8位bmp图片旋转C语言

好的，下面是一个C语言的示例代码，可以旋转一个8位BMP图片：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#pragma pack(push, 1)

typedef struct {
    char signature[2];
    int filesize;
    int reserved;
    int dataoffset;
    int headersize;
    int width;
    int height;
    short planes;
    short bitsperpixel;
    int compression;
    int imagesize;
    int xpixelspermeter;
    int ypixelspermeter;
    int colorsused;
    int colorsimportant;
} BMPHeader;

#pragma pack(pop)

int main(int argc, char* argv[]) {
    if (argc != 3) {
        printf("Usage: %s input.bmp output.bmp\n", argv[0]);
        return 1;
    }
    
    char* input_filename = argv[1];
    char* output_filename = argv[2];
    
    // 读取输入图片
    FILE* input_file = fopen(input_filename, "rb");
    if (!input_file) {
        printf("Failed to open input file: %s\n", input_filename);
        return 1;
    }
    
    BMPHeader header;
    fread(&header, sizeof(header), 1, input_file);
    
    if (header.signature[0] != 'B' || header.signature[1] != 'M') {
        printf("Invalid BMP file: %s\n", input_filename);
        fclose(input_file);
        return 1;
    }
    
    if (header.bitsperpixel != 8) {
        printf("Unsupported BMP format: %s\n", input_filename);
        fclose(input_file);
        return 1;
    }
    
    unsigned char* input_data = (unsigned char*)malloc(header.imagesize);
    fseek(input_file, header.dataoffset, SEEK_SET);
    fread(input_data, header.imagesize, 1, input_file);
    
    fclose(input_file);
    
    // 创建输出图片
    BMPHeader output_header = header;
    output_header.width = header.height;
    output_header.height = header.width;
    output_header.imagesize = header.width * header.height;
    
    FILE* output_file = fopen(output_filename, "wb");
    if (!output_file) {
        printf("Failed to open output file: %s\n", output_filename);
        free(input_data);
        return 1;
    }
    
    fwrite(&output_header, sizeof(output_header), 1, output_file);
    
    unsigned char* output_data = (unsigned char*)calloc(output_header.imagesize, 1);
    
    // 旋转图片
    for (int x = 0; x < header.width; x++) {
        for (int y = 0; y < header.height; y++) {
            int input_index = y * header.width + x;
            int output_x = header.height - y - 1;
            int output_y = x;
            int output_index = output_y * output_header.width + output_x;
            output_data[output_index] = input_data[input_index];
        }
    }
    
    fwrite(output_data, output_header.imagesize, 1, output_file);
    
    fclose(output_file);
    free(input_data);
    free(output_data);
    
    return 0;
}

注意：这段代码只是一个示例，可能需要进行一些调整才能适应你的具体需求。