用画布画多条线

public static void main(String[] args) { 
    Picture myPic = new Picture(600, 600); 
    Graphics canvas = myPic.getOffScreenGraphics(); 

    canvas.setColor(Color.WHITE); 
    canvas.fillRect(0, 0, 600, 600); 

    canvas.setColor(Color.BLACK); 
    int x1; 
    int y1; 
    int x2; 
    int y2; 
    int heading; 

    x1 = 300; 
    y1 = 300; 
    x2 = 300; 
    y2 = 300; 

    heading = 0; 



    String keyboard = JOptionPane.showInputDialog(null, 
      "Enter your input"); 

    if (keyboard != null) { 
     if (keyboard.isEmpty() || keyboard.contains(" ")) { 
      JOptionPane.showMessageDialog(
        null, 
        "Please enter an input", 
        "Error", 
        JOptionPane.ERROR_MESSAGE); 
      main(args); 
     } 


     int counth = 0; 
     int countg = 0; 
     int countPlus = 0; 
     int countMinus = 0; 
     int countK = 0; 
     int countR = 0; 
     int countG = 0; 
     int countB = 0; 
     int countC = 0; 
     int countO = 0; 


     for (int i = 0; i < keyboard.length(); i++) { 
      if (keyboard.charAt(i) == '+') { 
       if (heading == 0) { 
        heading = 1; 
       } else if (heading == 1) { 
        heading = 2; 
       } else if (heading == 2) { 
        heading = 3; 
       } else if (heading == 3) { 
        heading = 0; 
       } 
      } 
     } 
     countPlus++; 

     for (int i = 0; i < keyboard.length(); i++) { 
      if (keyboard.charAt(i) == '-') { 
       if (heading == 0) { 
        heading = 3; 
       } else if (heading == 1) { 
        heading = 0; 
       } else if (heading == 2) { 
        heading = 1; 
       } else if (heading == 3) { 
        heading = 2; 
       } 
      } 
     } 
     countMinus++; 


     for (int i = 0; i < keyboard.length(); i++) { 
      if (keyboard.charAt(i) == 'h' || keyboard.charAt(i) == 'f') { 
       if (heading == 0) { 
        counth++; 
        int k = 10 * (counth); 
        canvas.drawLine(x1, y1, x2, y2 + k); 

       } else if (heading == 1) { 
        counth++; 
        int k = 10 * (counth); 
        canvas.drawLine(x1, y1, x2 + k, y2); 
       } else if (heading == 2) { 
        counth++; 
        int k = 10 * (counth); 
        canvas.drawLine(x1, y1, x2, y2 - k); 
       } else if (heading == 3) { 
        counth++; 
        int k = 10 * (counth); 
        canvas.drawLine(x1, y1, x2 - k, y2); 
       } else if (heading > 3 || heading < 0) { 
        JOptionPane.showMessageDialog(
          null, 
          "Your heading is greater than 3 or less than 0", 
          "Error", 
          JOptionPane.ERROR_MESSAGE); 
        main(args); 
       } 
      } 

     } 



     for (int i = 0; i < keyboard.length(); i++) { 
      if (keyboard.charAt(i) == 'K') { 
       canvas.setColor(Color.BLACK); 
      } 
     } 
     countK++; 

     for (int i = 0; i < keyboard.length(); i++) { 
      if (keyboard.charAt(i) == 'R') { 
       canvas.setColor(Color.RED); 
      } 
     } 
     countR++; 

     for (int i = 0; i < keyboard.length(); i++) { 
      if (keyboard.charAt(i) == 'G') { 
       canvas.setColor(Color.GREEN); 
      } 
     } 
     countG++; 

     for (int i = 0; i < keyboard.length(); i++) { 
      if (keyboard.charAt(i) == 'B') { 
       canvas.setColor(Color.BLUE); 
      } 
     } 
     countB++; 

     for (int i = 0; i < keyboard.length(); i++) { 
      if (keyboard.charAt(i) == 'C') { 
       canvas.setColor(Color.CYAN); 
      } 
     } 
     countC++; 

     for (int i = 0; i < keyboard.length(); i++) { 
      if (keyboard.charAt(i) == 'O') { 
       canvas.setColor(Color.BLACK); 
      } 
     } 
     countO++; 


     System.out.println("h = " + counth); 
     System.out.println("g = " + countg); 
     System.out.println("+ = " + countPlus); 
     System.out.println("- = " + countMinus); 
     System.out.println("K = " + countK); 
     System.out.println("R = " + countR); 
     System.out.println("G = " + countG); 
     System.out.println("B = " + countB); 
     System.out.println("C = " + countC); 
     System.out.println("O = " + countO); 



     myPic.repaint(); 
    } else { 
     System.exit(0); 
    } 


}

我想根据用户输入绘制一些线条。用画布画多条线

输入是h和f，向前移动10个像素（两者都做同样的事情）和+或 - 改变方向线将90度顺时针移动+或逆时针移动 - （默认向上移动）。

例如，如果用户输入：“hhh”，该线将向上移动30个像素。

我遇到的问题是我希望用户能够输入hhh + hhh，并且它向上绘制一个30像素的线，然后转动并绘制30个像素，但是向右。但是在我的程序中，当我输入hhh + hhh时，它只是向右一个60像素的直线。

所以我的问题是：如何在指定的方向上看到+或 - 并绘制另一条线时，如何绘制线。

来源

2013-02-22 Mert

你错过了一些代码吗？你从来没有宣布“标题”变量，除非我是瞎子 – ChrisK 2013-02-22 00:36:20

以及我没有包括我的完整代码，但现在粘贴它。 - 完成 – Mert 2013-02-22 00:38:23

'... main（args）; ...'这是一个非常糟糕的主意，请使用某种类型的循环 – MadProgrammer 2013-02-22 01:03:43

代码没有经过充分测试，但我建议你：

删除两个循环的+和 - 。

for(int i =0; i < keyboard.length(); i++) 
    { 
if(keyboard.charAt(i) == '+') 
     heading++; 
if(keyboard.charAt(i) == '-') 
     heading--; 

if (heading < 0) 
    heading = 3; 
if (heading > 3) 
    heading = 0; 

if(keyboard.charAt(i) == 'h' || keyboard.charAt(i) == 'f') 
//Snip rest of heading code here 
}

您遇到的问题是，你是通过代码独立处理线描图码的多次循环。

虽然这可能无法解决您的问题，但它可能会让您走上正轨。

来源

2013-02-22 00:49:00 ChrisK

用画布画多条线

回答

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