Related
I had been trying to rotate an image around its center in using pygame.transform.rotate() but it's not working. Specifically the part that hangs is rot_image = rot_image.subsurface(rot_rect).copy(). I get the exception:
ValueError: subsurface rectangle outside surface area
Here is the code used to rotate an image:
def rot_center(image, angle):
"""rotate an image while keeping its center and size"""
orig_rect = image.get_rect()
rot_image = pygame.transform.rotate(image, angle)
rot_rect = orig_rect.copy()
rot_rect.center = rot_image.get_rect().center
rot_image = rot_image.subsurface(rot_rect).copy()
return rot_image
Short answer:
When you use pygame.transform.rotate the size of the new rotated image is increased compared to the size of the original image. You must make sure that the rotated image is placed so that its center remains in the center of the non-rotated image. To do this, get the rectangle of the original image and set the position. Get the rectangle of the rotated image and set the center position through the center of the original rectangle.
Returns a tuple from the function red_center, with the rotated image and the bounding rectangle of the rotated image:
def rot_center(image, angle, x, y):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(center = (x, y)).center)
return rotated_image, new_rect
Or write a function which rotates and .blit the image:
def blitRotateCenter(surf, image, topleft, angle):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(topleft = topleft).center)
surf.blit(rotated_image, new_rect)
Long answer:
An image (pygame.Surface) can be rotated by pygame.transform.rotate.
If that is done progressively in a loop, then the image gets distorted and rapidly increases:
while not done:
# [...]
image = pygame.transform.rotate(image, 1)
screen.blit(image, pos)
pygame.display.flip()
This is because the bounding rectangle of a rotated image is always greater than the bounding rectangle of the original image (except some rotations by multiples of 90 degrees).
The image gets distort because of the multiply copies. Each rotation generates a small error (inaccuracy). The sum of the errors is growing and the images decays.
That can be fixed by keeping the original image and "blit" an image which was generated by a single rotation operation form the original image.
angle = 0
while not done:
# [...]
rotated_image = pygame.transform.rotate(image, angle)
angle += 1
screen.blit(rotated_image, pos)
pygame.display.flip()
Now the image seems to arbitrary change its position, because the size of the image changes by the rotation and origin is always the top left of the bounding rectangle of the image.
This can be compensated by comparing the axis aligned bounding box of the image before the rotation and after the rotation.
For the following math pygame.math.Vector2 is used. Note in screen coordinates the y points down the screen, but the mathematical y axis points form the bottom to the top. This causes that the y axis has to be "flipped" during calculations
Set up a list with the 4 corner points of the bounding box:
w, h = image.get_size()
box = [pygame.math.Vector2(p) for p in [(0, 0), (w, 0), (w, -h), (0, -h)]]
Rotate the vectors to the corner points by pygame.math.Vector2.rotate:
box_rotate = [p.rotate(angle) for p in box]
Get the minimum and the maximum of the rotated points:
min_box = (min(box_rotate, key=lambda p: p[0])[0], min(box_rotate, key=lambda p: p[1])[1])
max_box = (max(box_rotate, key=lambda p: p[0])[0], max(box_rotate, key=lambda p: p[1])[1])
Calculate the "compensated" origin of the upper left point of the image by adding the minimum of the rotated box to the position. For the y coordinate max_box[1] is the minimum, because of the "flipping" along the y axis:
origin = (pos[0] + min_box[0], pos[1] - max_box[1])
rotated_image = pygame.transform.rotate(image, angle)
screen.blit(rotated_image, origin)
It is even possible to define a pivot on the original image. Compute the offset vector from the center of the image to the pivot and rotate the vector. A vector can be represented by pygame.math.Vector2 and can be rotated with pygame.math.Vector2.rotate. Notice that pygame.math.Vector2.rotate rotates in the opposite direction than pygame.transform.rotate. Therefore the angle has to be inverted:
Compute the vector from the center of the image to the pivot:
image_rect = image.get_rect(topleft = (pos[0] - originPos[0], pos[1]-originPos[1]))
offset_center_to_pivot = pygame.math.Vector2(pos) - image_rect.center
Rotate the vector
rotated_offset = offset_center_to_pivot.rotate(-angle)
Calculate the center of the rotated image:
rotated_image_center = (pos[0] - rotated_offset.x, pos[1] - rotated_offset.y)
Rotate and blit the image:
rotated_image = pygame.transform.rotate(image, angle)
rotated_image_rect = rotated_image.get_rect(center = rotated_image_center)
screen.blit(rotated_image, rotated_image_rect)
In the following example program, the function blitRotate(surf, image, pos, originPos, angle) does all the above steps and "blit" a rotated image to a surface.
