IText PDF 5 - 计算页面底部的剩余区域

Question

鉴于以下内容：如您所见，标题当前位于第 4 页，其内容位于第 5 页。我在本文档中有大约 25 个部分，有没有办法让页面上留下的区域，以评估我的标题和某些内容是否能够适应它？如果我可以评估，我可以使用将我的内容推送到另一个页面document().newPage()

Answer 1

您可以使用PdfPageEvent

这是一个示例：

import com.itextpdf.text.*;

import com.itextpdf.text.pdf.*;

import java.io.*;

public class App {

    public static void main(String[] args) throws FileNotFoundException, DocumentException {

        Document document = new Document(PageSize.A6, 20, 20, 20, 20);

        PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream("/tmp/out.pdf"));

        writer.setPageEvent(new PdfListener());

        document.open();

        for (int i = 0; i < 10; i++) {

            Paragraph paragraph = new Paragraph();

            paragraph.add(new Phrase("The chapter "+i));

            Chapter chapter = new Chapter(paragraph, 1);

            Section section1 = chapter.addSection("The section "+i+".1", 2);

            Section section2 = chapter.addSection("The section "+i+".2", 2);

            document.add(chapter);

            document.add(section1);

            document.add(section2);

        }

        document.close();

    }

    public static class PdfListener implements PdfPageEvent {

        public void onChapter(PdfWriter writer, Document dcmnt, float f, Paragraph prgrph) {

            if( f < 50.0f ){

                dcmnt.newPage();

            }

        }

        public void onChapterEnd(PdfWriter writer, Document dcmnt, float f) {}

        public void onSection(PdfWriter writer, Document dcmnt, float f, int i, Paragraph prgrph) {

            if( f < 50.0f ){

                dcmnt.newPage();

            }

        }

        public void onSectionEnd(PdfWriter writer, Document dcmnt, float f) {}

        public void onOpenDocument(PdfWriter writer, Document dcmnt) {}

        public void onStartPage(PdfWriter writer, Document dcmnt) {}

        public void onEndPage(PdfWriter writer, Document dcmnt) {}

        public void onCloseDocument(PdfWriter writer, Document dcmnt) {}

        public void onParagraph(PdfWriter writer, Document dcmnt, float f) {}

        public void onParagraphEnd(PdfWriter writer, Document dcmnt, float f) {}        

        public void onGenericTag(PdfWriter writer, Document dcmnt, Rectangle rctngl, String string) {}

    }

}

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