使用滑块在JPanel上绘制二次方程 [英] Drawing the Quadratic formula with sliders on a JPanel

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本文介绍了使用滑块在JPanel上绘制二次方程的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

所以，我试图做一个程序，你可以通过滑块输入二次公式（ax ^ 2 + bx + c）。然后，它会为您调整A，B和C绘制一个图表。



问题：



我写的超级油漆和滑块在一个地方的东西。
当我运行滑块时，滑块就位。



这是我的驱动程序类：

  import java.awt。*; 
 import javax.swing。*; 
 
 public class quadraticslider 
 {
 
 public static void main（String [] args）
 {
 JFrame frame = new JFrame二次滑块）; 
 frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）; 
 
 frame.getContentPane（）。add（new pp109quadraticpanel（））; 
 
 frame.pack（）; 
 frame.setVisible（true）; 
} 
}

这是面板类：

  import java.awt。*; 
 import javax.swing。*; 
 import javax.swing.event。*; 
 
 public class quadraticpanel extends JPanel 
 {
私有JPanel控件，graphPanel; 
 private JSlider ASlider，BSlider，CSlider; 
 private JLabel ALabel，BLabel，CLabel; 
 double A，B，C，x，Y; 
 
 // 
 // SLIDERS YO 
 // 
 public quadraticpanel（）
 {
 ASlider = new JSlider（JSlider.HORIZONTAL， 0，255，0）; 
 ASlider.setMajorTickSpacing（50）; 
 ASlider.setMinorTickSpacing（10）; 
 ASlider.setPaintTicks（true）; 
 ASlider.setPaintLabels（true）; 
 ASlider.setAlignmentX（Component.LEFT_ALIGNMENT）; 
 
 BSlider = new JSlider（JSlider.HORIZONTAL，0，255，0）; 
 BSlider.setMajorTickSpacing（50）; 
 BSlider.setMinorTickSpacing（10）; 
 BSlider.setPaintTicks（true）; 
 BSlider.setPaintLabel（true）; 
 BSlider.setAlignmentX（Component.LEFT_ALIGNMENT）; 
 
 CSlider = new JSlider（JSlider.HORIZONTAL，0，255，0）; 
 CSlider.setMajorTickSpacing（50）; 
 CSlider.setMinorTickSpacing（10）; 
 CSlider.setPaintTicks（true）; 
 CSlider.setPaintLabels（true）; 
 CSlider.setAlignmentX（Component.LEFT_ALIGNMENT）; 
 
 SliderListener listener = new SliderListener（）; 
 ASlider.addChangeListener（listener）; 
 BSlider.addChangeListener（listener）; 
 CSlider.addChangeListener（listener）; 
 
 
 ALabel = new JLabel（a：0）; 
 ALabel.setAlignmentX（Component.LEFT_ALIGNMENT）; 
 BLabel = newJLabel（b：0）; 
 BLabel.setAlignmentX（Component.LEFT_ALIGNMENT）; 
 CLabel = new JLabel（c：0）; 
 CLabel.setAlignmentX（Component.LEFT_ALIGNMENT）; 
 controls = new JPanel（）; 
 BoxLayout layout = new BoxLayout（controls，BoxLayout.Y_AXIS）; 
 controls.setLayout（layout）; 
 controls.add（ALabel）; 
 controls.add（ASlider）; 
 controls.add（Box.createRigidArea（new Dimension（0，20）））; 
 controls.add（BLabel）; 
 controls.add（BSlider）; 
 controls.add（Box.createRigidArea（new Dimension（0，20）））; 
 controls.add（CLabel）; 
 controls.add（CSlider）; 
 
 
 
 graphPanel = new JPanel（）; 
 graphPanel.setPreferredSize（new Dimension（500，500））; 
 graphPanel.setBackground（Color.white）; 
 
 add（controls）; 
 add（graphPanel）; 
 
 
 
 
} 
 
 //这里我使用等式，通过-10到10运行
 //从方程中获取双精度值，将
 //转换为int，然后以点为单位绘制二次方程。 
 
 public void paintComponent（Graphics page）
 {
 
 super.paintComponent（page）; 
 
 for（x = -10; x <= 10; x ++）
 {
 Y =（A *（Math.pow（x，2）））+ B * x）+（C）; 
 int g =（int）Math.round（x）; 
 int h =（int）Math.round（Y）; 
 page.setColor（Color.black）; 
 page.fillOval（g，h，1,1）; 
} 
 
