1 #define UINT16    unsigned short 2 #define DWORD    unsigned int 3 #define WORD    short 4 #define LONG    int 5  6 // Bitmap File Header ( 14 Bytes ) 7 typedef struct tagBITMAPFILEHEADER  8 {   9     UINT16 bfType;        // same as BM in ASCII.10     DWORD bfSize;         // the size of the BMP file in bytes11     UINT16 bfReserved1; 12     UINT16 bfReserved2; 13     DWORD bfOffBits;    // starting address, of the byte where the bitmap image data (Pixel Array) can be found.14 } BITMAPFILEHEADER, *PBITMAPFILEHEADER;15 16 // DIB头描述bitmap的信息，包括大小、压缩类型、颜色格式等，DIB头的大小根据版本不同，大小也不同。17 typedef struct tagBITMAPINFOHEADER18 {19     DWORD biSize;             // 4, the size of this header (40 bytes)20     LONG biWidth;             // 4, the bitmap width in pixels (signed integer).21     LONG biHeight;             // 4, the bitmap height in pixels (signed integer).22     WORD biPlanes;             // 2, the number of color planes being used. Must be set to 1.23     WORD biBitCount;         // 2, the number of bits per pixel, which is the color depth of the image. Typical values are 1, 4, 8, 16, 24 and 32.24     DWORD biCompression;     // 4, the compression method being used. 25     DWORD biSizeImage;         // 4, the image size. This is the size of the raw bitmap data, and should not be confused with the file size.26     LONG biXPelsPerMeter;     // 4, the horizontal resolution of the image.27     LONG biYPelsPerMeter;     // 4, the vertical resolution of the image. 28     DWORD biClrUsed;         // 4, the number of colors in the color palette, or 0 to default to 2^n.29     DWORD biClrImportant;    // 4, the number of important colors used, or 0 when every color is important; generally ignored.30 } BITMAPINFOHEADER;

