使用iText和Java保存tiff CCITTFaxDecode（来自PDF页面） [英] Save tiff CCITTFaxDecode (from PDF page) using iText and Java

问题描述

我正在使用iText提取嵌入的图像并将它们保存为单独的文件。 .jpg和.png文件出来了，但是我无法提取具有CCITTFaxDecode编码的tiff图像。

I'm using iText to extract embedded images and save them as separate files. The .jpg and .png files come out ok, but I cannot extract tiff images that have the CCITTFaxDecode encoding.

有没有人有办法保存tiff文件？

Does anyone have a way of saving the tiff files?

我发现了一些使用iTextSharp的样本C＃代码，价格为
使用/ CCITTFaxDecode过滤器从PDF中提取图像
它表示需要一个单独的tiff库来写出结果。根据那篇文章，CCITTFaxDecode压缩是针对tiff库的Compression.CCITTFAX4。

I found some sample C# code that uses iTextSharp at Extracting image from PDF with /CCITTFaxDecode filter It indicates a separate tiff library is needed to write out the results. According to that article, the "CCITTFaxDecode" compression is Compression.CCITTFAX4 for the tiff library.

要使用该文章的方法，我需要：
1. get一个tiff图书馆。
Java Image I / O API允许您以其他格式读写TIFF文件。
BufferedImage image = ImageIO.read（new File（image.tif））;

To use that article's method, I need: 1. get a tiff library. The Java Image I/O API will allow you to read and write TIFF files among other formats. BufferedImage image = ImageIO.read( new File( "image.tif" ) );

1. 查找用于从PDF获取位图属性的相应代码，例如：
   pd.Get（PdfName.WIDTH）.ToString（）（在C＃中）

推荐答案

我通过以下方式从扫描的pdf（即每页作为图像）中提取了一个tiff图像：

I extracted a tiff image from scanned pdf (that is the every page as image) in the following way:

...
PdfReader reader = new PdfReader("source.pdf");
PdfReaderContentParser parser = new PdfReaderContentParser(reader);
MyImageRenderListener listener = new MyImageRenderListener("destination.jpg");
for (int i = 1; i <= reader.getNumberOfPages(); i++) {
parser.processContent(i, listener);
 }
...

MyImageRenderListener.class的代码：

code of MyImageRenderListener.class:

class MyImageRenderListener implements RenderListener {
    protected String path = "";

    public MyImageRenderListener(String path) {
        this.path = path;
    }

    public void beginTextBlock() {
    }

    public void endTextBlock() {
    }

    public void renderImage(ImageRenderInfo renderInfo) {
        try {
            String filename;
            FileOutputStream os;
            PdfImageObject image = renderInfo.getImage();
            PdfName filter = (PdfName) image.get(PdfName.FILTER);

                   if (PdfName.CCITTFAXDECODE.equals(filter)) {
                      BufferedImage bufferedImage = image.getBufferedImage();
                  ImageIO.write(bufferedImage, "jpg", new FileOutputStream(filename));// save tif image as jpg


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

    public void renderText(TextRenderInfo renderInfo) {
    }
}

这篇关于使用iText和Java保存tiff CCITTFaxDecode（来自PDF页面）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！