PImage base64 encode and decode

snir102002

Hi everyone,

I would like to send a PImage over the network using JSON. I'm trying to make it work using base64 but i'm keep getting ClassCastException in decode stage. I noticed that if I save the BufferedImage to the hard drive and then load it using PApplet.loadImage(path), it works fine. Because I'm using Applets, I can't write to client's local file system, so I can't use this solution. Can anyone help? thanks

java.lang.ClassCastException: [I cannot be cast to [B
at sun.awt.image.ByteInterleavedRaster.getDataElements(ByteInterleavedRaster.java:364)
at processing.core.PImage.<init>(PImage.java:287)
at UserInterface.Applets.RecpieRenderingPApplet.DecodePImageFromBase64(RecpieRenderingPApplet.java:577)
at UserInterface.Applets.RecpieRenderingPApplet.setup(RecpieRenderingPApplet.java:75)
at processing.core.PApplet.handleDraw(PApplet.java:2281)
at processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:237)
at processing.core.PApplet.run(PApplet.java:2177)
at java.lang.Thread.run(Thread.java:745)




import org.apache.commons.codec.binary.Base64;



public String EncodePImageToBase64(PImage i_Image) throws UnsupportedEncodingException, IOException
 {
    String result = null;
    BufferedImage buffImage = (BufferedImage)i_Image.getNative();
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    ImageIO.write(buffImage, "PNG", out);
    byte[] bytes = out.toByteArray();
    result = Base64.encodeBase64URLSafeString(bytes);

    return result;
 }

 public PImage DecodePImageFromBase64(String i_Image64) throws IOException
 {
    PImage result = null;
    byte[] decodedBytes = Base64.decodeBase64(i_Image64);
    InputStream in = new ByteArrayInputStream(decodedBytes);
    BufferedImage bImageFromConvert = ImageIO.read(in);
    result = new PImage(bImageFromConvert);

    return result;
 }

PhiLho

"[I cannot be cast to [B" means the methods expected to find an array of bytes [B and found an array of integers [I.
Check ImageIO.read() if you can add some more parameters (like you did in write()), to help it interpreting the data.

snir102002

Hi PhiLho,

ImageIO.read() get only 1 parameter and I had no luck finding alternative.

snir102002

Well, after a couple of sleepless nights, I managed to solve the problem. Here is the solution:

    public PImage DecodePImageFromBase64(String i_Image64) throws IOException
    {
       PImage result = null;
       byte[] decodedBytes = Base64.decodeBase64(i_Image64);

       ByteArrayInputStream in = new ByteArrayInputStream(decodedBytes);
       BufferedImage bImageFromConvert = ImageIO.read(in);
       BufferedImage convertedImg = new BufferedImage(bImageFromConvert.getWidth(),     bImageFromConvert.getHeight(), BufferedImage.TYPE_INT_ARGB);
       convertedImg.getGraphics().drawImage(bImageFromConvert, 0, 0, null);
       result = new PImage(convertedImg);

       return result;
    }

PhiLho

Ah, I thought the problem was in the ImageIO.read() call. The problem of reporting errors without pointing out where they happened...
Glad you sorted out the problem by yourself.