Uncollapse when there’s only logos

css/ol.css

@@ -219,6 +219,9 @@ button.ol-full-screen-true:after {
 .ol-attribution.ol-collapsed ul {
   display: none;
 }
+.ol-attribution.ol-logo-only ul {
+  display: block;
+}
 .ol-attribution:not(.ol-collapsed) {
   background: rgba(255,255,255,0.8);
 }
@@ -229,10 +232,17 @@ button.ol-full-screen-true:after {
   height: 1.1em;
   line-height: 1em;
 }
+.ol-attribution.ol-logo-only {
+  background: transparent;
+  bottom: .4em;
+  height: 1.1em;
+  line-height: 1em;
+}
 .ol-attribution.ol-uncollapsible img {
   margin-top: -.2em;
   max-height: 1.6em;
 }
+.ol-attribution.ol-logo-only button,
 .ol-attribution.ol-uncollapsible button {
   display: none;
 }

src/ol/control/attributioncontrol.js

@@ -272,6 +272,12 @@ ol.control.Attribution.prototype.updateElement_ = function(frameState) {
     goog.style.setElementShown(this.element, renderVisible);
     this.renderedVisible_ = renderVisible;
   }
+  if (renderVisible &&
+      goog.object.isEmpty(this.attributionElementRenderedVisible_)) {
+    goog.dom.classlist.add(this.element, 'ol-logo-only');
+  } else {
+    goog.dom.classlist.remove(this.element, 'ol-logo-only');
+  }
 
   this.insertLogos_(frameState);