iso.py

# Nicolas Seriot
# 2021-09-16
# Isometric Towers
# Reimplementation of @bendotk art
# https://twitter.com/nst021/status/1437889678947110912
# Typical output: https://seriot.ch/visualization/iso.png

import cairo
import random

MARGIN = 100
W, H = 10, 40 # grid size
DW, DH = 60, 30 # diamond size
DW2, DH2 = int(DW/2), int(DH/2)
Z_MAX = 2
N = 300

def draw_surface(c, points, color):

    c.save()

    c.set_source_rgb(*color)
    c.set_line_width(1)
    
    [c.line_to(*p) for p in points]

    c.close_path()
    c.fill_preserve()
    c.set_source_rgb(0,0,0)

    c.set_line_join(cairo.LINE_CAP_SQUARE)
    c.stroke()

    c.restore()

def draw_grid(c):

    for x in range(W):
        for y in range(H):
            draw_tower(c, x, y, 0)

def diamond_coords(x, y):

    x_offset = DW2 if y % 2 != 0 else 0
        
    return (x * DW + x_offset, y * DH2)

def draw_tower(c, x, y, h):
    
    x, y = diamond_coords(x, y)
    
    c.save()

    c.translate(x, y)

    """
      5
    2   6
      3   - DH
    1   7
      4
      | DW2
    """

    p1 = (0,   DH2)
    p2 = (0,   DH2 + DH*h)
    p3 = (DW2, DH*h)
    p4 = (DW2, 0)
    p5 = (DW2, DH*h + DH)
    p6 = (DW,  DH2 + DH*h)
    p7 = (DW,  DH2)
    
    COLOR_RIGHT = (0.5,0.5,0.5)
    COLOR_TOP = (1,1,1)
    COLOR_LEFT = (0,0,0)
    
    draw_surface(c, [p2, p5, p6, p3], COLOR_TOP)
    draw_surface(c, [p1, p2, p3, p4], COLOR_LEFT)
    draw_surface(c, [p3, p6, p7, p4], COLOR_RIGHT)
    
    c.restore()

def draw_model(c, m):
    for y in range(len(m))[::-1]:
        for x in range(len(m[y])):
            z = m[y][x]
            if z > 0:
                draw_tower(c, x, y, z)

def main():

    # model is a 2D grid storing the height of towers
    m = [[0]*W for _ in range(H)]
    
    for _ in range(N):
        x = random.randint(0, W-1)
        y = random.randint(0, H-1)
        z = random.randint(0, Z_MAX)
    
        m[y][x] = z
    
    surface = cairo.ImageSurface(cairo.FORMAT_ARGB32,
                                 DW2+(W*DW) + MARGIN*2,
                                 int(H/2)*DH + MARGIN*3)
    c = cairo.Context(surface)
    
    cm = cairo.Matrix(yy=-1, y0=surface.get_height())
    c.transform(cm)
    
    c.translate(MARGIN, MARGIN)
    
    #c.set_antialias(cairo.ANTIALIAS_NONE)
    
    c.set_source_rgb(1,1,1)
    c.paint()
    
    c.set_source_rgb(0,0,0)
    c.set_line_width(1)
    
    #draw_grid(c)
    draw_model(c, m)
    
    #draw_tower(c, 1, 1, 0)
    #draw_tower(c, 1, 0, 1)
    
    surface.write_to_png("iso.png")

if __name__ == "__main__":
    
    main()