How to get list of points inside a polygon in python?

I suggest to use matplotlib contains_points()

from matplotlib.path import PathtupVerts=[(86, 52), (85, 52), (81, 53), (80, 52), (79, 48), (81, 49), (86, 53), (85, 51), (82, 54), (84, 54), (83, 49), (81, 52), (80, 50), (81, 48), (85, 50), (86, 54), (85, 54), (80, 48), (79, 50), (85, 49), (80, 51), (85, 53), (82, 49), (83, 54), (82, 53), (84, 49), (79, 49)]x, y = np.meshgrid(np.arange(300), np.arange(300)) # make a canvas with coordinatesx, y = x.flatten(), y.flatten()points = np.vstack((x,y)).T p = Path(tupVerts) # make a polygongrid = p.contains_points(points)mask = grid.reshape(300,300) # now you have a mask with points inside a polygon

Building upon RemcoGerlich's answer here's a validated function:

import numpy as npimport mahotasdef render(poly):    """Return polygon as grid of points inside polygon.    Input : poly (list of lists)    Output : output (list of lists)    """    xs, ys = zip(*poly)    minx, maxx = min(xs), max(xs)    miny, maxy = min(ys), max(ys)    newPoly = [(int(x - minx), int(y - miny)) for (x, y) in poly]    X = maxx - minx + 1    Y = maxy - miny + 1    grid = np.zeros((X, Y), dtype=np.int8)    mahotas.polygon.fill_polygon(newPoly, grid)    return [(x + minx, y + miny) for (x, y) in zip(*np.nonzero(grid))]

Example:

poly = [    [0, 0],    [0, 10],    [10, 10],    [10, 0]]plt.figure(None, (5, 5))x, y = zip(*render(poly))plt.scatter(x, y)x, y = zip(*poly)plt.plot(x, y, c="r")plt.show()

I think drawing the polygon and filling it is a good start, you're going to need something like that anyway and those algorithms are usually fine tuned in C. But don't use a RGB image, use a black/white image, and use numpy.where() to find the pixels where it's 1.

According to this question, the mahotas library has a fill_polygon function that works with numpy arrays.

I'm starting the following code from your function (I would subtract the minx and maxx too) but note that I can't test it at all, I'm not on my dev machine.

import numpy as npimport mahotasdef render(poly): # removed parameter 'z'    xs = [i[0] for i in poly]    ys = [i[1] for i in poly]    minx, maxx = min(xs), max(xs)    miny, maxy = min(ys), max(ys)    X = maxx - minx + 1    Y = maxy - miny + 1    newPoly = [(x - minx, y - miny) for (x, y) in poly]               grid = np.zeros((X, Y), dtype=np.int8)    mahotas.polygon.fill_polygon(newPoly, grid)    return [(x + minx, y + miny) for (x, y) in np.where(grid)]