Python 3 Pygame Drawing maze - pygame

Question

I'm Trying to create this maze outline by drawing lines in python with pygame, but the format is messed up and i'm not sure what is happening. I believe it is probably an issue with the logic I created for drawing the lines based on what character is active in the for loop.
import pygame
pygame.init()
global black, white
white = (255,255,255)
black = (0,0,0)
display_width = 1200
display_height = 800
gameDisplay = pygame.display.set_mode((display_width,display_height))
clock = pygame.time.Clock()
def draw_line(surface,color,start_pos,end_pos,width):
pygame.draw.line(surface,color,start_pos,end_pos,width)
def game_loop():
maze = "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+n\
| | | | | | |n\
+ +--+ + + +--+ + + + +--+--+ + +--+ +n\
| | | | | | | | | |n\
+ +--+ + + +--+--+ + +--+--+--+--+ + + +n\
| | | | | | | | | | |n\
+--+ +--+--+--+ + +--+ + +--+--+--+--+ + +n\
| | | | | |n\
+ + + +--+--+--+--+--+--+--+--+--+--+--+ +--+n\
| | | | | | |n\
+ +--+ + +--+ + +--+--+--+--+--+--+ + + +n\
| | | | | | | | |n\
+ +--+--+ +--+--+--+ +--+ + + +--+ + + +n\
| | | | | | | | |n\
+--+--+ +--+--+--+ + + +--+ +--+--+--+--+ +n\
| | | |n\
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+"
gameExit = False
WALL_LENGTH = 20
x=y=x2=y2=START=5
gameDisplay.fill(white)
for i in maze:
if i == "+" or i == "-":
x2+=WALL_LENGTH
draw_line(gameDisplay,black,(x,y),(x2,y2),5)
x+=WALL_LENGTH
elif i == "n":
y+=WALL_LENGTH*2
y2=y
x=START
x2=START
elif i == "|":
y2+=WALL_LENGTH*2
draw_line(gameDisplay,black,(x,y),(x2,y2),5)
x+=WALL_LENGTH
x2=x
y2=y
elif i == " ":
x+=WALL_LENGTH
x2=x
while not gameExit:
for event in pygame.event.get():
if event.type == pygame.QUIT: gameExit = True
pygame.display.update()
clock.tick(30)
game_loop()
pygame.quit()
quit()

Answer 1

The easiest way to debug this is to simply put a couple of print statements in your code and have a look at the x,y,x2,y2 variables.
I noticed the following problems:
The backslash at the end of a line tells python the string continues at the beginning of the next line. This means all the whitespace you have there to indent the maze is counted. By the time the code sees the first "|" or "+", the x counter is already at 245, shifting the whole line to the right. Remove the whitespace at the beginning of each maze line to fix this.
You count up your y value every time you have a new line. However, vertical lines only connect two horizontal lines, they're not really maze lines on their own. So you need to do either of two things:
a. Go down at the end of every even row and draw your walls downwards
b. Go down at the end of every odd row and draw your walls upwards (as I've done below)
Lastly, I'm not quite sure what your "+" are supposed to be. You currently use them to denote vertical lines, horizontal lines, corners, line ends, as well as intersections. You need to figure out different ASCII symbols for these cases and replace your "+" by the appropriate symbol and then adjust your code to draw whatever is required. Otherwise you end up drawing horizontal lines when you're supposed to draw vertical ones or vice versa.
Here is a somewhat fixed version of your code. It still does not properly deal with the "+", but I've made it draw the problematic lines in red so it should be easy to figure out the correct behavior.
import pygame
pygame.init()
global black, white
white = (255,255,255)
black = (0,0,0)
red = (255,0,0)
display_width = 1200
display_height = 800
gameDisplay = pygame.display.set_mode((display_width,display_height))
clock = pygame.time.Clock()
def draw_line(surface,color,start_pos,end_pos,width):
pygame.draw.line(surface,color,start_pos,end_pos,width)
def game_loop():
maze = "\
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+n\
| | | | | | |n\
+ +--+ + + +--+ + + + +--+--+ + +--+ +n\
| | | | | | | | | |n\
+ +--+ + + +--+--+ + +--+--+--+--+ + + +n\
| | | | | | | | | | |n\
+--+ +--+--+--+ + +--+ + +--+--+--+--+ + +n\
| | | | | |n\
+ + + +--+--+--+--+--+--+--+--+--+--+--+ +--+n\
| | | | | | |n\
+ +--+ + +--+ + +--+--+--+--+--+--+ + + +n\
| | | | | | | | |n\
+ +--+--+ +--+--+--+ +--+ + + +--+ + + +n\
| | | | | | | | |n\
+--+--+ +--+--+--+ + + +--+ +--+--+--+--+ +n\
| | | |n\
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+"
gameExit = False
WALL_LENGTH = 20
x=y=x2=y2=START=5
gameDisplay.fill(white)
linecount = 0
for i in maze:
if i == "-":
x2+=WALL_LENGTH
draw_line(gameDisplay,black,(x,y),(x2,y2),5)
x+=WALL_LENGTH
elif i == "+":
x2+=WALL_LENGTH
draw_line(gameDisplay,red,(x,y),(x2,y2),5)
x+=WALL_LENGTH
elif i == "n":
linecount+=1
if(linecount % 2 == 0):
y+=WALL_LENGTH*2
y2=y
x=START
x2=START
elif i == "|":
y2-=WALL_LENGTH*2
draw_line(gameDisplay,black,(x,y),(x2,y2),5)
x+=WALL_LENGTH
x2=x
y2=y
elif i == " ":
x+=WALL_LENGTH
x2=x
while not gameExit:
for event in pygame.event.get():
if event.type == pygame.QUIT: gameExit = True
pygame.display.update()
clock.tick(30)
game_loop()
pygame.quit()
quit()
Screenshot of the current maze output: