iText：无法打印∈，∩，Σ，∫，Δ√，mathematical等数学字符 [英] iText : Unable to print mathematical characters like ∈, ∩, ∑, ∫, ∆ √, ∠

问题描述

我正在使用iText 4.0.2版本进行pdf生成。我有一些字符/符号可以打印，如∈，∩，Σ，∫，△（数学符号）等等。
我的代码：

I am using iText 4.0.2 version for pdf generation. I have some characters/symbols to print like ∈, ∩, ∑, ∫, ∆ (Mathematical symbols) and many others. My code :

  Document document = new Document(PageSize.A4, 60, 60, 60, 60);
        try
        {
            PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream("/home/adeel/experiment.pdf"));

            document.open();

            String str = "this string will contains special character like this  ∈, ∩, ∑, ∫, ∆";

        BaseFont bfTimes = null;
        try {
            bfTimes = BaseFont.createFont(BaseFont.TIMES_ROMAN, BaseFont.CP1252, BaseFont.EMBEDDED);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Font fontnormal = new Font(bfTimes, 12, Font.NORMAL, Color.BLACK);
         Paragraph para = new Paragraph(str, fontnormal);
         document.add(para);

        document.close();
        writer.close();

        System.out.println("Done!");
    } catch (DocumentException e)
    {
        e.printStackTrace();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }

在上面的代码中，我将所有符号放在 str 并生成pdf文件。代替符号，我尝试在 str 中为符号添加unicode字符，但它没有用。

In the above code I am putting all the symbols in str and generating the pdf file. In place of symbols I tried putting unicode characters in str for the symbols but It didn't worked as well.

推荐答案

请查看 MathSymbols 示例。

• 首先，您需要一种支持所需符号的字体。顺便说一句，FreeSans.ttf就是这样的字体。然后你需要使用正确的编码。


• 你正在使用UNICODE，所以你需要 Identity-H 作为编码。 / li>
  
• 你还应该使用诸如 \ u2208 ， \ u229 之类的符号， \ u2211 ， \ u222b ， \ u2206 。这不是必须的，但这是一个很好的做法。

• First you need a font that supports the symbols you need. Incidentally, FreeSans.ttf is such a font. Then you need to use the right encoding.
• You're using UNICODE, so you need Identity-H as the encoding.
• You should also use notations such as \u2208, \u2229, \u2211, \u222b, \u2206. That's not a must, but it's good practice.

这就是它的完成方式：

public static final String DEST = "results/fonts/math_symbols.pdf";
public static final String FONT = "resources/fonts/FreeSans.ttf";
public static final String TEXT = "this string contains special characters like this  \u2208, \u2229, \u2211, \u222b, \u2206";

public void createPdf(String dest) throws IOException, DocumentException {
    Document document = new Document();
    PdfWriter.getInstance(document, new FileOutputStream(dest));
    document.open();
    BaseFont bf = BaseFont.createFont(FONT, BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
    Font f = new Font(bf, 12);
    Paragraph p = new Paragraph(TEXT, f);
    document.add(p);
    document.close();
}

结果如下： math_symbols.pdf

重要提示：您应该始终使用iText的最新官方版本。 iText 4.0.2 不是正式版。

Important: you should always use the most recent, official version of iText. iText 4.0.2 is not an official version.

这篇关于iText：无法打印∈，∩，Σ，∫，Δ√，mathematical等数学字符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！