在pygame中透明表面上渲染消除锯齿的文本

Question

我正在创建一个函数，它将一个字符串a分解为一行并返回一个表面，每一行都呈现在前一行之下。

例如：

Line1\nLine 2

渲染成：

Line1
Line2

无论如何，我的问题是我无法将正确透明的表面返回给调用函数。我尝试过使用颜色键，但它不适用于消除锯齿的文本。有没有办法可以做到这一点？谢谢你的回答。

我的代码:(目前在文字周围留下一个丑陋的紫色阴影）

def render_message(messages):
    surfaces = []
    height = 0
    max_width = 0

    for message in messages.split('\n'):
        surf = FONT.render(message, True, (0, 0, 0))
        surfaces.append(surf)
        height += surf.get_height() + 5
        if surf.get_width() > max_width:
            max_width = surf.get_width()

    result = pygame.Surface((max_width, height))
    result.fill((255, 0, 255))
    result.set_colorkey((255, 0, 255))

    top = 0
    for surface in surfaces:
        result.blit(surface, (max_width/2-surface.get_width()/2, top))
        top += surface.get_height() + 5

    return result

Answer 1

搞定了。主要不是我发现的是：没有AA =自动透明。使用AA，您还需要设置颜色键

这是一个工作示例，它切换BG以确保它是透明的。

import pygame
from pygame import Surface
#from pygame.locals import Rect, Color
from pygame.locals import *

class TextWall():
    def __init__(self, font=None, size=300):
        # for simplicity uses one font, one size for now.
        # You also can make font size, .text, etc be properties so they *automatically* toggle dirty bool.
        self.font_name = font
        self.font_size = size
        self.color_fg = Color("white")
        self.color_bg = Color("gray20")
        self.aa = True 
        self.text = "hi world"

        self.dirty = True
        self.font = pygame.font.Font(font, size)
        self.screen = pygame.display.get_surface()


    def _render(self):
        # re-render
        """no AA = automatic transparent. With AA you need to set the color key too"""
        self.dirty = False        
        self.text1 = self.font.render(self.text, self.aa, self.color_fg)            
        self.rect1 = self.text1.get_rect()

    def draw(self):
        # blits use cached surface, until text change makes it dirty
        if self.dirty or self.text1 is None: self._render()
        self.screen.blit(self.text1, self.rect1)

    def text(self, text):
        self.dirty = True
        self.text_message = text # parse

class Game():
    done = False
    def __init__(self):
        pygame.init()
        self.screen = pygame.display.set_mode ((640,480))
        self.text = Surface([200,100])

        self.text_wall = TextWall()
        self.toggle_bg = True
    def loop(self):
        while not self.done:
            self.handle_events()
            self.draw()

    def draw(self):
        if self.toggle_bg: bg = Color("darkred")
        else: bg = Color("gray20")

        self.screen.fill(bg)        
        self.text_wall.draw()        
        pygame.display.update()

    def handle_events(self):
        for event in pygame.event.get():
            if event.type == pygame.QUIT: self.done = True

            elif event.type == KEYDOWN:
                if event.key == K_ESCAPE: self.done = True                
                elif event.key == K_SPACE: self.toggle_bg = not self.toggle_bg
                elif event.key == K_a: 
                    self.text_wall.aa = not self.text_wall.aa
                    self.text_wall.dirty = True


if __name__ == "__main__":
    g = Game()
    g.loop()

编辑：改进代码，使用alpha通道而不是set_colorkey。

Answer 2

发布了第二个答案，因为这个问题比较复杂，人们可能希望同时看到这两个答案。

• 1，2减少/增加字体大小
• space切换BG

我把文字包好了。修改parse_text()以创建所需的文字列表。

import pygame
from pygame import Surface
from pygame.locals import *
# Todo: remove font object from TextLine() , to TextWall(). Then share a list of font's with any line.

"""Example of multi-line text class, with alpha transparency."""
lorem = """Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed aliquet
tellus eros, eu faucibus dui. Phasellus eleifend, massa id ornare sodales, est urna
congue tellus, vitae varius metus nunc non enim. Mauris elementum, arcu vitae tempor euismod, justo turpis malesuada est, sed dictum nunc nulla nec mauris. Cras felis eros, elementum vitae sollicitudin in, elementum et augue. Proin eget nunc at dui congue pretium. Donec ut ipsum ut lacus mollis tristique. In pretium varius dui eu dictum.

