新手，请问在java中画怎样画不同粗细的直线呢？

Question

利用BasicStroke类.
先创建一个BasicStroke类对象.然后通过Graphics2D 的setStroke 方法将直线的Styles传递给Graphics2D

Answer 1

import java.awt.*;
import java.awt.geom.*;
import java.awt.event.*;
import java.applet.*;public class FloatLine extends Applet
{
public void paint( Graphics g )
{
Rectangle r = getBounds();
Line2D.Float line;
line = new Line2D.Float(20,20,200,200);
g.setStroke(new BasicStroke(2.0f));
g.setColor( Color.red );
g.draw(line);
} public void processEvent( AWTEvent e )
{
if ( e.getID() == Event.WINDOW_DESTROY )
{
System.exit( 0 );
}
}
}
可是我这个简单的程序编译都不能通过呢？请高手指教

Answer 2

import java.awt.*;
import java.awt.geom.*;
import java.awt.event.*;
import java.applet.*;public class FloatLine extends Applet
{
public void paint( Graphics2D g )
{
Rectangle r = getBounds();
Line2D.Float line;
line = new Line2D.Float(20,20,200,200);
g.setStroke(new BasicStroke(2.0f));
g.setColor( Color.red );
g.draw(line);
} public void processEvent( AWTEvent e )
{
if ( e.getID() == Event.WINDOW_DESTROY )
{
System.exit( 0 );
}
}
}
这个小程序编译通过了，怎么不能在浏览器上画出相应的图形呢，请高手指教

Answer 3

画线直接用Graphics的drawLine方法就可以了

Answer 4

给你一个例子:
import java.awt.*;
import javax.swing.*;
import java.awt.geom.*;
import java.awt.event.*;
import java.applet.*;public class FloatLine extends JApplet
{
final static Color bg = Color.white;
    final static Color fg = Color.black;
    final static BasicStroke stroke = new BasicStroke(2.0f);
    final static BasicStroke wideStroke = new BasicStroke(8.0f);
    
    public void init() {
        //Initialize drawing colors
        setBackground(bg);
        setForeground(fg);
    }
    
public void paint( Graphics g )
{
Graphics2D g2 = (Graphics2D) g;
g2.setStroke(stroke);
g2.setColor( Color.red );
g2.drawLine(20,50,100,80);
g2.setStroke(wideStroke);
g2.drawLine(50,100,120,100);
}
 public static void main(String s[]) {
        JFrame f = new JFrame("FloatLine");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        JApplet applet = new FloatLine();
        f.getContentPane().add("Center", applet);
        applet.init();
        f.pack();
        f.setSize(new Dimension(550,400));
        f.show();
    }}

Answer 5

好像是Graphics#setStroke(java.awt.graphics.Stroke)

Answer 6

谢谢，问题已解决，特别感谢ztc16627(无语) ，因为你给的例子和我昨天晚上凑出来的一样，就是将Graphics的变量g强制转换成Graphics2D的g2

Answer 7

import java.awt.*;
import javax.swing.*;
import java.awt.geom.*;
import java.awt.event.*;
import java.applet.*;public class FloatLine extends JApplet
{
final static Color bg = Color.white;
    final static Color fg = Color.black;
    final static BasicStroke stroke = new BasicStroke(2.0f);
    final static BasicStroke wideStroke = new BasicStroke(8.0f);
    final static float dash1[] = {10.0f};                         //新加
    final static BasicStroke dashed = new BasicStroke(1.0f,       //新加
                                                      BasicStroke.CAP_BUTT, 
                                                      BasicStroke.JOIN_MITER, 
                                                      10.0f, dash1, 0.0f);
    
    public void init() {
        //Initialize drawing colors
        setBackground(bg);
        setForeground(fg);
    }
    
public void paint( Graphics g )
{
Graphics2D g2 = (Graphics2D) g;
g2.setStroke(dashed);
g2.setColor( Color.red );
g2.drawLine(20,50,100,80);
g2.setStroke(wideStroke);
g2.drawLine(50,100,120,100);
}
 public static void main(String s[]) {
        JFrame f = new JFrame("FloatLine");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        JApplet applet = new FloatLine();
        f.getContentPane().add("Center", applet);
        applet.init();
        f.pack();
        f.setSize(new Dimension(550,400));
        f.show();
    }}

Answer 8

谢谢ztc16627(无语)，那么请问虚线怎么画呢

Answer 9

你看看我刚刚贴的代码!!!final static float dash1[] = {10.0f};                         //新加
final static BasicStroke dashed = new BasicStroke(1.0f,       //新加
                                                      BasicStroke.CAP_BUTT, 
                                                      BasicStroke.JOIN_MITER, 
                                                      10.0f, dash1, 0.0f);
g2.setStroke(dashed);

Answer 10

你用
drawLine函数分别画出正方形的四条边.(分别设置它们的粗细)

Answer 11

这是自然，谢谢 ztc16627(无语)