Question

我有一个CompSci的学校作业，我们需要为线性方程式创建一个图。该图应具有绘制的轴，并且应具有从两个方程式绘制的两条线。我使图形本身正常工作，但似乎无法弄清楚如何正确设置直线的坐标。目前，我正在使用以下代码创建坐标并将其发送到图形：

    m.print("Slope as decimal: ");
    //gets slope of line. This will be changed so it will accept fractions like Rise/Run but not until the rest of the functionality works.
    double lslope = m.readDouble();
    //gets y intercept as B
    m.print("B as decimal: ");
    double lb = m.readDouble();

    //corresponds to the first coordinate
    double x11=0;
    double y11 = lslope*x11-lb*50;

    //corresponds to the second coordinate
    double x21=1000;
    double y21 = lslope*x21-lb*50;

    //outputs the coordinates of the two points just for the user's conveinience
    m.println(""+x11+"\n"+y11+"\n"+x21+"\n"+y21);

    //wingraph is a JFrame
    wingraph graph = new wingraph("Graph");
    graph.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
    graph.setSize(1000,1000);
    graph.setResizable(false);

    //the second set of 4 numbers will be a second line, but to get the graph working I'm just focusing on using one set. The setCoords method just sets the value of 8 coordinates inside a JFrame class which paints the X and Y axis in black, and then paints two lines with the specified coordinates in red.
    graph.setCoords(x11, y11, x21, y21, 1000,1000,1000,1000);

    //displays the graph
    graph.setVisible(true);

通过反转用户输入的斜率，我可以使线正常工作，但前提是lslope等于1。如何正确操作整数，以便无论斜率如何都能很好地显示图形有小数点，是整数还是正数或负数？

如果有帮助，我正在使用的JFrame的代码是：

    public class wingraph extends JFrame{

        public wingraph(String title){
            super(title);
            setLayout(new FlowLayout());
        }
        double xCoord1 = 0, yCoord1 = 0, xCoord2 = 0, yCoord2 = 0, xCoord12 = 0, yCoord12 = 0, xCoord22 = 0, yCoord22 = 0;
        public void setCoords(double x1, double y1, double x2, double y2, double x12, double y12, double x22, double y22){
            xCoord1 = x1;
            yCoord1 = y1;
            xCoord2 = x2;
            yCoord2 = y2;
            xCoord12 = x12;
            yCoord12 = y12;
            xCoord22 = x22;
            yCoord22 = y22;
        }        
        public void paint(Graphics g){
            g.setColor(Color.WHITE);
            g.fillRect(0, 0, this.getWidth(), this.getHeight());
            g.setColor(Color.BLACK);
            g.drawLine(this.getWidth()/2, 0, this.getWidth()/2, this.getHeight());
            g.drawLine(0, this.getHeight()/2, this.getWidth(), this.getHeight()/2);
            g.drawString("0",this.getWidth()/2-10,this.getHeight()/2-5);
            g.setColor(Color.red);
            g.drawLine((int) xCoord1,(int) yCoord1,(int) xCoord2,(int) yCoord2);
            g.drawLine((int) xCoord12,(int) yCoord12,(int) xCoord22,(int) yCoord22);
        }
}

感谢您的帮助。

修改

我的代码运行示例如下：

https://ibb.co/mVGFff

https://ibb.co/iMwbmL

https://ibb.co/mD080f

https://ibb.co/ezNct0

所有这些都存在问题，因为我需要将它们全部集中在轴和正确的格式上，例如：

https://ibb.co/cWstY0

https://ibb.co/goi0D0

对于仍然不清楚的情况，我深表歉意，但是我对Java还是陌生的，除了在笛卡尔平面上用等式y = mx + b绘制2条线外，我对如何确切地解释我想要的内容并不熟悉。

编辑2

如果用户为lslope输入1，为b输入0，我希望x和y变量为：

    x11 = 0;
    y11 = 1000;
    x21 = 1000;
    y21 = 0;

如果lslope = 2和b = 5我希望x和y变量为：

    x11 = 0
    y11 = 745;
    x21 = 1000;
    y21 = 245;

如果lslope = -1和b = 10我希望x和y变量为：

    x11 = 0
    y11 = 240;
    x21 = 1000;
    y21 = 740;

Java在JFrame中绘制线性方程图

0 个答案: