python给图片加半透明水印_python 图片格式转换png转jpg，如何利用python给图片添加半透明水印...

from PIL import Image

im = Image.open(r'd:\test2.png')

r, g, b, a = im.split()

im = Image.merge("RGB", (r, g, b))

im.save(r'D:\Python_Programming.jpg')

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#coding:utf-8

from PIL importImage, ImageDraw, ImageFontdefadd_text_to_image(image, text):

font= ImageFont.truetype('C:\Windows\Fonts\STXINGKA.TTF', 36)#添加背景

new_img = Image.new('RGBA', (image.size[0] * 3, image.size[1] * 3), (0, 0, 0, 0))

new_img.paste(image, image.size)#添加水印

font_len =len(text)

rgba_image= new_img.convert('RGBA')

text_overlay= Image.new('RGBA', rgba_image.size, (255, 255, 255, 0))

image_draw=ImageDraw.Draw(text_overlay)for i in range(0, rgba_image.size[0], font_len * 40 + 100):for j in range(0, rgba_image.size[1], 200):

image_draw.text((i, j), text, font=font, fill=(0, 0, 0, 50))

text_overlay= text_overlay.rotate(-45)

image_with_text=Image.alpha_composite(rgba_image, text_overlay)#裁切图片

image_with_text = image_with_text.crop((image.size[0], image.size[1], image.size[0] * 2, image.size[1] * 2))returnimage_with_textif __name__ == '__main__':

img= Image.open(r"d:\ww.jpg")

im_after= add_text_to_image(img, u'群主是个大流X')

im_after.save(r'd:\ww.png')

彩色转黑白

from PIL importImageimportmatplotlib.pyplot as pltimportnumpy as npimport matplotlib.cm as cm #cm是colormap的缩写

image_gray=Image.open('D:/ww.png').convert("L")

data=np.array(image_gray) #在显示灰度图像时array()方法将图像转换成Numpy的数组对象，图片得以显式，否则会出现错误

plt.imshow(data,cmap=cm.gray)#cmap:代表颜色图谱，默认绘制为RGB(A)颜色空间。

plt.savefig("d:/ww1.png")

plt.show()

裁剪

from PIL importImageimportmatplotlib.pyplot as pltimportnumpy as np

image=Image.open('D:/ww.jpg')

box=(100,100,400,400)

region=image.crop(box)

data=np.array(region)

plt.imshow(data)

plt.show()

旋转

from PIL importImageimportmatplotlib.pyplot as plt

image=Image.open('D:/ww.png')#读取图像

plt.imshow(image.rotate(180))#逆时针旋转180度

plt.show()#需要调用show()方法，不然图像只会在内存中而不显示出来