example to show how one can manage text blocks (->GUI building) in a convenient way

TextBlock_test.py

"""
how can we manage text blocks (->GUI building) in a convenient way?
This may be an answer. Contributors: .wkta-tom#7412 | S_P_Y#1331
"""
import pygame


def create_txtblock_surf(text, ft_obj, color=(0, 0, 0), bg_color=(255, 255, 255), alignment_f=0.0, debug=0):
    """
    goal = to produce a pygame surface
    append a pair (lbl, textRect) to render_list,one per line
    """
    render_list = list()
    mw = mh = -1
    toth = 0
    for line in text.split('\n'):
        text_lbl = ft_obj.render(line, True, color)
        w, h = text_lbl.get_size()
        if w > mw:
            mw = w
        if h > mh:
            mh = h
        toth += h
        render_list.append(text_lbl)

    # create surf, that represents txtblock
    surf = pygame.Surface((mw, toth))
    surf.fill(bg_color)

    # stack labels, to gen the txt block
    target_y = 0
    for lbl in render_list:
        curr_w = lbl.get_width()
        surf.blit(lbl, (alignment_f * (mw - curr_w), target_y))
        target_y += mh
    if debug:
        pygame.draw.rect(surf, 'red', ((0, 0), (mw - 1, toth - 1)), 1)
    return surf


class TextBlock(pygame.sprite.Sprite):
    ALIGN_LEFT, ALIGN_CENTER = 0, 1

    def __init__(self, ft_name, ft_size, text='', color=(0, 0, 0), bg_color=(255, 255, 255)):
        super().__init__()
        self.ft_obj = pygame.font.Font(ft_name, ft_size)
        self._color = color
        self._bg_color = bg_color
        self._align = self.ALIGN_CENTER
        self._debug = 0
        self.rect = None  # no position for now
        if '' == text:
            self._text = ''
            self.image = None
        else:
            self._text = text
            self._refresh_img()

    def _refresh_img(self):
        if self.rect:  # has a position
            prev_pos = self.rect.center
        else:
            prev_pos = None

        if self._align == self.ALIGN_CENTER:
            ts = create_txtblock_surf(self._text, self.ft_obj, self._color, self._bg_color, 0.5, self.debug)
        else:
            ts = create_txtblock_surf(self._text, self.ft_obj, self._color, self._bg_color, 0.0, self.debug)
        self.image = ts
        self.rect = self.image.get_rect()
        # restore previous position
        if prev_pos:
            self.rect.center = prev_pos

    @property
    def debug(self):
        return self._debug

    @debug.setter
    def debug(self, v):
        self._debug = 1 if v else 0
        self._refresh_img()

    @property
    def text_align(self):
        return self._align

    @text_align.setter
    def text_align(self, v):
        if v in (self.ALIGN_LEFT, self.ALIGN_CENTER):
            self._align = v
            self._refresh_img()
        else:
            raise ValueError

    @property
    def text(self):
        return self._text

    @text.setter
    def text(self, val):
        self._text = val
        self._refresh_img()

    def draw(self, scr):
        if self.image:
            pos = self.rect.topleft
            scr.blit(self.image, pos)


# - program body v -
pygame.init()
screen = pygame.display.set_mode((640, 480))
width, height = screen.get_size()

INIT_TXT = 'hello user this\nis\nsome\ndope\ntext'
ALT_TXT = 'i\nunderstand that\nyou watch the console'

block = TextBlock('pixel_font2.ttf', 32, INIT_TXT, (0, 0, 0))
block.rect.center = (width // 2, height // 2)  # lets center the text block

# - debug if needed, comment this line when you're done debugging
block.debug = 1

print('*~*~*\npress and hold the space bar ; press ENTER to change alignment')
ended = False

while not ended:
    for ev in pygame.event.get():
        if ev.type == pygame.QUIT:
            ended = True
        elif ev.type == pygame.KEYDOWN:
            if ev.key == pygame.K_RETURN:
                block.text_align = (block.text_align + 1) % 2  # switch text align
            elif ev.key == pygame.K_SPACE:
                block.text = ALT_TXT
        elif ev.type == pygame.KEYUP:
            if not pygame.key.get_pressed()[pygame.K_SPACE]:
                block.text = INIT_TXT
    screen.fill('white')
    block.draw(screen)
    pygame.display.update()
pygame.quit()
# - program body ^ -