图像处理PILLOW的使用

1.安装

pip install Pillow

2.使用

1)图片缩放

from PIL import Image
im = Image.open('dog.jpg')
w,h = im.size  #获取图像的尺寸
im.thumbnail((w/2,h/2)) #将图像缩放50%
#im.show()  #显示图片
im.save('dog_thumbnail.jpg') #保存图片

效果图:

2.图片模糊

im = Image.open('dog.jpg')
im2 = im.filter(ImageFilter.BLUR)
im2.save('dog_blur.jpg')

效果图:

3.生成验证码

from PIL import ImageDraw,ImageFont,ImageFilter
import random

#返回一个A-Z的随机字母
def randomChar():
    return chr(random.randint(65,90))

#随机颜色
def randomColor1():
    return (random.randint(64,255),random.randint(64,255),random.randint(64,255))

#随机颜色2
def randomColor2():
    return (random.randint(32,127),random.randint(32,127),random.randint(32,127))

width = 60 * 4
height = 60
#创建白色图片
image = Image.new('RGB',(width,height),(255,255,255))
#创建font对象
#OSError: cannot open resource 需要指定字体库的系统路径
#font = ImageFont.truetype("Arial.ttf",36)
font = ImageFont.truetype("C:/windows/fonts/Arial.ttf",36)
#创建Draw对象,用于向白色背景图片上绘图
draw = ImageDraw.Draw(image)
#填充每一个像素
for x in range(width):
    for y in range(height):
        draw.point((x,y),fill=randomColor1())

#输出文字
for i in range(4):
    draw.text((60*i+10,10),randomChar(),font=font,fill=randomColor2())

#模糊
image = image.filter(ImageFilter.BLUR)
image.save("captcha.jpg")

效果:

4.裁图,旋转,粘贴

from PIL import Image
im = Image.open('dog.jpg')
box = (100,50,350,250)  #要裁剪的矩形区域,坐标以左上角为原点
region = im.crop(box)  #返回裁剪到的图片
#region.show()
region = region.transpose(Image.ROTATE_180) #对图像进行旋转
im.paste(region,box)  #将旋转后的图像粘回原图
im.show()

效果图:

5.添加图片水印:

from PIL import Image

image = Image.open('dog.jpg')
logo = Image.open('logo.png')
logoW,logoH= logo.size
imageW,imageH = image.size
image.paste(logo,(imageW - logoW, imageH - logoH))
image.show()

效果:

6.添加透明文字水印:

参考: http://pythoncentral.io/watermark-images-python-2x/

def add_watermark(in_file, text,font,out_file='watermark.jpg', angle=23, opacity=0.25):
    '''
    :param in_file: 要添加水印的图片
    :param text:  文字水印内容
    :param out_file: 添加水印后的图片
    :param font:水印字体
    :param angle: 水印旋转角度
    :param opacity: 水印透明度
    '''
    img = Image.open(in_file).convert('RGB')
    watermark = Image.new('RGBA', img.size, (0, 0, 0, 0))
    size = 2
    n_font = ImageFont.truetype(font, size)
    #getsize返回水印文字对应字体大小的宽度和高度
    n_width, n_height = n_font.getsize(text)
    #找到使得水印文字宽度最接近图片宽度的字体大小
    while n_width + n_height < watermark.size[0]:
        size += 2
        n_font = ImageFont.truetype(font, size)
        n_width, n_height = n_font.getsize(text)
    draw = ImageDraw.Draw(watermark, 'RGBA')
    draw.text(((watermark.size[0] - n_width) / 2,
               (watermark.size[1] - n_height) / 2),
              text, font=n_font)
    watermark = watermark.rotate(angle, Image.BICUBIC)
    alpha = watermark.split()[3]
    #通过降低亮度和对比度来降低水印的透明度
    alpha = ImageEnhance.Brightness(alpha).enhance(opacity)
    #设置透明度
    watermark.putalpha(alpha)
    #添加水印
    Image.composite(watermark, img, watermark).save(out_file, 'JPEG')

FONT = 'C:/Windows/fonts/Arial.ttf'
add_watermark('dog.jpg','python',font=FONT)

效果图:

相关资料:

https://pillow.readthedocs.io/en/latest/handbook/tutorial.html

http://pillow-cn.readthedocs.io/zh_CN/latest/handbook/tutorial.html