 
} 
 
 
 public class SliderListener实现ChangeListener 
 {
 /// 
 ///通过滑块读取用户输入。 
 /// 
 
 public void stateChanged（ChangeEvent event）
 {
 A = ASlider.getValue（）; 
 B = BSlider.getValue（）; 
 C = CSlider.getValue（）; 
 
 ALabel.setText（a：+ A）; 
 BLabel.setText（b：+ B）; 
 CLabel.setText（c：+ C）; 
 
} 
} 
}


方案

这些示例使用 JFreeChart 可能感兴趣。如此处所示，您可以使用 SwingWorker 和此示例使用 JSlider 更新图表。



img src =https://i.stack.imgur.com/nnEje.pngalt =image>



附录：您的代码的此变体可能会指导你向前走。注意




  • 覆盖 graphPanel 中的相关方法。


  • 缩放和取消坐标，如此处所示。 p>


  • 考虑 JSpinner 的小数值。



  • 使用常见的命名惯例清楚。

    • >另请参阅 初始主题 。




  import java.awt。*; 
 import javax.swing。*; 
 import javax.swing.event.ChangeEvent; 
 import javax.swing.event.ChangeListener; 
 
 / ** @see http://stackoverflow.com/a/20556929/230513 * / 
 public class QuadraticSlider {
 
 private static final int N = 500; 
 private static final int A = 1; 
 private static final int B = 0; 
 private static final int C = 0; 
 
 public static void main（String [] args）{
 EventQueue.invokeLater（new Runnable（）{
 
 @Override 
 public void run ）{
 JFrame frame = new JFrame（Quadratic Slider）; 
 frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）; 
 frame.add（new QuadraticPanel（））; 
 frame .pack（）; 
 frame.setVisible（true）; 
} 
}）; 
} 
 
私人静态类QuadraticPanel扩展JPanel {
 
私人Box控件; 
 private JPanel graphPanel; 
 private JSlider aSlider，bSlider，cSlider; 
 private JLabel aLabel，bLabel，cLabel; 
 double a，b，c，x，y; 
 
 public QuadraticPanel（）{
 aSlider = new JSlider（JSlider.HORIZONTAL，-25，25，A）; 
 aSlider.setMajorTickSpacing（10）; 
 aSlider.setMinorTickSpacing（5）; 
 aSlider.setPaintTicks（true）; 
 aSlider.setPaintLabel（true）; 
 aSlider.setAlignmentX（Component.LEFT_ALIGNMENT）; 
 
 bSlider = new JSlider（JSlider.HORIZONTAL，-10，10，B）; 
 bSlider.setMajorTickSpacing（5）; 
 bSlider.setMinorTickSpacing（1）; 
 bSlider.setPaintTicks（true）; 
 bSlider.setPaintLabels（true）; 
 bSlider.setAlignmentX（Component.LEFT_ALIGNMENT）; 
 
 cSlider = new JSlider（JSlider.HORIZONTAL，-100，100，C）; 
 cSlider.setMajorTickSpacing（50）; 
 cSlider.setMinorTickSpacing（10）; 
 cSlider.setPaintTicks（true）; 
 cSlider.setPaintLabels（true）; 
 cSlider.setAlignmentX（Component.LEFT_ALIGNMENT）; 
 
 SliderListener listener = new SliderListener（）; 
 aSlider.addChangeListener（listener）; 
 bSlider.addChangeListener（listener）; 
 cSlider.addChangeListener（listener）; 
 
 aLabel = new JLabel（a：0）; 
 bLabel = new JLabel（b：0）; 
 cLabel = new JLabel（c：0）; 
 controls = new Box（BoxLayout.Y_AXIS）; 
 controls.add（aLabel）; 
 controls.add（aSlider）; 
 controls.add（Box.createRigidArea（new Dimension（0，20）））; 
 controls.add（bLabel）; 
 controls.add（bSlider）; 
 controls.add（Box.createRigidArea（new Dimension（0，20）））; 
 controls.add（cLabel）; 
 controls.add（cSlider）; 
 
 graphPanel = new JPanel（）{
 private static final int SCALE = 5; 
 @Override 
 public Dimension getPreferredSize（）{
 return new Dimension（N，N）; 
} 
 
