brightness_contrast()函数是Python Wand ImageMagick库中的内置函数，用于更改图像的亮度和对比度。
用法：
brightness_contrast(brightness, contrast, channel)
参数：该函数接受上面提到的和下面定义的三个参数：
- Brightness:此参数用于指定介于-100到100之间的亮度值。默认值为0。
- Contrast:此参数用于指定对比度值，该值介于-100到100之间。默认值为0。
- channel:此参数用于将图像通道的值指定为未定义的‘red’, ‘gray’，‘cyan’, ‘green’，‘magenta’, ‘blue’，‘yellow’, ‘alpha’，‘opacity’, ‘black’，‘index’, ‘composite_channels’，‘all_channels，‘sync_channels’, ‘default_channels’。
返回值：此函数返回Wand ImageMagick对象。
原始图片：
范例1：
# Import library from Image
from wand.image import Image
# Import the image
with Image(filename ='../geeksforgeeks.png') as image:
# Clone the image in order to process
with image.clone() as brightness_contrast:
# Invoke brightness_contrast function with brightness as 50, Contrast as 17
# channel as Red
brightness_contrast.brightness_contrast(int(50), int(17), 'Red')
# Save the image
brightness_contrast.save(filename ='brightness_contrast1.jpg')输出：
范例2：
# Import libraries from the wand
from wand.image import Image
from wand.drawing import Drawing
from wand.color import Color
with Drawing() as draw:
# Set Stroke color the circle to black
draw.stroke_color = Color('black')
# Set Width of the circlw to 2
draw.stroke_width = 1
# Set the fill color to 'White (# FFFFFF)'
draw.fill_color = Color('white')
# Invoke Circle function with center at 50, 50 and radius 25
draw.circle((200, 200), # Center point
(100, 100)) # Perimeter point
# Set the font style
draw.font = '../Helvetica.ttf'
# Set the font size
draw.font_size = 30
with Image(width = 400, height = 400, background = Color('# 45ff33')) as pic:
# Set the text and its location
draw.text(int(pic.width / 3), int(pic.height / 2), 'GeeksForGeeks !')
# Draw the picture
draw(pic)
# Invoke brightness_contrast function with Brightness as -44, Contrast as 33
# Channel as Red
pic.brightness_contrast(int(-44), int(33), 'Red')
# Save the image
pic.save(filename ='brightness_contrast2.jpg')输出：
注：本文由纯净天空筛选整理自 Wand brightness_contrast() function – Python。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。