Pygame screen display issue - python

import pygame
pygame.init()
display_width = (640)
display_height = (480)
title = pygame.display.set_caption("test")
IMG = pygame.image.load("image.png")
screen = pygame.display.set_mode((display_width,display_height))
screen.blit(IMG,(1,1))
pygame.display.update()
Whenever I use pygame, even simple displays like this are skewed for me. it shows 0,0 at around the middle of my display screen and i dont know why. Basically, it is showing - x values on the x axis help!
I am using python 2.7 and this seems to not be a coding issue, but rather something else. please help! ty

I've not been able to replicate your problem with the above code in Python 2.7.12, the image is a red, fifty-pixel square:
Here's an extended demo that will draw the image around the cursor position based on the mouse button clicked. Perhaps that'll help you get towards the behaviour you're after.
import pygame
if __name__ == "__main__":
pygame.init()
screen_width, screen_height = 640, 480
screen = pygame.display.set_mode((screen_width, screen_height))
pygame.display.set_caption('Blit Demo')
clock = pygame.time.Clock() #for limiting FPS
FPS = 10
exit_demo = False
# start with a white background
screen.fill(pygame.Color("white"))
img = pygame.image.load("image.png")
width, height = img.get_size()
pos = (1,1) # initial position to draw the image
# main loop
while not exit_demo:
for event in pygame.event.get():
if event.type == pygame.QUIT:
exit_demo = True
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_ESCAPE:
# fill the screen with white, erasing everything
screen.fill(pygame.Color("white"))
elif event.type == pygame.MOUSEBUTTONUP:
if event.button == 1: # left
pos = (event.pos[0] - width, event.pos[1] - height)
elif event.button == 2: # middle
pos = (event.pos[0] - width // 2, event.pos[1] - height // 2)
elif event.button == 3: # right
pos = event.pos
# draw the image here
screen.blit(img, pos)
# update screen
pygame.display.update()
clock.tick(FPS)
pygame.quit()
quit()

Related

python object stops moving at the boundaries

I'm experimenting, and I'm trying to get a circle to move along a line but stop once it reaches the edge of the screen. once this happens I can no longer go back the other way. There's probably a simple fix I'm not seeing, and it would be helpful to have someone point me in the right direction. Please keep in mind I am still a beginner.
from pygame import *
import random
import math
import os #Displays the pygame window at the top left of the screen
os.environ['SDL_VIDEO_WINDOW_POS'] = "%d, %d" %(0,25)
init() #Starts pygame
font.init()
LENGTH = 1000 #Creates Screen that is 1000 X 700
WIDTH = 700
SIZE = (LENGTH, WIDTH)
Screen = display.set_mode(SIZE)
#Defines colours
BLACK = (0,0,0)
WHITE = (255,255,255)
RED = (255,0,0)
running = True
CaptainY = 350
Key = 0
while running:
for evnt in event.get(): # checks all events that happen
if evnt.type == QUIT: # if event type is quit the program stops running
running = False
if evnt.type == KEYDOWN:
Key = evnt.key
if evnt.type == KEYUP:
Key = 0
if 20 < CaptainY < 680:
if Key == K_UP:
CaptainY -= 5
if Key == K_DOWN:
CaptainY += 5
draw.rect(Screen, BLACK, (0,0, LENGTH, WIDTH))
draw.circle(Screen, WHITE, (950, CaptainY), 15)
if Key == K_ESCAPE:
print(CaptainY)
display.flip()
quit()
The program is doing what you told it: Move only if the y-position is between 20 and 680. If it's less than 20, this condition won't be True and the circle won't be able move anymore.
# You only move if this is True.
if 20 < CaptainY < 680:
Instead of stopping the movement, you should just move the position back, so that the circle ends up on the screen. Here's a complete example with a few more changes:
import pygame # Avoid * imports, since they make code harder to read and cause bugs.
pygame.init()
screen = pygame.display.set_mode((1000, 700))
HEIGHT = screen.get_height()
BLACK = (0,0,0)
WHITE = (255,255,255)
clock = pygame.time.Clock() # Use a clock to limit the frame rate.
running = True
captain_y = 350
captain_radius = 15
while running:
# Handle events.
for evnt in pygame.event.get():
if evnt.type == pygame.QUIT:
running = False
elif evnt.type == pygame.KEYDOWN:
if evnt.key == pygame.K_ESCAPE:
running = False
# To see if a key is being held down, use `pygame.key.get_pressed()`.
pressed_keys = pygame.key.get_pressed()
# Move if up or down keys are pressed.
if pressed_keys[pygame.K_UP]:
captain_y -= 5
elif pressed_keys[pygame.K_DOWN]:
captain_y += 5
# Update the game.
# Reset the position if the circle is off screen.
if captain_y - captain_radius <= 0:
captain_y = 0 + captain_radius
elif captain_y + captain_radius >= HEIGHT:
captain_y = HEIGHT - captain_radius
# Draw everything.
screen.fill(BLACK)
pygame.draw.circle(screen, WHITE, (950, captain_y), captain_radius)
pygame.display.flip()
clock.tick(60) # Cap the frame rate at 60 fps.
pygame.quit()