 @Override 
 public void paintComponent（Graphics g）{
 super.paintComponent（g）; 
 for（x = -10; x <= 10; x ++）{
 y = a * x * x + b * x + c; 
 g.setColor（Color.black）; 
 int w =（int）（x * SCALE）+ N / 2; 
 int h =（int）（-y * SCALE）+ N / 2; 
 g.fillOval（w，h，5，5）; 
} 
} 
}; 
 graphPanel.setBackground（Color.white）; 
 
 add（controls）; 
 add（graphPanel）; 
 listener.stateChanged（null）; 
} 
 
类SliderListener实现ChangeListener {
 
 @Override 
 public void stateChanged（ChangeEvent event）{
a = aSlider.getValue（） / 5d; 
 b = bSlider.getValue（）; 
 c = cSlider.getValue（）; 
 
 aLabel.setText（a：+ a）; 
 bLabel.setText（b：+ b）; 
 cLabel.setText（c：+ c）; 
 
 repaint（）; 
} 
} 
} 
}


So, I'm trying to make a program where you can input the quadratic formula (ax^2+bx+c) via sliders. Then it draws a graph as you adjust for A, B, and C.

Issues:

I want the stuff I wrote in super paint and the sliders to be in one place. The sliders are in place when I run it. There's space with the correct background where I want my graph in the panel but no actual graph.

Here's my driver class:

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

public class quadraticslider
{

     public static void main (String[] args)
   {
      JFrame frame = new JFrame ("Quadratic Slider");
      frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);

      frame.getContentPane().add(new pp109quadraticpanel());

      frame.pack();
      frame.setVisible(true);
   }
}

Here's the panel class:

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

public class quadraticpanel extends JPanel
{
   private JPanel controls, graphPanel;
   private JSlider ASlider, BSlider, CSlider;
   private JLabel ALabel, BLabel, CLabel;
   double A, B, C, x,Y;

  //
  //SLIDERS YO
  //
   public quadraticpanel()
   {
      ASlider = new JSlider (JSlider.HORIZONTAL, 0, 255, 0);
      ASlider.setMajorTickSpacing (50);
      ASlider.setMinorTickSpacing (10);
      ASlider.setPaintTicks (true);
      ASlider.setPaintLabels (true);
      ASlider.setAlignmentX (Component.LEFT_ALIGNMENT);

      BSlider = new JSlider (JSlider.HORIZONTAL, 0, 255, 0);
      BSlider.setMajorTickSpacing (50);
      BSlider.setMinorTickSpacing (10);
      BSlider.setPaintTicks (true);
      BSlider.setPaintLabels (true);
      BSlider.setAlignmentX (Component.LEFT_ALIGNMENT);

      CSlider = new JSlider (JSlider.HORIZONTAL, 0, 255, 0);
      CSlider.setMajorTickSpacing (50);
      CSlider.setMinorTickSpacing (10);
      CSlider.setPaintTicks (true);
      CSlider.setPaintLabels (true);
      CSlider.setAlignmentX (Component.LEFT_ALIGNMENT);

      SliderListener listener = new SliderListener();
      ASlider.addChangeListener (listener);
      BSlider.addChangeListener (listener);
      CSlider.addChangeListener (listener);


      ALabel = new JLabel ("a: 0");
      ALabel.setAlignmentX (Component.LEFT_ALIGNMENT);
      BLabel = new JLabel ("b: 0");
      BLabel.setAlignmentX (Component.LEFT_ALIGNMENT);
      CLabel = new JLabel ("c: 0");
      CLabel.setAlignmentX (Component.LEFT_ALIGNMENT);
      controls = new JPanel();
      BoxLayout layout = new BoxLayout (controls, BoxLayout.Y_AXIS);
      controls.setLayout (layout);
      controls.add (ALabel);
      controls.add (ASlider);
      controls.add (Box.createRigidArea (new Dimension (0, 20)));
      controls.add (BLabel);
      controls.add (BSlider);
      controls.add (Box.createRigidArea (new Dimension (0, 20)));
      controls.add (CLabel);
      controls.add (CSlider);



      graphPanel = new JPanel();
      graphPanel.setPreferredSize (new Dimension (500, 500));
      graphPanel.setBackground (Color.white);

      add (controls); 
      add (graphPanel);




   }   

    //Here I'm taking the equation, running it through -10 to 10
    //It takes the doubles from the equation, converts
    //it to int then draws the quadratic formula in dots.

     public void paintComponent(Graphics page)
   {  

     super.paintComponent (page);

     for ( x=-10; x <= 10; x++)
     {
         Y = (A*(Math.pow(x,2)))+(B*x)+(C);
         int g = (int)Math.round(x);
         int h = (int)Math.round(Y);
         page.setColor (Color.black);
          page.fillOval (g, h, 1, 1);
      }


    }


   public class SliderListener implements ChangeListener
   {
///
///Reads the user input via slider.
///

      public void stateChanged (ChangeEvent event)
      {
         A = ASlider.getValue();
         B = BSlider.getValue();
         C = CSlider.getValue();

         ALabel.setText ("a: " + A);
         BLabel.setText ("b: " + B);
         CLabel.setText ("c: " + C);

      }
   }
}

解决方案

These examples using JFreeChart may be of interest. As shown here, you can animate the rendering using SwingWorker, and this example updates a chart using a JSlider.

