Re: [pygame] Tiling a Rotated Bitmap

[Kamilche <kamilche@xxxxxxxxxxxx>]

Pete Shinners wrote:
> I would expect you could do this. You'll need to rotate the surface, and 
>  then blit it back onto itself 8 times with offsets. The offsets will be 
> the rotated corners of the original image rect.

Yeah, it didn't work. It seems like it should, but run the following 
code (your code worked up into a program), and wave the mouse back and 
forth to change the angle.

Odd, huh? It's a tricky bit, apparently. The only hits I found on the 
internet were for software patents I didn't understand.

--Kamilche


import pygame
import math

filename=r"C:\Documents and Settings\Administrator\Desktop\batik.jpg"

SCREENWIDTH = 640
SCREENHEIGHT = 480

def Rotated(surf, degrees = 0):
    # rotate surface
    print 'Rotated ', degrees, ' degrees.'
    rotsurf = pygame.transform.rotate(surf, degrees)

    # compute the offsets needed
    c = math.cos(math.radians(degrees))
    s = math.sin(math.radians(degrees))
    widthx = (surf.get_width() - 1) * c
    widthy = (surf.get_width() - 1) * s
    heightx = (surf.get_height() - 1) * s
    heighty = (surf.get_height() - 1) * c

    # the 8 positions, corners first
    positions = [
        (widthx + heightx, widthy + heighty),
        (widthx - heightx, widthy - heighty),
        (-widthx + heightx, -widthy + heighty),
        (-widthx - heightx, -widthy - heighty),
        (widthx, widthy),
        (-widthx, -widthy),
        (heightx, heighty),
        (-heightx, -heighty),
    ]

    # apply the blits
    for pos in positions:
        rotsurf.blit(rotsurf, pos)
    return rotsurf

def main():
    pygame.init()
    bg = pygame.display.set_mode((SCREENWIDTH, SCREENHEIGHT), 0, 32)

    quit = 0
    pic = pygame.image.load(filename).convert_alpha()
    pic2 = pic
    while not quit:
        bg.fill((255, 0, 0, 255))
        bg.blit(pic2, (0, 0))
        pygame.display.flip()
        for e in pygame.event.get():
            if e.type == pygame.QUIT:
                quit = 1
                break
            elif e.type == pygame.MOUSEMOTION:
                pic2 = Rotated(pic, e.pos[0])

    pygame.quit()

main()