surf is the target Surface
image is the Surface which has to be rotated and blit
pos is the position of the pivot on the target Surface surf (relative to the top left of surf)
originPos is position of the pivot on the image Surface (relative to the top left of image)
angle is the angle of rotation in degrees
This means, the 2nd argument (pos) of blitRotate is the position of the pivot point in the window and the 3rd argument (originPos) is the position of the pivot point on the rotating Surface:
Minimal example: repl.it/#Rabbid76/PyGame-RotateAroundPivot
import pygame
pygame.init()
screen = pygame.display.set_mode((300, 300))
clock = pygame.time.Clock()
def blitRotate(surf, image, pos, originPos, angle):
# offset from pivot to center
image_rect = image.get_rect(topleft = (pos[0] - originPos[0], pos[1]-originPos[1]))
offset_center_to_pivot = pygame.math.Vector2(pos) - image_rect.center
# roatated offset from pivot to center
rotated_offset = offset_center_to_pivot.rotate(-angle)
# roatetd image center
rotated_image_center = (pos[0] - rotated_offset.x, pos[1] - rotated_offset.y)
# get a rotated image
rotated_image = pygame.transform.rotate(image, angle)
rotated_image_rect = rotated_image.get_rect(center = rotated_image_center)
# rotate and blit the image
surf.blit(rotated_image, rotated_image_rect)
# draw rectangle around the image
pygame.draw.rect(surf, (255, 0, 0), (*rotated_image_rect.topleft, *rotated_image.get_size()),2)
def blitRotate2(surf, image, topleft, angle):
rotated_image = pygame.transform.rotate(image, angle)
new_rect = rotated_image.get_rect(center = image.get_rect(topleft = topleft).center)
surf.blit(rotated_image, new_rect.topleft)
pygame.draw.rect(surf, (255, 0, 0), new_rect, 2)
try:
image = pygame.image.load('AirPlaneFront.png')
except:
text = pygame.font.SysFont('Times New Roman', 50).render('image', False, (255, 255, 0))
image = pygame.Surface((text.get_width()+1, text.get_height()+1))
pygame.draw.rect(image, (0, 0, 255), (1, 1, *text.get_size()))
image.blit(text, (1, 1))
w, h = image.get_size()
angle = 0
done = False
while not done:
clock.tick(60)
for event in pygame.event.get():
if event.type == pygame.QUIT:
done = True
pos = (screen.get_width()/2, screen.get_height()/2)
screen.fill(0)
blitRotate(screen, image, pos, (w/2, h/2), angle)
#blitRotate2(screen, image, pos, angle)
angle += 1
pygame.draw.line(screen, (0, 255, 0), (pos[0]-20, pos[1]), (pos[0]+20, pos[1]), 3)
pygame.draw.line(screen, (0, 255, 0), (pos[0], pos[1]-20), (pos[0], pos[1]+20), 3)
pygame.draw.circle(screen, (0, 255, 0), pos, 7, 0)
pygame.display.flip()
pygame.quit()
exit()
See also Rotate surface and the answers to the questions:
How can you rotate an image around an off center pivot in Pygame
How to rotate an image around its center while its scale is getting larger(in Pygame)
How to rotate an image(player) to the mouse direction?
