"""
Drop shadows with PIL.
Author: Kevin Schluff
License: Python license
"""
from PIL import Image, ImageFilter
def dropShadow( image, offset=(5,5), background=0xffffff, shadow=0x444444,
border=8, iterations=3):
"""
Add a gaussian blur drop shadow to an image.
image - The image to overlay on top of the shadow.
offset - Offset of the shadow from the image as an (x,y) tuple. Can be
positive or negative.
background - Background colour behind the image.
shadow - Shadow colour (darkness).
border - Width of the border around the image. This must be wide
enough to account for the blurring of the shadow.
iterations - Number of times to apply the filter. More iterations
produce a more blurred shadow, but increase processing time.
"""
# Create the backdrop image -- a box in the background colour with a
# shadow on it.
totalWidth = image.size[0] + abs(offset[0]) + 2*border
totalHeight = image.size[1] + abs(offset[1]) + 2*border
back = Image.new(image.mode, (totalWidth, totalHeight), background)
# Place the shadow, taking into account the offset from the image
shadowLeft = border + max(offset[0], 0)
shadowTop = border + max(offset[1], 0)
back.paste(shadow, [shadowLeft, shadowTop, shadowLeft + image.size[0],
shadowTop + image.size[1]] )
# Apply the filter to blur the edges of the shadow. Since a small kernel
# is used, the filter must be applied repeatedly to get a decent blur.
n = 0
while n < iterations:
back = back.filter(ImageFilter.BLUR)
n += 1
# Paste the input image onto the shadow backdrop
imageLeft = border - min(offset[0], 0)
imageTop = border - min(offset[1], 0)
back.paste(image, (imageLeft, imageTop))
return back
if __name__ == "__main__":
import sys
image = Image.open(sys.argv[1])
image.thumbnail( (200,200), Image.ANTIALIAS)
dropShadow(image).show()
dropShadow(image, background=0xeeeeee, shadow=0x444444, offset=(0,5)).show()
