WIP: Upgrade to Python3, change dependencies

Due to old pangocairo bindings seemingly not being updated anymore
I resorted to using cffi-based bindings for now.
Current problems with pango and pangocairo bindings is that they are
incomplete, and it seems like outside HTML parsing there are some broken
things about font rendering, which I need to deal with. I might look
into rebuilding this functionality using something else, maybe Pillow.

Health check was disabled for now so I can focus on image rendering.

render.py

@@ -1,15 +1,14 @@
-import json
+
 import math
 import os
-import StringIO
+import io
 import subprocess
-import tempfile
 import time
 
-import cairo
+import cairocffi as cairo
 import flask
-import pango
-import pangocairo
+import pangocffi as pango
+import pangocairocffi as pangocairo
 
 class App(flask.Flask):
     def __init__(self, *args, **kwargs):
@@ -50,26 +49,27 @@ class Renderer(object):
         if y != -1:
             self.context.translate(x, y)
 
-        pangocairo_context = pangocairo.CairoContext(self.context)
-        pangocairo_context.set_antialias(cairo.ANTIALIAS_SUBPIXEL)
-        layout = pangocairo_context.create_layout()
-        layout.set_width(self.width*pango.SCALE)
-        layout.set_alignment(pango.ALIGN_CENTER)
+        self.context.set_antialias(cairo.ANTIALIAS_SUBPIXEL)
+        layout = pangocairo.create_layout(self.context)
+        layout.width = pango.units_from_double(self.width)
+        layout.alignment = pango.Alignment.CENTER
 
         if html:
             # Absolutely horrifying hack to fix broken text wrapping
-            layout.set_markup('<span font_desc="%s">%s</span>' % (fontname, text))
+            layout.apply_markup('<span font_desc="%s">%s</span>' % (fontname, text))
         else:
-            font = pango.FontDescription(fontname)
-            layout.set_font_description(font)
-            layout.set_text(text)
+            font = pango.FontDescription()
+            font.family = "Sans"
+            font.size = 65
+            layout.font_description = font
+            layout.text = text
 
         if y == -1:
-            self.context.translate(0, (self.height - layout.get_size()[1]/pango.SCALE)/2)
+            self.context.translate(0, (self.height - pango.units_to_double(layout.get_size()[1]))/2)
 
         self.context.set_source_rgb(0, 0, 0)
-        pangocairo_context.update_layout(layout)
-        pangocairo_context.show_layout(layout)
+        pangocairo.update_layout(self.context, layout)
+        pangocairo.show_layout(self.context, layout)
 
         self.context.restore()
 
@@ -99,10 +99,12 @@ def healthcheck():
                 return False, line
         mark = False
 
-@app.route('/health')
-def health():
-    ok, details = healthcheck()
-    return json.dumps({'ok': ok, 'details': details})
+# TODO: Uncomment and fix this
+
+# @app.route('/health')
+# def health():
+#     ok, details = healthcheck()
+#     return json.dumps({'ok': ok, 'details': details})
 
 @app.route('/stuff/preview/<int:size>/')
 def stuff_preview(size):
@@ -111,7 +113,7 @@ def stuff_preview(size):
     r = Renderer()
     r.render_text(text, 'Sans {}'.format(size), 0, -1, html)
 
-    sio = StringIO.StringIO()
+    sio = io.BytesIO()
     r.surface.write_to_png(sio)
     sio.seek(0)
     return flask.send_file(sio, mimetype='image/png')
@@ -122,7 +124,7 @@ def stuff_print(size):
     if not healthcheck()[0]:
         return 'Printer is down.'
     last = app.last
-    print last, time.time() - last
+    print(last, time.time() - last)
     if time.time() - last < DELAY:
         return 'Please wait {} more seconds before next print.'.format(int(DELAY - (time.time() - last)))
     text = flask.request.args.get('text')