package cn.zju.edu.liuxing;

import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
/**
*　简单高斯模糊算法
*
*　@param　args
*　@throws　IOException　[参数说明]
*
*　@return　void　[返回类型说明]
*　@exception　throws　[违例类型]　[违例说明]
*　@see　[类、类#方法、类#成员]
*/
public class GaussianBlur {
	public static void main(String[] args) throws IOException {
		BufferedImage img = ImageIO.read(new File("./a.jpg")); //将这个图片拷贝到你项目根目录下
		System.out.println(img);
		int height = img.getHeight();
		int width = img.getWidth();
		int[][] martrix = new int[3][3];
		int[] values = new int[9];
		for (int i = 0; i < width; i++)
			for (int j = 0; j < height; j++) {
				readPixel(img, i, j, values);
				fillMatrix(martrix, values);
				img.setRGB(i, j, avgMatrix(martrix));
			}
		ImageIO.write(img, "jpeg", new File("./test.jpg"));
	}

	private static void readPixel(BufferedImage img, int x, int y, int[] pixels) {
		int xStart = x - 1;
		int yStart = y - 1;
		int current = 0;
		for (int i = xStart; i < 3 + xStart; i++)
			for (int j = yStart; j < 3 + yStart; j++) {
				int tx = i;
				if (tx < 0) {
					tx = -tx;

				} else if (tx >= img.getWidth()) {
					tx = x;
				}
				int ty = j;
				if (ty < 0) {
					ty = -ty;
				} else if (ty >= img.getHeight()) {
					ty = y;
				}
				pixels[current++] = img.getRGB(tx, ty);

			}
	}

	private static void fillMatrix(int[][] matrix, int[] values) {
		int filled = 0;
		for (int i = 0; i < matrix.length; i++) {
			int[] x = matrix[i];
			for (int j = 0; j < x.length; j++) {
				x[j] = values[filled++];
			}
		}
	}

	private static int avgMatrix(int[][] matrix) {
		int r = 0;
		int g = 0;
		int b = 0;
		for (int i = 0; i < matrix.length; i++) {
			int[] x = matrix[i];
			for (int j = 0; j < x.length; j++) {
				if (j == 1) {
					continue;
				}
				Color c = new Color(x[j]);
				r += c.getRed();
				g += c.getGreen();
				b += c.getBlue();
			}
		}
		return new Color(r / 8, g / 8, b / 8).getRGB();

	}
}