Fix LabelLayer MultipartGeometryBehaviourEnum.CommonCenter

terribletim · FObermaier · commit 14bde2babefd · 2020-03-16T16:11:48.000+01:00
diff --git a/SharpMap/Layers/LabelLayer.cs b/SharpMap/Layers/LabelLayer.cs
@@ -548,9 +548,9 @@ private List<BaseLabel> CreateLabelDefinitions(Graphics g, MapViewport map, Feat
                 
                 if (feature.Geometry is IGeometryCollection)
                 {
+                    var geoms = feature.Geometry as IGeometryCollection;
                     if (MultipartGeometryBehaviour == MultipartGeometryBehaviourEnum.All)
                     {
-                        var geoms = feature.Geometry as IGeometryCollection;
                         for (int j = 0; j < geoms.Count; j++)
                         {
                             BaseLabel lbl = CreateLabelDefinition(feature, geoms.GetGeometryN(j), text, rotation,
@@ -561,30 +561,47 @@ private List<BaseLabel> CreateLabelDefinitions(Graphics g, MapViewport map, Feat
                     }
                     else if (MultipartGeometryBehaviour == MultipartGeometryBehaviourEnum.CommonCenter)
                     {
-                        BaseLabel lbl = CreateLabelDefinition(feature, feature.Geometry, text, rotation, priority, style, map, g, _getLocationMethod, factory);
-                        if (lbl != null)
-                            labels.Add(lbl);
+                        if (geoms.NumGeometries > 0)
+                        {
+                            var pt = geoms.Centroid;
+                            var closest = double.MaxValue;
+                            var idxOfClosest = 0;
+                            for (var j = 0; j < geoms.NumGeometries; j++)
+                            {
+                                var geom = geoms.GetGeometryN(j);
+                                var dist = geom.Distance(pt);
+                                if (dist < closest)
+                                {
+                                    closest = dist;
+                                    idxOfClosest = j;
+                                }
+                            }
+
+                            BaseLabel lbl = CreateLabelDefinition(feature, geoms.GetGeometryN(idxOfClosest), text,
+                                rotation, priority, style, map, g, _getLocationMethod, factory);
+                            if (lbl != null)
+                                labels.Add(lbl);
+                        }
                     }
                     else if (MultipartGeometryBehaviour == MultipartGeometryBehaviourEnum.First)
                     {
-                        if ((feature.Geometry as IGeometryCollection).NumGeometries > 0)
+                        if (geoms.NumGeometries > 0)
                         {
-                            BaseLabel lbl = CreateLabelDefinition(feature, (feature.Geometry as IGeometryCollection).GetGeometryN(0), text,
+                            BaseLabel lbl = CreateLabelDefinition(feature, geoms.GetGeometryN(0), text,
                                 rotation, priority, style, map, g, _getLocationMethod, factory);
                             if (lbl != null)
                                 labels.Add(lbl);
                         }
                     }
                     else if (MultipartGeometryBehaviour == MultipartGeometryBehaviourEnum.Largest)
                     {
-                        var coll = (feature.Geometry as IGeometryCollection);
-                        if (coll.NumGeometries > 0)
+                        if (geoms.NumGeometries > 0)
                         {
                             var largestVal = 0d;
                             var idxOfLargest = 0;
-                            for (var j = 0; j < coll.NumGeometries; j++)
+                            for (var j = 0; j < geoms.NumGeometries; j++)
                             {
-                                var geom = coll.GetGeometryN(j);
+                                var geom = geoms.GetGeometryN(j);
                                 if (geom is ILineString && ((ILineString) geom).Length > largestVal)
                                 {
                                     largestVal = ((ILineString) geom).Length;
@@ -607,7 +624,7 @@ private List<BaseLabel> CreateLabelDefinitions(Graphics g, MapViewport map, Feat
                                 }
                             }
 
-                            BaseLabel lbl = CreateLabelDefinition(feature, coll.GetGeometryN(idxOfLargest), text, rotation, priority, style,
+                            BaseLabel lbl = CreateLabelDefinition(feature, geoms.GetGeometryN(idxOfLargest), text, rotation, priority, style,
                                 map, g, _getLocationMethod, factory);
                             if (lbl != null)
                                 labels.Add(lbl);

