可调整大小的角度

Question

我在一个框架中有一个角度（我画两条线）。我想让它灵活的框架;我的意思是，当用户扩展时，框架角度也会扩大，反之亦然。我尝试了很多例子，但我无法解决它。有人可以帮忙吗？

import java.awt.*; 
import java.awt.event.*; 
import java.awt.geom.*; 

public class LineDraw extends Frame { 
    Line2D line1 = new Line2D.Double(200, 200, 100, 300); 
    Stroke drawingStroke1 = new BasicStroke(3, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL, 0, 
      new float[] { 9 }, 0); 
    Line2D line2 = new Line2D.Double(200, 200, 200, 300); 

    public void paint(Graphics g) { 
     Graphics2D graph = (Graphics2D) g; 
     graph.setPaint(Color.red); 
     graph.draw(line2); 
     graph.setStroke(drawingStroke1); 
     graph.setPaint(Color.green); 
     graph.draw(line1); 

    } 

    public static void main(String args[]) { 
     Frame frame = new LineDraw(); 
     frame.addWindowListener(new WindowAdapter() { 
      public void windowClosing(WindowEvent we) { 
       System.exit(0); 
      } 
     }); 
     frame.setSize(300, 250); 
     frame.setVisible(true); 
    } 
} 

Answer 1

这里是在Swing中完成的。所有东西都在EDT中完成，就像Swing所预期的那样，因为它不是线程安全的。它是双缓冲的。为什么JLabel/Icon组合？据我所知，这只是最好的方式，而且我很难给你一个关于为什么的历史/技术解释 - 这就是它的设计方式。另一种方法是参与BufferStrategy，但开始变得更加复杂的恕我直言。

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.*; 
import java.awt.geom.*; 

public class LineDrawSwing extends JLabel implements Icon { 
    Line2D line1, line2; 

    public LineDrawSwing() { this.setIcon(this); } 

    Stroke drawingStroke1 = new BasicStroke(3, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL, 0, 
      new float[] { 9 }, 0); 

    public static void main(String args[]) { 
     JFrame frame = new JFrame(); 
     frame.addWindowListener(new WindowAdapter() { 
      public void windowClosing(WindowEvent we) { 
       System.exit(0); 
      } 
     }); 
     frame.add(new LineDrawSwing()); 
     frame.validate(); 
     frame.setSize(300, 250); 
     frame.setVisible(true); 
    } 

    @Override 
    public void paintIcon(Component c, Graphics g, int x, int y) { 
     Dimension size = getSize(); 
     line1 = new Line2D.Double(size.width/2, size.height-10, 10, 10); 
     line2 = new Line2D.Double(size.width/2, size.height-10, size.width-10, 10); 
     Graphics2D graph = (Graphics2D) g; 
     graph.setPaint(Color.red); 
     graph.draw(line2); 
     graph.setStroke(drawingStroke1); 
     graph.setPaint(Color.green); 
     graph.draw(line1); 
    } 

    @Override 
    public int getIconHeight() { 
     return getSize().height; 
    } 

    @Override 
    public int getIconWidth() { 
     return getSize().width; 
    } 
} 

Answer 2

如果坚持使用AWT，我会使用ComponentListener跟踪Frame的大小更改并相应地重置行坐标。

您可能会忽略创建/更新Frame.paint()上下文中的行，但这不是一个非常干净的实现，有很多隐含的逻辑和假设，因此可能存在一些问题。

所以这里是ComponentListener方法。我不得不做出一些关于你想让你的线条从哪里得到的假设，因为你不清楚这一点。 （如果你可以更清楚一点，我可以更新这个例子。）

import java.awt.*; 
import java.awt.event.*; 
import java.awt.geom.*; 

public class LineDraw extends Canvas implements ComponentListener { 
    Line2D line1, line2; 

    public LineDraw() { 
     this.addComponentListener(this); 
    } 

    // set up lines every size update 
    public void componentResized(ComponentEvent e) { 
     Dimension size = getSize(); 
     line1 = new Line2D.Double(size.width/2, size.height-10, 10, 10); 
     line2 = new Line2D.Double(size.width/2, size.height-10, size.width-10, 10); 
    } 

    // required to satisfy ComponentListener interface 
    public void componentHidden(ComponentEvent e) { } 
    public void componentMoved(ComponentEvent e) { } 
    public void componentShown(ComponentEvent e) { } 

    // paint, main both as before 

    Stroke drawingStroke1 = new BasicStroke(3, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL, 0, 
      new float[] { 9 }, 0); 

    public void paint(Graphics g) { 
     Graphics2D graph = (Graphics2D) g; 
     graph.setPaint(Color.red); 
     graph.draw(line2); 
     graph.setStroke(drawingStroke1); 
     graph.setPaint(Color.green); 
     graph.draw(line1); 
    } 

    public static void main(String args[]) { 
     Frame frame = new Frame(); 
     frame.addWindowListener(new WindowAdapter() { 
      public void windowClosing(WindowEvent we) { 
       System.exit(0); 
      } 
     }); 
     frame.add(new LineDraw()); 
     frame.validate(); 
     frame.setSize(300, 250); 
     frame.setVisible(true); 
    } 
}