在没有其他库的情况下以纯c / c ++编写BMP图像

Question

在我的算法中，我需要创建信息输出。我必须在bmp文件中写入布尔矩阵。它必须是单色图像，如果该元素上的矩阵为真，则像素为白色。主要问题是bmp标头以及如何编写此标头。

Answer 1

看看这是否对您有用...在这段代码中，我有3个二维数组，分别称为red，green和blue。每个元素的大小为[width] [height]，每个元素对应一个像素-我希望这是有道理的！

FILE *f;

unsigned char *img = NULL;

int filesize = 54 + 3*w*h;  //w is your image width, h is image height, both int

img = (unsigned char *)malloc(3*w*h);

memset(img,0,3*w*h);

for(int i=0; i<w; i++)

{

    for(int j=0; j<h; j++)

    {

        x=i; y=(h-1)-j;

        r = red[i][j]*255;

        g = green[i][j]*255;

        b = blue[i][j]*255;

        if (r > 255) r=255;

        if (g > 255) g=255;

        if (b > 255) b=255;

        img[(x+y*w)*3+2] = (unsigned char)(r);

        img[(x+y*w)*3+1] = (unsigned char)(g);

        img[(x+y*w)*3+0] = (unsigned char)(b);

    }

}

unsigned char bmpfileheader[14] = {'B','M', 0,0,0,0, 0,0, 0,0, 54,0,0,0};

unsigned char bmpinfoheader[40] = {40,0,0,0, 0,0,0,0, 0,0,0,0, 1,0, 24,0};

unsigned char bmppad[3] = {0,0,0};

bmpfileheader[ 2] = (unsigned char)(filesize    );

bmpfileheader[ 3] = (unsigned char)(filesize>> 8);

bmpfileheader[ 4] = (unsigned char)(filesize>>16);

bmpfileheader[ 5] = (unsigned char)(filesize>>24);

bmpinfoheader[ 4] = (unsigned char)(       w    );

bmpinfoheader[ 5] = (unsigned char)(       w>> 8);

bmpinfoheader[ 6] = (unsigned char)(       w>>16);

bmpinfoheader[ 7] = (unsigned char)(       w>>24);

bmpinfoheader[ 8] = (unsigned char)(       h    );

bmpinfoheader[ 9] = (unsigned char)(       h>> 8);

bmpinfoheader[10] = (unsigned char)(       h>>16);

bmpinfoheader[11] = (unsigned char)(       h>>24);

f = fopen("img.bmp","wb");

fwrite(bmpfileheader,1,14,f);

fwrite(bmpinfoheader,1,40,f);

for(int i=0; i<h; i++)

{

    fwrite(img+(w*(h-i-1)*3),3,w,f);

    fwrite(bmppad,1,(4-(w*3)%4)%4,f);

}

free(img);

fclose(f);