Original file line number	Diff line number	Diff line change
`@@ -548,9 +548,9 @@ private List<BaseLabel> CreateLabelDefinitions(Graphics g, MapViewport map, Feat`
`548`	`548`
`549`	`549`	`if (feature.Geometry is IGeometryCollection)`
`550`	`550`	`{`
	`551`	`+ var geoms = feature.Geometry as IGeometryCollection;`
`551`	`552`	`if (MultipartGeometryBehaviour == MultipartGeometryBehaviourEnum.All)`
`552`	`553`	`{`
`553`		`- var geoms = feature.Geometry as IGeometryCollection;`
`554`	`554`	`for (int j = 0; j < geoms.Count; j++)`
`555`	`555`	`{`
`556`	`556`	`BaseLabel lbl = CreateLabelDefinition(feature, geoms.GetGeometryN(j), text, rotation,`
`@@ -561,30 +561,47 @@ private List<BaseLabel> CreateLabelDefinitions(Graphics g, MapViewport map, Feat`
`561`	`561`	`}`
`562`	`562`	`else if (MultipartGeometryBehaviour == MultipartGeometryBehaviourEnum.CommonCenter)`
`563`	`563`	`{`
`564`		`- BaseLabel lbl = CreateLabelDefinition(feature, feature.Geometry, text, rotation, priority, style, map, g, _getLocationMethod, factory);`
`565`		`- if (lbl != null)`
`566`		`- labels.Add(lbl);`
	`564`	`+ if (geoms.NumGeometries > 0)`
	`565`	`+ {`
	`566`	`+ var pt = geoms.Centroid;`
	`567`	`+ var closest = double.MaxValue;`
	`568`	`+ var idxOfClosest = 0;`
	`569`	`+ for (var j = 0; j < geoms.NumGeometries; j++)`
	`570`	`+ {`
	`571`	`+ var geom = geoms.GetGeometryN(j);`
	`572`	`+ var dist = geom.Distance(pt);`
	`573`	`+ if (dist < closest)`
	`574`	`+ {`
	`575`	`+ closest = dist;`
	`576`	`+ idxOfClosest = j;`
	`577`	`+ }`
	`578`	`+ }`
	`579`	`+`
	`580`	`+ BaseLabel lbl = CreateLabelDefinition(feature, geoms.GetGeometryN(idxOfClosest), text,`
	`581`	`+ rotation, priority, style, map, g, _getLocationMethod, factory);`
	`582`	`+ if (lbl != null)`
	`583`	`+ labels.Add(lbl);`
	`584`	`+ }`
`567`	`585`	`}`
`568`	`586`	`else if (MultipartGeometryBehaviour == MultipartGeometryBehaviourEnum.First)`
`569`	`587`	`{`
`570`		`- if ((feature.Geometry as IGeometryCollection).NumGeometries > 0)`
	`588`	`+ if (geoms.NumGeometries > 0)`
`571`	`589`	`{`
`572`		`- BaseLabel lbl = CreateLabelDefinition(feature, (feature.Geometry as IGeometryCollection).GetGeometryN(0), text,`
	`590`	`+ BaseLabel lbl = CreateLabelDefinition(feature, geoms.GetGeometryN(0), text,`
`573`	`591`	`rotation, priority, style, map, g, _getLocationMethod, factory);`
`574`	`592`	`if (lbl != null)`
`575`	`593`	`labels.Add(lbl);`
`576`	`594`	`}`
`577`	`595`	`}`
`578`	`596`	`else if (MultipartGeometryBehaviour == MultipartGeometryBehaviourEnum.Largest)`
`579`	`597`	`{`
`580`		`- var coll = (feature.Geometry as IGeometryCollection);`
`581`		`- if (coll.NumGeometries > 0)`
	`598`	`+ if (geoms.NumGeometries > 0)`
`582`	`599`	`{`
`583`	`600`	`var largestVal = 0d;`
`584`	`601`	`var idxOfLargest = 0;`
`585`		`- for (var j = 0; j < coll.NumGeometries; j++)`
	`602`	`+ for (var j = 0; j < geoms.NumGeometries; j++)`
`586`	`603`	`{`
`587`		`- var geom = coll.GetGeometryN(j);`
	`604`	`+ var geom = geoms.GetGeometryN(j);`
`588`	`605`	`if (geom is ILineString && ((ILineString) geom).Length > largestVal)`
`589`	`606`	`{`
`590`	`607`	`largestVal = ((ILineString) geom).Length;`
`@@ -607,7 +624,7 @@ private List<BaseLabel> CreateLabelDefinitions(Graphics g, MapViewport map, Feat`
`607`	`624`	`}`
`608`	`625`	`}`
`609`	`626`
`610`		`- BaseLabel lbl = CreateLabelDefinition(feature, coll.GetGeometryN(idxOfLargest), text, rotation, priority, style,`
	`627`	`+ BaseLabel lbl = CreateLabelDefinition(feature, geoms.GetGeometryN(idxOfLargest), text, rotation, priority, style,`
`611`	`628`	`map, g, _getLocationMethod, factory);`
`612`	`629`	`if (lbl != null)`
`613`	`630`	`labels.Add(lbl);`