How to set the pivot point (center of rotation) for pygame.transform.rotate()?
How do you point the barrel towards mouse in pygame?
There are some problems with the top answer: The position of the previous rect needs to be available in the function, so that we can assign it to the new rect, e.g.:
rect = new_image.get_rect(center=rect.center)
In the other answer the location is obtained by creating a new rect from the original image, but that means it will be positioned at the default (0, 0) coordinates.
The example below should work correctly. The new rect needs the center position of the old rect, so we pass it as well to the function. Then rotate the image, call get_rect to get a new rect with the correct size and pass the center attribute of the old rect as the center argument. Finally, return both the rotated image and the new rect as a tuple and unpack it in the main loop.
import pygame as pg
def rotate(image, rect, angle):
"""Rotate the image while keeping its center."""
# Rotate the original image without modifying it.
new_image = pg.transform.rotate(image, angle)
# Get a new rect with the center of the old rect.
rect = new_image.get_rect(center=rect.center)
return new_image, rect
def main():
clock = pg.time.Clock()
screen = pg.display.set_mode((640, 480))
gray = pg.Color('gray15')
blue = pg.Color('dodgerblue2')
image = pg.Surface((320, 200), pg.SRCALPHA)
pg.draw.polygon(image, blue, ((0, 0), (320, 100), (0, 200)))
# Keep a reference to the original to preserve the image quality.
orig_image = image
rect = image.get_rect(center=(320, 240))
angle = 0
done = False
while not done:
for event in pg.event.get():
if event.type == pg.QUIT:
done = True
angle += 2
image, rect = rotate(orig_image, rect, angle)
screen.fill(gray)
screen.blit(image, rect)
pg.display.flip()
clock.tick(30)
if __name__ == '__main__':
pg.init()
main()
pg.quit()
Here's another example with a rotating pygame sprite.
import pygame as pg
class Entity(pg.sprite.Sprite):
def __init__(self, pos):
super().__init__()
self.image = pg.Surface((122, 70), pg.SRCALPHA)
pg.draw.polygon(self.image, pg.Color('dodgerblue1'),
((1, 0), (120, 35), (1, 70)))
# A reference to the original image to preserve the quality.
self.orig_image = self.image
self.rect = self.image.get_rect(center=pos)
self.angle = 0
def update(self):
self.angle += 2
self.rotate()
def rotate(self):
"""Rotate the image of the sprite around its center."""
# `rotozoom` usually looks nicer than `rotate`. Pygame's rotation
# functions return new images and don't modify the originals.
self.image = pg.transform.rotozoom(self.orig_image, self.angle, 1)
# Create a new rect with the center of the old rect.
self.rect = self.image.get_rect(center=self.rect.center)
def main():
screen = pg.display.set_mode((640, 480))
clock = pg.time.Clock()
all_sprites = pg.sprite.Group(Entity((320, 240)))
while True:
for event in pg.event.get():
if event.type == pg.QUIT:
return
all_sprites.update()
screen.fill((30, 30, 30))
all_sprites.draw(screen)
pg.display.flip()
clock.tick(30)
if __name__ == '__main__':
pg.init()
main()
pg.quit()
You are deleting the rect that rotate creates. You need to preserve rect, since it changes size when rotated.
If you want to preserve the objects location, do:
def rot_center(image, angle):
"""rotate a Surface, maintaining position."""
loc = image.get_rect().center #rot_image is not defined
rot_sprite = pygame.transform.rotate(image, angle)
rot_sprite.get_rect().center = loc
return rot_sprite
# or return tuple: (Surface, Rect)
# return rot_sprite, rot_sprite.get_rect()
Found the problem: Example works good, but needs equal dimensions for width and height. Fixed pictures and it works.
