objpolyline.java

用java编写的画图面板程序（有源代码）

package project.paint;

import java.awt.BasicStroke;
import java.awt.Graphics2D;
import java.awt.Point;

//折线类
class ObjPolyline extends BaseObject {
	private int x1,y1,x2,y2;
	public ObjPolyline() {
		super();
		type=BaseObject.PENCIL;
	}
	public String toString() {
		return "折线 "+String.valueOf(getLength())+" 个点";
	}
	public void addPoint(int x,int y) {
		X.add(x);
		Y.add(y);
	}
	public void moveObject(int xBuff,int yBuff) {
		for (int i=getLength()-1; i>=0; i--) {
			setPoint(i,getPointX(i)+xBuff,getPointY(i)+yBuff);
		}
	}
	public void draw(Graphics2D g2d) {
		g2d.setPaint(color);
		g2d.setStroke(new BasicStroke(stroke,BasicStroke.CAP_ROUND,BasicStroke.JOIN_BEVEL));
		
		/* 用 drawPolyline 画 */
		int len=getLength();
		int[] x=new int[len];
		int[] y=new int[len];
		for (int i=0; i<len; i++) {
			x[i]=(Integer)(X.get(i));
			y[i]=(Integer)(Y.get(i));
		}
		g2d.drawPolyline(x,y,len);
//		shape=new Polygon(x,y,len);		//封闭折线
//		g2d.draw(shape);
		/* */
		
		/* 循环画线 *
		for (int i=0; i<getLength()-1; i++) {
			int x1=getPointX(i);
			int y1=getPointY(i);
			int x2=getPointX(i+1);
			int y2=getPointY(i+1);
			g2d.drawLine(x1,y1,x2,y2);
		}
		/* */
		getXYs();
	}
	public void changeSize(int x,int y) {
		addPoint(x,y);
	}
	public void drawLastLine(Graphics2D g2d) {
		g2d.setPaint(color);
		g2d.setStroke(new BasicStroke(stroke,BasicStroke.CAP_ROUND,BasicStroke.JOIN_BEVEL));
		int i=getLength()-1;
		g2d.drawLine(getPointX(i-1),getPointY(i-1),getPointX(i),getPointY(i));
	}
	public int getMinX() {
		return x1;
	}
	public int getMinY() {
		return y1;
	}
	public int getMaxX() {
		return x2;
	}
	public int getMaxY() {
		return y2;
	}
	public boolean isCursorIn(int x,int y) {
		getXYs();
		if (x>=x1 && x<=x2 && y>=y1 && y<=y2)
			return true;
		else
			return false;
	}
	public void setGradientPaint(Point x,Point y) {
		return;
	}
	public boolean canResizeObject(int x,int y) {
		return false;
	}
	private void getXYs() {
		x1=getPointX(0);
		y1=getPointY(0);
		x2=x1;
		y2=y1;
		for (int i=0; i<getLength(); i++) {
			int xx=getPointX(i);
			int yy=getPointY(i);
			if (xx<x1)
				x1=xx;
			if (yy<y1)
				y1=yy;
			if (xx>x2)
				x2=xx;
			if (yy>y2)
				y2=yy;
		}
	}
}