Server-side SVG to PNG (or some other image format) in python

Question

Currently I'm using rsvg to load the svg (from a string, not from a file) and drawing to cairo. Anyone know a better way? I use PIL elsewhere in my application, but I don't know of a way to do this with PIL.

Answer 1

I have inkscape installed so I am just farming out the process to the inkscape command with inkscape -f file.svg -e file.png

Using this code:

import subprocess
inkscape_dir=r"C:\Program Files (x86)\Inkscape"
assert os.path.isdir(inkscape_dir)
os.chdir(inkscape_dir)
subprocess.Popen(['inkscape.exe',"-f",fname,"-e",fname_png])

I am on windows 7, and got the Windows 5 Error [Access Denied] (or something like that) until I switched to the inkscape directory

Answer 2

Here's what I currently have:

import cairo
import rsvg

def convert(data, ofile, maxwidth=0, maxheight=0):

    svg = rsvg.Handle(data=data)

    x = width = svg.props.width
    y = height = svg.props.height
    print "actual dims are " + str((width, height))
    print "converting to " + str((maxwidth, maxheight))

    yscale = xscale = 1

    if (maxheight != 0 and width > maxwidth) or (maxheight != 0 and height > maxheight):
        x = maxwidth
        y = float(maxwidth)/float(width) * height
        print "first resize: " + str((x, y))
        if y > maxheight:
            y = maxheight
            x = float(maxheight)/float(height) * width
            print "second resize: " + str((x, y))
        xscale = float(x)/svg.props.width
        yscale = float(y)/svg.props.height

    surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, x, y)
    context = cairo.Context(surface)
    context.scale(xscale, yscale)
    svg.render_cairo(context)
    surface.write_to_png(ofile)

Answer 3

How about imagemagic? - http://www.imagemagick.org/script/magick-vector-graphics.php It can read/write from/to stdin/stdout so You can integrate it with your app even if You don't want to use files

Answer 4

You can also use PhantomJS for this (see http://phantomjs.org/screen-capture.html)

From a shell:

phantomjs rasterize.js http://ariya.github.com/svg/tiger.svg tiger.png

Or from python using selenium:

from selenium import webdriver  
driver = webdriver.PhantomJS()
driver.set_window_size(1024, 768) 
driver.get('http://ariya.github.com/svg/tiger.svg')
driver.save_screenshot('tiger.png')