Everything you need for drawing an image in pygame
game_display = pygame.display.set_mode((800, 600))
x = 0
y = 0
angle = 0
img = pygame.image.load("resources/image.png")
img = pygame.transform.scale(img, (50, 50)) # image size
def draw_img(self, image, x, y, angle):
rotated_image = pygame.transform.rotate(image, angle)
game_display.blit(rotated_image, rotated_image.get_rect(center=image.get_rect(topleft=(x, y)).center).topleft)
# run this method with your loop
def tick():
draw_img(img, x, y, angle)
I had to modify skrx solution as below, this way works for me.
angle=0
roll = true
while roll:
# clean surface with your background color
gameDisplay.fill(color)
self.image = yourImage
rotate_image = pygame.transform.rotate(self.image, angle)
rect = rotate_image.get_rect()
pos = (((your_surface_width - rect.width)/2),((your_surface_height - rect.height)/2))
gameDisplay.blit(rotate_image,pos)
pygame.display.flip()
angle+=2
if angle == 360:
roll=False
I'm trying to make a white rectangle rotate like a the hands of a clock in pygame using this code,
import random, pygame, math, sys
from pygame.locals import *
Blue = (0,0,255)
Black = (0, 0, 0)
Green = (0,255,0)
White = (255,255,255)
pygame.init()
DISPLAYSURF = pygame.display.set_mode((400, 300))
pygame.display.set_caption('Sailing!')
FPS = 30
fpsClock = pygame.time.Clock()
Sail = pygame.Surface([100,10])
Sail.set_colorkey (Black)
Sail.fill(White)
degrees = 0
hyp = 100
x = 200
y = 150
while True:
for event in pygame.event.get():
if event.type == QUIT:
pygame.quit()
sys.exit()
adj = 10 * math.cos(degrees)
opp = 10 * math.sin(degrees)
dx = adj + 200
dy = opp + 150
rotatedSail = pygame.transform.rotate(Sail, degrees)
Sail_rect = Sail.get_rect(topleft = (dx, dy))
DISPLAYSURF.fill(Blue)
DISPLAYSURF.blit(rotatedSail, Sail_rect)
pygame.display.flip()
fpsClock.tick(FPS)
degrees += 1
but the rectangle rotates in a weird way. I would appreciate it if you could keep the suggestion as simple and as close to my code as possible, because I'm just starting to learn. Plus i know it's easier to do it using an image of a rectangle, but I'm trying to use a surface.
can anyone help?
You need to get the bounding rectangle of the rotated rectangle and set the center of the rectangle by (x, y) (see also How do I rotate an image around its center using PyGame?):
while True:
for event in pygame.event.get():
if event.type == QUIT:
pygame.quit()
sys.exit()
rotatedSail = pygame.transform.rotate(Sail, degrees)
rotatedSail_rect = rotatedSail.get_rect(center = (x, y))
DISPLAYSURF.fill(Blue)
DISPLAYSURF.blit(rotatedSail, rotatedSail_rect)
pygame.display.flip()
fpsClock.tick(FPS)
degrees += 1
To rotate the object around another point than the center point is much more complicate. A general solution is described in the answer to How can you rotate an image around an off center pivot in PyGame.
Complete Example:
import pygame, math, sys
from pygame.locals import *
Blue = (0,0,255)
Black = (0, 0, 0)
Green = (0,255,0)
White = (255,255,255)
pygame.init()
DISPLAYSURF = pygame.display.set_mode((400, 300))
pygame.display.set_caption('Sailing!')