  1 int bitmap_file_generate( char *name, int width, int height )  2 {  3     FILE *fp = NULL;  4     unsigned char *pData;  5     unsigned char *pp;  6     int i, j;  7     int iFileSize;  8       9     unsigned char bfType1, bfType2; 10     unsigned int bfSize; 11     unsigned short bfReserved1, bfReserved2; 12     unsigned int bfOffBits; 13     unsigned int biSize; 14     int biWidth, biHeight; 15     unsigned short biPlanes; 16     unsigned short biBitCount; 17     unsigned int biCompression; 18     unsigned int biSizeImage; 19     unsigned int biXPelsPerMeter; 20     unsigned int biYPelsPerMeter; 21     unsigned int biClrUsed; 22     unsigned int biClrImportant; 23      24     // offset[0:1] 25     bfType1   = ‘B‘; 26     bfType2   = ‘M‘; 27     // offset[2:5] 28     bfSize    = width * height * 3 + 54; 29     // offset[6:7] 30     bfReserved1 = 0; 31     // offsset[8:9] 32     bfReserved2 = 0; 33     // offset[10:13] 34     bfOffBits = 54; 35     // offset[14:17] 36     biSize = 40; 37     // offset[18:21] 38     biWidth = width; 39     // offset[22:25] 40     biHeight = height; 41     // offset[26:27] 42     biPlanes = 1; 43     // offset[28:29] 44     biBitCount = 24; 45     // offset[30:33] 46     biCompression = 0; 47     // offset[34:37] 48     biSizeImage = width * height * 3; 49     // offset[38:41] 50     biXPelsPerMeter = 2835; 51     // offset[42:45] 52     biYPelsPerMeter = 2835; 53     // offset[46:49] 54     biClrUsed = 0; 55     // offset[50:53] 56     biClrImportant = 0; 57      58      59     fp = fopen(name, "wb+"); 60     if( fp == NULL ) 61     { 62         printf("create file err, fopen: %p\n", fp); 63         return -1;     64     } 65      66     pData = http://www.mamicode.com/(unsigned char *)malloc(biWidth*biHeight*3+54);//malloc(iFileSize); 67     if(pData =http://www.mamicode.com/= NULL) 68     { 69         printf("pData malloc err\n"); 70         return -2; 71     } 72      73     // same as BM in ASCII. 74     pData[0] = bfType1; 75     pData[1] = bfType2; 76      77     // the size of the BMP file in bytes. bmp文件的实际大小 78     pData[2] = (unsigned char)((bfSize>>0) & 0xff); 79     pData[3] = (unsigned char)((bfSize>>8) & 0xff); 80     pData[4] = (unsigned char)((bfSize>>16) & 0xff);     81     pData[5] = (unsigned char)((bfSize>>24) & 0xff); 82      83     // reserved 84     pData[6] = (unsigned char)((bfReserved1>>0) & 0xff); 85     pData[7] = (unsigned char)((bfReserved1>>8) & 0xff); 86     // reserved 87     pData[8] = (unsigned char)((bfReserved2>>0) & 0xff); 88     pData[9] = (unsigned char)((bfReserved2>>0) & 0xff); 89      90     // the offset, i.e. starting address, of the byte where the bitmap image data (Pixel Array) can be found. 91     // 颜色数据的偏移地址，实际为：54 = 14 + 40 92     pData[10] = (unsigned char)((bfOffBits>>0) & 0xff); 93     pData[11] = (unsigned char)((bfOffBits>>8) & 0xff); 94     pData[12] = (unsigned char)((bfOffBits>>16) & 0xff);     95     pData[13] = (unsigned char)((bfOffBits>>24) & 0xff); 96      97     // the size of this header (40 bytes) 98     pData[14] = (unsigned char)((biSize>>0) & 0xff); 99     pData[15] = (unsigned char)((biSize>>8) & 0xff);100     pData[16] = (unsigned char)((biSize>>16) & 0xff);    101     pData[17] = (unsigned char)((biSize>>24) & 0xff);102     103     // the bitmap width in pixels (signed integer).104     pData[18] = (unsigned char)((biWidth>>0) & 0xff);105     pData[19] = (unsigned char)((biWidth>>8) & 0xff);106     pData[20] = (unsigned char)((biWidth>>16) & 0xff);107     pData[21] = (unsigned char)((biWidth>>24) & 0xff);108     109     // the bitmap height in pixels (signed integer).110     pData[22] = (unsigned char)((biHeight>>0) & 0xff);111     pData[23] = (unsigned char)((biHeight>>8) & 0xff);112     pData[24] = (unsigned char)((biHeight>>16) & 0xff);113     pData[25] = (unsigned char)((biHeight>>24) & 0xff);114     115     // the number of color planes being used. Must be set to 1.116     pData[26] = (unsigned char)((biPlanes>>0) & 0xff);117     pData[27] = (unsigned char)((biPlanes>>8) & 0xff);118     119     // the number of bits per pixel, which is the color depth of the image. Typical values are 1, 4, 8, 16, 24 and 32.120     pData[28] = (unsigned char)((biBitCount>>0) & 0xff);121     pData[29] = (unsigned char)((biBitCount>>8) & 0xff);122     123     // the compression method being used. See the next table for a list of possible values.124     pData[30] = (unsigned char)((biCompression>>0) & 0xff);125     pData[31] = (unsigned char)((biCompression>>8) & 0xff);126     pData[32] = (unsigned char)((biCompression>>16) & 0xff);127     pData[33] = (unsigned char)((biCompression>>24) & 0xff);128     129     // the image size. This is the size of the raw bitmap data, and should not be confused with the file size.130     pData[34] = (unsigned char)((biSizeImage>>0) & 0xff);131     pData[35] = (unsigned char)((biSizeImage>>8) & 0xff);132     pData[36] = (unsigned char)((biSizeImage>>16) & 0xff);133     pData[37] = (unsigned char)((biSizeImage>>24) & 0xff);134     135     // the horizontal resolution of the image. (pixel per meter, signed integer)136     pData[38] = (unsigned char)((biXPelsPerMeter>>0) & 0xff);137     pData[39] = (unsigned char)((biXPelsPerMeter>>8) & 0xff);138     pData[40] = (unsigned char)((biXPelsPerMeter>>16) & 0xff);139     pData[41] = (unsigned char)((biXPelsPerMeter>>24) & 0xff);140     141     // the vertical resolution of the image. (pixel per meter, signed integer)142     pData[42] = (unsigned char)((biYPelsPerMeter>>0) & 0xff);143     pData[43] = (unsigned char)((biYPelsPerMeter>>8) & 0xff);144     pData[44] = (unsigned char)((biYPelsPerMeter>>16) & 0xff);145     pData[45] = (unsigned char)((biYPelsPerMeter>>24) & 0xff);  146     147      // the number of colors in the color palette, or 0 to default to 2^n.148     pData[46] = (unsigned char)((biClrUsed>>0) & 0xff);149     pData[47] = (unsigned char)((biClrUsed>>8) & 0xff);150     pData[48] = (unsigned char)((biClrUsed>>16) & 0xff);151     pData[49] = (unsigned char)((biClrUsed>>24) & 0xff);  152     153      // the number of important colors used, or 0 when every color is important; generally ignored.154     pData[50] = (unsigned char)((biClrImportant>>0) & 0xff);155     pData[51] = (unsigned char)((biClrImportant>>8) & 0xff);156     pData[52] = (unsigned char)((biClrImportant>>16) & 0xff);157     pData[53] = (unsigned char)((biClrImportant>>24) & 0xff);     158 159 160     pp = &pData[54];161     for(i = 0; i < biHeight; i++)162     {163         for(j = 0; j < biWidth; j++)164         {165             set_color(pp, biWidth, biHeight, i, j, i+j, i, j);  // 随便填有点颜色166         }167     } 168     169     iFileSize = fwrite(pData, 1, bfSize, fp);170     printf("generate file iFileSize: %d\n", iFileSize);171     172     free(pData);173     174     fclose(fp);175     176     return 0;177 }

1 void set_color( unsigned char *pp, int w, int h, 2     int x, int y, unsigned char r, unsigned char g, unsigned char b )3 {4     pp[y*w*3+x*3+0] = (unsigned char)r;5     pp[y*w*3+x*3+1] = (unsigned char)g;6     pp[y*w*3+x*3+2] = (unsigned char)b;7 }

 1 int main(int argc, char *argv[]) 2 { 3     int ret; 4     char *file_name; 5      6     if( argc != 2 ) 7     { 8         printf("please input bitmap file_name\n"); 9         printf("usage: %s bitmap_file_name\n", argv[0]);10         return 0;11     }12     13     file_name = argv[1];14     15     ret = bitmap_file_generate(file_name, 1024*10, 1024*10);16     17     printf("bitmap_file_generate, ret: %d\n", ret);18 19     return 0;    20 }