删除文本时如何在pygame中缩小文本框？答案

【问题标题】：how to shrink a textbox in pygame when you delete text?删除文本时如何在pygame中缩小文本框？
【发布时间】：2020-10-13 23:59:33
【问题描述】：

当用户输入或删除文本时，我希望矩形根据输入的文本量缩小和增长。这个过程工作得很好，除了一个小错误。当您删除文本时，会形成一个空矩形来代替已删除的字母。我该如何解决这个问题？

from pygame import *

init()
screen = display.set_mode((800, 600))

name_font = font.Font(None, 32)
name_text = ''

class Rectangle:

    def __init__(self, x, y):
        self.active = False
        self.x = x
        self.y = y
        self.text_surface = name_font.render(name_text, True, (255, 255, 255))
        self.rect_width = max(140, 10 + self.text_surface.get_width())
        self.input_rect = Rect(x, y, self.rect_width, 32)
        self.input_rect.w = self.text_surface.get_width() + 10
        self.click_value = 10


    def naming(self, events):
        global rect_1
        global name_text

        for e in events:
            if e.type == MOUSEBUTTONDOWN:
                if self.input_rect.x + self.click_value >= mx >= self.input_rect.x - 10 and self.input_rect.y + 26 >= my >= self.input_rect.y - 10:
                    self.active = True
                else:
                    self.active = False

            if e.type == KEYDOWN:
                if self.active:
                    if e.key == K_BACKSPACE:
                        name_text = name_text[:-1]
                        screen.fill((0, 0, 0))
                    else:
                        name_text += e.unicode
                        self.click_value += 7

                    self.text_surface = name_font.render(name_text, True, (255, 255, 255))

    def draw(self, screen):
        draw.rect(screen, (0, 0, 0), self.input_rect, 0)
        draw.rect(screen, (255, 255, 255), self.input_rect, 2)
        self.input_rect.w = self.text_surface.get_width() + 10
        screen.blit(self.text_surface, (self.input_rect.x + 5, self.input_rect.y + 5))


rect_1 = Rectangle(200, 200)

while True:
    mx, my = mouse.get_pos()
    events = event.get()
    for e in events:
        if e.type == QUIT:
            quit()

    rect_1.naming(events)
    rect_1.draw(screen)
    display.update()
    time.delay(1)

【问题讨论】：

标签： python text pygame draw

【解决方案1】：

你必须在绘制之前计算输入矩形的宽度：

class Rectangle:
    # [...]

    def draw(self, screen):
        self.input_rect.w = self.text_surface.get_width() + 10
        draw.rect(screen, (0, 0, 0), self.input_rect, 0)
        draw.rect(screen, (255, 255, 255), self.input_rect, 2)
        screen.blit(self.text_surface, (self.input_rect.x + 5, self.input_rect.y + 5))

但是，如果您要每帧清除屏幕，则错误的顺序并不重要。该错误几乎不会引起注意，因为它仅对单个帧可见。每帧清屏，K_BACKSPACE情况下不清屏：

while True:
    mx, my = mouse.get_pos()
    events = event.get()
    for e in events:
        if e.type == QUIT:
            quit()

    rect_1.naming(events)

    screen.fill((0, 0, 0)) # <---
    rect_1.draw(screen)
    display.update()
    time.delay(1)

【讨论】：