Pygame blit image with mouse event

I use Pygame in this code. This is like a game that when user hit mouse button, from the mouse position comes a laser image that will go up, and eventually go out of the screen. I am trying to blit an image when the user hit mouse button. This code I am using does not work and I do not know why. My problem starts at the main for loop
import pygame
# Initialize Pygame
pygame.init()
#___GLOBAL CONSTANTS___
# Define some colors
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
GREEN = (0, 255, 0)
RED = (255, 0, 0)
# Set the height and width of the screen
screen_width = 500
screen_height = 500
screen = pygame.display.set_mode([screen_width, screen_height])
#Load Laser image of spaceship
laser_image = pygame.image.load('laserRed16.png').convert()
#Load sound music
sound = pygame.mixer.Sound('laser5.ogg')
# Loop until the user clicks the close button.
done = False
# Used to manage how fast the screen updates
clock = pygame.time.Clock()
# -------- Main Program Loop -----------
while not done:
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
elif event.type == pygame.MOUSEBUTTONDOWN:
# Get the current mouse position. This returns the position
# as a list of two numbers.
sound.play()
#Get the mouse position
mouse_position = pygame.mouse.get_pos()
mouse_x = mouse_position[0]
mouse_y = mouse_position[1]
# Set the laser image when the spaceship fires
for i in range(50):
screen.blit(laser_image,[mouse_x + laser_x_vector,mouse_y + laser_x_vector])
laser_x_vector += 2
laser_x_vector += 2
# Clear the screen
screen.fill(WHITE)
#Limit to 20 sec
clock.tick(20)
# Go ahead and update the screen with what we've drawn.
pygame.display.flip()
pygame.quit()
You fill the screen after you blit the lazer, so the lazer will not appear. You should fill before you blit the lazer so the lazer appears.
The others have already explained why you don't see the laser. Here's a working solution for you. First I suggest to use pygame.Rects for the positions of the lasers and put them into a list (rects can also be used for collision detection). Then iterate over these positions/rects in the main while loop, update and blit them. I also show you how to remove rects that are off screen.
import pygame
pygame.init()
WHITE = (255, 255, 255)
GREEN = (0, 255, 0)
screen_width = 500
screen_height = 500
screen = pygame.display.set_mode([screen_width, screen_height])
laser_image = pygame.Surface((10, 50))
laser_image.fill(GREEN)
done = False
clock = pygame.time.Clock()
laser_rects = []
laser_velocity_y = -20
while not done:
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
elif event.type == pygame.MOUSEBUTTONDOWN:
# Turn the mouse position into a rect with the dimensions
# of the laser_image. You can use the event.pos instead
# of pygame.mouse.get_pos() and pass it as the `center`
# or `topleft` argument.
laser_rect = laser_image.get_rect(center=event.pos)
laser_rects.append(laser_rect)
remaining_lasers = []
for laser_rect in laser_rects:
# Change the y-position of the laser.
laser_rect.y += laser_velocity_y
# Only keep the laser_rects that are on the screen.
if laser_rect.y > 0:
remaining_lasers.append(laser_rect)
# Assign the remaining lasers to the laser list.
laser_rects = remaining_lasers
screen.fill(WHITE)
# Now iterate over the lasers rect and blit them.
for laser_rect in laser_rects:
screen.blit(laser_image, laser_rect)
pygame.display.flip()
clock.tick(30) # 30 FPS is smoother.
pygame.quit()

