fix: check if Array instead of number

data/olStyles/point_simpleoffset.ts

@@ -0,0 +1,15 @@
+import OlStyle from 'ol/style/Style';
+import OlStyleCircle from 'ol/style/Circle';
+import OlStyleFill from 'ol/style/Fill';
+
+const olSimplePoint = new OlStyle({
+  image: new OlStyleCircle({
+    radius: 6,
+    fill: new OlStyleFill({
+      color: '#FF0000'
+    }),
+    displacement: [1,1]
+  })
+});
+
+export default olSimplePoint;

data/styles/point_simpleoffset.ts

@@ -0,0 +1,19 @@
+import { Style } from 'geostyler-style';
+
+const pointSimpleOffset: Style = {
+  name: 'OL Style',
+  rules: [
+    {
+      name: 'OL Style Rule 0',
+      symbolizers: [{
+        kind: 'Mark',
+        wellKnownName: 'circle',
+        color: '#FF0000',
+        radius: 6,
+        offset: [1, 1]
+      }]
+    }
+  ]
+};
+
+export default pointSimpleOffset;

src/OlStyleParser.spec.ts

@@ -13,6 +13,7 @@ import OlFeature from 'ol/Feature';
 import OlStyleParser, { OlParserStyleFct } from './OlStyleParser';
 
 import point_simplepoint from '../data/styles/point_simplepoint';
+import point_simpleoffset from '../data/styles/point_simpleoffset';
 import point_icon from '../data/styles/point_icon';
 import point_icon_sprite from '../data/styles/point_icon_sprite';
 import point_dynamic_icon from '../data/styles/point_dynamic_icon';
@@ -58,6 +59,7 @@ import filter_comparison_propertyFunction from '../data/styles/filter_comparison
 import ol_function_marksymbolizer from '../data/olStyles/function_markSymbolizer';
 import ol_function_nested_fillsymbolizer from '../data/olStyles/function_nested_fillSymbolizer';
 import ol_point_simplepoint from '../data/olStyles/point_simplepoint';
+import ol_point_simpleoffset from '../data/olStyles/point_simpleoffset';
 import ol_point_icon from '../data/olStyles/point_icon';
 import ol_point_icon_sprite from '../data/olStyles/point_icon_sprite';
 import ol_point_simplesquare from '../data/olStyles/point_simplesquare';
@@ -155,6 +157,11 @@ describe('OlStyleParser implements StyleParser', () => {
       expect(geoStylerStyle).toBeDefined();
       expect(geoStylerStyle).toEqual(point_simplepoint);
     });
+    it('can read an OpenLayers PointSymbolizer with displacement', async () => {
+      const { output: geoStylerStyle } = await styleParser.readStyle(ol_point_simpleoffset);
+      expect(geoStylerStyle).toBeDefined();
+      expect(geoStylerStyle).toEqual(point_simpleoffset);
+    });
     it('can read an OpenLayers IconSymbolizer', async () => {
       const { output: geoStylerStyle } = await styleParser.readStyle(ol_point_icon);
       expect(geoStylerStyle).toBeDefined();
@@ -459,6 +466,17 @@ describe('OlStyleParser implements StyleParser', () => {
       expect(olCircle.getRadius()).toBeCloseTo(expecSymb.radius as number);
       expect(olCircle.getFill()?.getColor()).toEqual(expecSymb.color);
     });
+    it('can write an OpenLayers PointSymbolizer with displacement', async () => {
+      let { output: olStyle } = await styleParser.writeStyle(point_simpleoffset);
+      olStyle = olStyle as OlStyle;
+      expect(olStyle).toBeDefined();
+
+      const expecSymb = point_simpleoffset.rules[0].symbolizers[0] as MarkSymbolizer;
+      const olCircle: OlStyleCircle = olStyle.getImage() as OlStyleCircle;
+
+      expect(olCircle).toBeDefined();
+      expect(olCircle.getDisplacement()).toEqual(expecSymb.offset);
+    });
     it('can write an OpenLayers IconSymbolizer', async () => {
       let { output: olStyle } = await styleParser.writeStyle(point_icon);
       olStyle = olStyle as OlStyle;

src/OlStyleParser.ts

@@ -1046,7 +1046,7 @@ export class OlStyleParser implements StyleParser<OlStyleLike> {
       radius: radius ?? 5,
       rotation: typeof(markSymbolizer.rotate) === 'number' ? markSymbolizer.rotate * Math.PI / 180 : undefined,
       stroke: stroke,
-      displacement: typeof(markSymbolizer.offset) === 'number' ? markSymbolizer.offset : undefined
+      displacement: Array.isArray(markSymbolizer.offset) ? markSymbolizer.offset.map(Number) : undefined
     };
 
     switch (markSymbolizer.wellKnownName) {