python - 警告 : QT_DEVICE_PIXEL_RATIO is deprecated

Question

我使用 matplotlib 和 openCV 来绘制一些阈值方法，并抛出以下没有输出的警告:

Warning: QT_DEVICE_PIXEL_RATIO is deprecated. Instead use:
QT_AUTO_SCREEN_SCALE_FACTOR to enable platform plugin controlled per-screen factors. QT_SCREEN_SCALE_FACTORS to set per-screen factors. QT_SCALE_FACTOR to set the application global scale factor.

我使用的是 Ubuntu 19.04

import cv2 as cv
from matplotlib import pyplot as plt

img = cv.imread('gradient.jpg', 0)

_, th1 = cv.threshold(img, 50, 255, cv.THRESH_BINARY)
_, th2 = cv.threshold(img, 200, 255, cv.THRESH_BINARY_INV)
_, th3 = cv.threshold(img, 200, 255, cv.THRESH_TRUNC)
_, th4 = cv.threshold(img, 127, 255, cv.THRESH_TOZERO)
_, th5 = cv.threshold(img, 127, 255, cv.THRESH_TOZERO_INV)

titles = ['Original Image', 'BINARY', 'BINARY_INV', 'TRUNC', 'TOZERO', 'TOZERO_INV']
images = [img, th1, th2, th3, th4, th5]

for i in range(6):
    plt.subplot(2, 3, i + 1), plt.imshow(images[i], 'gray')
    plt.title(titles[i])
    plt.xticks([]), plt.yticks([])

Answer 1

谢谢大家。只适合我Elyte's answer成功了。要在 python 中使用它，您可以使用:

from os import environ

def suppress_qt_warnings():
    environ["QT_DEVICE_PIXEL_RATIO"] = "0"
    environ["QT_AUTO_SCREEN_SCALE_FACTOR"] = "1"
    environ["QT_SCREEN_SCALE_FACTORS"] = "1"
    environ["QT_SCALE_FACTOR"] = "1"

if __name__ == "__main__":
    suppress_qt_warnings()
    
    # Init QT etc...