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package qtrees;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Representation of a Quad-tree
* @author Camil Staps, s4498062
*/
public class QTree {
/** the root of the tree */
QTNode root;
/**
* Construct the tree based on an ASCII representation of a bitstream on a reader
* @param input the reader
*/
public QTree( Reader input ) {
root = readQTree( input );
}
/**
* Construct the tree based on a bitmap
* @param bitmap the bitmap
*/
public QTree( Bitmap bitmap ) {
root = bitmap2QTree( 0, 0, bitmap.getWidth(), bitmap );
}
/**
* Fill a bitmap based on this tree
* @param bitmap the bitmap
*/
public void fillBitmap ( Bitmap bitmap ) {
root.fillBitmap(0, 0, bitmap.getWidth(), bitmap);
}
/**
* Write the quad-tree as compressed bitstream
* @param sb the Writer to write to
* @throws IOException is passed on from Writer
*/
public void writeQTree( Writer sb ) throws IOException {
root.writeNode( sb );
}
/**
* Read a Quad-tree node based on an ASCII representation of a bitstream on a Reader
* @param input the Reader
* @return the node
*/
private static QTNode readQTree( Reader input ) {
try {
int read = input.read();
if (read == '1') {
GreyNode node = new GreyNode();
for (int i = 0; i < 4; i++)
node.setChild(i, readQTree(input));
return node;
} else {
read = input.read();
if (read == '1') {
return new WhiteLeaf();
} else {
return new BlackLeaf();
}
}
} catch (IOException ex) {
Logger.getLogger(QTree.class.getName()).log(Level.SEVERE, null, ex);
return null;
}
}
/**
* Get a (compressed) node from a (part of a) bitmap
* @param x the x coordinate of the top left corner
* @param y the y coordinate of the top left corner
* @param width the width of the part to read
* @param bitmap the bitmap
* @return the (compressed) node
*/
public static QTNode bitmap2QTree( int x, int y, int width, Bitmap bitmap ) {
if (width == 1) {
if (bitmap.getBit(x,y)) {
return new WhiteLeaf();
} else {
return new BlackLeaf();
}
} else {
GreyNode node = new GreyNode();
node.setChild(0, bitmap2QTree(x, y, width / 2, bitmap));
node.setChild(1, bitmap2QTree(x + width / 2, y, width / 2, bitmap));
node.setChild(2, bitmap2QTree(x + width / 2, y + width / 2, width / 2, bitmap));
node.setChild(3, bitmap2QTree(x, y + width / 2, width / 2, bitmap));
return node.compress();
}
}
}
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