FPS = 30
fpsClock = pygame.time.Clock()
Sail = pygame.Surface([100,10])
Sail.set_colorkey (Black)
Sail.fill(White)
degrees = 0
hyp = 100
x = 200
y = 150
def blitRotate(surf, image, pos, originPos, angle):
# calcaulate the axis aligned bounding box of the rotated image
w, h = image.get_size()
sin_a, cos_a = math.sin(math.radians(angle)), math.cos(math.radians(angle))
min_x, min_y = min([0, sin_a*h, cos_a*w, sin_a*h + cos_a*w]), max([0, sin_a*w, -cos_a*h, sin_a*w - cos_a*h])
# calculate the translation of the pivot
pivot = pygame.math.Vector2(originPos[0], -originPos[1])
pivot_rotate = pivot.rotate(angle)
pivot_move = pivot_rotate - pivot
# calculate the upper left origin of the rotated image
origin = (pos[0] - originPos[0] + min_x - pivot_move[0], pos[1] - originPos[1] - min_y + pivot_move[1])
# get a rotated image
rotated_image = pygame.transform.rotate(image, angle)
# rotate and blit the image
surf.blit(rotated_image, origin)
while True:
for event in pygame.event.get():
if event.type == QUIT:
pygame.quit()
sys.exit()
DISPLAYSURF.fill(Blue)
blitRotate(DISPLAYSURF, Sail, (x, y), (0, 5), degrees)
pygame.display.flip()
fpsClock.tick(FPS)
degrees += 1
I want to move the image of a Rect object, is this possible?
examples:
1 - make a waterfall with the water animated (make the water image scroll)
2 - adjust location of the image not the rect
note: these are just examples not the code I am working on
You can shift the surface image in place with pygame.Surface.scroll. For instance, call
water_surf.scroll(0, 1)
However, this will not satisfy you. See pygame.Surface.scroll:
Move the image by dx pixels right and dy pixels down. dx and dy may be negative for left and up scrolls respectively. Areas of the surface that are not overwritten retain their original pixel values.
You may want to write a function that overwrites the areas wich are not overwritten, with the pixel that is scrolled out of the surface:
def scroll_y(surf, dy):
scroll_surf = surf.copy()
scroll_surf.scroll(0, dy)
if dy > 0:
scroll_surf.blit(surf, (0, dy-surf.get_height()))
else:
scroll_surf.blit(surf, (0, surf.get_height()+dy))
return scroll_surf
once per frame to create a water flow effect like a waterfall.
To center an image in a rectangular area, you need to get the bounding rectangle of the image and set the center of the rectnagle through the center of the area. Use the rectangle to blit the image:
area_rect = pygame.Rect(x, y, w, h)
image_rect = surf.get_rect()
image_rect.center = area_rect.center
screen.blit(surf, image_rect)
The same in one line:
screen.blit(surf, surf.get_rect(center = area_rect.center))
Minimal example:
repl.it/#Rabbid76/PyGame-SCroll
import pygame
def scroll_y(surf, dy):
scroll_surf = surf.copy()
scroll_surf.scroll(0, dy)
if dy > 0:
scroll_surf.blit(surf, (0, dy-surf.get_height()))
else:
scroll_surf.blit(surf, (0, surf.get_height()+dy))
return scroll_surf
pygame.init()
window = pygame.display.set_mode((400, 400))
clock = pygame.time.Clock()
rain_surf = pygame.image.load('rain.png')
dy = 0
run = True
while run:
clock.tick(60)
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
window_center = window.get_rect().center
scroll_surf = scroll_y(rain_surf, dy)
dy = (dy + 1) % rain_surf.get_height()
window.fill(0)
window.blit(scroll_surf, scroll_surf.get_rect(center = window_center))
pygame.display.flip()
pygame.quit()
exit()
I have a display area and a surface that is blitted on the display. On the surface is an image, in this case a rect. In the future it may be multiple rects or lines drawn on the surface keep that in mind.
I am trying to enlarge (by pressing x) the Rect named Sprite that is on SpriteSurface and SpriteSurface as well as the whole display window. The SpriteSurface image should be centered despite the resize. Currently the window will enlarge and the image stays centered, but if you uncomment the spritesizeX and Y lines the image gets larger but too big too fast and the window doesn't seem to enlarge big enough. Lowering the values shows that the offset of centering gets thrown off after the first resize. I feel like the solution should be relatively easy but im stumped. Any help would be appreciated.
