curve.java~45~

本程序用JAVA编制

package curve;

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.util.Vector;
import java.lang.Math;

public class curve {
  Graphics myGC;
  Font graphFont;
  int axisH;
  int axisW;
  int xOrigin;
  int yOrigin;
  int xSpacing;
  int ySpacing;

  public curve(Graphics g) {
    myGC=g;
    graphFont=new Font("宋体",Font.PLAIN,12);
    myGC.setFont(graphFont);
    myGC.setColor(new Color(255,255,255));
  }

  public void fillImage(int W,int H){
    myGC.fillRect(0,0,W,H);
  }

  // ******** 画坐标轴 ********
  public void drawAxes(int W,int H){
    axisW=W-100;
    axisH=H-100;

    xOrigin=(W-axisW)/2;
    yOrigin=(H-axisH)/2+axisH;

    // 绘制具有3D效果的坐标轴
    myGC.setColor(Color.black);
    myGC.drawLine(xOrigin,yOrigin,xOrigin+axisW,yOrigin);
    myGC.drawLine(xOrigin,yOrigin,xOrigin,yOrigin-axisH);

    // 绘制 X 轴坐标箭头
    int x1=xOrigin+axisW;
    int triXx[]={x1-4,x1,x1-4,x1-4};
    int triXy[]={yOrigin+2,yOrigin,yOrigin-2,yOrigin+2};
    Polygon triangleX=new Polygon(triXx,triXy,4);
    myGC.drawPolygon(triangleX);
    myGC.fillPolygon(triangleX);
    myGC.drawString("X",xOrigin+axisW+5,yOrigin+4);
  }

  // ******** 绘制刻度 ********
  public void makeHashMarks(int nXHash,float yTop){
    xSpacing=axisW/(nXHash);
    ySpacing=axisH/10;

    // 绘制 X 轴刻度
    myGC.setColor(Color.black);
    int x=xOrigin+xSpacing;
    myGC.drawString(Integer.toString(0),xOrigin,yOrigin+20); // 原点
    for(int t=0;t<nXHash-1;t++){
      //myGC.drawLine(x,yOrigin,x,yOrigin-3);
      myGC.setColor(Color.black);
      myGC.drawString(Integer.toString(t+1),x,yOrigin+20);

      myGC.setColor(Color.lightGray);
      myGC.drawLine(x,yOrigin-1,x,yOrigin-axisH);  // 竖直网格
      x+=xSpacing;
    }

    // 绘制 Y 轴刻度
    int y=yOrigin-ySpacing;
    float scaleY=yTop/10;
    float sum=0;

    for(int t=0;t<10;t++){
      //myGC.drawLine(xOrigin,y,xOrigin-3,y);
      //myGC.drawLine(xOrigin,y,xOrigin+(nXHash-1)*xSpacing,y); // 水平网格
      int xx=xOrigin+(nXHash-1)*xSpacing;
      int x0=xOrigin+1;

      // 水平网格(虚线) 每段虚线长6，空白4
      while(x0<xOrigin+(nXHash-1)*xSpacing){
        myGC.setColor(Color.lightGray);
        //myGC.setColor(Color.white);
        myGC.drawLine(x0,y,x0+6,y);
        x0+=10;
      }
      // 最顶端为实线
      myGC.drawLine(xOrigin,yOrigin-axisH,xOrigin+(nXHash-1)*xSpacing,yOrigin-axisH);
      // 清除虚线在坐标轴以外的部分
      myGC.setColor(new Color(255,255,255));
      myGC.fillRect(xx+1,yOrigin-axisH,6,axisH);
      // 写 Y 轴刻度值
      sum+=scaleY;
      myGC.setColor(Color.black);
      String str=Float.toString(sum);
      myGC.drawString(str.substring(0,str.indexOf(".")+2),xOrigin-25,y+4);
      y-=ySpacing;
    }
  }

  // ******** 清除 X 轴刻度 ********
  public void clearXHashMarks(){
    myGC.setColor(new Color(255,255,255));
    myGC.fillRect(xOrigin,yOrigin+1,xOrigin+axisW,yOrigin+5);
  }
  // ******** 清除 Y 轴刻度值 ********
  public void clearYHashMarks(){
    myGC.setColor(new Color(255,255,255));
    myGC.fillRect(xOrigin-30,yOrigin-axisH-10,30,axisH+10);
  }

  // 清除整个绘图区域
  public void clearScreen(){
    myGC.setColor(new Color(255,255,255));
    myGC.fillRect(xOrigin,(yOrigin-axisH)-20,axisW+30,axisH+20);
  }

  // ******** 在曲线的顶端绘制标题 s代表标题 ********
  public void makeTitle(String s){
    //String temp=s;
    int yTemp=(yOrigin-axisH)/2;
    int xTemp=xOrigin;
    // 清除以前的文本
    myGC.setColor(new Color(100,150,150));
    myGC.fillRect(xTemp,yTemp-15,axisW,20);

    myGC.setColor(Color.blue);
    myGC.drawString(s,xTemp,yTemp);
  }

  // ******** 确定矢量中的最大的 Y 值 ********

   public float getMaxY(Vector v){
      float max=0;
      for(int i=0;i<v.size();i++){
        float temp=((Float)v.elementAt(i)).floatValue();
        if(temp>max) max=temp;
      }
      return(max);
  }

  // ******** 取坐标轴的最大长度 ********
  /*public float getTopY(Vector v){
    float yTop=0;
    float y_max=getMaxY(v);
    if(y_max>=10){
      yTop=((int)(getMaxY(v)/10)+1)*10;
      //yTop=Math.round(getMaxY(v))+1;
    }else {
      yTop=((y_max%10)+0.1)*10.0;
    }
    return yTop;
  }*/

  // ******** 给定包含数据的矢量对象，该方法将在图像上显示数据,v 代表初始化的矢量对象。
  public void showData(Vector v){
    int xPoint;
    int yPoint;
    // 确定第一个数据点的 X 坐标
    xPoint=xOrigin;
    int oldX=0;
    int oldY=0;
    float max=getMaxY(v);

    // 在数据点上绘制小圆
    for(int j=0;j<v.size();j++){
      yPoint=yOrigin-(int)((axisH/max)*((Float)v.elementAt(j)).floatValue());
      myGC.setColor(Color.blue);
      myGC.fillRect(xPoint-1,yPoint,3,3);

      // 在数据点间绘制线--红色
      myGC.setColor(Color.red);
      if ((oldX!=0)&&(oldY!=0)){
        myGC.drawLine(oldX-xSpacing,oldY,xPoint,yPoint);
      }

      // 在数据点旁边写数据点值--蓝色
      myGC.setColor(Color.blue);
      String coordString=Float.toString(((Float)v.elementAt(j)).floatValue());
      myGC.drawString(coordString,xPoint+5,yPoint-5);

      xPoint+=xSpacing;
      oldX=xPoint;
      oldY=yPoint;
    }
  }
}