Created attachment 22552 [details]
input test case powerpoint file

See the attached file testcase1in.ppt as the input file to the following test code which tries to substitute the string $$DATE$$ with the current date/time:

package pptMaker;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.poi.hslf.HSLFSlideShow;
import org.apache.poi.hslf.usermodel.SlideShow;
import org.apache.poi.hslf.model.*;

/**
 * Test file to take an input file, change its contents based on a predefined template
 * string, and write the output
 */

public class ModifyDate {
	
	public static final String _inputPPTFile = "/Users/djboulia/Downloads/testcase1in.ppt";
	public static final String _outputPPTFile = "/Users/djboulia/Downloads/testcase1out.ppt";

	/**
	 * @param args
	 */
	public static void main(String[] args) throws IOException {
		 SlideShow ppt = new SlideShow(new HSLFSlideShow(_inputPPTFile));

		 //get slides 
		  Slide[] slide = ppt.getSlides();
		  for (int i = 0; i < slide.length; i++){
			System.out.println( "Slide " + i);
			
		    Shape[] sh = slide[i].getShapes();
		    for (int j = 0; j < sh.length; j++){
		      //name of the shape
		      String name = sh[j].getShapeName();

		      //shapes's anchor which defines the position of this shape in the slide
		      java.awt.Rectangle anchor = sh[j].getAnchor();

		      if (sh[j] instanceof Line){
		        Line line = (Line)sh[j];
		        //work with Line
		        System.out.println( "Found a Line!");
		      } else if (sh[j] instanceof AutoShape){
		        AutoShape shape = (AutoShape)sh[j];
		        //work with AutoShape
		        System.out.println( "Found an AutoShape!");
		      } else if (sh[j] instanceof TextBox){
	                TextBox shape = (TextBox)sh[j];
	                //work with TextBox
	                String str = shape.getText();
	                               
	                System.out.println( "Found a TextBox!");
	                System.out.println( str );
	                
	                if (str.indexOf("$$DATE$$") >=0 ) {
	                    System.out.println( "Found $$DATE$$!!" );
	                    java.util.Date now = new java.util.Date();
	                    str = str.replaceAll("[$][$]DATE[$][$]", now.toString());
	 
				        if (str.compareTo(shape.getText())!=0) {
					        shape.setText( str );
				        }
	                    System.out.println( "Replacement string is " + str ); 
	                }
	                		        
		      } else if (sh[j] instanceof Picture){
		        Picture shape = (Picture)sh[j];
		        //work with Picture
		        System.out.println( "Found a Picture!");
		        
		      } else {
		    	  System.out.println("Found unknown shape: "+name);
		      }
		    }
		  }
		  
	    //save changes in a new file
	    FileOutputStream out = new FileOutputStream(_outputPPTFile);
	    ppt.write(out);
	    out.close();

	}

}

Running this on poi-3.1 results in a corrupt PowerPoint file.  (Loading it in Office 2004 on the Mac results in a blank page.)

After some investigation, it appears that there are cases where TextRun.changeRichTextRun incorrectly calculates the new length of the paragraph properties when called via setRawText.

The proposed patch resets the size of the paragraph and character properties to the correct length when setRawText is called which avoids the problem in changeRichTextRun.