Smarter opacity handling

src/ol/PluggableMap.js

@@ -39,7 +39,7 @@ import {create as createTransform, apply as applyTransform} from './transform.js
  * @property {boolean} animate
  * @property {import("./transform.js").Transform} coordinateToPixelTransform
  * @property {null|import("./extent.js").Extent} extent
- * @property {Array<*>} declutterItems
+ * @property {Array<DeclutterItems>} declutterItems
  * @property {import("./coordinate.js").Coordinate} focus
  * @property {number} index
  * @property {Array<import("./layer/Layer.js").State>} layerStatesArray
@@ -54,6 +54,13 @@ import {create as createTransform, apply as applyTransform} from './transform.js
  */
 
 
+/**
+ * @typedef {Object} DeclutterItems
+ * @property {Array<*>} items Declutter items of an executor.
+ * @property {number} opacity Layer opacity.
+ */
+
+
 /**
  * @typedef {function(PluggableMap, ?FrameState): any} PostRenderFunction
  */

src/ol/render.js

@@ -122,9 +122,10 @@ export function renderDeclutterItems(frameState, declutterTree) {
   }
   const items = frameState.declutterItems;
   for (let z = items.length - 1; z >= 0; --z) {
-    const zIndexItems = items[z];
+    const item = items[z];
+    const zIndexItems = item.items;
     for (let i = 0, ii = zIndexItems.length; i < ii; i += 3) {
-      declutterTree = zIndexItems[i].renderDeclutter(zIndexItems[i + 1], zIndexItems[i + 2], declutterTree);
+      declutterTree = zIndexItems[i].renderDeclutter(zIndexItems[i + 1], zIndexItems[i + 2], item.opacity, declutterTree);
     }
   }
   items.length = 0;

src/ol/render/canvas/Executor.js

@@ -416,10 +416,11 @@ class Executor extends Disposable {
   /**
    * @param {import("../canvas.js").DeclutterGroup} declutterGroup Declutter group.
    * @param {import("../../Feature.js").FeatureLike} feature Feature.
+   * @param {number} opacity Layer opacity.
    * @param {?} declutterTree Declutter tree.
    * @return {?} Declutter tree.
    */
-  renderDeclutter(declutterGroup, feature, declutterTree) {
+  renderDeclutter(declutterGroup, feature, opacity, declutterTree) {
     if (declutterGroup && declutterGroup.length > 5) {
       const groupCount = declutterGroup[4];
       if (groupCount == 1 || groupCount == declutterGroup.length - 5) {
@@ -438,13 +439,19 @@ class Executor extends Disposable {
           declutterTree.insert(box);
           for (let j = 5, jj = declutterGroup.length; j < jj; ++j) {
             const declutterData = /** @type {Array} */ (declutterGroup[j]);
-            if (declutterData) {
-              if (declutterData.length > 11) {
-                this.replayTextBackground_(declutterData[0],
-                  declutterData[13], declutterData[14], declutterData[15], declutterData[16],
-                  declutterData[11], declutterData[12]);
-              }
-              drawImage.apply(undefined, declutterData);
+            const context = declutterData[0];
+            const currentAlpha = context.globalAlpha;
+            if (currentAlpha !== opacity) {
+              context.globalAlpha = opacity;
+            }
+            if (declutterData.length > 11) {
+              this.replayTextBackground_(declutterData[0],
+                declutterData[13], declutterData[14], declutterData[15], declutterData[16],
+                declutterData[11], declutterData[12]);
+            }
+            drawImage.apply(undefined, declutterData);
+            if (currentAlpha !== opacity) {
+              context.globalAlpha = currentAlpha;
             }
           }
         }

src/ol/render/canvas/ExecutorGroup.js

@@ -430,10 +430,11 @@ export function getCircleArray(radius) {
  * @param {!Object<string, Array<*>>} declutterReplays Declutter replays.
  * @param {CanvasRenderingContext2D} context Context.
  * @param {number} rotation Rotation.
+ * @param {number} opacity Opacity.
  * @param {boolean} snapToPixel Snap point symbols and text to integer pixels.
- * @param {Array<Array<*>>} declutterItems Declutter items.
+ * @param {Array<import("../../PluggableMap.js").DeclutterItems>} declutterItems Declutter items.
  */
-export function replayDeclutter(declutterReplays, context, rotation, snapToPixel, declutterItems) {
+export function replayDeclutter(declutterReplays, context, rotation, opacity, snapToPixel, declutterItems) {
   const zs = Object.keys(declutterReplays).map(Number).sort(numberSafeCompareFunction);
   const skippedFeatureUids = {};
   for (let z = 0, zz = zs.length; z < zz; ++z) {
@@ -443,7 +444,10 @@ export function replayDeclutter(declutterReplays, context, rotation, snapToPixel
       const executor = executorData[i++];
       if (executor !== currentExecutor) {
         currentExecutor = executor;
-        declutterItems.push(executor.declutterItems);
+        declutterItems.push({
+          items: executor.declutterItems,
+          opacity: opacity
+        });
       }
       const transform = executorData[i++];
       executor.execute(context, transform, rotation, skippedFeatureUids, snapToPixel);

src/ol/renderer/canvas/Layer.js

@@ -79,7 +79,7 @@ class CanvasLayerRenderer extends LayerRenderer {
   useContainer(target, transform, opacity) {
     const layerClassName = this.getLayer().getClassName();
     let container, context;
-    if (target) {
+    if (target && target.style.opacity === '') {
       const canvas = target.firstElementChild;
       if (canvas instanceof HTMLCanvasElement) {
         context = canvas.getContext('2d');

src/ol/renderer/canvas/VectorLayer.js

@@ -164,7 +164,7 @@ class CanvasVectorLayerRenderer extends CanvasLayerRenderer {
     if (declutterReplays) {
       const viewHints = frameState.viewHints;
       const hifi = !(viewHints[ViewHint.ANIMATING] || viewHints[ViewHint.INTERACTING]);
-      replayDeclutter(declutterReplays, context, rotation, hifi, frameState.declutterItems);
+      replayDeclutter(declutterReplays, context, rotation, 1, hifi, frameState.declutterItems);
     }
 
     if (clipped) {
@@ -174,8 +174,9 @@ class CanvasVectorLayerRenderer extends CanvasLayerRenderer {
     this.postRender(context, frameState);
 
     const opacity = layerState.opacity;
-    if (opacity !== parseFloat(canvas.style.opacity)) {
-      canvas.style.opacity = opacity;
+    const container = this.container;
+    if (opacity !== parseFloat(container.style.opacity)) {
+      container.style.opacity = opacity === 1 ? '' : opacity;
     }
 
     return this.container;

src/ol/renderer/canvas/VectorTileLayer.js

@@ -478,7 +478,7 @@ class CanvasVectorTileLayerRenderer extends CanvasTileLayerRenderer {
       }
     }
     if (declutterReplays) {
-      replayDeclutter(declutterReplays, context, rotation, hifi, frameState.declutterItems);
+      replayDeclutter(declutterReplays, context, rotation, layerState.opacity, hifi, frameState.declutterItems);
     }
 
     return this.container;