使用 Apache POI 时获取 excel 文件中的图像大小（高度和宽度）而不是原始大小（对于 xls 和 xlsx 文件）

Question

目前我们正在开发一个将 xls 和 xlsx 文件转换为 html 的 api，我们希望保留图像（在 excel 文件中的大小和位置）我们希望获得与我们在excel文件（调整大小后）。我们尝试了这种方法：

    for (HSSFPictureData pic : workbook.getAllPictures()) {
    InputStream in = new ByteArrayInputStream(pic.getData());
    BufferedImage image = ImageIO.read(in);
    System.out.println(image.getWidth() + ":" + image.getHeight());
}

但它返回的是原始大小，而不是我们在 excel 文件中调整大小的那个。有什么方法可以实现吗？

Answer 1

Workbook.getAllPictures() 获取嵌入在Excel 文件中的所有图片文件。这些图片文件包含纯图片数据。所以没有任何方法可以得到缩放后的图片大小。

缩放后的图片包含在图纸中，并固定在图纸的单元格中。因此，要获得缩放的图片，需要遍历图纸以从中获取Pictures。从Picture 可以得到工作表中的锚定位置、锚点的尺寸（也称为缩放大小）以及PictureData。

完整示例（使用当前的apache poi 5.0.0 测试和工作，同时适用于HSSF 和XSSF）。

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFDrawing;
import org.apache.poi.hssf.usermodel.HSSFPatriarch;
import org.apache.poi.ss.util.ImageUtils;
import org.apache.poi.util.Units;

import java.awt.Dimension;

import java.io.FileInputStream;

import java.util.List;

class ExcelGetPicturesWithPositionAndSize {

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

  //Workbook workbook = WorkbookFactory.create(new FileInputStream("ExcelWithImages.xlsx"));
  Workbook workbook = WorkbookFactory.create(new FileInputStream("ExcelWithImages.xls"));

  for (Sheet sheet : workbook) {
   String sheetname = sheet.getSheetName();

   Drawing drawing = sheet.getDrawingPatriarch();
   
   List<?> shapes = null;
   if (drawing instanceof XSSFDrawing) {
    shapes = ((XSSFDrawing)drawing).getShapes();
   } else if (drawing instanceof HSSFPatriarch) {
    shapes = ((HSSFPatriarch)drawing).getChildren();
   }
   
   for (Object shape : shapes) {
    if (shape instanceof Picture) {
     Picture picture = (Picture)shape;
     
     String shapename = picture.getShapeName();
     int row = picture.getClientAnchor().getRow1();
     int col = picture.getClientAnchor().getCol1();
System.out.println(
 "Picture with Shapename: " + shapename + 
 " is located sheet: " + sheetname + 
 ", row: " + row + 
 ", col: " + col
 );

     Dimension dimension = ImageUtils.getDimensionFromAnchor(picture);
System.out.println(
 "Picture's size in EMU: width=" + dimension.getWidth() + ", height=" + dimension.getHeight() +
 ", in pixel: width=" + dimension.getWidth()/Units.EMU_PER_PIXEL + ", height=" + dimension.getHeight()/Units.EMU_PER_PIXEL
 ); 
 
     PictureData pictureData =  picture.getPictureData();
System.out.println(
 "Picture's data: bytes=" + pictureData.getData().length +
 ", mime type=" + pictureData.getMimeType() +
 ", suggested file extension=" + pictureData.suggestFileExtension()
 ); 

    }
   } 
  }

  workbook.close();
 }
}