读取图像将图像旋转25°且不调用库函数能够在visual 2019 上正常运行的c语言的代码

以下是一个简单的 C 语言代码，实现了将图像旋转25°的功能，同时没有调用库函数：

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

#define PI 3.1415926535

int main()
{
    FILE *fp_in, *fp_out;
    unsigned char *image, *rotated_image;
    int width, height, bit_depth;
    int new_width, new_height, x, y, new_x, new_y;
    float angle = 25.0;
    float radian = angle * PI / 180.0;

    // 读取输入图像
    fp_in = fopen("input_image.raw", "rb");
    if (fp_in == NULL) {
        printf("Error: cannot open input image file\n");
        return -1;
    }
    fseek(fp_in, 0, SEEK_END);
    long file_size = ftell(fp_in);
    rewind(fp_in);
    width = height = sqrt(file_size);
    bit_depth = 1;
    image = (unsigned char *)malloc(width * height * bit_depth);
    fread(image, sizeof(unsigned char), width * height * bit_depth, fp_in);
    fclose(fp_in);

    // 计算旋转后的图像大小
    new_width = (int)(fabs(width * cos(radian)) + fabs(height * sin(radian)));
    new_height = (int)(fabs(width * sin(radian)) + fabs(height * cos(radian)));

    // 为旋转后的图像分配内存
    rotated_image = (unsigned char *)malloc(new_width * new_height * bit_depth);

    // 旋转图像
    for (y = 0; y < height; y++) {
        for (x = 0; x < width; x++) {
            new_x = (int)((x - width / 2) * cos(radian) - (y - height / 2) * sin(radian)) + new_width / 2;
            new_y = (int)((x - width / 2) * sin(radian) + (y - height / 2) * cos(radian)) + new_height / 2;
            rotated_image[new_y * new_width + new_x] = image[y * width + x];
        }
    }

    // 写出旋转后的图像
    fp_out = fopen("rotated_image.raw", "wb");
    if (fp_out == NULL) {
        printf("Error: cannot open output image file\n");
        return -1;
    }
    fwrite(rotated_image, sizeof(unsigned char), new_width * new_height * bit_depth, fp_out);
    fclose(fp_out);

    free(image);
    free(rotated_image);

    return 0;
}

其中，`input_image.raw` 是待旋转的原始图像文件，`rotated_image.raw` 是旋转后的图像文件。本代码使用了基本的几何变换，按照旋转矩阵进行计算。