Refactor svgtemplate into a neat context class SVGTemplate

renderlib.py

@@ -6,9 +6,8 @@ import re
 import glob
 import shutil
 import errno
-import logging
 import subprocess
-import svgtemplate
+from svgtemplate import SVGTemplate
 from lxml import etree
 from urllib.request import urlopen
 from wand.image import Image
@@ -18,10 +17,6 @@ fps = 25
 debug = True
 args = None
 
-cssutils.ser.prefs.lineSeparator = ' '
-cssutils.log.setLevel(logging.FATAL)
-
-
 def loadProject(projectname):
     sys.path.append(os.path.join(os.path.dirname(os.path.abspath(__file__)), projectname))
     return __import__(projectname)
@@ -131,10 +126,10 @@ def cachedRenderFrame(frame, frameNr, task, cache):
         elif not skip_rendering:
             cache[frame] = frameNr
 
-        svgstr = svgtemplate.open(task)
-        svgstr = svgtemplate.replacetext(svgstr, task)
-        svgstr = svgtemplate.transform(svgstr, frame, task)
-        svgfile = svgtemplate.write(svgstr, task)
+        with SVGTemplate(task) as svg:
+            svg.replacetext()
+            svg.transform(frame)
+            svgfile = svg.write()
 
         outfile = '{0}/.frames/{1:04d}.png'.format(task.workdir, frameNr)
         renderFrame(svgfile, task, outfile)
@@ -144,9 +139,9 @@ def cachedRenderFrame(frame, frameNr, task, cache):
 
 
 def rendertask_image(task):
-    svgstr = svgtemplate.open(task)
-    svgstr = svgtemplate.replacetext(svgstr, task)
-    svgfile = svgtemplate.write(svgstr, task)
+    with SVGTemplate(task) as svg:
+        svg.replacetext()
+        svgfile = svg.write()
     renderFrame(svgfile, task, task.outfile)
 
 def rendertask_video(task):

svgtemplate.py

@@ -1,22 +1,38 @@
 # vim: tabstop=4 shiftwidth=4 expandtab
 import builtins
 import cssutils
+import logging
 import os
 from lxml import etree
 from xml.sax.saxutils import escape as xmlescape
 
-def open(task):
-    with builtins.open(os.path.join(task.workdir, task.infile), 'r') as fp:
-        return fp.read()
+cssutils.ser.prefs.lineSeparator = ' '
+cssutils.log.setLevel(logging.FATAL)
 
-def replacetext(svgstr, task):
-    for key in task.parameters.keys():
-        svgstr = svgstr.replace(key, xmlescape(str(task.parameters[key])))
-    return svgstr
+class SVGTemplate:
+    def __init__(self, task):
+        self.task = task
 
-def transform(svgstr, frame, task):
+    def __enter__(self):
+        with builtins.open(os.path.join(self.task.workdir, self.task.infile), 'r') as fp:
+            self.svgstr = fp.read()
+        return self
+
+    def write(self):
+        # open the output-file (named ".gen.svg" in the workdir)
+        outfile = os.path.join(self.task.workdir, '.gen.svg')
+        with builtins.open(outfile, 'w') as fp:
+            # write the generated svg-text into the output-file
+            fp.write(self.svgstr)
+        return outfile
+
+    def replacetext(self):
+        for key in self.task.parameters.keys():
+            self.svgstr = self.svgstr.replace(key, xmlescape(str(self.task.parameters[key])))
+
+    def transform(self, frame):
         parser = etree.XMLParser(huge_tree=True)
-    svg = etree.fromstring(svgstr.encode('utf-8'), parser)
+        svg = etree.fromstring(self.svgstr.encode('utf-8'), parser)
         # apply the replace-pairs to the input text, by finding the specified xml-elements by their id and modify their css-parameter the correct value
         for replaceinfo in frame:
             (id, type, key, value) = replaceinfo
@@ -32,12 +48,7 @@ def transform(svgstr, frame, task):
         # if '$subtitle' in task.parameters and task.parameters['$subtitle'] == '':
         #   child = svg.findall(".//*[@id='subtitle']")[0]
         #   child.getparent().remove(child)
-    return etree.tostring(svg, encoding='unicode')
+        self.xmlstr = etree.tostring(svg, encoding='unicode')
 
-def write(svgstr, task):
-    # open the output-file (named ".gen.svg" in the workdir)
-    outfile = os.path.join(task.workdir, '.gen.svg')
-    with builtins.open(outfile, 'w') as fp:
-        # write the generated svg-text into the output-file
-        fp.write(svgstr)
-    return outfile
+    def __exit__(self, exception_type, exception_value, traceback):
+        pass