使用Java IText为现有PDF文档设置新页面大小

Question

我想为我现有的PDF文档设置一个新的页面大小，而不裁剪内容。我正在编写下面的代码，但它只是从底部裁剪我的PDF文件，导致内容丢失。

目前的尺寸是8.26“X 11.69”，我需要使它的8.5“X 11”。

我的代码只将11.59转换为11。试图更改8.26，但它不起作用。

有谁能帮忙吗？我将ITextPDF-5.5.8与Java一起使用。

import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.GrayColor;
import com.itextpdf.text.pdf.PdfArray;
import com.itextpdf.text.pdf.PdfContentByte;
import com.itextpdf.text.pdf.PdfDictionary;
import com.itextpdf.text.pdf.PdfName;
import com.itextpdf.text.pdf.PdfNumber;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfRectangle;
import com.itextpdf.text.pdf.PdfStamper;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;



public class PageSize {

    public static final String SRC = "C:/Temp/BC.pdf";
    public static final String DEST = "C:/Temp/BC_New.pdf";

    public static void main(String[] args) throws IOException, DocumentException {
        File file = new File(DEST);
        file.getParentFile().mkdirs();
        new PageSize().manipulatePdf(SRC, DEST);
    }

    public void manipulatePdf(String src, String dest) throws IOException, DocumentException {
        PdfReader reader = new PdfReader(src);
        int n = reader.getNumberOfPages();
        PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
        // properties
        PdfContentByte over;
        PdfDictionary pageDict;
        PdfRectangle rect = new PdfRectangle(55, 76, 560, 816);
        PdfArray mediabox;
        float llx, lly, ury,llz;
        // loop over every page
        for (int i = 1; i <= n; i++) {
            pageDict = reader.getPageN(i);
            mediabox = pageDict.getAsArray(PdfName.MEDIABOX);
            llx = mediabox.getAsNumber(0).floatValue();
            lly = mediabox.getAsNumber(1).floatValue();
            llz = mediabox.getAsNumber(2).floatValue();
            ury = mediabox.getAsNumber(3).floatValue();
            mediabox.set(1, new PdfNumber((lly + 50)));
            over = stamper.getOverContent(i);
            over.saveState();
                       over.restoreState();
        }



        stamper.close();
        reader.close();
    }
}

import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.GrayColor;
import com.itextpdf.text.pdf.PdfArray;
import com.itextpdf.text.pdf.PdfContentByte;
import com.itextpdf.text.pdf.PdfDictionary;
import com.itextpdf.text.pdf.PdfName;
import com.itextpdf.text.pdf.PdfNumber;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfRectangle;
import com.itextpdf.text.pdf.PdfStamper;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;



public class PageSize {

    public static final String SRC = "C:/Temp/Test.pdf";
    public static final String DEST = "C:/Temp/BC_New.pdf";

    public static void main(String[] args) throws IOException, DocumentException {
        File file = new File(DEST);
        file.getParentFile().mkdirs();
        new PageSize().manipulatePdf(SRC, DEST);
    }

    public void manipulatePdf(String src, String dest) throws IOException, DocumentException {
        PdfReader reader = new PdfReader(src);
        int n = reader.getNumberOfPages();
        PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
        // properties
        PdfContentByte over;
        PdfDictionary pageDict;
        PdfArray mediabox;
        float llx, lly, ury,llz;
        // loop over every page
        for (int i = 1; i <= n; i++) {
            pageDict = reader.getPageN(i);
            mediabox = pageDict.getAsArray(PdfName.MEDIABOX);
            llx = mediabox.getAsNumber(0).floatValue();
            lly = mediabox.getAsNumber(1).floatValue();
            ury = mediabox.getAsNumber(3).floatValue();
            mediabox.set(0, new PdfNumber((llx - 17)));
            mediabox.set(1, new PdfNumber((lly + 50)));
            over = stamper.getOverContent(i);
            over.saveState();
                       over.restoreState();
        }



        stamper.close();
        reader.close();
    }
}

谢谢布鲁诺。：）

Answer 1

您正在更改页面大小而不更改内容。

如果您想缩小内容，那么您需要更复杂的代码。有关示例，请参见缩小pdf页面的内容。在官方文档中也有一个例子：如何在现有的PDF文件中收缩页面？

PdfReader reader = new PdfReader(src);
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
int n = reader.getNumberOfPages();
PdfDictionary page;
PdfArray crop;
PdfArray media;
for (int p = 1; p <= n; p++) {
    page = reader.getPageN(p);
    media = page.getAsArray(PdfName.CROPBOX);
    if (media == null) {
        media = page.getAsArray(PdfName.MEDIABOX);
    }
    crop = new PdfArray();
    crop.add(new PdfNumber(0));
    crop.add(new PdfNumber(0));
    crop.add(new PdfNumber(media.getAsNumber(2).floatValue() / 2));
    crop.add(new PdfNumber(media.getAsNumber(3).floatValue() / 2));
    page.put(PdfName.MEDIABOX, crop);
    page.put(PdfName.CROPBOX, crop);
    stamper.getUnderContent(p).setLiteral("\nq 0.5 0 0 0.5 0 0 cm\nq\n");
    stamper.getOverContent(p).setLiteral("\nQ\nQ\n");
}
stamper.close();
reader.close();

如果您想要放大内容，那么您可以简单地更改UserUnit。更改用户单元在官方文档中也有解释：如何在现有PDF中旋转和缩放页面？

float factor = 2.5f;
PdfReader reader = new PdfReader(src);
int n = reader.getNumberOfPages();
PdfDictionary page;
for (int p = 1; p <= n; p++) {
    page = reader.getPageN(p);
    if (page.getAsNumber(PdfName.USERUNIT) == null)
        page.put(PdfName.USERUNIT, new PdfNumber(factor));
}
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
stamper.close();
reader.close();

    mediabox = pageDict.getAsArray(PdfName.MEDIABOX);
    llx = mediabox.getAsNumber(0).floatValue();
    lly = mediabox.getAsNumber(1).floatValue();
    ury = mediabox.getAsNumber(3).floatValue();
    mediabox.set(0, new PdfNumber((llx - 17)));
    mediabox.set(1, new PdfNumber((lly + 50)));