在 JavaFX 中显示 pdf [英] Displaying pdf in JavaFX

问题描述

在 JavaFX 中开发桌面应用程序，需要显示 pdf.我读到 JavaFX(当前版本)不支持 pdf 查看/显示，我也阅读了 JPedal.

Developing a desktop application in JavaFX which requires to display a pdf. I read that there is no support for pdf viewing/displaying in JavaFX(current version), I read about JPedal too.

现在，问题:

1. 是否有任何外部组件或库可以在 JavaFX 中查看 pdf?它应该是一个免费软件.
2. (如果我必须使用 JPedal) 如何将它嵌入到我的应用程序中.

1. Is there any external component or library to view pdf in JavaFX? It should be a freeware.
2. (If I have to use JPedal) How can I embed it in my application.

推荐答案

JPedalFX 示例代码和用法

使用 JPedalFX 的示例代码随 JPedalFX 下载提供.

Sample code on using JPedalFX is provided with the JPedalFX download.

对我来说有点蹩脚，但我只会在此处粘贴从 JPedalFX 库提供的示例查看器中复制的示例代码片段.该代码依赖于 JPedalFX 发行版中包含的 jpedal_lgpl.jar 文件，该文件位于类路径(或应用程序 jar 清单中引用的库路径)上.

Kind of lame on my part, but I'll just paste snippets sample code here that have been copied from the sample viewer provided with the JPedalFX library. The code relies on the jpedal_lgpl.jar file included with the JPedalFX distribution being on the classpath (or the library path referenced in the manifest of your application jar).

如果您对 JPedalFX 的使用还有其他问题，我建议您直接联系 IDR 解决方案(他们已经在过去).

Should you have further questions regarding usage of JPedalFX, I suggest you contact IDR solutions directly (they have been responsive to me in the past).

// get file path.
FileChooser fc = new FileChooser();
fc.setTitle("Open PDF file...");
fc.getExtensionFilters().add(new FileChooser.ExtensionFilter("PDF Files", "*.pdf"));     
File f = fc.showOpenDialog(stage.getOwner());
String filename = file.getAbsolutePath();

// open file.
PdfDecoder pdf = new PdfDecoder();
pdf.openPdfFile(filename);
showPage(1);
pdf.closePdfFile();

. . . 

/**
 * Update the GUI to show a specified page.
 * @param page 
 */
private void showPage(int page) {

    //Check in range
    if (page > pdf.getPageCount())
        return;
    if (page < 1)
        return;

    //Store
    pageNumber = page;


    //Show/hide buttons as neccessary
    if (page == pdf.getPageCount())
        next.setVisible(false);
    else
        next.setVisible(true);

    if (page == 1)
        back.setVisible(false);
    else
        back.setVisible(true);


    //Calculate scale
    int pW = pdf.getPdfPageData().getCropBoxWidth(page);
    int pH = pdf.getPdfPageData().getCropBoxHeight(page);

    Dimension s = Toolkit.getDefaultToolkit().getScreenSize();

    s.width -= 100;
    s.height -= 100;

    double xScale = (double)s.width / pW;
    double yScale = (double)s.height / pH;
    double scale = xScale < yScale ? xScale : yScale;

    //Work out target size
    pW *= scale;
    pH *= scale;

    //Get image and set
    Image i = getPageAsImage(page,pW,pH);
    imageView.setImage(i);

    //Set size of components
    imageView.setFitWidth(pW);
    imageView.setFitHeight(pH);
    stage.setWidth(imageView.getFitWidth()+2);
    stage.setHeight(imageView.getFitHeight()+2);
    stage.centerOnScreen();
}

/**
 * Wrapper for usual method since JFX has no BufferedImage support.
 * @param page
 * @param width
 * @param height
 * @return 
 */
private Image getPageAsImage(int page, int width, int height) {

    BufferedImage img;
    try {
        img = pdf.getPageAsImage(page);

        //Use deprecated method since there's no real alternative 
        //(for JavaFX 2.2+ can use SwingFXUtils instead).
        if (Image.impl_isExternalFormatSupported(BufferedImage.class))
            return javafx.scene.image.Image.impl_fromExternalImage(img);

    } catch(Exception e) {
        e.printStackTrace();
    }

    return null;
}

/**
 * ===========================================
 * Java Pdf Extraction Decoding Access Library
 * ===========================================
 *
 * Project Info:  http://www.jpedal.org
 * (C) Copyright 1997-2008, IDRsolutions and Contributors.
 *
 *  This file is part of JPedal
 *
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


 *
 * ---------------
 * JPedalFX.java
 * ---------------
 */

SwingLabs PDF 渲染器

此外，我过去使用基于 SwingLabs Swing 的旧 pdf 渲染器和 JavaFX 为我的 JavaFX 网络浏览器渲染 pdf.虽然在我开发浏览器时，Swing/JavaFX 集成不是 JavaFX 支持的功能，但它对我来说仍然很好.集成代码位于 PDFViewer.java 和 BrowserWindow.java.

Additionaly, I used an old SwingLabs Swing based pdf renderer with JavaFX in the past for rendering pdf's for my JavaFX web browser. Although the Swing/JavaFX integration wasn't a supported feature of JavaFX at the time that I developed the browser, it still worked fine for me. Code for integration is in PDFViewer.java and BrowserWindow.java.

请注意，在 Swing 应用程序中嵌入 JavaFX 支持Java 8 支持 Java 2.2 和 在 JavaFX 中嵌入 Swing 应用.

Note that embedding JavaFX in a Swing app is supported in Java 2.2 and embedding a Swing app in JavaFX is supported in Java 8.

这篇关于在 JavaFX 中显示 pdf的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！