +108,19 @@ void TestQgsProjUtils::searchPath()
 #endif
 }
 
+void TestQgsProjUtils::gridsUsed()
+{
+#if PROJ_VERSION_MAJOR>=6
+  // ensure local user-writable path is present in Proj search paths
+  const QList< QgsDatumTransform::GridDetails > grids = QgsProjUtils::gridsUsed( QStringLiteral( "+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +inv +proj=hgridshift +grids=GDA94_GDA2020_conformal_and_distortion.gsb +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1" ) );
+  QCOMPARE( grids.count(), 1 );
+  QCOMPARE( grids.at( 0 ).shortName, QStringLiteral( "GDA94_GDA2020_conformal_and_distortion.gsb" ) );
+#if PROJ_VERSION_MINOR>=2
+  QCOMPARE( grids.at( 0 ).packageName, QStringLiteral( "proj-datumgrid-oceania" ) );
+  QVERIFY( grids.at( 0 ).directDownload );
+#endif
+#endif
+}
+
 QGSTEST_MAIN( TestQgsProjUtils )
 #include "testqgsprojutils.moc"