Switch charts rendering to Pillow

Pillow (or PIL) is much lighter dependency than Cairo/Pango. Also it
turns out to be easier to use.

docs/config.rst

@@ -345,6 +345,13 @@ SITE_TITLE
 
 Site title to be used in website and emails as well.
 
+.. setting:: TTF_FONT
+
+TTF_FONT
+--------
+
+TrueType font to be used for widgets and charts.
+
 .. setting:: WHOOSH_INDEX
 
 WHOOSH_INDEX

docs/install.rst

@@ -22,6 +22,8 @@ Whoosh
     http://bitbucket.org/mchaput/whoosh/
 PyCairo
     http://cairographics.org/pycairo/
+PIL or Pillow library
+    http://python-imaging.github.io/
 PyGtk
     http://www.pygtk.org/
 south

requirements.txt

@@ -5,3 +5,4 @@ django-registration==0.8
 Whoosh>=2.3
 Translate-Toolkit>=1.10.0
 lxml>=3.1.0
+Pillow

trans/requirements.py

@@ -19,6 +19,8 @@
 #
 
 from distutils.version import LooseVersion
+import importlib
+
 
 
 def get_version_module(module, name, url, optional=False):
@@ -27,7 +29,7 @@ def get_version_module(module, name, url, optional=False):
     exception with name and URL.
     '''
     try:
-        mod = __import__(module)
+        mod = importlib.import_module(module)
     except ImportError:
         if optional:
             return None
@@ -173,6 +175,16 @@ def get_versions():
         '0.7',
     ))
 
+    name = 'Pillow (PIL)'
+    url = 'http://python-imaging.github.io/'
+    mod = get_version_module('PIL.Image', name, url)
+    result.append((
+        name,
+        url,
+        mod.VERSION,
+        '1.1.6',
+    ))
+
     return result
 
 

trans/views/charts.py

@@ -24,16 +24,14 @@ Charting library for Weblate.
 from trans.models import Change
 from lang.models import Language
 from trans.views.helper import get_project_translation
+from weblate import appsettings
 from django.shortcuts import render_to_response, get_object_or_404
 from django.template import RequestContext
 from django.http import HttpResponse
 from django.contrib.auth.models import User
 from cStringIO import StringIO
 from django.core.urlresolvers import reverse
-import cairo
-import pango
-import pangocairo
-import math
+from PIL import Image, ImageDraw, ImageFont
 
 
 def render_activity(activity):
@@ -45,48 +43,24 @@ def render_activity(activity):
     step = 780.0 / len(activity)
     width = step / 2
 
-    # Prepare cairo surface and context
-    surface = cairo.ImageSurface(cairo.FORMAT_RGB24, 800, 100)
-    ctx = cairo.Context(surface)
-
-    # Render background
-    ctx.set_source_rgb(1, 1, 1)
-    ctx.rectangle(0, 0, 800, 100)
-    ctx.fill()
+    # Prepare image
+    image = Image.new('RGB', (800, 100), 'white')
+    draw = ImageDraw.Draw(image)
 
     # Render axises
-    ctx.new_path()
-    ctx.set_line_width(1)
-    ctx.set_source_rgb(0, 0, 0)
-    ctx.move_to(15, 5)
-    ctx.line_to(15, 85)
-    ctx.line_to(795, 85)
-    ctx.stroke()
-
-    # Context for text rendering
-    pangocairo_context = pangocairo.CairoContext(ctx)
-    pangocairo_context.set_antialias(cairo.ANTIALIAS_SUBPIXEL)
-    font = pango.FontDescription('Sans 8')
-
-    # Rotate context for vertical text
-    ctx.rotate(-math.pi / 2)
-
-    # Create Y axis label
-    layout = pangocairo_context.create_layout()
-    layout.set_width(80)
-    layout.set_alignment(pango.ALIGN_RIGHT)
-    layout.set_font_description(font)
-    layout.set_text(str(maximum))
+    draw.line(((15, 5), (15, 85), (795, 85)), fill='black')
 
-    # Render Y axis label
-    ctx.move_to(-5, 0)
-    ctx.set_source_rgb(0, 0, 0)
-    pangocairo_context.update_layout(layout)
-    pangocairo_context.show_layout(layout)
+    # Load font
+    font = ImageFont.truetype(appsettings.TTF_FONT, 11)
 
-    # Rotate context back
-    ctx.rotate(math.pi / 2)
+    # Create Y axis label
+    y_label = str(maximum)
+    text = Image.new('L', font.getsize(y_label), 'white')
+    draw_txt = ImageDraw.Draw(text)
+    draw_txt.text((0, 0), y_label, font=font, fill='black')
+    text = text.transpose(Image.ROTATE_90)
 
+    image.paste(text, (2, 5))
     # Counter for rendering ticks
     last = -40
 
@@ -96,35 +70,31 @@ def render_activity(activity):
         current = offset * step
 
