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diff --git a/pointless/viewer/screen.js b/pointless/viewer/screen.js
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+++ b/pointless/viewer/screen.js
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+/*
+ * screen.js
+ * Part of Pointless Viewer, a Beamer presentation viewer
+ * Copyright 2018 Pacien TRAN-GIRARD
+ * License: GNU GPL v3
+ */
+
+"use strict";
+
+class Screen {
+  constructor(window, secondary=false) {
+    this.window = window;
+    this.secondary = secondary;
+    this.canvas = window.document.getElementById("screen");
+    this.context = this.canvas.getContext("2d");
+    this.page = null;
+
+    var self = this;
+    this.window.addEventListener("resize", function() {
+      self._refreshPage();
+    });
+  }
+
+  setPage(page) {
+    this.page = page;
+    this._refreshPage();
+  }
+
+  _resizeScreen(ratio) {
+    var windowRatio = this.window.innerWidth / this.window.innerHeight;
+    var scaleFactor = ratio / windowRatio;
+    this.canvas.width = this.window.innerWidth * Math.min(scaleFactor, 1);
+    this.canvas.height = this.window.innerHeight / Math.max(scaleFactor, 1);
+  }
+
+  _setOffset() {
+    var xOffset = this.secondary ? -this.canvas.width : 0;
+    this.context.transform(1, 0, 0, 1, xOffset, 0);
+  }
+
+  _paintPage() {
+    var renderRatio = this.canvas.height / this.page.getViewport(1).height;
+    var renderViewport = this.page.getViewport(renderRatio);
+    var renderContext = { canvasContext: this.context, viewport: renderViewport };
+    this.page.render(renderContext);
+  }
+
+  _refreshPage() {
+    if (this.page == null) return;
+    var viewport = this.page.getViewport(1);
+    var ratio = (viewport.width / 2) / viewport.height;
+    this._resizeScreen(ratio);
+    this._setOffset();
+    this._paintPage();
+  }
+}