Proin pulvinar metus nec mi semper semper. Pellentesque habitant morbi tristique
senectus et netus et malesuada fames ac turpis egestas. Proin in diam odio. Vestibulum
at neque sed ante sodales eleifend quis id dui. Mauris sollicitudin, metus a semper consectetur,
est lectus varius erat, sit amet ultrices tortor nisi id justo. Aliquam elementum vestibulum dui ut auctor. Mauris commodo sapien vitae augue tempus sagittis. Morbi a nibh lectus, sed porta nibh. Donec et est ac dui sodales aliquet tristique et arcu. Nullam enim felis, posuere vel rutrum eu, euismod a purus. Morbi porta cursus libero, id rutrum elit lacinia vitae.

In condimentum ultrices ipsum, ut convallis odio egestas et. Cras at egestas elit. Morbi
quis neque ligula. Sed tempor, sem at fringilla rhoncus, diam quam mollis nisi, vitae semper
mi massa sit amet tellus. Vivamus congue commodo ornare. Morbi et mi non sem malesuada rutrum. Etiam est purus, interdum ut placerat sit amet, tempus eget eros. Duis eget augue quis diam facilisis blandit. Ut vulputate adipiscing eleifend. """

class TextLine(object):
    # Manages drawing and caching a single line of text
    # You can make font size, .color_fg etc be properties so they *automatically* toggle dirty bool.
    def __init__(self, font=None, size=16, text="hi world"):        
        self.font_name = font
        self.font_size = size
        self.color_fg = Color("white")
        self.color_bg = Color("gray20")

        self._aa = True 
        self._text = text                
        self.font = pygame.font.Font(font, size)
        self.screen = pygame.display.get_surface()

        self.dirty = True
        self.image = None
        self._render()

    def _render(self):
        # render for cache
        """no AA = automatic transparent. With AA you need to set the color key too"""
        self.dirty = False        
        self.image = self.font.render(self._text, self.aa, self.color_fg)            
        self.rect = self.image.get_rect()

    def draw(self):
        # Call this do draw, always prefers to use cache
        if self.dirty or (self.image is None): self._render()
        self.screen.blit(self.image, self.rect)        

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

    @text.setter
    def text(self, text):
        self.dirty = True
        self._text = text

    @property
    def aa(self): return self._aa

    @aa.setter
    def aa(self, aa):
        self.dirty = True
        self._aa = aa

class TextWall(object):
    # Manages multiple lines of text / paragraphs.
    def __init__(self, font=None, size=16):
        self.font = font
        self.font_size = size        
        self.offset = Rect(20,20,1,1) # offset of whole wall

        self.screen = pygame.display.get_surface()
        self.dirty = True
        self.text_lines = []
        self._text_paragraph = "Empty\nText"
        self._render()

    def _render(self):
        # render list 
        self.dirty = False
        self.text_lines = [ TextLine(self.font, self.font_size, line) for line in self._text_paragraph ]        

        # offset whole paragraph
        self.text_lines[0].rect.top = self.offset.top

        # offset the height of each line
        prev = Rect(0,0,0,0)        
        for t in self.text_lines:
            t.rect.top += prev.bottom
            t.rect.left = self.offset.left
            prev = t.rect

    def parse_text(self, text):
        # parse raw text to something usable
        self._text_paragraph = text.split("\n")
        self._render()

    def draw(self):
        # draw with cached surfaces    
        if self.dirty: self._render()
        for text in self.text_lines: text.draw()

    @property
    def font_size(self):
        return self._font_size

    @font_size.setter
    def font_size(self, size):
        self.dirty = True
        self._font_size = size

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

    @text.setter
    def text(self, text_paragraph):
        self.dirty = True
        self.parse_text(text_paragraph)

class Game():
    done = False
    def __init__(self):
        pygame.init()
        self.screen = pygame.display.set_mode ((640,480))
        self.text = Surface([200,100])

        self.text_wall = TextWall()
        self.toggle_bg = True

        self.text_wall.parse_text(lorem)

    def loop(self):
        while not self.done:
            self.handle_events()
            self.draw()

    def draw(self):
        if self.toggle_bg: bg = Color("gray60")
        else: bg = Color("gray20")

        self.screen.fill(bg)        
        self.text_wall.draw()        
        pygame.display.update()

    def handle_events(self):
        for event in pygame.event.get():
            if event.type == pygame.QUIT: self.done = True

            elif event.type == KEYDOWN:
                if event.key == K_ESCAPE: self.done = True                
                elif event.key == K_SPACE: self.toggle_bg = not self.toggle_bg
                elif event.key == K_1: self.text_wall.font_size -= 3
                elif event.key == K_2: self.text_wall.font_size += 3

if __name__ == "__main__":
    g = Game()
    g.loop()

Answer 3

最好的解决方案是不使用颜色键，而是使用 Alpha 通道。而不是这样：

result = pygame.Surface((max_width, height))
result.fill((255, 0, 255))
result.set_colorkey((255, 0, 255))

试试这个：

result = pygame.Surface((max_width, height), pygame.SRCALPHA)