如何把这个图片做成heat map

Question

数值越大越红，数值越小越蓝色，周围有虚化效果.

Answer 1

大概的实现了下，虚化效果没做^^

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javax.imageio.ImageIO;

/**

• 类DrawHeatImage.java的实现描述：TODO 类实现描述

• @author broust 2016年4月4日 下午7:27:44
  */
  public class DrawHeatImage {

  /**

  • 绘制热点图
  • @param heatList 热点数量
  • @param colNum 一行布局多少个热点
  • @param gridSize 单元格子的大小－－只能绘制正方形

  • @return
    */
    private static BufferedImage drawHeatImage(List heatList, int colNum, int gridSize) {

    // 计算出图像的尺寸
    int width = colNum * gridSize;
    int height = (int) (heatList.size() / colNum)*gridSize;

    if (heatList.size() % colNum != 0) {
    height += gridSize;
    }

    // 创建bufferedImage
    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    Graphics2D g2d = image.createGraphics();
    // 底色
    g2d.setColor(Color.white);
    // 整个画布为白色
    g2d.fillRect(0, 0, width, height);
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

    // 开始绘制格子
    for (int i = 0; i < heatList.size(); i++) {
    g2d.setColor(getColor(heatList.get(i)));
    int lineN = i / colNum;
    int colN = i % colNum;
    int x = colN * gridSize;
    int y = lineN * gridSize;
    g2d.fillRect(x, y, gridSize, gridSize);
    }
    g2d.dispose();
    return image;
    }

  /**

  • 获取颜色
  • @param rate [0-255]
  • @return / private static Color getColor(int rate) { /*
    • 红色:(255,0,0) --->蓝色：(0,0,255) [红，黄，蓝] */ rate = rate < 0 ? 0 : rate > 255 ? 255 : rate; return new Color(rate, 0, 255 - rate); }

  /**

  • 保存到文件
  • @param filePath
  • @param image
  • @throws IOException */ private static void storeToFile(String filePath, BufferedImage image) throws IOException { File file = new File(filePath); ImageIO.write(image, "JPEG", file); }

  /**

  • 测试数据
  • @param nums
  • @return */ private static List testData(int nums) { List list = new ArrayList(); Random r = new Random(); for (int i = 0; i < nums; i++) { list.add(r.nextInt(nums)); } return list; }

  public static void main(String[] args) throws IOException {
  List heatDataList = testData(100);
  String filePath = "/Users/broust/tmp/xx/heatImage.jpg";
  storeToFile(filePath, drawHeatImage(heatDataList, 10, 20));
  }
  }