package org.openslx.graph;

import java.awt.image.BufferedImage;
import java.awt.image.DataBufferInt;
import java.awt.image.SinglePixelPackedSampleModel;
import java.io.OutputStream;

import ar.com.hjg.pngj.ImageInfo;
import ar.com.hjg.pngj.ImageLineByte;
import ar.com.hjg.pngj.PngWriter;

public class PngRenderer
{
	private final ImageInfo imageInfo;
	private final SinglePixelPackedSampleModel samplemodel;
	private final int[] srcImageRawData;
	private final ImageLineByte line;
	private final byte[] lineBytes;

	public PngRenderer( BufferedImage image )
	{
		imageInfo = new ImageInfo( image.getWidth(), image.getHeight(), 8, false );
		DataBufferInt db = ( (DataBufferInt)image.getRaster().getDataBuffer() );
		samplemodel = (SinglePixelPackedSampleModel)image.getSampleModel();
		line = new ImageLineByte( imageInfo );
		lineBytes = line.getScanline();
		srcImageRawData = db.getData();
	}
	
	public void render( OutputStream os )
	{
		PngWriter pngWriter = new PngWriter( os, imageInfo );
		for ( int row = 0; row < imageInfo.rows; row++ ) {
			int elem = samplemodel.getOffset( 0, row );
			for ( int col = 0, j = 0; col < imageInfo.cols; col++ ) {
				int sample = srcImageRawData[elem++];
				lineBytes[j++] = (byte) ( ( sample & 0xFF0000 ) >> 16 ); // R
				lineBytes[j++] = (byte) ( ( sample & 0xFF00 ) >> 8 ); // G
				lineBytes[j++] = (byte) ( sample & 0xFF ); // B
			}
			pngWriter.writeRow( line, row );
		}
		pngWriter.end();
	}
	
}