JFreeChart & iText : black image when creating pdf

问题:

I am using JFreeChart 1.0.9 to create a chart, and iText 1.3.1 to display this chart in a PDF file. To do so, I am creating a JFreeChart, and then converting it to a byte array :

final TimeSeriesCollection dataset = new TimeSeriesCollection();
final TimeSeries s1 = new TimeSeries("Series 1", Minute.class);
s1.add(new Minute(0, 0, 7, 12, 2003), 1.2);
s1.add(new Minute(30, 12, 7, 12, 2003), 3.0);   // 12h30  => value = 3
s1.add(new Minute(15, 14, 7, 12, 2003), 8.0);

final TimeSeries s2 = new TimeSeries("Series 2", Minute.class);
s2.add(new Minute(0, 3, 7, 12, 2003), 0.0);
s2.add(new Minute(30, 9, 7, 12, 2003), 0.0);
s2.add(new Minute(15, 10, 7, 12, 2003), 0.0);

dataset.addSeries(s1);
dataset.addSeries(s2);
XYDataset dataset2 = dataset;

final JFreeChart chart = ChartFactory.createTimeSeriesChart(
            "Sample Chart",
            "Date", 
            "Value",
            dataset2,
            true,
            true,
            false
);
chart.setBackgroundPaint(Color.white);
ChartRenderingInfo info = new ChartRenderingInfo(new StandardEntityCollection());

BufferedImage originalImage = chart.createBufferedImage(500, 300, info);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write( originalImage, "jpg", baos );
byte[] imageInByte = baos.toByteArray();

Then I am simply putting this byte array in the PDF file using iText as follow :

Document document=new Document();
PdfWriter.getInstance(document,new FileOutputStream("hello.pdf"));
document.open(); 

Image image = Image.getInstance(imageInByte);
document.add(image);

document.close();

But when I open my PDF file, the area where my image should be is all black.

Do you have an idea of what could be the cause of it?

回答1:

It looks like the image is being inverted during the conversion process. Try the following code

package demo;

import java.awt.Color;
import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.JFreeChart;
import org.jfree.data.time.Minute;
import org.jfree.data.time.TimeSeries;
import org.jfree.data.time.TimeSeriesCollection;
import org.jfree.data.xy.XYDataset;

import com.lowagie.text.Document;
import com.lowagie.text.DocumentException;
import com.lowagie.text.pdf.PdfWriter;


public class PDF {

    public static void main(String[] args) {
        final TimeSeriesCollection dataset = new TimeSeriesCollection();
        final TimeSeries s1 = new TimeSeries("Series 1", Minute.class);
        s1.add(new Minute(0, 0, 7, 12, 2003), 1.2);
        s1.add(new Minute(30, 12, 7, 12, 2003), 3.0);   // 12h30  => value = 3
        s1.add(new Minute(15, 14, 7, 12, 2003), 8.0);

        final TimeSeries s2 = new TimeSeries("Series 2", Minute.class);
        s2.add(new Minute(0, 3, 7, 12, 2003), 0.0);
        s2.add(new Minute(30, 9, 7, 12, 2003), 0.0);
        s2.add(new Minute(15, 10, 7, 12, 2003), 0.0);

        dataset.addSeries(s1);
        dataset.addSeries(s2);
        XYDataset dataset2 = dataset;

        final JFreeChart chart = ChartFactory.createTimeSeriesChart(
                    "Sample Chart",
                    "Date", 
                    "Value",
                    dataset2,
                    true,
                    true,
                    false
        );
        chart.setBackgroundPaint(Color.white);
        java.awt.Image originalImage = chart.createBufferedImage(500, 300);
        try {           
            Document document=new Document();
            PdfWriter.getInstance(document,new FileOutputStream("hello.pdf"));
            document.open(); 
            com.lowagie.text.Image image1 = com.lowagie.text.Image.getInstance(originalImage,Color.white);
            document.add(image1);
            document.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (DocumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }
}

Using the latest version of iText You I get this PDF

hopefully you will get the same

I have made the follwing changes to you code

java.awt.Image originalImage = chart.createBufferedImage(500, 300);

having Removed

ChartRenderingInfo info = new ChartRenderingInfo(new StandardEntityCollection());

As its not needed. I've also removed the ByteArrayOutputStream and replaced it with

   com.lowagie.text.Image image1 = com.lowagie.text.Image.getInstance(originalImage,Color.white);

Note the use of full names for com.lowagie.text.Image and java.awt.Image as both AWT and Lowagie have classes called Image.