pygame: drawing a selection rectangle with the mouse

I have written a simple breakout game in pygame and am writing a level editor. Everything was working until I tried to add a selecting rectangle that has the transparent look (like the one on my desktop background). I can get a rectangle (sorta) but everything else vanishes, and it isn't semi-transparent.
code:
pygame.init()
screen = pygame.display.set_mode(size)
mousescreen = pygame.Surface((screen.get_size())).convert_alpha()
...
in the designing loop:
global xpos, ypos, theBricks, clock, mousedrag, mouseRect
global designing, titles
global theLevels, level, cur_max_level, max_level
mousedrag = False
mouseRect = None
mouseDown = False
while designing:
events = pygame.event.get()
for event in events:
if event.type == pygame.QUIT:
sys.exit()
elif event.type == pygame.MOUSEBUTTONDOWN:
mouseDown = True
mpos = pygame.mouse.get_pos()
x_position = mpos[0]
y_position = mpos[1]
xpos = ((x_position-left)/BRW) * BRW + left
ypos = ((y_position-top)/BRH) * BRH + top
elif event.type == MOUSEMOTION:
if mouseDown:
newx_pos = mpos[0]
newy_pos = mpos[1]
mousedrag = True
if mousedrag:
mouseRect = Rect(newx_pos, newy_pos, xpos, ypos)
elif event.type == MOUSEBUTTONUP:
if mousedrag:
mousedrag = False
else:
if is_a_brick(xpos, ypos):
del_brick(xpos, ypos)
else:
make_brick(xpos, ypos)
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_q:
designing = False
titles = True
...
in the update screen function:
for bricks in theBricks:
pygame.draw.rect(screen, GREEN, bricks.rect)
if mousedrag:
pygame.draw.rect(mousescreen, RED, mouseRect, 50)
screen.blit(mousescreen, (0,0))
pygame.draw.rect(screen, WHITE, (xpos, ypos, BRW, BRH))
pygame.display.update()
The rectangle is not transparent and everything else vanishes off the screen? Where am I going wrong?
I'm not sure if .convert_alpha() is creating a transparent screen like you think. Try setting the alpha level on mousescreen explicitly:
mousescreen = pygame.Surface((screen.get_size()))
mousescreen.set_alpha(100) # this value doesn't have to be 100
Another way to achieve the same effect is to draw your rect as 4 lines directly onto the screen which means you don't have to have mousescreen at all. In your update screen function:
if mousedrag:
mouseRectCorners = [mouseRect.topleft,
mouseRect.topright,
mouseRect.bottomright,
mouseRect.bottomleft]
pygame.draw.lines(screen, RED, True, mouseRectCorners, 50)
Just make sure you draws these lines after any other objects or they might get hidden. I'm not sure if this option is really considered best practice but it's always good to have options.

Python/Pygame mouse position does not update (blit function)

