Pygame Button with rounded Corners, border_radius argument does not work

Question

I am currently learning pygame. When programming rectangles with rounded corners I encountered a problem.

pygame.draw.rect() draw a rectangle rect

Answer 1

I ran into this and had to do it myself already, I might as well share.

Try these, one draws rectangles with rounded corners and the other draws bordered rounded rectangles. They use anti-aliased circles to draw the corners because otherwise they look pretty jagged:

import pygame.gfxdraw

def draw_rounded_rect(surface, rect, color, corner_radius):
    ''' Draw a rectangle with rounded corners.
    Would prefer this: 
        pygame.draw.rect(surface, color, rect, border_radius=corner_radius)
    but this option is not yet supported in my version of pygame so do it ourselves.

    We use anti-aliased circles to make the corners smoother
    '''
    if rect.width < 2 * corner_radius or rect.height < 2 * corner_radius:
        raise ValueError(f"Both height (rect.height) and width (rect.width) must be > 2 * corner radius ({corner_radius})")

    # need to use anti aliasing circle drawing routines to smooth the corners
    pygame.gfxdraw.aacircle(surface, rect.left+corner_radius, rect.top+corner_radius, corner_radius, color)
    pygame.gfxdraw.aacircle(surface, rect.right-corner_radius-1, rect.top+corner_radius, corner_radius, color)
    pygame.gfxdraw.aacircle(surface, rect.left+corner_radius, rect.bottom-corner_radius-1, corner_radius, color)
    pygame.gfxdraw.aacircle(surface, rect.right-corner_radius-1, rect.bottom-corner_radius-1, corner_radius, color)

    pygame.gfxdraw.filled_circle(surface, rect.left+corner_radius, rect.top+corner_radius, corner_radius, color)
    pygame.gfxdraw.filled_circle(surface, rect.right-corner_radius-1, rect.top+corner_radius, corner_radius, color)
    pygame.gfxdraw.filled_circle(surface, rect.left+corner_radius, rect.bottom-corner_radius-1, corner_radius, color)
    pygame.gfxdraw.filled_circle(surface, rect.right-corner_radius-1, rect.bottom-corner_radius-1, corner_radius, color)

    rect_tmp = pygame.Rect(rect)

    rect_tmp.width -= 2 * corner_radius
    rect_tmp.center = rect.center
    pygame.draw.rect(surface, color, rect_tmp)

    rect_tmp.width = rect.width
    rect_tmp.height -= 2 * corner_radius
    rect_tmp.center = rect.center
    pygame.draw.rect(surface, color, rect_tmp)


def draw_bordered_rounded_rect(surface, rect, color, border_color, corner_radius, border_thickness):
    if corner_radius < 0:
        raise ValueError(f"border radius ({corner_radius}) must be >= 0")

    rect_tmp = pygame.Rect(rect)
    center = rect_tmp.center

    if border_thickness:
        if corner_radius <= 0:
            pygame.draw.rect(surface, border_color, rect_tmp)
        else:
            draw_rounded_rect(surface, rect_tmp, border_color, corner_radius)

        rect_tmp.inflate_ip(-2*border_thickness, -2*border_thickness)
        inner_radius = corner_radius - border_thickness + 1
    else:
        inner_radius = corner_radius

    if inner_radius <= 0:
        pygame.draw.rect(surface, color, rect_tmp)
    else:
        draw_rounded_rect(surface, rect_tmp, color, inner_radius)