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/*
* Beamer Viewer, a web-based PDF presentation viewer
* Copyright 2018-2024 Pacien TRAN-GIRARD
* SPDX-License-Identifier: EUPL-1.2
*/
"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() {
this.window.addEventListener("resize", () => this._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)
};
}
_getScreenOffsets(secondary, width, height) {
if (!secondary) return { xOffset: 0, yOffset: 0 };
const viewport = this.page.getViewport(1);
if (viewport.width > viewport.height)
return { xOffset: -width, yOffset: 0 };
else
return { xOffset: 0, yOffset: -height };
}
_getSlideSizeRatio() {
const viewport = this.page.getViewport(1);
if (viewport.width > viewport.height)
return (viewport.width / 2) / viewport.height;
else
return viewport.width / (viewport.height / 2);
}
_getScaleFactor(width, height) {
const viewport = this.page.getViewport(1);
if (viewport.width > viewport.height)
return height / viewport.height;
else
return width / viewport.width;
}
_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)
};
this.page
.render(renderContext)
.then(() => this._showCanvas(canvas));
}
_repaint() {
if (this.page == null) return;
const screenRatio = this._getSlideSizeRatio();
const { width, height } = this._getScreenSize(screenRatio);
const scaleFactor = this._getScaleFactor(width, height);
const { xOffset, yOffset } =
this._getScreenOffsets(this.secondary, width, height);
const { canvas, context } =
this._newCanvas(width, height, xOffset, yOffset);
this._render(canvas, context, scaleFactor);
}
}
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