What is the most efficient way of drawing a grid with Pygame? - python-3.x

Question

Is there a significant difference in term of performance drawing one rectangle for every cell of the grid compared to drawing the grid using horizontal and vertical lines ?

Answer 1

Yes, using lines drawing is one or more order of magnitude faster than drawing rectangles. The code below times both methods.
import pygame
import os
import time
TITLE = "Draw grid"
WINDOWS_LOCATION = '100,100'
WIDTH = 710
HEIGHT = 710
FPS = 1
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
CELL_SIZE = 15
GRID_COORD_MARGIN_SIZE = 20
class Grid():
def __init__(self, surface, cellSize, axisLabels):
self.surface = surface
self.colNb = surface.get_width() // cellSize
self.lineNb = surface.get_height() // cellSize
self.cellSize = cellSize
self.axisLabels = axisLabels
self.grid = [[0 for i in range(self.colNb)] for j in range(self.lineNb)]
self.font = pygame.font.SysFont('arial', 12, False)
def drawUseRect(self):
for li in range(self.lineNb):
liCoord = GRID_COORD_MARGIN_SIZE + li * CELL_SIZE
if self.axisLabels:
if li < 10:
ident = ' '
else:
ident = ' '
text = self.font.render(ident + str(li), 1, (0, 0, 0))
self.surface.blit(text, (0, liCoord))
for co in range(self.colNb):
colCoord = GRID_COORD_MARGIN_SIZE + co * CELL_SIZE
if self.axisLabels:
if co < 10:
ident = ' '
else:
ident = ' '
text = self.font.render(ident + str(co), 1, (0, 0, 0))
self.surface.blit(text, (colCoord, 1))
pygame.draw.rect(self.surface, BLACK, pygame.Rect(liCoord, colCoord, CELL_SIZE, CELL_SIZE), 1)
def drawUseLine(self):
for li in range(self.lineNb):
liCoord = GRID_COORD_MARGIN_SIZE + li * CELL_SIZE
if self.axisLabels:
if li < 10:
ident = ' '
else:
ident = ' '
text = self.font.render(ident + str(li), 1, (0, 0, 0))
self.surface.blit(text, (0, liCoord))
pygame.draw.line(self.surface, BLACK, (GRID_COORD_MARGIN_SIZE, liCoord), (self.surface.get_width(), liCoord))
for co in range(self.colNb):
colCoord = GRID_COORD_MARGIN_SIZE + co * CELL_SIZE
if self.axisLabels:
if co < 10:
ident = ' '
else:
ident = ' '
text = self.font.render(ident + str(co), 1, (0, 0, 0))
self.surface.blit(text, (colCoord, 1))
pygame.draw.line(self.surface, BLACK, (colCoord, GRID_COORD_MARGIN_SIZE), (colCoord,self.surface.get_height()))
# setting Pygame window position (ok on Windows ...)
os.environ['SDL_VIDEO_WINDOW_POS'] = WINDOWS_LOCATION
pygame.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption(TITLE)
clock = pygame.time.Clock()
running = True
axisLabels = False
grid = Grid(surface=screen, cellSize=CELL_SIZE, axisLabels=axisLabels)
while running:
clock.tick(FPS)
for event in pygame.event.get():
# check for closing window
if event.type == pygame.QUIT:
running = False
screen.fill(WHITE)
start = time.time()
grid.drawUseRect()
print("draw using rect: {}".format(time.time() - start))
start = time.time()
grid.drawUseLine()
print("draw using line: {}".format(time.time() - start))
# *after* drawing everything, flip the display
pygame.display.flip()
pygame.quit()
Here's a example of the timing output on a Windows 10 tablet pc:
draw using rect: 0.04449152946472168
draw using line: 0.0008492469787597656
draw using rect: 0.012907981872558594
draw using line: 0.0
draw using rect: 0.027329683303833008
draw using line: 0.002046346664428711
draw using rect: 0.019585847854614258
draw using line: 0.0009150505065917969
draw using rect: 0.022649049758911133
draw using line: 0.0009458065032958984
draw using rect: 0.022264480590820312
draw using line: 0.0017306804656982422
draw using rect: 0.022340059280395508
draw using line: 0.0009708404541015625
draw using rect: 0.04112124443054199
draw using line: 0.0019001960754394531
And here's a comparison of the visual result of drawing the grid (variable axisLabel set to True):