JAVA生成直方图Image

8年前
本程序修改至http://blog.csdn.net/lazy_p/article/details/5400268 ,以前是用的applet来呈现效果的。修改为返回一张BufferedImage图片,便于应用到项目中去,比如Web、C/S

架构的程序都能应用。

package com.image.histogram;    import java.awt.Color;  import java.awt.Font;  import java.awt.FontMetrics;  import java.awt.Graphics;  import java.awt.image.BufferedImage;  import java.io.File;  import java.io.IOException;    import javax.imageio.ImageIO;    /**   * 柱状图   *   * @author lazy_p   * @date 2010-3-20   */  public class PlaneHistogram {      private final int histogramWidth = 15;// 柱形图的宽度      private final int histogramPitch = 10;// 柱形图的间距      private float scaling = 1f;// 缩放的比例      private int maxStrWidth = 0; // 字符串需要的最大宽度        /**       * <pre>       *   参数b[i]和str[i]必须对应       * </pre>       *       * @param g       * @param title       * @param v       * @param str       * @param color       *            可以为空       */      public BufferedImage paintPlaneHistogram(String title, int[] v,              String[] str, Color[] color) {          int width = str.length * histogramWidth+str.length*histogramPitch+50;          int height = 255;          scaling = calculateScale(v, height);//计算缩放比例                    BufferedImage bufferImage = new BufferedImage(width, height,                  BufferedImage.TYPE_INT_RGB);          Graphics g = bufferImage.getGraphics();          g.setColor(Color.WHITE);          g.fillRect(0, 0, width, height);          FontMetrics metrics = null;            g.setFont(new Font(null, Font.BOLD, 18));          g.setColor(Color.RED);            g.drawString(title, (bufferImage.getWidth() - g.getFontMetrics()                  .stringWidth(title)) >> 1, 30);// 画标题            g.setFont(new Font(null, Font.PLAIN, 12));            metrics = g.getFontMetrics();            g.setColor(Color.BLACK);            g.drawLine(10, 0, 10, height - 15); // 画Y坐标          g.drawLine(10, height - 15, width, height - 15);// 画X坐标                    int j = 0;          int colorCount=color.length;                    for (int i = 0; i < v.length; ++i) {                if (color != null){                  g.setColor(color[j]);// 设置前景色                  if(j+1<colorCount){                      j++;                  }else{                      j=0;                  }              }else{                  g.setColor(Color.RED);              }                int x = 20 + i                      * (histogramPitch + histogramWidth + (maxStrWidth >> 1));// 计算出X坐标              int y = height - 16 - (int) (v[i] * scaling); // 计算出Y坐标                // 画占的比例              g.drawString(v[i] + "", x                      - ((metrics.stringWidth(v[i] + "") - histogramWidth) >> 1),                      y);                // 画平面的柱状图              g.drawRect(x, y, histogramWidth, (int) (v[i] * scaling));              g.fillRect(x, y, histogramWidth, (int) (v[i] * scaling));                // 画每一项表示的东西              g.drawString(str[i], x                      - ((metrics.stringWidth(str[i]) - histogramWidth) >> 1),                      height - 2);          }            return bufferImage;      }            /**       * 计算缩放比例       * @param v       * @param h 图片的高度       * @return       */      public float calculateScale(int[] v , int h){          float scale = 1f;          int max = Integer.MIN_VALUE;          for(int i=0 , len=v.length ; i < len ;++i){              if(v[i]>h && v[i]>max){                  max=v[i];              }          }          if(max > h){              scale=((int)(h*1.0f/max*1000))*1.0f/1000;          }          return scale;      }            public static void main(String[] args)  {          PlaneHistogram planeHistogram = new PlaneHistogram();            BufferedImage image = planeHistogram.paintPlaneHistogram("颜色直方图",                          new int[]{100,200,300}, new String[]{"a" , "b" , "c"} ,  new Color[] {Color.RED, Color.GREEN, Color.BLACK, Color.BLUE });          File output = new File("G:/333.jpg");          try {              ImageIO.write(image, "jpg", output);          } catch (IOException e) {              e.printStackTrace();          }      }    }


转自:http://blog.csdn.net/lazy_p/article/details/7206088