xorpreview.java

定要上载质量高而定要上载质量高而定要上载质量高而定要上载质量高而定要上载质量高而

package org.flexdock.docking.drag.preview;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Polygon;
import java.awt.Stroke;
import java.util.Map;

import org.flexdock.docking.Dockable;
import org.flexdock.docking.drag.effects.DefaultPreview;

public class XORPreview extends DefaultPreview {
	
	public void drawPreview(Graphics2D g, Polygon p, Dockable dockable, Map dragInfo) {
		float[] pattern = { 1.0f, 1.0f };
		Stroke stroke = new BasicStroke(1, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER, 1f, pattern, 0f);
		g.setStroke(stroke);
		
		g.setColor(Color.BLACK);
		g.setXORMode(Color.WHITE);
		drawPolygon(g, p, 3);
	}
	
	private void drawPolygon(Graphics2D g, Polygon p, int thickness) {
		Point center = getCenterOfGravity(p);
		for(int i=0; i<thickness; i++) {
			g.drawPolygon(p);
			gravitate(p, center, 1);
		}
	}
	
	private void gravitate(Polygon p, Point center, int step) {
		int len = p.npoints;
		
		for(int i=0; i<len; i++) {
			int deltaX = center.x > p.xpoints[i]? step: -step;
			int deltaY = center.y > p.ypoints[i]? step: -step;
			p.xpoints[i] += deltaX;
			p.ypoints[i] += deltaY;
		}
	}
	
	private Point getCenterOfGravity(Polygon p) {
		int x = 0;
		int y = 0;
		int len = p.npoints;
		for(int i=0; i<len; i++) {
			x += p.xpoints[i];
			y += p.ypoints[i];
		}
		return new Point(x/len, y/len);
	}
}