问题
Using PIL in Python, I am superimposing a PNG image on top of another, larger image. The smaller image is semi-transparent.
I would like for the area behind the smaller image to be blurred on the larger image. The following code blurs a rectangular area:
box = (3270, 1150, 4030, 2250) # (x1, y1, x2, y2)
ic = outputImage.crop(box)
ic = ic.filter(ImageFilter.BoxBlur(20))
outputImage.paste(ic, box)
However, I need to blur a rectangular area that has rounded corners.
This is what the superimposed image looks like:
So, is it possible to define a custom shape for a cropped area in PIL?
If not, is it possible to at least crop circle-shaped areas? (For full coverage and without any overhang, my area would have to broken down into 6 sub-areas: 4 circles and 2 rectangles. Doing all this will slow down my code, but I will take whatever solution I can get.)
I understand that this can be done with Numpy, but I would prefer to use PIL because everything else in this script is already coded with PIL.
回答1:
Take a look at this example (rounded_rectangle function from here):
from PIL import Image
from PIL import ImageDraw
from PIL import ImageFilter
def rounded_rectangle(draw, xy, rad, fill=None):
x0, y0, x1, y1 = xy
draw.rectangle([ (x0, y0 + rad), (x1, y1 - rad) ], fill=fill)
draw.rectangle([ (x0 + rad, y0), (x1 - rad, y1) ], fill=fill)
draw.pieslice([ (x0, y0), (x0 + rad * 2, y0 + rad * 2) ], 180, 270, fill=fill)
draw.pieslice([ (x1 - rad * 2, y1 - rad * 2), (x1, y1) ], 0, 90, fill=fill)
draw.pieslice([ (x0, y1 - rad * 2), (x0 + rad * 2, y1) ], 90, 180, fill=fill)
draw.pieslice([ (x1 - rad * 2, y0), (x1, y0 + rad * 2) ], 270, 360, fill=fill)
# Open an image
im = Image.open(INPUT_IMAGE_FILENAME)
# Create rounded rectangle mask
mask = Image.new('L', im.size, 0)
draw = ImageDraw.Draw(mask)
rounded_rectangle(draw, (im.size[0]//4, im.size[1]//4, im.size[0]//4*3, im.size[1]//4*3), rad=40, fill=255)
mask.save('mask.png')
# Blur image
blurred = im.filter(ImageFilter.GaussianBlur(20))
# Paste blurred region and save result
im.paste(blurred, mask=mask)
im.save(OUTPUT_IMAGE_FILENAME)
Input image:
Mask:
Output image:
Tested with Python 2.7.12 and Pillow 3.1.2 (it doesn't have BoxBlur).
来源:https://stackoverflow.com/questions/50792424/how-to-blur-non-rectangular-or-circular-area-of-image-with-python-pil