计算机图形学作业
编写一个读取bmp图的程序
并把rgb 存储在二维数组中

部分参考

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.file.Paths;
import java.util.Arrays;public class Graph {/*一些成员变量*/// 文件头Filehead filehead = new Filehead();byte[] fileheadByte = new byte[14];// 信息头byte[] mapinfoByte = new byte[40];MapInfohead mapInfohead = new MapInfohead();// rgbRgb rgb;/*主函数*/public static void main(String[] args) {String path = "F:\\\\test1.bmp";Graph graph = new Graph();graph.loadBmp24(path);}/*** 读取bmp文件** @param path 文件路径*/public void loadBmp24(String path) {// 得到文件  测试文件是像素点16*9 的bmp 文件File file = Paths.get("F:\\\\test1.bmp").toFile();if(!file.exists()){try {throw new FileNotFoundException("没找到文件");} catch (FileNotFoundException e) {e.printStackTrace();}}System.out.println("文件名为"+file.getName());try {FileInputStream fileInputStream = new FileInputStream(file);// 读文件头 放入数组fileInputStream.read(fileheadByte, 0, 14);System.out.println("文件头Byte 14位如下");System.out.println(Arrays.toString(fileheadByte));unpackFileHead(fileheadByte);// 读信息头 放入数组fileInputStream.read(mapinfoByte, 0, 40);System.out.println("信息头Byte 40位如下");System.out.println(Arrays.toString(mapinfoByte));unpackMapInfoHead(mapinfoByte);unpackRgb(fileInputStream);// 输出rgb矩阵System.out.println(rgb);} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}/*** 解析文件头** @param fileheadByte 文件头数组*/public void unpackFileHead(byte[] fileheadByte) {filehead.bfType = load2BytetoInt(fileheadByte, 1);filehead.bfSize = load4BytetoInt(fileheadByte, 5);filehead.bfReserverd1 = load2BytetoInt(fileheadByte, 7);filehead.bfReserverd2 = load2BytetoInt(fileheadByte, 9);filehead.bfOffBits = load4BytetoInt(fileheadByte, 13);}/*** 解析信息头** @param mapinfoByte 信息头数组*/public void unpackMapInfoHead(byte[] mapinfoByte) {mapInfohead.biSize = load4BytetoInt(mapinfoByte, 3);mapInfohead.biWidth = load4BytetoInt(mapinfoByte, 7);mapInfohead.biHeight = load4BytetoInt(mapinfoByte, 11);mapInfohead.biPlanes = load2BytetoInt(mapinfoByte, 13);mapInfohead.biBitCount = load2BytetoInt(mapinfoByte, 15);mapInfohead.biCompression = load4BytetoInt(mapinfoByte, 19);mapInfohead.biSizeImage = load4BytetoInt(mapinfoByte, 23);mapInfohead.biXPelsPerMeter = load4BytetoInt(mapinfoByte, 27);mapInfohead.biYPelsPerMeter = load4BytetoInt(mapinfoByte, 31);mapInfohead.biClrUsed = load4BytetoInt(mapinfoByte, 35);mapInfohead.biClrImportant = load4BytetoInt(mapinfoByte, 39);}/*** 解析 rgb 矩阵** @param fileInputStream*/public void unpackRgb(FileInputStream fileInputStream) {int width = mapInfohead.biWidth;int height = mapInfohead.biHeight;rgb = new Rgb(width, height);// 字节填充int skip_width = 0;int m = width * 3 % 4;if (m != 0) {skip_width = 4 - m;}// 此处代码来自https://blog.csdn.net/meiyoutongguo/article/details/9243899for (int i = height - 1; i >=0; i--) {for (int j = 0; j < width; j++) {try {// 这里遍历的时候，一定要注意本来像素是有RGB来表示，// 但是在存储的时候由于windows是小段存储，所以在内存中是BGR顺序。rgb.blue[i][j] = fileInputStream.read();rgb.green[i][j] = fileInputStream.read();rgb.red[i][j] = fileInputStream.read();// 这里一定要知道，其实系统在给位图数据中添加填充0的时候，都是加在每行的最后。// 但是我们在使用dis.skipBytes（）这个方法的时候，却不一定要在最后一列。// 系统在填充数据的时候，在数据上加了标记。// 所以dis.skipBytes（）这个方法只要调用了，那么系统就会自动不读取填充数据。if (j == 0) {fileInputStream.skip(skip_width);}} catch (IOException e) {e.printStackTrace();}}}}/*** 4 字节转int** @param head  字节数组* @param index 开始的索引* @return*/public int load4BytetoInt(byte[] head, int index) {// 注意index 是索引位置从0 开始return (((head[index] & 0xff) << 24)| ((head[index - 1] & 0xff) << 16)| ((head[index - 2] & 0xff) << 8)| (head[index - 3] & 0xff));}/*** 2 字节转int** @param head  字节数组* @param index 开始的索引* @return*/public int load2BytetoInt(byte[] head, int index) {return (((head[index] & 0xff) << 8)| (head[index - 1] & 0xff));}
}class Filehead {/*total 14 byte*/public int bfType;// size  4 bytepublic int bfSize;public int bfReserverd1;public int bfReserverd2;// size 4 bytepublic int bfOffBits;}class MapInfohead {/*total 40 byte*/int biSize;int biWidth;int biHeight;// size 2 byteint biPlanes;// size 2 byteint biBitCount;int biCompression;int biSizeImage;int biXPelsPerMeter;int biYPelsPerMeter;int biClrUsed;int biClrImportant;
}class Rgb {int[][] red;int[][] green;int[][] blue;int width;int heigh;Rgb(int width, int heigh) {this.width = width;this.heigh = heigh;red = new int[heigh][width];green = new int[heigh][width];blue = new int[heigh][width];}@Overridepublic String toString() {// 输出rgb矩阵StringBuilder stringBuilder = new StringBuilder();for (int i = 0; i < heigh; i++) {for (int j = 0; j < width; j++) {stringBuilder.append(String.format("(%03d,%03d,%03d)",red[i][j],green[i][j],blue[i][j]));}stringBuilder.append("\n");}return stringBuilder.toString();}
}

结果如图