Don't allow building QGIS on proj 6.0 versions

Require at least 6.1.0. We need proj_normalize_for_visualization,
and the workarounds for building without it are too extensive,
too fragile, and result in too much spaghetti code.

Gotta make the hard call here ;)

cmake/FindProj.cmake

@@ -57,6 +57,9 @@ IF (PROJ_FOUND)
      STRING(REGEX REPLACE "^.*PROJ_VERSION_MINOR +([0-9]+).*$" "\\1" PROJ_VERSION_MINOR "${proj_version}")
      STRING(REGEX REPLACE "^.*PROJ_VERSION_PATCH +([0-9]+).*$" "\\1" PROJ_VERSION_PATCH "${proj_version}")
      STRING(CONCAT PROJ_VERSION_STR "(" ${PROJ_VERSION_MAJOR} "." ${PROJ_VERSION_MINOR} "." ${PROJ_VERSION_PATCH} ")")
+     IF ((PROJ_VERSION_MAJOR EQUAL 6) AND (PROJ_VERSION_MINOR EQUAL 0))
+       MESSAGE (FATAL_ERROR "Cannot build QGIS using Proj ${PROJ_VERSION_MAJOR}.${PROJ_VERSION_MINOR}.${PROJ_VERSION_PATCH} Use 6.1.0 or higher.")
+     ENDIF ((PROJ_VERSION_MAJOR EQUAL 6) AND (PROJ_VERSION_MINOR EQUAL 0))
    ELSE(EXISTS ${PROJ_INCLUDE_DIR}/proj.h)
      SET(PROJ_VERSION_MAJOR 4)
    ENDIF(EXISTS ${PROJ_INCLUDE_DIR}/proj.h)

src/core/qgscoordinatetransform.cpp

@@ -652,7 +652,18 @@ void QgsCoordinateTransform::transformCoords( int numPoints, double *x, double *
   // if the source/destination projection is lat/long, convert the points to radians
   // prior to transforming
   ProjData projData = d->threadLocalProjData();
-#if PROJ_VERSION_MAJOR<6
+
+  int projResult = 0;
+#if PROJ_VERSION_MAJOR>=6
+  proj_errno_reset( projData );
+  proj_trans_generic( projData, direction == ForwardTransform ? PJ_FWD : PJ_INV,
+                      x, sizeof( double ), numPoints,
+                      y, sizeof( double ), numPoints,
+                      z, sizeof( double ), numPoints,
+                      nullptr, sizeof( double ), 0 );
+  projResult = proj_errno( projData );
+  // ewww - this logic is gross. We should drop support for PROJ 6.0 as quickly as possible and dump this code (in favour of built in methods used for >=6.1 builds)
+#else
   bool sourceIsLatLong = false;
   bool destIsLatLong = false;
 
@@ -672,28 +683,7 @@ void QgsCoordinateTransform::transformCoords( int numPoints, double *x, double *
   }
 #endif
 
-  int projResult = 0;
-#if PROJ_VERSION_MAJOR>=6
-  const bool sourceAxisOrderSwapped =  direction == ForwardTransform ? d->mSourceAxisOrderSwapped : d->mDestAxisOrderSwapped;
-
-  proj_errno_reset( projData );
-  proj_trans_generic( projData, direction == ForwardTransform ? PJ_FWD : PJ_INV,
-                      !sourceAxisOrderSwapped ? x : y, sizeof( double ), numPoints,
-                      !sourceAxisOrderSwapped ? y : x, sizeof( double ), numPoints,
-                      z, sizeof( double ), numPoints,
-                      nullptr, sizeof( double ), 0 );
-  projResult = proj_errno( projData );
-  // ewww - this logic is gross. We should drop support for PROJ 6.0 as quickly as possible and dump this code (in favour of built in methods used for >=6.1 builds)
-  if ( projResult == 0 && ( d->mSourceAxisOrderSwapped != d->mDestAxisOrderSwapped ) )
-  {
-    size_t size = sizeof( double ) * numPoints;
-    void *tmp = malloc( size );
-    memcpy( tmp, x, size );
-    memcpy( x, y, size );
-    memcpy( y, tmp, size );
-    free( tmp );
-  }
-#else
+#if PROJ_VERSION_MAJOR<6
   if ( direction == ReverseTransform )
   {
     projResult = pj_transform( destProj, sourceProj, numPoints, 0, x, y, z );