         # Render bar
-        ctx.new_path()
-        ctx.set_source_rgb(0, 67.0 / 255, 118.0 / 255)
-        ctx.rectangle(
-            20 + current,
-            84,
-            width,
-            - 1.0 - value[1] * 78.0 / maximum
+        draw.rectangle(
+            (
+                20 + current,
+                84,
+                20 + current + width,
+                84 - value[1] * 78.0 / maximum
+            ),
+            fill=(0, 67, 118)
         )
-        ctx.fill()
 
         # Skip axis labels if they are too frequent
         if current < last + 40:
             continue
         last = current
 
-        # Create text
-        layout = pangocairo_context.create_layout()
-        layout.set_font_description(font)
-        layout.set_text(value[0].strftime('%m/%d'))
-
-        # Render text
-        ctx.move_to(15 + current, 86)
-        ctx.set_source_rgb(0, 0, 0)
-        pangocairo_context.update_layout(layout)
-        pangocairo_context.show_layout(layout)
+        # X-Axis ticks
+        draw.text(
+            (15 + current, 86),
+            value[0].strftime('%m/%d'),
+            font=font, fill='black'
+        )
 
     # Render surface to PNG
     out = StringIO()
-    surface.write_to_png(out)
+    image.save(out, 'PNG')
 
     # Return response
     return HttpResponse(content_type='image/png', content=out.getvalue())

weblate/appsettings.py

@@ -139,3 +139,6 @@ PRE_COMMIT_SCRIPTS = get('PRE_COMMIT_SCRIPTS', ())
 SCRIPT_CHOICES = [
     (script, get_script_name(script)) for script in PRE_COMMIT_SCRIPTS
 ] + [('', '')]
+
+# Font for charts and widgets
+TTF_FONT = get('TTF_FONT', os.path.join(WEB_ROOT, 'ttf', 'DejaVuSans.ttf'))

weblate/ttf/LICENSE

+Fonts are (c) Bitstream (see below). DejaVu changes are in public domain.
+Glyphs imported from Arev fonts are (c) Tavmjong Bah (see below)
+
+Bitstream Vera Fonts Copyright
+------------------------------
+
+Copyright (c) 2003 by Bitstream, Inc. All Rights Reserved. Bitstream Vera is
+a trademark of Bitstream, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of the fonts accompanying this license ("Fonts") and associated
+documentation files (the "Font Software"), to reproduce and distribute the
+Font Software, including without limitation the rights to use, copy, merge,
+publish, distribute, and/or sell copies of the Font Software, and to permit
+persons to whom the Font Software is furnished to do so, subject to the
+following conditions:
+
+The above copyright and trademark notices and this permission notice shall
+be included in all copies of one or more of the Font Software typefaces.
+
+The Font Software may be modified, altered, or added to, and in particular
+the designs of glyphs or characters in the Fonts may be modified and
+additional glyphs or characters may be added to the Fonts, only if the fonts
+are renamed to names not containing either the words "Bitstream" or the word
+"Vera".
+
+This License becomes null and void to the extent applicable to Fonts or Font
+Software that has been modified and is distributed under the "Bitstream
+Vera" names.
+
+The Font Software may be sold as part of a larger software package but no
+copy of one or more of the Font Software typefaces may be sold by itself.
+
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF COPYRIGHT, PATENT,
+TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL BITSTREAM OR THE GNOME
+FOUNDATION BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, INCLUDING
+ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
+THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM OTHER DEALINGS IN THE
+FONT SOFTWARE.
+
+Except as contained in this notice, the names of Gnome, the Gnome
+Foundation, and Bitstream Inc., shall not be used in advertising or
+otherwise to promote the sale, use or other dealings in this Font Software
+without prior written authorization from the Gnome Foundation or Bitstream
+Inc., respectively. For further information, contact: fonts at gnome dot
+org. 
+
+Arev Fonts Copyright
+------------------------------
+
+Copyright (c) 2006 by Tavmjong Bah. All Rights Reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the fonts accompanying this license ("Fonts") and
+associated documentation files (the "Font Software"), to reproduce
+and distribute the modifications to the Bitstream Vera Font Software,
+including without limitation the rights to use, copy, merge, publish,
+distribute, and/or sell copies of the Font Software, and to permit
+persons to whom the Font Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright and trademark notices and this permission notice
+shall be included in all copies of one or more of the Font Software
+typefaces.
+
+The Font Software may be modified, altered, or added to, and in
+particular the designs of glyphs or characters in the Fonts may be
+modified and additional glyphs or characters may be added to the
+Fonts, only if the fonts are renamed to names not containing either
+the words "Tavmjong Bah" or the word "Arev".
+
+This License becomes null and void to the extent applicable to Fonts
+or Font Software that has been modified and is distributed under the 
+"Tavmjong Bah Arev" names.
+
+The Font Software may be sold as part of a larger software package but
+no copy of one or more of the Font Software typefaces may be sold by
+itself.
+
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL
+TAVMJONG BAH BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.
+
+Except as contained in this notice, the name of Tavmjong Bah shall not
+be used in advertising or otherwise to promote the sale, use or other
+dealings in this Font Software without prior written authorization
+from Tavmjong Bah. For further information, contact: tavmjong @ free
+. fr.
+
+$Id: LICENSE 2133 2007-11-28 02:46:28Z lechimp $