python PyGame 应用程序中的 SVG 渲染

SVG rendering in a PyGame application

提问by Pierre-Jean Coudert

In a pyGameapplication, I would like to render resolution-free GUI widgets described in SVG.

在pyGame应用程序中，我想渲染 SVG 中描述的无分辨率 GUI 小部件。

What tool and/or library can I use to reach this goal ?

我可以使用什么工具和/或库来达到这个目标？

(I like the OCEMP GUItoolkit but it seems to be bitmap dependent for its rendering)

（我喜欢OCEMP GUI工具包，但它的渲染似乎依赖于位图）

采纳答案by Johan Dahlin

This is a complete example which combines hints by other people here. It should render a file called test.svg from the current directory. It was tested on Ubuntu 10.10, python-cairo 1.8.8, python-pygame 1.9.1, python-rsvg 2.30.0.

这是一个完整的例子，它结合了其他人的提示。它应该从当前目录呈现一个名为 test.svg 的文件。它在 Ubuntu 10.10、python-cairo 1.8.8、python-pygame 1.9.1、python-rsvg 2.30.0 上进行了测试。

#!/usr/bin/python

import array
import math

import cairo
import pygame
import rsvg

WIDTH = 512
HEIGHT = 512

data = array.array('c', chr(0) * WIDTH * HEIGHT * 4)
surface = cairo.ImageSurface.create_for_data(
    data, cairo.FORMAT_ARGB32, WIDTH, HEIGHT, WIDTH * 4)

pygame.init()
window = pygame.display.set_mode((WIDTH, HEIGHT))
svg = rsvg.Handle(file="test.svg")
ctx = cairo.Context(surface)
svg.render_cairo(ctx)

screen = pygame.display.get_surface()
image = pygame.image.frombuffer(data.tostring(), (WIDTH, HEIGHT),"ARGB")
screen.blit(image, (0, 0)) 
pygame.display.flip() 

clock = pygame.time.Clock()
while True:
    clock.tick(15)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            raise SystemExit

回答by zgoda

The question is quite old but 10 years passed and there is new possibility that works and does not require librsvganymore. There is Cython wrapper over nanosvg libraryand it works:

这个问题已经很老了，但是 10 年过去了，有新的可能性可以工作并且不再需要librsvg。nanosvg 库上有Cython 包装器，它可以工作：

from svg import Parser, Rasterizer


def load_svg(filename, surface, position, size=None):
    if size is None:
        w = surface.get_width()
        h = surface.get_height()
    else:
        w, h = size
    svg = Parser.parse_file(filename)
    rast = Rasterizer()
    buff = rast.rasterize(svg, w, h)
    image = pygame.image.frombuffer(buff, (w, h), 'ARGB')
    surface.blit(image, position)

I found Cairo/rsvg solution too complicated to get to work because of dependencies are quite obscure to install.

我发现 Cairo/rsvg 解决方案太复杂而无法开始工作，因为安装依赖项非常模糊。

回答by Torsten Marek

You can use Cairo(with PyCairo), which has support for rendering SVGs. The PyGame webpage has a HOWTOfor rendering into a buffer with a Cairo, and using that buffer directly with PyGame.

您可以使用Cairo（使用 PyCairo），它支持渲染 SVG。PyGame 网页有一个HOWTO，用于使用 Cairo 渲染到缓冲区中，并直接在 PyGame 中使用该缓冲区。

回答by Alec Thomas

I realise this doesn't exactly answer your question, but there's a library called Squirtlethat will render SVG files using either Pyglet or PyOpenGL.

我意识到这并不能完全回答您的问题，但是有一个名为Squirtle的库可以使用 Pyglet 或 PyOpenGL 渲染 SVG 文件。

回答by Dickon Reed

pygamesvgseems to do what you want (though I haven't tried it).

pygamesvg似乎可以做你想做的事（虽然我还没有尝试过）。

回答by Pierre-Jean Coudert

Cairo cannot render SVG out of the box. It seems we have to use librsvg.

Cairo 无法立即渲染 SVG。看来我们必须使用 librsvg。

Just found those two pages:

刚找到那两页：

• Rendering SVG with libRSVG,Python and c-types
• How to use librsvg from Python

• 使用 libRSVG、Python 和 c-types 渲染 SVG
• 如何使用 Python 中的 librsvg

Something like this should probably work (render test.svgto test.png):

像这样的东西应该可以工作（将test.svg渲染到test.png）：

import cairo
import rsvg

WIDTH, HEIGHT  = 256, 256
surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, WIDTH, HEIGHT)

ctx = cairo.Context (surface)

svg = rsvg.Handle(file="test.svg")
svg.render_cairo(ctx)

surface.write_to_png("test.png")

回答by Dave

The last comment crashed when I ran it because svg.render_cairo() is expecting a cairo context and not a cairo surface. I created and tested the following function and it seems to run fine on my system.

最后一条评论在我运行时崩溃了，因为 svg.render_cairo() 期望的是 cairo 上下文而不是 cairo 表面。我创建并测试了以下函数，它似乎在我的系统上运行良好。

import array,cairo, pygame,rsvg

def loadsvg(filename,surface,position):
    WIDTH = surface.get_width()
    HEIGHT = surface.get_height()
    data = array.array('c', chr(0) * WIDTH * HEIGHT * 4)
    cairosurface = cairo.ImageSurface.create_for_data(data, cairo.FORMAT_ARGB32, WIDTH, HEIGHT, WIDTH * 4)
    svg = rsvg.Handle(filename)
    svg.render_cairo(cairo.Context(cairosurface))
    image = pygame.image.frombuffer(data.tostring(), (WIDTH, HEIGHT),"ARGB")
    surface.blit(image, position) 

WIDTH = 800
HEIGHT = 600
pygame.init()
window = pygame.display.set_mode((WIDTH, HEIGHT))
screen = pygame.display.get_surface()

loadsvg("test.svg",screen,(0,0))

pygame.display.flip() 

clock = pygame.time.Clock()
while True:
    clock.tick(15)
    event = pygame.event.get()
    for e in event:
        if e.type == 12:
            raise SystemExit

回答by goncalopp

Based on other answers, here's a function to read a SVG file into a pygame image - including correcting color channel order and scaling:

根据其他答案，这里有一个将 SVG 文件读入 pygame 图像的函数 - 包括校正颜色通道顺序和缩放：

def pygame_svg( svg_file, scale=1 ):
    svg = rsvg.Handle(file=svg_file)
    width, height= map(svg.get_property, ("width", "height"))
    width*=scale; height*=scale
    data = array.array('c', chr(0) * width * height * 4)
    surface = cairo.ImageSurface.create_for_data( data, cairo.FORMAT_ARGB32, width, height, width*4)
    ctx = cairo.Context(surface)
    ctx.scale(scale, scale)
    svg.render_cairo(ctx)

    #seemingly, cairo and pygame expect channels in a different order...
    #if colors/alpha are funny, mess with the next lines
    import numpy
    data= numpy.fromstring(data, dtype='uint8')
    data.shape= (height, width, 4)
    c= data.copy()
    data[::,::,0]=c[::,::,1]
    data[::,::,1]=c[::,::,0]
    data[::,::,2]=c[::,::,3]
    data[::,::,3]=c[::,::,2]

    image = pygame.image.frombuffer(data.tostring(), (width, height),"ARGB")
    return image