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_internal/editor/esm/vs/base/browser/pixelRatio.js

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+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+import { getWindowId, onDidUnregisterWindow } from './dom.js';
+import { Emitter, Event } from '../common/event.js';
+import { Disposable, markAsSingleton } from '../common/lifecycle.js';
+/**
+ * See https://developer.mozilla.org/en-US/docs/Web/API/Window/devicePixelRatio#monitoring_screen_resolution_or_zoom_level_changes
+ */
+class DevicePixelRatioMonitor extends Disposable {
+    constructor(targetWindow) {
+        super();
+        this._onDidChange = this._register(new Emitter());
+        this.onDidChange = this._onDidChange.event;
+        this._listener = () => this._handleChange(targetWindow, true);
+        this._mediaQueryList = null;
+        this._handleChange(targetWindow, false);
+    }
+    _handleChange(targetWindow, fireEvent) {
+        this._mediaQueryList?.removeEventListener('change', this._listener);
+        this._mediaQueryList = targetWindow.matchMedia(`(resolution: ${targetWindow.devicePixelRatio}dppx)`);
+        this._mediaQueryList.addEventListener('change', this._listener);
+        if (fireEvent) {
+            this._onDidChange.fire();
+        }
+    }
+}
+class PixelRatioMonitorImpl extends Disposable {
+    get value() {
+        return this._value;
+    }
+    constructor(targetWindow) {
+        super();
+        this._onDidChange = this._register(new Emitter());
+        this.onDidChange = this._onDidChange.event;
+        this._value = this._getPixelRatio(targetWindow);
+        const dprMonitor = this._register(new DevicePixelRatioMonitor(targetWindow));
+        this._register(dprMonitor.onDidChange(() => {
+            this._value = this._getPixelRatio(targetWindow);
+            this._onDidChange.fire(this._value);
+        }));
+    }
+    _getPixelRatio(targetWindow) {
+        const ctx = document.createElement('canvas').getContext('2d');
+        const dpr = targetWindow.devicePixelRatio || 1;
+        const bsr = ctx.webkitBackingStorePixelRatio ||
+            ctx.mozBackingStorePixelRatio ||
+            ctx.msBackingStorePixelRatio ||
+            ctx.oBackingStorePixelRatio ||
+            ctx.backingStorePixelRatio || 1;
+        return dpr / bsr;
+    }
+}
+class PixelRatioMonitorFacade {
+    constructor() {
+        this.mapWindowIdToPixelRatioMonitor = new Map();
+    }
+    _getOrCreatePixelRatioMonitor(targetWindow) {
+        const targetWindowId = getWindowId(targetWindow);
+        let pixelRatioMonitor = this.mapWindowIdToPixelRatioMonitor.get(targetWindowId);
+        if (!pixelRatioMonitor) {
+            pixelRatioMonitor = markAsSingleton(new PixelRatioMonitorImpl(targetWindow));
+            this.mapWindowIdToPixelRatioMonitor.set(targetWindowId, pixelRatioMonitor);
+            markAsSingleton(Event.once(onDidUnregisterWindow)(({ vscodeWindowId }) => {
+                if (vscodeWindowId === targetWindowId) {
+                    pixelRatioMonitor?.dispose();
+                    this.mapWindowIdToPixelRatioMonitor.delete(targetWindowId);
+                }
+            }));
+        }
+        return pixelRatioMonitor;
+    }
+    getInstance(targetWindow) {
+        return this._getOrCreatePixelRatioMonitor(targetWindow);
+    }
+}
+/**
+ * Returns the pixel ratio.
+ *
+ * This is useful for rendering <canvas> elements at native screen resolution or for being used as
+ * a cache key when storing font measurements. Fonts might render differently depending on resolution
+ * and any measurements need to be discarded for example when a window is moved from a monitor to another.
+ */
+export const PixelRatio = new PixelRatioMonitorFacade();
+//# sourceMappingURL=pixelRatio.js.map