Settings.py
spriteSizeX = 30
spriteSizeY = 30
SpHalfX = int(round(spriteSizeX / 2))
SpHalfY = int(round(spriteSizeY / 2))
multiplyer = 3
windowSizeX = int(round(spriteSizeX * multiplyer))
windowSizeY = int(round(spriteSizeY * multiplyer))
HalfWinX = int(round((windowSizeX / 2) - SpHalfX))
HalfWinY = int(round((windowSizeY / 2) - SpHalfY))
Orange = (238,154,0)
Gold = (255,215,0)
Black = (0,0,0)
Blue = (0,0,255)
Gray = (128,128,128)
DarkGray = (100,100,100)
Green = (0,128,0)
Lime = (0,255,0)
Purple = (128,0,128)
Red = (255,0,0)
Teal = (0,200, 128)
Yellow = (255,255,0)
White = (255,255,255)
run = True
SpriteCapture.py
#!/usr/local/bin/python3.6
import sys, pygame
from pygame.locals import *
from settings import *
pygame.init()
pygame.display.set_caption("Sprite Capture")
Screen = pygame.display.set_mode((windowSizeX, windowSizeY),RESIZABLE)
SpriteSurface = pygame.Surface((spriteSizeX,spriteSizeY))
Sprite = Rect(0,0,spriteSizeX,spriteSizeY)
while run == True:
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
if pygame.key.get_pressed()[pygame.K_s]:
pygame.image.save(SpriteSurface, 'img1.png')
run = False
if pygame.key.get_pressed()[pygame.K_q]:
run = False
if pygame.key.get_pressed()[pygame.K_z]:
#spriteSizeX += 10
#spriteSizeY += 10
windowSizeX += -10
windowSizeY += -10
HalfWinX = int(round(windowSizeX / 2 - SpHalfX))
HalfWinY = int(round(windowSizeY / 2 - SpHalfY))
Screen = pygame.display.set_mode((windowSizeX, windowSizeY),RESIZABLE)
SpriteSurface = pygame.Surface((spriteSizeX,spriteSizeY))
if pygame.key.get_pressed()[pygame.K_x]:
#spriteSizeX += 10
#spriteSizeY += 10
windowSizeX += 10
windowSizeY += 10
HalfWinX = int(round(windowSizeX / 2 - SpHalfX))
HalfWinY = int(round(windowSizeY / 2 - SpHalfY))
Screen = pygame.display.set_mode((windowSizeX, windowSizeY),RESIZABLE)
SpriteSurface = pygame.Surface((spriteSizeX,spriteSizeY))
Sprite = Sprite = Rect(0,0,spriteSizeX,spriteSizeY)
Screen.fill(Black)
pygame.draw.rect(SpriteSurface,Orange,Sprite)
Screen.blit(SpriteSurface, (HalfWinX,HalfWinY))
pygame.display.flip()
If you want to scale your surfaces or rects according to the screen size, you can define a zoom_factor variable which you can just increase when a key gets pressed and then use it to scale the window and the surfaces. Multiply it by the original screen width and height to scale the window, and also scale your surfaces with pygame.transform.rotozoom and pass the zoom_factor as the scale argument.
import sys
import pygame
from pygame.locals import *
width = 30
height = 30
multiplyer = 3
window_width = round(width * multiplyer)
window_height = round(height * multiplyer)
zoom_factor = 1
ORANGE = (238,154,0)
BLACK = (0,0,0)
pygame.init()
screen = pygame.display.set_mode((window_width, window_height), RESIZABLE)
screen_rect = screen.get_rect() # A rect with the size of the screen.
clock = pygame.time.Clock()
# Keep a reference to the original image to preserve the quality.
ORIG_SURFACE = pygame.Surface((width, height))
ORIG_SURFACE.fill(ORANGE)
surface = ORIG_SURFACE
# Center the rect on the screen's center.
rect = surface.get_rect(center=screen_rect.center)
run = True
while run:
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_q:
run = False
elif event.key == pygame.K_z:
zoom_factor = round(zoom_factor-.1, 1)
# Scale the screen.
w, h = int(window_width*zoom_factor), int(window_height*zoom_factor)
screen = pygame.display.set_mode((w, h), RESIZABLE)
screen_rect = screen.get_rect() # Get a new rect.
