To accomplish this task, you can utilize the Pillow library's ImageDraw module. Start by defining the coordinates to create a polygon and then apply a wide line with rounded corners for outlining.
from operator import itemgetter
from pathlib import Path
from PIL import Image, ImageDraw
def generate_custom_mask(directory, filename, point_list, h, w):
custom_mask = Image.new('L', (w, h), color=0)
draw_tool = ImageDraw.Draw(custom_mask)
draw_tool.polygon(point_list, fill=255, outline=255)
draw_tool.line(point_list, fill=255, width=5, joint='curve')
custom_mask.save(Path(directory)/filename)
return custom_mask
padding = 25
point_list = [(114, 197), (96, 77), (110, 42), (138, 56,), (166, 124), (166, 174), (154, 195)]
w = max(point_list, key=itemgetter(0))[0] + padding
h = max(point_list, key=itemgetter(1))[1] + padding
created_mask = generate_custom_mask('\.', 'output_image.png', point_list, h, w)
created_mask.show()
Shown below is an enlarged view of the polygon without an outline on the left, and with the added outline on the right side. The visual impact may be minimal due to the image resolution used in this demonstration.
https://i.stack.imgur.com/y8NIy.png