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Image not serializable

Posted on 1998-11-13
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Last Modified: 2012-06-22
May I know how can I grap the image in a canvas a send it to a client and based on the object received, the client will paint the image back to a canvas...

I've tried the writeObject function but it is not able to write an Image object coz Image object does not implements java.io.Serializable
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Question by:ctusa
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imladris earned 100 total points
ID: 1227407
You can use the PixelGrabber class from the java.awt.image package to get an integer array that represents the image. Use the constructor that takes an Image argument:

public PixelGrabber(Image img,int x,int y,int w,int h,int []pix,int off,int scansize);

The production of pixel data is initiated with the command:

public boolean grabPixels() throws InterruptedException;

from the same class.
You can break this down into bytes, send it across, and on the other end it can be reassembled with a Toolkit.createImage call.

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by:imladris
ID: 1227408
P.S. there is a createImage method in the Toolkit that takes a byte array as an argument.

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by:imladris
ID: 1227409
P.P.S. scansize can simply be set to the width of the image in pixels.

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Expert Comment

by:heyhey_
ID: 1227410
you have to trap the Image pixel data into a byte array, then (eventually) encode it, than send it
, decode it and show it

so very quickly
Image image = new Image (....mycanvas.getSize())  - creaty new image with the size of canvas
mycanvas.paint(image.getGraphics())  - trap the canvas image into an offscreen image

PixelGrabber pg = new PixelGrabber(imgage, x, y, w, h, pixels, 0, w); - to grab pixels from the image
(see java.awt.image.PixelGrabber  docs)
than you can
1. code the byte array as a Gif file and use Toolkit.CreateImage(bytes) on the client computer
2. send the raw data and implement ImageProducer that creates Image from the raw data

I have no time to write you sample code at moment, so if you have more specific questions please post them here, i'll try to answer (an post code) during the weekend ...
Also can give you the URL of free GIF encoder (byte[] -> gifData) with sources if you need it

hope this helps
  heyhey

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Author Comment

by:ctusa
ID: 1227411
Thanx, but I noticed that the conversion of int[] to byte[] is very very slow... is there a faster way...? That's b4 sending across the network...juz local processing power only...
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