Handle layer opacity in the composite renderer

rendering/cases/linestring-style-opacity/main.js

@@ -0,0 +1,70 @@
+import Map from '../../../src/ol/CompositeMap.js';
+import View from '../../../src/ol/View.js';
+import Feature from '../../../src/ol/Feature.js';
+import LineString from '../../../src/ol/geom/LineString.js';
+import VectorLayer from '../../../src/ol/layer/Vector.js';
+import VectorSource from '../../../src/ol/source/Vector.js';
+import Style from '../../../src/ol/style/Style.js';
+import Stroke from '../../../src/ol/style/Stroke.js';
+
+
+const vectorSource = new VectorSource();
+let feature;
+
+feature = new Feature({
+  geometry: new LineString([[-60, 60], [45, 60]])
+});
+vectorSource.addFeature(feature);
+
+feature = new Feature({
+  geometry: new LineString([[-60, -50], [30, 10]])
+});
+feature.setStyle(new Style({
+  stroke: new Stroke({color: '#f00', width: 3})
+}));
+vectorSource.addFeature(feature);
+
+feature = new Feature({
+  geometry: new LineString([[-110, -100], [0, 100], [100, -90]])
+});
+feature.setStyle(new Style({
+  stroke: new Stroke({
+    color: 'rgba(55, 55, 55, 0.75)',
+    width: 5,
+    lineCap: 'square',
+    lineDash: [4, 8],
+    lineJoin: 'round'
+  })
+}));
+vectorSource.addFeature(feature);
+
+feature = new Feature({
+  geometry: new LineString([[-80, 80], [80, 80], [-40, -90]])
+});
+feature.setStyle([
+  new Style({
+    stroke: new Stroke({color: '#F2F211', width: 5})
+  }),
+  new Style({
+    stroke: new Stroke({color: '#292921', width: 1})
+  })
+]);
+vectorSource.addFeature(feature);
+
+
+new Map({
+  pixelRatio: 1,
+  layers: [
+    new VectorLayer({
+      opacity: 0.5,
+      source: vectorSource
+    })
+  ],
+  target: 'map',
+  view: new View({
+    center: [0, 0],
+    resolution: 1
+  })
+});
+
+render();