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node_modules/ol/src/interaction/DragRotate.js

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+/**
+ * @module ol/interaction/DragRotate
+ */
+import PointerInteraction from './Pointer.js';
+import {FALSE} from '../functions.js';
+import {
+  altShiftKeysOnly,
+  mouseActionButton,
+  mouseOnly,
+} from '../events/condition.js';
+import {disable} from '../rotationconstraint.js';
+
+/**
+ * @typedef {Object} Options
+ * @property {import("../events/condition.js").Condition} [condition] A function that takes an
+ * {@link module:ol/MapBrowserEvent~MapBrowserEvent} and returns a boolean
+ * to indicate whether that event should be handled.
+ * Default is {@link module:ol/events/condition.altShiftKeysOnly}.
+ * @property {number} [duration=250] Animation duration in milliseconds.
+ */
+
+/**
+ * @classdesc
+ * Allows the user to rotate the map by clicking and dragging on the map,
+ * normally combined with an {@link module:ol/events/condition} that limits
+ * it to when the alt and shift keys are held down.
+ *
+ * This interaction is only supported for mouse devices.
+ * @api
+ */
+class DragRotate extends PointerInteraction {
+  /**
+   * @param {Options} [opt_options] Options.
+   */
+  constructor(opt_options) {
+    const options = opt_options ? opt_options : {};
+
+    super({
+      stopDown: FALSE,
+    });
+
+    /**
+     * @private
+     * @type {import("../events/condition.js").Condition}
+     */
+    this.condition_ = options.condition ? options.condition : altShiftKeysOnly;
+
+    /**
+     * @private
+     * @type {number|undefined}
+     */
+    this.lastAngle_ = undefined;
+
+    /**
+     * @private
+     * @type {number}
+     */
+    this.duration_ = options.duration !== undefined ? options.duration : 250;
+  }
+
+  /**
+   * Handle pointer drag events.
+   * @param {import("../MapBrowserEvent.js").default} mapBrowserEvent Event.
+   */
+  handleDragEvent(mapBrowserEvent) {
+    if (!mouseOnly(mapBrowserEvent)) {
+      return;
+    }
+
+    const map = mapBrowserEvent.map;
+    const view = map.getView();
+    if (view.getConstraints().rotation === disable) {
+      return;
+    }
+    const size = map.getSize();
+    const offset = mapBrowserEvent.pixel;
+    const theta = Math.atan2(size[1] / 2 - offset[1], offset[0] - size[0] / 2);
+    if (this.lastAngle_ !== undefined) {
+      const delta = theta - this.lastAngle_;
+      view.adjustRotationInternal(-delta);
+    }
+    this.lastAngle_ = theta;
+  }
+
+  /**
+   * Handle pointer up events.
+   * @param {import("../MapBrowserEvent.js").default} mapBrowserEvent Event.
+   * @return {boolean} If the event was consumed.
+   */
+  handleUpEvent(mapBrowserEvent) {
+    if (!mouseOnly(mapBrowserEvent)) {
+      return true;
+    }
+
+    const map = mapBrowserEvent.map;
+    const view = map.getView();
+    view.endInteraction(this.duration_);
+    return false;
+  }
+
+  /**
+   * Handle pointer down events.
+   * @param {import("../MapBrowserEvent.js").default} mapBrowserEvent Event.
+   * @return {boolean} If the event was consumed.
+   */
+  handleDownEvent(mapBrowserEvent) {
+    if (!mouseOnly(mapBrowserEvent)) {
+      return false;
+    }
+
+    if (
+      mouseActionButton(mapBrowserEvent) &&
+      this.condition_(mapBrowserEvent)
+    ) {
+      const map = mapBrowserEvent.map;
+      map.getView().beginInteraction();
+      this.lastAngle_ = undefined;
+      return true;
+    } else {
+      return false;
+    }
+  }
+}
+
+export default DragRotate;