如何在 poi word run.addPicture() 中动态设置图像大小? [英] How to set image size is dynamically in poi word run.addPicture()?

问题描述

XWPFDocument doc= new XWPFDocument();
InputStream a = someMethod(underConditions(inputimage));
paragraph.createRun().addPicture(a, Document.PICTURE_TYPE_PNG, "", Units.toEMU(20), Units.toEMU(20));
a.close();
doc.write(new FileOutputStream("CreateWordHeaderFooter.docx"));
doc.close();

这是在poi word中添加图片的简单代码.但是 InputStream a 在不同的条件下是不同的.如果inputimage小Units.toEMU(20)，Units.toEMU(20)就大，如果inputimage大Units.toEMU(20), Units.toEMU(20) 太小了.在这种情况下，图像会失真.

This is simple code for add a image in poi word. But InputStream a is different under different conditions. If inputimage is small Units.toEMU(20), Units.toEMU(20) is to big, and if inputimage is big Units.toEMU(20), Units.toEMU(20) is too small. In this conditions images are distorted.

所以我的问题是:如何根据不同的图像设置动态图像大小?

So my question is: how to set dynamic image size based on different image?

推荐答案

所以我们需要从文件中确定图像的首选尺寸.已经有很多关于如何做到这一点的讨论.搜索关键词:java 从图片文件中获取维度.最简单的可能性是使用 ImageIO 从文件中读取 BufferedImage 然后具有 width 和 height 属性.

So we need determining the preferred dimensions of the images from their files. There are already much discussions on how to do that. Search keywords: java get dimension from image file. Simplest possibility is using ImageIO to read BufferedImage from the file which then has widthand height properties.

示例:

import java.io.*;

import org.apache.poi.xwpf.usermodel.*;

import org.apache.poi.util.Units;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.awt.Dimension;

public class CreateWordImagesPreferredSize {

 static Dimension getImageDimension(File imgFile) throws IOException {
  BufferedImage img = ImageIO.read(imgFile);
  return new Dimension(img.getWidth(), img.getHeight());
 }

 public static void main(String[] args) throws Exception {

  XWPFDocument doc= new XWPFDocument();

  XWPFParagraph paragraph = doc.createParagraph();
  XWPFRun run = paragraph.createRun();  
  run.setText("The Images:");

  String[] images = new String[]{"Koala.png", "Scannen.jpg", "Winter.bmp"};

  for (int i = 0 ; i < images.length; i++) {

   paragraph = doc.createParagraph();
   run = paragraph.createRun();
  
   File imgFile = new File(images[i]);
   Dimension dim = getImageDimension(imgFile);
   System.out.println(dim);

   double width = dim.getWidth();
   double height = dim.getHeight();

   double scaling = 1.0;
   if (width > 72*6) scaling = (72*6)/width; //scale width not to be greater than 6 inches

   InputStream in = new FileInputStream(imgFile);
   paragraph.createRun().addPicture(in, Document.PICTURE_TYPE_PNG, images[i], 
    Units.toEMU(width*scaling), Units.toEMU(height*scaling));
   in.close();

  }

  FileOutputStream out = new FileOutputStream("CreateWordImagesPreferredSize.docx");
  doc.write(out);
  out.close();
  doc.close();        
 }
}

注意:如果原始尺寸更大，我会将图像缩放到不大于 6 英寸宽.所以它将适合一页宽度.不会缩放较小的图像.

Note: I do scaling the image to be not greater than 6 inches width if its original size is greater. So it will fit into one page width. Smaller images will not be scaled.

根据评论，如果你不能使用File而必须使用InputStream，那么你需要知道，BufferedImage img = ImageIO.read(imgStream); 当然是从流中读取.因此，流将在此之后结束.所以 .addPicture(imgStream,...) 然后需要一个新打开的流.

As from the comments, if you cannot using File but must using InputStream, then you need to know, that BufferedImage img = ImageIO.read(imgStream); of course reads from the stream. So the stream will be at its end after that. So .addPicture(imgStream,...) will need a newly opened stream then.

示例:

import java.io.*;

import org.apache.poi.xwpf.usermodel.*;

import org.apache.poi.util.Units;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.awt.Dimension;

public class CreateWordImagesPreferredSizeStream {

 static InputStream getInputStream(String filename) throws Exception {
  return new FileInputStream(filename);
 }

 public static void main(String[] args) throws Exception {

  XWPFDocument doc= new XWPFDocument();

  XWPFParagraph paragraph = doc.createParagraph();
  XWPFRun run = paragraph.createRun();  
  run.setText("The Images:");

  String[] images = new String[]{"Koala.png", "Scannen.jpg", "Winter.bmp"};

  for (int i = 0 ; i < images.length; i++) {

   paragraph = doc.createParagraph();
   run = paragraph.createRun();

   InputStream imgStream = getInputStream(images[i]);

   BufferedImage img = ImageIO.read(imgStream);
   double w = img.getWidth();
   double h = img.getHeight();
   imgStream.close();

   System.out.println(w);
   System.out.println(h);

   double scaling = 1.0;
   if (w > 72*6) scaling = (72*6)/w; //scale width not to be greater than 6 inches

   imgStream = getInputStream(images[i]);

   paragraph.createRun().addPicture(imgStream, Document.PICTURE_TYPE_PNG, images[i], 
    Units.toEMU(w*scaling), Units.toEMU(h*scaling));
   imgStream.close();

  }

  FileOutputStream out = new FileOutputStream("CreateWordImagesPreferredSize.docx");
  doc.write(out);
  out.close();
  doc.close();    
 }
}

这篇关于如何在 poi word run.addPicture() 中动态设置图像大小?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！