Python下的图片编辑

Python下的图像处理

python代码

import struct

def read_bmp(test):
    with open("test.bmp", "rb") as f:
        # 读取文件头部信息
        header = f.read(54)

        # 解析文件头部信息
        width = struct.unpack("<I", header[18:22])[0]
        height = struct.unpack("<I", header[22:26])[0]
        bits_per_pixel = struct.unpack("<H", header[28:30])[0]

        # 计算每行像素所占字节数（包括对齐）
        row_bytes = (bits_per_pixel * width + 31) // 32 * 4

        # 初始化像素数据矩阵
        pixels = [[(0, 0, 0) for _ in range(width)] for _ in range(height)]

        # 跳至像素数据开始位置
        f.seek(54)

        # 逐行读取像素数据
        for i in range(height):
            # 每行按顺序读取像素值
            for j in range(width):
                b, g, r = struct.unpack("BBB", f.read(3))
                pixels[i][j] = (r, g, b)

            # 跳过对齐字节
            f.read(row_bytes - width * 3)

        return pixels, width, height

def write_bmp(file_path, pixels, width, height):
    with open(file_path, "wb") as f:
        # BMP文件头部信息
        header = b"\x42\x4d"  # BM
        file_size = width * height * 3 + 54
        header += struct.pack("<I", file_size)
        header += b"\x00\x00\x00\x00"
        data_offset = 54
        header += struct.pack("<I", data_offset)

        # BMP信息头信息
        info_header_size = 40
        planes = 1
        bits_per_pixel = 24
        compression = 0
        image_size = width * height * 3
        x_pixels_per_meter = 0
        y_pixels_per_meter = 0
        total_colors = 0
        important_colors = 0

        info_header = struct.pack("<IiiHHIIiiII", info_header_size, width, height, planes, bits_per_pixel,
                                  compression, image_size, x_pixels_per_meter, y_pixels_per_meter, total_colors,
                                  important_colors)

        # 写入BMP文件头部信息和信息头信息
        f.write(header)
        f.write(info_header)

        # 写入像素数据
        for row in pixels:
            for r, g, b in row:
                f.write(struct.pack("BBB", b, g, r))

    print("Write BMP file success!")


# 读取BMP图像文件
pixels, width, height = read_bmp("example.bmp")

# 在矩阵中绘制一条从左上角到右下角的红色直线
for i in range(height):
    for j in range(width):
        if i == j:
            pixels[i][j] = (255, 0, 0)

# 将修改后的像素数据写入新的BMP文件
write_bmp("output.bmp", pixels, width, height)


但出现了一些问题导致输出的output.bmp无法打开，不知道是哪里出现了问题
![](https://img2023.cnblogs.com/blog/3263914/202310/3263914-20231023000631441-612151951.png)