python外库--pillow

1. 作用

图像处理库

2. 操作

from PIL import Image # 引入Image类

# 创建一个新的图片
def img_create(outfile, mode='RGB', size=(100, 100), color='red'):
    new_img= Image.new(mode, size, color) # 创建一个新的Image实例
    new_img.save(outfile)

# 展示图片
def img_open(infile):
    with Image.open(infile) as im: # 读取图片，读取不成功抛出IOError
        print(im.format, im.size, im.mode) # 图片格式， 图片像素， 图片模式（一般RGB）
        im.show() # debian下不管用，需要安装xv

# 读写图片
def img_save(infile, outfile):
    try:
        Image.open(infile).save(outfile) # 打开图片并保存为另外的格式
        # open时，pillow获取文件信息如format、mode，余下数据需要时出处理
    except IOError:
        print('connot convert {}'.format(infile))

# 转换模式 mode
def img_convert(infile, outfile, mode):
    with Image.open(infile) as im:
        im_copy = im.copy()
        im_copy.convert(mode).save(outfile)
        # mode参数: 1\L\P\RGB\RGBA\CMYK\YCbCr\LAB\HSV\I\F

# 缩略图
def img_thumbnail(infile, outfile, size=(100, 200)):
    with Image.open(infile) as im:
        im.thumbnail(size)
        im.save(outfile)

# 复制图片
def img_copy(infile, outfile):
    with Image.open(infile) as im:
        im.copy().save(outfile)

# 剪裁图片
def img_crop(infile, outfile, size=(100, 100, 400, 400)):
    with Image.open(infile) as im:
        im.crop(size).save(outfile) # size=(左， 顶， 右， 底)，左上角为坐标原点，
        # (100, 100, 400, 400) 表示300*300的像素，就是右-左， 底-顶

# 粘贴图片
def img_paste(infile, outfile, size=(200, 200, 400, 400)):
    with Image.open(infile) as im:
        im_crop = im.crop(size)
        crop_width, crop_height = im_crop.size
        width, height = im.size
        im_copy = im.copy()
        
        for left in range(0, width, crop_width):
            for top in range(0, height, crop_height):
                im_copy.paste(im_crop, (left, top))
        im_copy.save(outfile)

# 调整图片大小
def img_resize(infile, outfile, size=(200, 400), expand=True):
    with Image.open(infile) as im:
        im.resize(size, expand).save(outfile) # 参数expand=True适应原图片

# 翻转图片
def img_transpose(infile, outfile, flip_point): # flip_point为翻转参数
    with Image.open(infile) as im:
        im.transpose(flip_point).save(outfile)
        # 参数flip_point : 
        # Image.ROTATE_90/180/270 类似rotate()没有性能差别。
        # Image.FLIP_LEFT_RIGHT
        # Image.FLIP_TOP_BUTTOM


# 旋转图片
def img_rotate(infile, outfile, size=90):
    with Image.open(infile) as im:
        im.rotate(size).save(outfile)

# 移动图片
def img_roll(infile, outfile, delta):
    with Image.open(infile) as im:
        image = im.copy() # 复制图片
        x, y = image.size

        delta = delta % x # 防止delta比x大
        if delta == 0: 
            image.save(outfile)
            return

        part1 = image.crop((0, 0, delta, y))
        part2 = image.crop((delta, 0, x, y))
        image.paste(part2, (0, 0, x - delta, y))
        image.paste(part1, (x - delta, 0, x, y))
        image.save(outfile)

from PIL import ImageFilter
# 图片过滤
def img_filter(infile, outfile, filter_point): # filter_point模糊模式
    with Image.open(infile) as im:
        im.filter(filter_point).save(outfile)
        # 参数filter_point参照pillow文档ImageFileter

def img_point(infile, outfile):
    with Image.open(infile) as im:
        im_point = im.point(lambda i: i * 2) # 高级函数，日，类似Map
        im_point.save(outfile)

###要进行图案、文字的绘制，可使用ImageDraw###

if __name__ == '__main__':
    # img_create('timg_new.jpeg', mode='RGB', size=(100, 100), color='blue')
    # img_open('timg_new.jpeg')
    # img_save('timg.jpeg', 'timg_conv.png')
    # img_convert('timg.jpeg', 'timg_convert.jpeg', 'L')
    # img_thumbnail('timg.jpeg', 'timg_thum.jpeg', size=(100, 200))
    # img_copy('timg.jpeg', 'timg_copy.jpeg')
    # img_crop('timg.jpeg', 'timg_crop.jpeg', size=(100, 100, 400, 400))
    # img_paste('timg.jpeg', 'timg_past.jpeg', size=(200, 200, 400, 400))
    # img_resize('timg.jpeg','timg_resi.jpeg', size=(200, 400))
    # img_transpose('timg.jpeg', 'timg_righ.jpeg', Image.FLIP_LEFT_RIGHT)
    # img_transpose('timg.jpeg', 'timg_bott.jpeg', Image.FLIP_TOP_BOTTOM) 
    # img_rotate('timg.jpeg', 'timg_rota.jpeg', size=90)
    # img_roll('timg.jpeg', 'timg_roll.jpeg', 500)
    # img_filter('timg.jpeg', 'timg_filt.jpeg', ImageFilter.EMBOSS)
    img_point('timg.jpeg', 'timg_poin.jpeg')

3. 文档

pillow文档