带有圆角的 Pygame 按钮，border_radius 参数不起作用

Question

我目前正在学习 pygame。在编写圆角矩形时遇到了问题。

pygame.draw.rect() 画一个矩形 矩形（表面，颜色，矩形）-> 矩形 矩形（表面，颜色，矩形，宽度=0，border_radius=0，border_radius=-1，border_top_left_radius=-1，border_top_right_radius=-1，border_bottom_left_radius=-1）-> Rect 在给定的表面上绘制一个矩形。

border_radius (int) -- （可选）用于绘制圆角矩形。支持的范围是 [0, min(height, width) / 2]，其中 0 表示没有圆角的矩形。

这是pygame官方文档的描述。

username_rect = pg.rect.Rect(screenwidth/2 - 1/8*screenwidth, screenheight*1/5, 1/4*screenwidth, username_title_render.get_height() + 10)
pg.draw.rect(screen, (0,0,0), username_rect,border_radius = 15)

这里是主要部分。但随后我收到此错误消息：

TypeError: 'border_radius' is an invalid keyword argument for this function

我已经尝试添加“width=2”参数，但它说参数太多。不幸的是，取其他数字也无济于事。 我目前正在使用 pygame 版本 2.0.0.dev6 (SDL 2.0.10, python 3.8.1)

如果你能帮助我，我会很高兴，提前非常感谢！

Answer 1

该文档适用于 2.0.0.dev7，根据this PR，border_radius 是在 2.0.0.dev6、GitHub reference 发布后添加的。因此，您正在尝试使用尚未出现的东西。您可以尝试从源代码构建并使用关键字（尽管稳定性不是承诺）。或者你可以尝试使用矩形和圆形的组合来达到效果。

Answer 2

我遇到了这个，必须自己做，我不妨分享一下。

试试这些，一个绘制圆角矩形，另一个绘制带边框的圆角矩形。他们使用抗锯齿圆来绘制角，否则它们看起来很锯齿：

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)