Unicode characters not converting from pptx to png

Question

I have written a program to convert PPTX to PNG. All the conversion happens fine only issue is where ever there is UNICODE character in PPTX file - it converts that to a junk character. Here is the code. I tried to add fonts but that did not help. This is what PPTX contains - "/ˌinəˈvāSHən/". It converts letters i, n, v, a, S, H, n fine but not others.

    FileInputStream is = new FileInputStream(strTempPath);
    XMLSlideShow pptx = new XMLSlideShow(is);
    is.close();
    double zoom = 2; // magnify it by 2
    AffineTransform at = new AffineTransform();
    at.setToScale(zoom, zoom);
    Dimension pgsize = pptx.getPageSize();             
    XSLFSlide[] slide = pptx.getSlides();

    }              
    // BufferedImage img = new BufferedImage((int)Math.ceil(pgsize.width*zoom), (int)Math.ceil(pgsize.height*zoom), BufferedImage.TYPE_INT_RGB);
    BufferedImage img = new BufferedImage(pgsize.width, pgsize.height, BufferedImage.TYPE_INT_RGB);
    Graphics2D graphics = img.createGraphics();
    //graphics.setTransform(at);                
    graphics.setPaint(Color.white);
    graphics.fill(new Rectangle2D.Float(0, 0, pgsize.width, pgsize.height));
    slide[iPageNo].draw(graphics);             
    // FileOutputStream output = new ByteArrayOutputStream("C:/Temp/aspose/word/slide-" + (10 + 1) + ".png");        
    output = new ByteArrayOutputStream();
    javax.imageio.ImageIO.write(img, "png", output);

This is how I am trying to add fonts but still did not convert.

        Font customFont = Font.createFont(Font.TRUETYPE_FONT, new File("/usr/share/fonts/GEInspRg.ttf")).deriveFont(12f);
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        //register the font
        ge.registerFont(Font.createFont(Font.TRUETYPE_FONT, new File("/usr/share/fonts/GEInspRg.ttf")));
        graphics.setFont(customFont);

---

Here is the code I have: also given in the original question: And my test PPTX contains this word - /ˌinəˈvāSHən/ in addition to other English letter words.

package foo;

import java.awt.Dimension; 
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import org.apache.poi.xslf.usermodel.XMLSlideShow;
import org.apache.poi.xslf.usermodel.XSLFSlide;

public class PPTXToPNG {

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

    FileInputStream is = new FileInputStream("C:/Temp/PPTXToImage/unicode_test.pptx");      

    XMLSlideShow ppt = new XMLSlideShow(is);
    is.close();
    double zoom = 2;
    AffineTransform at = new AffineTransform();
    at.setToScale(zoom, zoom);
    Dimension pgsize = ppt.getPageSize();
    XSLFSlide[] slide = ppt.getSlides();

    BufferedImage img = new BufferedImage((int)Math.ceil(pgsize.width*zoom),
            (int)Math.ceil(pgsize.height*zoom), BufferedImage.TYPE_INT_RGB);
    Graphics2D graphics = img.createGraphics();

    graphics.setTransform(at);
    graphics.fill(new Rectangle2D.Float(0, 0, pgsize.width, pgsize.height));

    // Draw first page in the PPTX. First page starts at 0 position
    slide[0].draw(graphics);

    FileOutputStream out = new FileOutputStream("C:/Temp/PPTXToImage/ConvertedSlide.png");  
    javax.imageio.ImageIO.write(img, "png", out);
    out.close();
    System.out.println("DONE");

   }
}

Answer 1

As Jongware pointed out above, the characters are not available in the "GE Inspira" font, as you can see in the example programm below - so you'll need some /ˌinəˈvāSHən/ (innovation) to come around that ;)

There are several approaches I can think off:

• I'm not sure if this graphics.setFont(customFont); for setting the in your code was just a test, but normally POI will use (and set) the font, which was specified in the document. So the easiest would be to replace the font in the original document with a font which supports phonetics (see the wikipedia unicode article for suitable fonts). Btw. if you try to use that font in Libre Office and insert these phonetics you'll also get "junk" chars.

• you could use something like fontforge to add the missing chars to your preferred font from a different font (but of course it need to be used - see above). It would look a bit strange, but better than rectangles ...

• you could check beforehand if certain chars in the text-runs are supported for the specified font and insert a new text-run element with an alternative font for the unsupported chars

• I know that PDFs have some kind of font substitution going on, in case a font (or even a character???) can't be found, I haven't found a similar mechanism for java in a short search ... maybe there's also a solution in this way ...

(tested with POI 3.10-beta1)

import java.awt.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.*;
import org.apache.poi.xslf.usermodel.*;

public class UnicodePPT {
    public static void main(String[] args) throws Exception {
        // create a sample pptx
        XMLSlideShow ss = new XMLSlideShow();
        Dimension pgsize = ss.getPageSize();             

        XSLFSlide slide = ss.createSlide();
        XSLFTextBox tb = slide.createTextBox();
        tb.setShapeType(XSLFShapeType.HEART);
        int shapeSize = 150;
        tb.setAnchor(new Rectangle2D.Double(pgsize.getWidth()/2-shapeSize/2, pgsize.getHeight()/2-shapeSize/2, shapeSize, shapeSize));
        tb.setLineWidth(2);
        tb.setLineColor(Color.BLACK);
        XSLFTextParagraph par = tb.addNewTextParagraph();
        tb.setVerticalAlignment(VerticalAlignment.DISTRIBUTED);
        par.setTextAlign(TextAlign.CENTER);
        XSLFTextRun run = par.addNewTextRun();
        run.setText("/\u02CCin\u0259\u02C8v\u0101SH\u0259n/");
        run.setFontFamily("DejaVu Serif");
        run.setFontSize(12);
        par.addLineBreak();
        run = par.addNewTextRun();
        run.setText("/\u02CCin\u0259\u02C8v\u0101SH\u0259n/");
        run.setFontFamily("GE Inspira");
        run.setFontSize(12);

        // set the font
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        InputStream is = new FileInputStream("src/main/resources/GEInspRg.TTF");
        Font font = Font.createFont(Font.TRUETYPE_FONT, is);
        is.close();
        ge.registerFont(font);  

        is = new FileInputStream("src/main/resources/DejaVuSerif.ttf");
        font = Font.createFont(Font.TRUETYPE_FONT, is);
        is.close();
        ge.registerFont(font);  

        // render it
        double zoom = 2; // magnify it by 2
        AffineTransform at = new AffineTransform();
        at.setToScale(zoom, zoom);

        BufferedImage img = new BufferedImage((int)Math.ceil(pgsize.width*zoom), (int)Math.ceil(pgsize.height*zoom), BufferedImage.TYPE_INT_RGB);
        Graphics2D graphics = img.createGraphics();
        graphics.setTransform(at);                
        graphics.setPaint(Color.white);
        graphics.fill(new Rectangle2D.Float(0, 0, pgsize.width, pgsize.height));
        slide.draw(graphics);             

        FileOutputStream fos = new FileOutputStream("unicodeppt.png");
        javax.imageio.ImageIO.write(img, "png", fos);       
        fos.close();
    }
}