I'm trying to make a simple menu using Pygame but I found that whenever I use pygame.mouse.get_position, it does blit what i want but i have to keep move my mouse to make my picture keep blitting.
import pygame
import sys
pygame.init()
screen = pygame.display.set_mode((800,600))
pygame.display.set_caption('cursor test')
cursorPng = pygame.image.load('resources/images/cursor.png')
start = pygame.image.load('resources/images/menuStart.jpg')
enemy = pygame.image.load('resources/images/enemy-1.png')
white = (255,255,255)
black = (0,0,0)
clock = pygame.time.Clock()
FPS = 60
while True:
screen.fill(white)
pygame.mouse.set_visible(False)
x,y = pygame.mouse.get_pos()
x = x - cursorPng.get_width()/2
y = y - cursorPng.get_height()/2
screen.blit(cursorPng,(x,y))
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
sys.exit()
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_ESCAPE:
pygame.quit()
sys.exit()
elif event.type == pygame.MOUSEMOTION:
if x < 50 and y < 250:
screen.blit(enemy,(100,100))
clock.tick(FPS)
pygame.display.update()
what's wrong?
Take a look at your code:
for event in pygame.event.get():
...
elif event.type == pygame.MOUSEMOTION:
if x < 50 and y < 250:
screen.blit(enemy,(100,100))
You check for events, and if you detect that the mouse is being moved (and only then), you draw the image to the screen.
If you want to draw the image even if the mouse is not being moved, just stop checking for the MOUSEMOTION event and simply draw the image always:
while True:
screen.fill(white)
pygame.mouse.set_visible(False)
x,y = pygame.mouse.get_pos()
x = x - cursorPng.get_width()/2
y = y - cursorPng.get_height()/2
screen.blit(cursorPng,(x,y))
if x < 50 and y < 250:
screen.blit(enemy,(100,100))
for event in pygame.event.get():
...
You need to blit into the screen a Surface and a Rect.
First, use this snippet I use for loading images. It makes sure the image is loaded correctly:
def loadImage(name, alpha=False):
"Loads given image"
try:
surface = pygame.image.load(name)
except pygame.error:
raise SystemExit('Could not load image "%s" %s' %
(name, pygame.get_error()))
if alpha:
corner = surface.get_at((0, 0))
surface.set_colorkey(corner, pygame.RLEACCEL)
return surface.convert_alpha()
Second, when you get the Surface, get its rect like this:
cursorSurf = loadImage('resources/images/cursor.png')
cursorRect = cursorSurf.get_rect()
Then, inside the update do the following:
cursorRect.center = pygame.mouse.get_pos()
And finnally, blit to screen like this:
screen.blit(cursorSurf, cursorRect)
Now you will notice your Mouse is being rendered correctly without having to move your mouse.

image is bad with python in pygame

I have a program in python:
import sys, random, pygame
from pygame.locals import *
pygame.init()
# Preparing Pygame
size = width, height = 718, 502
screen = pygame.display.set_mode(size)
framerate = pygame.time.Clock()
pygame.display.set_caption('Flappy Cube')
#Peparing background
background_x = 0
background_y = 0
background = pygame.image.load("background.jpg")
#Preparing Cube
cube_x = 100
cube_y = 200
cube_unscaled = pygame.image.load("cube.png")
cube = pygame.transform.smoothscale(cube_unscaled, (64, 64))
#Preparing Tubes
tube_x = 750
tube_y= 300
tube_unscaled = pygame.image.load("tube.png")
tube = pygame.transform.smoothscale(tube_unscaled, (125, 500))
# The main game loop
def exit_game():
sys.exit()
while True:
#Background
screen.blit(background, (background_x,background_y))
background_x = background_x+254.5
screen.blit(cube,(cube_x, cube_y))
#Tube
tube_x = tube_x -.075
screen.blit(tube,(tube_x, tube_y))
# If exit
for event in pygame.event.get():
if event.type == pygame.QUIT: exit_game()
# If Space Key is presed
elif event.type == pygame.KEYDOWN and event.key == K_SPACE:
cube_y = cube_y-10
#If Clicked
elif pygame.mouse.get_pressed()[0]:
cube_y = cube_y-10
framerate.tick(60)
pygame.display.flip()
run_game()
I get this result: http://i.stack.imgur.com/MKYRM.png
I have to boost framerate.tick(60) to framerate.tick(700) it looks a glichy. when I program the gravity the multiple images won't look good.
how can i fix the images been drawn multiple times before the screen updates?
Try:
cube_unscaled = pygame.image.load("cube.png").convert_alpha()
You shouldn't need to boost your FPS in such way, 60 is a good value.
Also, I like better this order for your main loop: check events, draw, update, tick.
I don't think it makes a difference to your problem, but I think it easier to understand that way.
while True:
# If exit
for event in pygame.event.get():
if event.type == pygame.QUIT: exit_game()
# If Space Key is presed
elif event.type == pygame.KEYDOWN and event.key == K_SPACE:
cube_y = cube_y-10
#If Clicked
elif pygame.mouse.get_pressed()[0]:
cube_y = cube_y-10
#Background
screen.blit(background, (background_x,background_y))
background_x = background_x+254.5
screen.blit(cube,(cube_x, cube_y))
#Tube
tube_x = tube_x -.075
screen.blit(tube,(tube_x, tube_y))
pygame.display.flip()
framerate.tick(60)
I fixed it! I just needed to fill the screen with black before "bliting" it.

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