src/core/qgscoordinatetransform_p.cpp

@@ -100,8 +100,6 @@ QgsCoordinateTransformPrivate::QgsCoordinateTransformPrivate( const QgsCoordinat
   , mDestCRS( other.mDestCRS )
   , mSourceDatumTransform( other.mSourceDatumTransform )
   , mDestinationDatumTransform( other.mDestinationDatumTransform )
-  , mSourceAxisOrderSwapped( other.mSourceAxisOrderSwapped )
-  , mDestAxisOrderSwapped( other.mDestAxisOrderSwapped )
 {
   //must reinitialize to setup mSourceProjection and mDestinationProjection
   initialize();
@@ -193,19 +191,6 @@ bool QgsCoordinateTransformPrivate::initialize()
   // create proj projections for current thread
   ProjData res = threadLocalProjData();
 
-#if PROJ_VERSION_MAJOR>=6
-#if PROJ_VERSION_MINOR<1
-  // because proj 6.0 does not have proj_normalize_for_visualization - we have to handle this manually and inefficiently!
-  PJ_CONTEXT *context = QgsProjContext::get();
-  QgsProjUtils::proj_pj_unique_ptr sourceCrs( proj_get_source_crs( context, res ) );
-  if ( sourceCrs )
-    mSourceAxisOrderSwapped = QgsProjUtils::axisOrderIsSwapped( sourceCrs.get() );
-  QgsProjUtils::proj_pj_unique_ptr destCrs( proj_get_target_crs( context, res ) );
-  if ( destCrs )
-    mDestAxisOrderSwapped = QgsProjUtils::axisOrderIsSwapped( destCrs.get() );
-#endif
-#endif
-
 #ifdef COORDINATE_TRANSFORM_VERBOSE
   QgsDebugMsg( "From proj : " + mSourceCRS.toProj4() );
   QgsDebugMsg( "To proj   : " + mDestCRS.toProj4() );
@@ -311,7 +296,6 @@ ProjData QgsCoordinateTransformPrivate::threadLocalProjData()
   locker.changeMode( QgsReadWriteLocker::Write );
 
 #if PROJ_VERSION_MAJOR>=6
-#if PROJ_VERSION_MINOR>=1
   QgsProjUtils::proj_pj_unique_ptr transform;
   if ( !mProjCoordinateOperation.isEmpty() )
     transform.reset( proj_create( context, mProjCoordinateOperation.toUtf8().constData() ) );
@@ -493,12 +477,6 @@ ProjData QgsCoordinateTransformPrivate::threadLocalProjData()
 
   ProjData res = transform.release();
   mProjProjections.insert( reinterpret_cast< uintptr_t>( context ), res );
-
-#else
-  // proj 6.0 does not have proj_normalize_for_visualization - we have to handle this manually and inefficiently!
-  ProjData res = proj_create_crs_to_crs( context, mSourceProjString.toUtf8().constData(), mDestProjString.toUtf8().constData(), nullptr );
-  mProjProjections.insert( reinterpret_cast< uintptr_t>( context ), res );
-#endif
 #else
 #ifdef USE_THREAD_LOCAL
   Q_NOWARN_DEPRECATED_PUSH

src/core/qgscoordinatetransform_p.h

@@ -127,9 +127,6 @@ class QgsCoordinateTransformPrivate : public QSharedData
     Q_DECL_DEPRECATED int mDestinationDatumTransform = -1;
     QString mProjCoordinateOperation;
 
-    bool mSourceAxisOrderSwapped = false;
-    bool mDestAxisOrderSwapped = false;
-
 #if PROJ_VERSION_MAJOR<6
 
     /**

src/core/qgsdatumtransform.cpp

@@ -313,11 +313,10 @@ QgsDatumTransform::TransformDetails QgsDatumTransform::transformDetailsFromPj( P
   if ( !op )
     return details;
 
-#if PROJ_VERSION_MINOR >= 1 // really, QGIS is pretty broken on PROJ 6.0 due to the absence of proj_normalize_for_visualization. Just don't use it.
   QgsProjUtils::proj_pj_unique_ptr normalized( proj_normalize_for_visualization( pjContext, op ) );
   if ( normalized )
     details.proj = QString( proj_as_proj_string( pjContext, normalized.get(), PJ_PROJ_5, nullptr ) );
-#endif
+
   if ( details.proj.isEmpty() )
     details.proj = QString( proj_as_proj_string( pjContext, op, PJ_PROJ_5, nullptr ) );
   details.name = QString( proj_get_name( op ) );