apache poi ppt to png emf

Question

我想问一下关于图书馆的APACHE POI。我有一个.pptx文件和我在互联网上找到的例子，我将每张幻灯片分成不同的图像。当幻灯片contang.png，.jpeg图像时，这工作得很好，但只要我在幻灯片中的.emf文件这个图像消失。所以我想要有相同的幻灯片副本，但也要使用.emf文件。这可能吗？

版本：Apache的POI 3.12

非常感谢

Answer 1

正如评论所说，EMF不支持开箱即用...和FreeHep决定有LGPL license这是不可能的，我们将include in our release。

在POI你基本上有两种选择，以提供自定义图像渲染：

• 实施，并通过setRenderingHint(Drawable.IMAGE_RENDERER, new MyImageRendener())注册Graphics2D上下文ImageRenderer实施。其缺点是，它会被要求任何的图像和你失去的默认处理位图/ WMF图像
• 或提供自定义DrawFactory供应自己DrawPictureShape实施 - 如下面的例子 - 它只是转移到EMF呈现在必要时
  （看这个例子中，在当前POI ImageRenderer处理看起来并不灵活，而不是有一个全球性的处理器和，它可能会更好每个登记内容类型的处理程序...）

除了usual POI component我已经包含freehep-graphics2d,freehep-graphicsbase,freehep-graphicsio，freehep-graphicsio-emf和freehep-io。

的例子还远未完成，但我猜你至少脚踏启动：

package org.apache.poi.xslf; 

import java.awt.Dimension; 
import java.awt.Graphics2D; 
import java.awt.Insets; 
import java.awt.RenderingHints; 
import java.awt.geom.AffineTransform; 
import java.awt.geom.Rectangle2D; 
import java.awt.image.BufferedImage; 
import java.io.ByteArrayInputStream; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.IOException; 
import java.io.InputStream; 

import javax.imageio.ImageIO; 

import org.apache.poi.sl.draw.DrawFactory; 
import org.apache.poi.sl.draw.DrawPictureShape; 
import org.apache.poi.sl.draw.Drawable; 
import org.apache.poi.sl.draw.ImageRenderer; 
import org.apache.poi.sl.usermodel.PictureData; 
import org.apache.poi.sl.usermodel.PictureData.PictureType; 
import org.apache.poi.sl.usermodel.PictureShape; 
import org.apache.poi.util.POILogFactory; 
import org.apache.poi.util.POILogger; 
import org.apache.poi.xslf.usermodel.XMLSlideShow; 
import org.apache.poi.xslf.usermodel.XSLFPictureShape; 
import org.apache.poi.xslf.usermodel.XSLFSlide; 
import org.freehep.graphicsio.emf.EMFInputStream; 
import org.freehep.graphicsio.emf.EMFRenderer; 
import org.junit.Test; 

public class TestEMFRender { 
    private final static POILogger LOG = POILogFactory.getLogger(TestEMFRender.class); 

    @Test 
    public void render() throws Exception { 
     XMLSlideShow ppt = getDummy(); 

     Dimension pgsize = ppt.getPageSize(); 
     BufferedImage img = new BufferedImage((int)pgsize.getWidth(), (int)pgsize.getHeight(), BufferedImage.TYPE_INT_ARGB); 
     Graphics2D graphics = initGraphicsCtx(img); 

     // draw stuff 
     ppt.getSlides().get(0).draw(graphics); 

     // save the result 
     File outfile = new File("bla.png"); 
     ImageIO.write(img, "PNG", outfile); 

     // cleanup 
     graphics.dispose(); 
     img.flush(); 
     ppt.close(); 
    } 

    static XMLSlideShow getDummy() throws IOException { 
     XMLSlideShow ppt = new XMLSlideShow(); 
     FileInputStream fis = new FileInputStream("kiwilogo.emf"); 
     PictureData pd = ppt.addPicture(fis, PictureType.EMF); 
     fis.close(); 
     XSLFSlide sl = ppt.createSlide(); 
     XSLFPictureShape ps = sl.createPicture(pd); 
     ps.setAnchor(new Rectangle2D.Double(100, 100, 100, 100)); 
     return ppt; 
    } 

    static Graphics2D initGraphicsCtx(BufferedImage img) { 
     Graphics2D graphics = img.createGraphics(); 
     // default rendering options 
     graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 
     graphics.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY); 
     graphics.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC); 
     graphics.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON); 

     // custom draw factory 
     DrawFactory df = new DrawFactory(){ 
      public DrawPictureShape getDrawable(PictureShape<?,?> shape) { 
       return new DrawPictureShapeEmf(shape); 
      } 
     }; 
     graphics.setRenderingHint(Drawable.DRAW_FACTORY, df); 

     df.fixFonts(graphics); 

     return graphics; 
    } 

    static class DrawPictureShapeEmf extends DrawPictureShape { 
     public DrawPictureShapeEmf(PictureShape<?,?> shape) { 
      super(shape); 
     } 


     @Override 
     public void drawContent(Graphics2D graphics) { 
      PictureData data = getShape().getPictureData(); 
      if(data == null) return; 

      Rectangle2D anchor = getAnchor(graphics, getShape()); 
      Insets insets = getShape().getClipping(); 

      try { 
       String contentType = data.getContentType(); 
       ImageRenderer renderer = 
        PictureType.EMF.contentType.equals(contentType) 
        ? new ImgRenderer() 
        : super.getImageRenderer(graphics, contentType); 

       renderer.loadImage(data.getData(), data.getContentType()); 
       renderer.drawImage(graphics, anchor, insets); 
      } catch (IOException e) { 
       LOG.log(POILogger.ERROR, "image can't be loaded/rendered.", e); 
      } 
     } 

    } 


    static class ImgRenderer implements ImageRenderer { 
     EMFRenderer emfRenderer; 

     public void loadImage(InputStream data, String contentType) throws IOException { 
      emfRenderer = new EMFRenderer(new EMFInputStream(data)); 
     } 

     public void loadImage(byte[] data, String contentType) throws IOException { 
      loadImage(new ByteArrayInputStream(data), contentType); 
     } 

     public Dimension getDimension() { 
      return emfRenderer.getSize(); 
     } 

     public void setAlpha(double alpha) { 
     } 

     public BufferedImage getImage() { 
      return null; 
     } 

     public BufferedImage getImage(Dimension dim) { 
      return null; 
     } 

     public boolean drawImage(Graphics2D ctx, Rectangle2D graphicsBounds) { 
      return drawImage(ctx, graphicsBounds, null); 
     } 

     public boolean drawImage(Graphics2D ctx, Rectangle2D graphicsBounds, Insets clip) { 
      AffineTransform at = ctx.getTransform(); 
      try { 
       Dimension emfDim = emfRenderer.getSize(); 
       // scale output bounds to image bounds 
       ctx.translate(graphicsBounds.getX(), graphicsBounds.getY()); 
       ctx.scale(graphicsBounds.getWidth()/emfDim.getWidth(), graphicsBounds.getHeight()/emfDim.getHeight()); 

       // TODO: handle clipping 

       emfRenderer.paint(ctx); 

       return true; 
      } catch (RuntimeException e) { 
       // TODO: logging 
       return false; 
      } finally { 
       ctx.setTransform(at); 
      } 
     } 

    } 
}