Addendum: This variation of your code may guide you going forward. Note,

  • Override relevant methods in your graphPanel.

  • Scale and invert coordinates, as shown here.

  • Consider JSpinner for fractional values.

  • Use constants for consistency.

  • Use common naming conventions for clarity.

  • See also Initial Threads.

import java.awt.*;
import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

/** @see http://stackoverflow.com/a/20556929/230513 */
public class QuadraticSlider {

    private static final int N = 500;
    private static final int A = 1;
    private static final int B = 0;
    private static final int C = 0;

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                JFrame frame = new JFrame("Quadratic Slider");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new QuadraticPanel());
                frame.pack();
                frame.setVisible(true);
            }
        });
    }

    private static class QuadraticPanel extends JPanel {

        private Box controls;
        private JPanel graphPanel;
        private JSlider aSlider, bSlider, cSlider;
        private JLabel aLabel, bLabel, cLabel;
        double a, b, c, x, y;

        public QuadraticPanel() {
            aSlider = new JSlider(JSlider.HORIZONTAL, -25, 25, A);
            aSlider.setMajorTickSpacing(10);
            aSlider.setMinorTickSpacing(5);
            aSlider.setPaintTicks(true);
            aSlider.setPaintLabels(true);
            aSlider.setAlignmentX(Component.LEFT_ALIGNMENT);

            bSlider = new JSlider(JSlider.HORIZONTAL, -10, 10, B);
            bSlider.setMajorTickSpacing(5);
            bSlider.setMinorTickSpacing(1);
            bSlider.setPaintTicks(true);
            bSlider.setPaintLabels(true);
            bSlider.setAlignmentX(Component.LEFT_ALIGNMENT);

            cSlider = new JSlider(JSlider.HORIZONTAL, -100, 100, C);
            cSlider.setMajorTickSpacing(50);
            cSlider.setMinorTickSpacing(10);
            cSlider.setPaintTicks(true);
            cSlider.setPaintLabels(true);
            cSlider.setAlignmentX(Component.LEFT_ALIGNMENT);

            SliderListener listener = new SliderListener();
            aSlider.addChangeListener(listener);
            bSlider.addChangeListener(listener);
            cSlider.addChangeListener(listener);

            aLabel = new JLabel("a: 0");
            bLabel = new JLabel("b: 0");
            cLabel = new JLabel("c: 0");
            controls = new Box(BoxLayout.Y_AXIS);
            controls.add(aLabel);
            controls.add(aSlider);
            controls.add(Box.createRigidArea(new Dimension(0, 20)));
            controls.add(bLabel);
            controls.add(bSlider);
            controls.add(Box.createRigidArea(new Dimension(0, 20)));
            controls.add(cLabel);
            controls.add(cSlider);

            graphPanel = new JPanel() {
                private static final int SCALE = 5;
                @Override
                public Dimension getPreferredSize() {
                    return new Dimension(N, N);
                }

                @Override
                public void paintComponent(Graphics g) {
                    super.paintComponent(g);
                    for (x = -10; x <= 10; x++) {
                        y = a * x * x + b * x + c;
                        g.setColor(Color.black);
                        int w = (int) (x * SCALE) + N / 2;
                        int h = (int) (-y * SCALE) + N / 2;
                        g.fillOval(w, h, 5, 5);
                    }
                }
            };
            graphPanel.setBackground(Color.white);

            add(controls);
            add(graphPanel);
            listener.stateChanged(null);
        }

        class SliderListener implements ChangeListener {

            @Override
            public void stateChanged(ChangeEvent event) {
                a = aSlider.getValue() / 5d;
                b = bSlider.getValue();
                c = cSlider.getValue();

                aLabel.setText("a: " + a);
                bLabel.setText("b: " + b);
                cLabel.setText("c: " + c);

                repaint();
            }
        }
    }
}

这篇关于使用滑块在JPanel上绘制二次方程的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

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