Prototyping/Download Sample Cut-up Share

Challenge: create an Inkscape extension to directly import images from the openclipart site.

(interpreter)? your_script (--param=value)* /path/to/input/SVGfile | inkscape

Inscape Effects: Hello World

To create/install an inkscape extension, you need to place it in the Inkscape extensions folder ($HOME/.config/inkscape/extensions/ or /usr/share/inkscape/extensions).

First thing you need is an "inx" file, an "inkscape-extension" XML file that describes your extension to Inkscape. This is pretty much the simplest form of an effect: NB The "submenu" item selects which Menu your effect will be presented under (in this case, we create a new menu called "Python"), and the "_name" element sets the name of the Effect itself.

helloworld.inx

<?xml version="1.0" encoding="UTF-8"?>
<inkscape-extension xmlns="http://www.inkscape.org/namespace/inkscape/extension">
	<_name>Hello World</_name>
	<id>pzi.helloworld</id>
	<dependency type="executable" location="extensions">helloworld.py</dependency>
    <effect>
        <object-type>all</object-type>
        <effects-menu>
            <submenu _name="Python"/>
        </effects-menu>
    </effect>
    <script>
    	<command reldir="extensions" interpreter="python">helloworld.py</command>
    </script>
</inkscape-extension>

Inkscape reads the inx files when it starts, so Inkscape needs to be restarted when an inx file is added or changed. Luckily, changes to the script do not require that Inkscape get restarted.

Now, for some code, a "Hello World", that does nothing (yet)...

helloworld.py

import sys, codecs
from lxml import etree

f = codecs.open(sys.argv[-1], encoding="utf-8")
doc = etree.parse(f)
sys.stdout.write(etree.tostring(doc, encoding="utf-8", xml_declaration=True))

helloworld.py (with log)

import sys, codecs
from lxml import etree

log = open("helloworld.log", "w")
log.write("argv: " + str(sys.argv))
log.close()

f = codecs.open(sys.argv[-1], encoding="utf-8")
doc = etree.parse(f)
sys.stdout.write(etree.tostring(doc, encoding="utf-8", xml_declaration=True))

import sys, codecs, argparse
from lxml import etree

parser = argparse.ArgumentParser(description="My first Inkscape effect")
parser.add_argument('--id', action="append", help="id(s) of selected elements")
parser.add_argument('path', help="path of svg file to open")

args = parser.parse_args()

f = codecs.open(args.path, encoding="utf-8")
doc = etree.parse(f)
sys.stdout.write(etree.tostring(doc, encoding="utf-8", xml_declaration=True))

Tools that will be useful: Python, lxml.etree, xpath

http://www.openclipart.org/docs/api

Get some feeds. NB wget's O option (and that's a CAPITAL O), allows to save to a reasonable filename of your choice.

wget http://www.openclipart.org/media/feed/rss/woman -O woman.xml
wget http://www.openclipart.org/media/feed/rss/man -O man.xml

Creating a simple HTML page from the feed

import codecs, sys, lxml.etree, urllib2

# Open Live URL
f = urllib2.urlopen("http://www.openclipart.org/media/feed/rss/woman")

# Open the filename given on the command line
# f = codecs.open(sys.argv[1], encoding="utf-8")

# Read in the XML file
doc = lxml.etree.parse(f)

# This is a Python dictionary containing
# the xml "namespaces" that we may use
NS = {
    'media': 'http://search.yahoo.com/mrss/',
    'dc': 'http://purl.org/dc/elements/1.1/',
    'cc': 'http://creativecommons.org/ns#',
    'atom': 'http://www.w3.org/2005/Atom',
}

# Loop over the item elements
for item in doc.xpath("//item"):
    # NB: the "." at the start of the xpaths
    # makes the query relative to the current (context)
    # ie the particular item (and not the whole document)

    svg = item.xpath(".//enclosure/@url")[0]
    thumbnail_url = item.xpath(".//media:thumbnail/@url", namespaces=NS)[0]
    creator = item.xpath(".//dc:creator/text()", namespaces=NS)[0]
    title = item.xpath(".//title/text()")[0]
    link = item.xpath(".//link/text()")[0]

    # Output some HTML
    print """<div>
<a href="{1}"><img src="{2}" />{0}</a>
</div>""".format(title, link, thumbnail_url)

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