From 4ac79e422129e654e48909017a50b066b2f587d1 Mon Sep 17 00:00:00 2001
From: pacien
Date: Fri, 24 Aug 2018 01:39:40 +0200
Subject: Handle click and touch events

---
 pointless/viewer/screen/screen.js | 110 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 pointless/viewer/screen/screen.js

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

diff --git a/pointless/viewer/screen/screen.js b/pointless/viewer/screen/screen.js
new file mode 100644
index 0000000..bf7a049
--- /dev/null
+++ b/pointless/viewer/screen/screen.js
@@ -0,0 +1,110 @@
+/*
+ * Pointless Viewer, a web-based Beamer presentation viewer
+ * Copyright (C) 2018 Pacien TRAN-GIRARD
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+"use strict";
+
+class Screen {
+  constructor(window, secondary=false, withTimer=false) {
+    this.window = window;
+    this.secondary = secondary;
+
+    this.canvasId = "screen";
+    this.page = null;
+
+    this.timer = withTimer ? new Timer(window) : null;
+    this.pageTurnCount = 0;
+
+    this._registerListeners();
+    this._hideWelcomeScreen();
+  }
+
+  setPage(page) {
+    if (this.pageTurnCount++ === 1 && this.timer != null)
+      this.timer.start();
+
+    this.page = page;
+    this._repaint();
+  }
+
+  _registerListeners() {
+    const self = this;
+    this.window.addEventListener("resize", function() {
+      self._repaint();
+    });
+  }
+
+  _hideWelcomeScreen() {
+    const welcomeScreen = this.window.document.getElementById("welcomeScreen");
+    welcomeScreen.style.display = "none";
+  }
+
+  _getScreenSize(ratio) {
+    const windowRatio = this.window.innerWidth / this.window.innerHeight;
+    const horizontalScaleFactor = ratio / windowRatio;
+    return {
+      width: this.window.innerWidth * Math.min(horizontalScaleFactor, 1),
+      height: this.window.innerHeight / Math.max(horizontalScaleFactor, 1)
+    };
+  }
+
+  _getSlideSizeRatio() {
+    const viewport = this.page.getViewport(1);
+    return (viewport.width / 2) / viewport.height;
+  }
+
+  _newCanvas(width, height, xOffset, yOffset) {
+    const canvas = document.createElement("canvas");
+    canvas.width = width;
+    canvas.height = height;
+
+    const context = canvas.getContext("2d");
+    context.transform(1, 0, 0, 1, xOffset, yOffset);
+
+    return { canvas: canvas, context: context };
+  }
+
+  _showCanvas(canvas) {
+    const oldCanvas = this.window.document.getElementById(this.canvasId);
+    canvas.id = oldCanvas.id;
+    canvas.classList = oldCanvas.classList;
+    oldCanvas.replaceWith(canvas);
+  }
+
+  _render(canvas, context, scaleFactor) {
+    const renderContext = {
+      canvasContext: context,
+      viewport: this.page.getViewport(scaleFactor)
+    };
+
+    const self = this;
+    this.page.render(renderContext).then(function() {
+      self._showCanvas(canvas);
+    });
+  }
+
+  _repaint() {
+    if (this.page == null) return;
+
+    const screenRatio = this._getSlideSizeRatio();
+    const { width, height } = this._getScreenSize(screenRatio);
+    const scaleFactor = height / this.page.getViewport(1).height;
+    const xOffset = this.secondary ? -width : 0;
+    const { canvas, context } = this._newCanvas(width, height, xOffset, 0);
+    this._render(canvas, context, scaleFactor);
+  }
+}
-- 
cgit v1.2.3