From 447ad917da78126acab9b529fe7254074336aa72 Mon Sep 17 00:00:00 2001
From: pacien
Date: Wed, 18 Jul 2018 21:57:35 +0200
Subject: First working prototype

---
 pointless/viewer/screen.js | 56 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 pointless/viewer/screen.js

(limited to 'pointless/viewer/screen.js')

diff --git a/pointless/viewer/screen.js b/pointless/viewer/screen.js
new file mode 100644
index 0000000..8a6891c
--- /dev/null
+++ b/pointless/viewer/screen.js
@@ -0,0 +1,56 @@
+/*
+ * 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();
+  }
+}
-- 
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