python PIL和CV对 图片的读取，显示，裁剪，拉伸，保存

PIL 图片操作

读取图片

img = Image.open("a.jpg")

显示图片

im.show() # im是Image对象，im是numpy类型，通过Image.fromarray(nparr, mode='RGB')函数转换为Image对象

图片的size

(width, height) = img.size

图片的模式

mode = img.mode

裁剪

img_c = img.crop(x1,y1,x2,y2)

拉伸图片

img = img.resize((size,size), Image.ANTIALIAS)

保存图片

img.save(path)

ImageDraw

imDrwa = ImageDraw.Draw(img)
# boxes = [[10, 20, 129, 255],[126, 0, 221, 164]]
imDrwa.rectangle((x1, y1, x2, y2), outline="red")  # 画矩形
r = 2
x1 = 100
y1 = 100
imDrwa.ellipse((x1-r, y1-r, x1+r, y1+r), fill=(255,0,255)) # 画椭圆，r固定为圆
img.show()

图片过大加载，opencv加载30M+报错

from PIL import Image, ImageFile

ImageFile.LOAD_TRUNCATED_IMAGES = True

img = Image.open(path).convert("RGB")
img = np.array(img)
img = img[:,:,::-1]

OpenCV

读取图片

im = cv2.imread()

显示图片

cv2.imshow('image',img)
cv2.waitKey(0)
cv2.destroyAllWindows()

拉伸

img=cv2.resize(image,(size,size),interpolation = cv2.INTER_AREA)

保存图片

cv2.imwrite('1.jpg',img, [int( cv2.IMWRITE_JPEG_QUALITY), 95]) # 默认95

opencv压缩图片

import cv2 as cv

def resize_image(src_path, rate, save_path):
    img = cv.imread(src_path)
    h,w,c = img.shape
    resize_img = cv.resize(img, (int(w * rate), int(h * rate)), interpolation=cv.INTER_AREA)
    cv.imwrite(save_path, resize_img, [int(cv.IMWRITE_JPEG_QUALITY), 95])


src_path = r"C:\Users\RoseC\Desktop\219.jpg" # 原图片
rate = 0.5 # 压缩的比例
save_path = r"C:\Users\RoseC\Desktop\example.jpg" # 保存图片
resize_image(src_path, rate, save_path)