# Scale the ORIG_SURFACE (the original won't be modified).
surface = pygame.transform.rotozoom(ORIG_SURFACE, 0, zoom_factor)
rect = surface.get_rect(center=screen_rect.center) # Get a new rect.
elif event.key == pygame.K_x:
zoom_factor = round(zoom_factor+.1, 1)
w, h = int(window_width*zoom_factor), int(window_height*zoom_factor)
screen = pygame.display.set_mode((w, h), RESIZABLE)
screen_rect = screen.get_rect()
surface = pygame.transform.rotozoom(ORIG_SURFACE, 0, zoom_factor)
rect = surface.get_rect(center=screen_rect.center)
# Note that the rect.w/screen_rect.w ratio is not perfectly constant.
print(zoom_factor, screen_rect.w, rect.w, rect.w/screen_rect.w)
screen.fill(BLACK)
screen.blit(surface, rect) # Blit the surface at the rect.topleft coords.
pygame.display.flip()
clock.tick(60)
Alternatively, you could just blit all of your surfaces onto a background surface, then scale this background with pygame.transform.rotozoom each frame and blit it onto the screen. However, scaling a big background surface each frame will be bad for the performance.
I want to add gradient to the ball in this program & also possibly the waves drawn to fade into the colour of the background (as if glowing) instead of one colour fills.
I've looked at tons of tutorials however none of them are making much sense to my syntax, the general idea to me is confusing as I have moving objects that draw the space I want to add gradient to quite slowly. Can anyone give an insight into how I can do this?
code:
import sys, pygame, math
from pygame.locals import *
# set up of constants
WHITE = (255, 255, 255)
DARKRED = (128, 0, 0)
RED = (255, 0, 0)
BLACK = ( 0, 0, 0)
GREEN = ( 0, 255, 0)
BLUE = ( 0, 0, 255)
BGCOLOR = WHITE
screen = pygame.display.set_mode()
WINDOWWIDTH = 800 # width of the program's window, in pixels
WINDOWHEIGHT = 800 # height in pixels
WIN_CENTERX = int(WINDOWWIDTH / 2) # the midpoint for the width of the window
WIN_CENTERY = int(WINDOWHEIGHT / 2) # the midpoint for the height of the window
screen = pygame.display.get_surface()
FPS = 160 # frames per second to run at
AMPLITUDE = 80 # how many pixels tall the waves with rise/fall.
