# -*- encoding: utf-8 -*-
# @Author: SWHL
# @Contact: liekkaskono@163.com
from io import BytesIO
from pathlib import Path
from typing import Any, Union
import cv2
import numpy as np
from PIL import Image, UnidentifiedImageError
root_dir = Path(__file__).resolve().parent
InputType = Union[str, np.ndarray, bytes, Path, Image.Image]
class LoadImage:
def __init__(self):
pass
def __call__(self, img: InputType) -> np.ndarray:
if not isinstance(img, InputType.__args__):
raise LoadImageError(
f"The img type {type(img)} does not in {InputType.__args__}"
)
origin_img_type = type(img)
img = self.load_img(img)
img = self.convert_img(img, origin_img_type)
return img
def load_img(self, img: InputType) -> np.ndarray:
if isinstance(img, (str, Path)):
self.verify_exist(img)
try:
img = self.img_to_ndarray(Image.open(img))
except UnidentifiedImageError as e:
raise LoadImageError(f"cannot identify image file {img}") from e
return img
if isinstance(img, bytes):
img = self.img_to_ndarray(Image.open(BytesIO(img)))
return img
if isinstance(img, np.ndarray):
return img
if isinstance(img, Image.Image):
return self.img_to_ndarray(img)
raise LoadImageError(f"{type(img)} is not supported!")
def img_to_ndarray(self, img: Image.Image) -> np.ndarray:
if img.mode == "1":
img = img.convert("L")
return np.array(img)
return np.array(img)
def convert_img(self, img: np.ndarray, origin_img_type: Any) -> np.ndarray:
if img.ndim == 2:
return cv2.cvtColor(img, cv2.COLOR_GRAY2BGR)
if img.ndim == 3:
channel = img.shape[2]
if channel == 1:
return cv2.cvtColor(img, cv2.COLOR_GRAY2BGR)
if channel == 2:
return self.cvt_two_to_three(img)
if channel == 3:
if issubclass(origin_img_type, (str, Path, bytes, Image.Image)):
return cv2.cvtColor(img, cv2.COLOR_RGB2BGR)
return img
if channel == 4:
return self.cvt_four_to_three(img)
raise LoadImageError(
f"The channel({channel}) of the img is not in [1, 2, 3, 4]"
)
raise LoadImageError(f"The ndim({img.ndim}) of the img is not in [2, 3]")
@staticmethod
def cvt_two_to_three(img: np.ndarray) -> np.ndarray:
"""gray + alpha → BGR"""
img_gray = img[..., 0]
img_bgr = cv2.cvtColor(img_gray, cv2.COLOR_GRAY2BGR)
img_alpha = img[..., 1]
not_a = cv2.bitwise_not(img_alpha)
not_a = cv2.cvtColor(not_a, cv2.COLOR_GRAY2BGR)
new_img = cv2.bitwise_and(img_bgr, img_bgr, mask=img_alpha)
new_img = cv2.add(new_img, not_a)
return new_img
@staticmethod
def cvt_four_to_three(img: np.ndarray) -> np.ndarray:
"""RGBA → BGR"""
r, g, b, a = cv2.split(img)
new_img = cv2.merge((b, g, r))
not_a = cv2.bitwise_not(a)
not_a = cv2.cvtColor(not_a, cv2.COLOR_GRAY2BGR)
new_img = cv2.bitwise_and(new_img, new_img, mask=a)
mean_color = np.mean(new_img)
if mean_color <= 0.0:
new_img = cv2.add(new_img, not_a)
else:
new_img = cv2.bitwise_not(new_img)
return new_img
@staticmethod
def verify_exist(file_path: Union[str, Path]):
if not Path(file_path).exists():
raise LoadImageError(f"{file_path} does not exist.")
class LoadImageError(Exception):
pass