在 Python 中使用 PIL 绘制圆形渐变

我正在使用 Python 创建图像，使用

myImage = Image.new('RGB', (250, 250), 'rgb(155,89,182)')

这实际上创建了图像。但是有没有办法创建一个具有我选择的颜色背景但带有渐变的图像？我想选blue作为我的颜色，我想要图像边缘为深蓝色，图像中心为浅蓝色。使用简单的 PIL 和 Python 可以吗？

先感谢您。

The code depends on how you want the gradient to look.

You could make it a rectangular gradient which would look like this:

Or you could make it a round gradient like this:

这将是圆形渐变的代码：

import Image
import math

imgsize = (250, 250) #The size of the image

image = Image.new('RGB', imgsize) #Create the image

innerColor = [80, 80, 255] #Color at the center
outerColor = [0, 0, 80] #Color at the corners


for y in range(imgsize[1]):
    for x in range(imgsize[0]):

        #Find the distance to the center
        distanceToCenter = math.sqrt((x - imgsize[0]/2) ** 2 + (y - imgsize[1]/2) ** 2)

        #Make it on a scale from 0 to 1
        distanceToCenter = float(distanceToCenter) / (math.sqrt(2) * imgsize[0]/2)

        #Calculate r, g, and b values
        r = outerColor[0] * distanceToCenter + innerColor[0] * (1 - distanceToCenter)
        g = outerColor[1] * distanceToCenter + innerColor[1] * (1 - distanceToCenter)
        b = outerColor[2] * distanceToCenter + innerColor[2] * (1 - distanceToCenter)


        #Place the pixel        
        image.putpixel((x, y), (int(r), int(g), int(b)))

image.save('circlegradient.jpg')

对于每个像素，它设置介于两者之间的红色、绿色和蓝色值innerColor and outerColor取决于像素到中心的距离。

这将是矩形渐变的代码：

import Image

imgsize = (250, 250) #The size of the image

image = Image.new('RGB', imgsize) #Create the image

innerColor = [80, 80, 255] #Color at the center
outerColor = [0, 0, 80] #Color at the edge


for y in range(imgsize[1]):
    for x in range(imgsize[0]):

        #Find the distance to the closest edge
        distanceToEdge = min(abs(x - imgsize[0]), x, abs(y - imgsize[1]), y)

        #Make it on a scale from 0 to 1
        distanceToEdge = float(distanceToEdge) / (imgsize[0]/2)

        #Calculate r, g, and b values
        r = innerColor[0] * distanceToEdge + outerColor[0] * (1 - distanceToEdge)
        g = innerColor[1] * distanceToEdge + outerColor[1] * (1 - distanceToEdge)
        b = innerColor[2] * distanceToEdge + outerColor[2] * (1 - distanceToEdge)


        #Place the pixel        
        image.putpixel((x, y), (int(r), int(g), int(b)))

image.save('rectgradient.jpg')

其工作原理相同，只不过它测量的是到最近边缘的距离，而不是中心的距离。