# standard pygame setup code
pygame.init()
FPSCLOCK = pygame.time.Clock()
DISPLAYSURF = pygame.display.set_mode((WINDOWWIDTH, WINDOWHEIGHT), pygame.RESIZABLE)
pygame.display.set_caption('Window title')
fontObj = pygame.font.Font('freesansbold.ttf', 16)
# variables that track visibility modes
showSine = True
showSquare = True
pause = False
xPos = 0
step = 0 # the current input f
posRecord = {'sin': [], 'square': []} # keeps track of the ball positions for drawing the waves
yPosSquare = AMPLITUDE # starting position
# main application loop
while True:
# event handling loop for quit events
for event in pygame.event.get():
if event.type == QUIT or (event.type == KEYUP and event.key == K_ESCAPE):
pygame.quit()
sys.exit()
# fill the screen to draw from a blank state
DISPLAYSURF.fill(BGCOLOR)
# sine wave
yPos = -1 * math.sin(step) * AMPLITUDE
posRecord['sin'].append((int(xPos), int(yPos) + WIN_CENTERY))
if showSine:
# draw the sine ball and label
pygame.draw.circle(DISPLAYSURF, RED, (int(xPos), int(yPos) + WIN_CENTERY), 10)
sinLabelRect.center = (int(xPos), int(yPos) + WIN_CENTERY + 20)
DISPLAYSURF.blit(sinLabelSurf, sinLabelRect)
# draw the waves from the previously recorded ball positions
if showSine:
for x, y in posRecord['sin']:
pygame.draw.circle(DISPLAYSURF, DARKRED, (x,y), 4)
#drawing horizontal lines
# square
posRecord['square'].append((int(xPos), int(yPosSquare) + WIN_CENTERY))
if showSquare:
# draw the sine ball and label
pygame.draw.circle(DISPLAYSURF, GREEN, (int(xPos), int(yPosSquare) + WIN_CENTERY), 10)
squareLabelRect.center = (int(xPos), int(yPosSquare) + WIN_CENTERY + 20)
DISPLAYSURF.blit(squareLabelSurf, squareLabelRect)
# draw the waves from the previously recorded ball positions
if showSquare:
for x, y in posRecord['square']:
pygame.draw.circle(DISPLAYSURF, BLUE, (x, y), 4)
# draw the border
pygame.draw.rect(DISPLAYSURF, BLACK, (0, 0, WINDOWWIDTH, WINDOWHEIGHT), 1)
pygame.display.update()
FPSCLOCK.tick(FPS)
if not pause:
xPos += 1
#wave movement
if xPos > WINDOWWIDTH:
#sine
xPos = 0
posRecord['sin'] = []
step = 0
# square
yPosSquare = AMPLITUDE
posRecord['square'] = []
else:
#sine
step += 0.008
#step %= 2 * math.pi
# square
# jump top and bottom every 100 pixels
if xPos % 100 == 0:
yPosSquare *= -1
# add vertical line
for x in range(-AMPLITUDE, AMPLITUDE):
posRecord['square'].append((int(xPos), int(x) + WIN_CENTERY))
Use SPACE to change background color.
First line use only transparency - and has no problem with different background color.
Second line changes only circles color - and depends on background color.
Third and fourth line (it is the same line with different starting color) change circles color and transparency - and depends on background color.
Second and last line look good on one color background and need more work to find good-looking fading.
import pygame
pygame.init()
screen = pygame.display.set_mode((600,200))
#--------------------------------------
# circles positions and transparency (x,y, alpha)
circles = []
for x in range(100):
circles.append( [100+x*3, 200, x*2] )
#--------------------------------------
white = True # background color
#--------------------------------------
running = True
while running:
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_ESCAPE:
running = False
elif event.key == pygame.K_SPACE:
white = not white
#--------------------------------------
if white:
screen.fill((255,255,255))
else:
screen.fill((0,0,0))
#--------------------------------------
# first
circle_img = pygame.Surface((20,20))
pygame.draw.circle(circle_img, (255,0,0), (10,10), 10)
circle_img.set_colorkey(0)
for x in circles:
circle_img.set_alpha(x[2])
screen.blit(circle_img, (x[0],40))
#--------------------------------------
# second
circle_img = pygame.Surface((20,20))
for x in circles:
pygame.draw.circle(circle_img, (255,255-x[2],255-x[2]), (10,10), 10)
circle_img.set_colorkey(0)
screen.blit(circle_img, (x[0],90))
#--------------------------------------
# last
circle_img = pygame.Surface((20,20))
for x in circles:
pygame.draw.circle(circle_img, (255,255-x[2],255-x[2]), (10,10), 10)
circle_img.set_colorkey(0)
circle_img.set_alpha(x[2])
screen.blit(circle_img, (x[0],140))
#--------------------------------------
pygame.display.flip()
pygame.quit()