Fix rendering polys/lines with reprojection errors under proj 6

nyalldawson · nyalldawson · commit cf91c09c3c16 · 2019-05-22T03:43:48.000+10:00
diff --git a/src/core/qgscoordinatetransform.cpp b/src/core/qgscoordinatetransform.cpp
@@ -346,15 +346,15 @@ void QgsCoordinateTransform::transformPolygon( QPolygonF &poly, TransformDirecti
     polyData++;
   }
 
+  QString err;
   try
   {
     transformCoords( nVertices, x.data(), y.data(), z.data(), direction );
   }
-  catch ( const QgsCsException & )
+  catch ( const QgsCsException &e )
   {
-    // rethrow the exception
-    QgsDebugMsg( QStringLiteral( "rethrowing exception" ) );
-    throw;
+    // record the exception, but don't rethrow it until we've recorded the coordinates we *could* transform
+    err = e.what();
   }
 
   QPointF *destPoint = poly.data();
@@ -366,6 +366,10 @@ void QgsCoordinateTransform::transformPolygon( QPolygonF &poly, TransformDirecti
     destPoint->ry() = *srcY++;
     destPoint++;
   }
+
+  // rethrow the exception
+  if ( !err.isEmpty() )
+    throw QgsCsException( err );
 }
 
 void QgsCoordinateTransform::transformInPlace(
diff --git a/src/core/symbology/qgssymbol.cpp b/src/core/symbology/qgssymbol.cpp
@@ -124,7 +124,14 @@ QPolygonF QgsSymbol::_getLineString( QgsRenderContext &context, const QgsCurve &
   //transform the QPolygonF to screen coordinates
   if ( ct.isValid() )
   {
-    ct.transformPolygon( pts );
+    try
+    {
+      ct.transformPolygon( pts );
+    }
+    catch ( QgsCsException & )
+    {
+      // we don't abort the rendering here, instead we remove any invalid points and just plot those which ARE valid
+    }
   }
 
   // remove non-finite points, e.g. infinite or NaN points caused by reprojecting errors
@@ -176,7 +183,14 @@ QPolygonF QgsSymbol::_getPolygonRing( QgsRenderContext &context, const QgsCurve
   //transform the QPolygonF to screen coordinates
   if ( ct.isValid() )
   {
-    ct.transformPolygon( poly );
+    try
+    {
+      ct.transformPolygon( poly );
+    }
+    catch ( QgsCsException & )
+    {
+      // we don't abort the rendering here, instead we remove any invalid points and just plot those which ARE valid
+    }
   }
 
   // remove non-finite points, e.g. infinite or NaN points caused by reprojecting errors

Original file line number	Diff line number	Diff line change
`@@ -346,15 +346,15 @@ void QgsCoordinateTransform::transformPolygon( QPolygonF &poly, TransformDirecti`
`346`	`346`	`polyData++;`
`347`	`347`	`}`
`348`	`348`
	`349`	`+ QString err;`
`349`	`350`	`try`
`350`	`351`	`{`
`351`	`352`	`transformCoords( nVertices, x.data(), y.data(), z.data(), direction );`
`352`	`353`	`}`
`353`		`- catch ( const QgsCsException & )`
	`354`	`+ catch ( const QgsCsException &e )`
`354`	`355`	`{`
`355`		`- // rethrow the exception`
`356`		`- QgsDebugMsg( QStringLiteral( "rethrowing exception" ) );`
`357`		`- throw;`
	`356`	`+ // record the exception, but don't rethrow it until we've recorded the coordinates we could transform`
	`357`	`+ err = e.what();`
`358`	`358`	`}`
`359`	`359`
`360`	`360`	`QPointF *destPoint = poly.data();`
`@@ -366,6 +366,10 @@ void QgsCoordinateTransform::transformPolygon( QPolygonF &poly, TransformDirecti`
`366`	`366`	`destPoint->ry() = *srcY++;`
`367`	`367`	`destPoint++;`
`368`	`368`	`}`
	`369`	`+`
	`370`	`+ // rethrow the exception`
	`371`	`+ if ( !err.isEmpty() )`
	`372`	`+ throw QgsCsException( err );`
`369`	`373`	`}`
`370`	`374`
`371`	`375`	`void QgsCoordinateTransform::transformInPlace(`