Re: [pygame] hoe to create the RoundRect ?

["Alistair Buxton" <a.j.buxton@xxxxxxxxx>]

Here is another way to do it. This method using clipping to draw the
rounded rectangle in six drawing operations: left and right sides (1
rect), top and bottom sides (1 rect), then each corner (4 ellipses.)
It can draw unfilled round rects without trashing the background, and
it's arguments are very similar to those of rect and ellipse, with
just 2 extra parameters: xr and yr, which are the radius of the corner
ellipses in x and y respectively. It should respect the current clip
region if there is one, and restore it afterwards - but I have not
tested this.

-- 
Alistair Buxton
a.j.buxton@xxxxxxxxx

import pygame
from pygame.locals import *
import sys, os
if sys.platform == 'win32' or sys.platform == 'win64':
    os.environ['SDL_VIDEO_CENTERED'] = '1'
pygame.init()

Screen = (800,600)

icon = pygame.Surface((1,1)); icon.set_alpha(0); pygame.display.set_icon(icon)
pygame.display.set_caption("Rounded Rectangle Demo - Ian Mallett - 2008")
surface = pygame.display.set_mode(Screen)

def GetInput():
    key = pygame.key.get_pressed()
    for event in pygame.event.get():
        if event.type == QUIT or key[K_ESCAPE]:
            pygame.quit(); sys.exit()

def DrawRoundRect(surface, color, rect, width, xr, yr):
    clip = surface.get_clip()
    
    # left and right
    surface.set_clip(clip.clip(rect.inflate(0, -yr*2)))
    pygame.draw.rect(surface, color, rect.inflate(1-width,0), width)

    # top and bottom
    surface.set_clip(clip.clip(rect.inflate(-xr*2, 0)))
    pygame.draw.rect(surface, color, rect.inflate(0,1-width), width)

    # top left corner
    surface.set_clip(clip.clip(rect.left, rect.top, xr, yr))
    pygame.draw.ellipse(surface, color, pygame.Rect(rect.left, rect.top, 2*xr, 2*yr), width)

    # top right corner
    surface.set_clip(clip.clip(rect.right-xr, rect.top, xr, yr))
    pygame.draw.ellipse(surface, color, pygame.Rect(rect.right-2*xr, rect.top, 2*xr, 2*yr), width)

    # bottom left
    surface.set_clip(clip.clip(rect.left, rect.bottom-yr, xr, yr))
    pygame.draw.ellipse(surface, color, pygame.Rect(rect.left, rect.bottom-2*yr, 2*xr, 2*yr), width)

    # bottom right
    surface.set_clip(clip.clip(rect.right-xr, rect.bottom-yr, xr, yr))
    pygame.draw.ellipse(surface, color, pygame.Rect(rect.right-2*xr, rect.bottom-2*yr, 2*xr, 2*yr), width)

    surface.set_clip(clip)

def main():
    while True:
        GetInput()
        surface.fill((0,0,0))
        DrawRoundRect(surface, (255,0,0), pygame.Rect(100, 100, 200, 200), 0, 32, 32)
        DrawRoundRect(surface, (0,255,0), pygame.Rect(100, 100, 200, 200), 1, 32, 32)

        DrawRoundRect(surface, (0,0,255), pygame.Rect(450,100,250,300), 2, 32, 32)

        DrawRoundRect(surface, (0,0,255), pygame.Rect(150,350,200,200), 0, 32, 32)
        DrawRoundRect(surface, (0,255,0), pygame.Rect(150,350,200,200), 16, 32, 32)

        DrawRoundRect(surface, (0,255,0), pygame.Rect(400,450,350,64), 3, 32, 32)
        pygame.display.flip()

if __name__ == '__main__': main()