Support SVG in Sphinx Latex building (#220)

* [Doc] Try use image converter instead of svg2pdf which requires more dependencies

* [Doc] Add img converter to conf.py

* [Doc] Bug fix in importing imgconverter package

* [Doc] Try to fix the bug when importing python packages

* [Doc] bug fix

* [Doc] Try to use imgconverter rather than cairo

* [Doc] Add svg to latex config in sphinx configuration file

* [Doc] Try cairo svg converter

* [Doc] Correct bugs in compiling latexpdf

* [Doc] Use latest image in building readthedocs

* [Doc] Now use readthedocs docker image in building online documentation

* [Doc] Correct typo in readthedocs setting

* [Doc] Try to use inkscape converter as imgconverter converted SVG to black images

* [Doc] Try RSVG

.readthedocs.yml

@@ -5,6 +5,10 @@
 # Required configuration file version
 version: 2
 
+# Specify docker image for building the doc
+build:
+  image: latest
+
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
   builder: dirhtml
@@ -16,5 +20,6 @@ formats: all
 # Optionally set the version of Python and requirements required to build your docs
 python:
   version: 3.7
+  system_packages: true
   install:
     - requirements: docs/requirements.txt

docs/requirements.txt

@@ -11,7 +11,7 @@ sphinxcontrib-bibtex<2.0.0
 # Package required to embed youtube video
 sphinxcontrib-yt
 
-# Package required to convert svg for pdf builder
+# Package required to convert SVG for latex building
 sphinxcontrib-svg2pdfconverter
 
 #Work-around bug "AttributeError: 'Values' object has no attribute 'character_level_inline_markup'" with docutils 0.13.1

docs/source/conf.py

@@ -23,26 +23,12 @@ import sphinx_rtd_theme
 #html_theme = "sphinx_rtd_theme"
 #html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
-# Import sphinxcontrib.bibtex
-have_sphinxcontrib_bibtex = True
-try:
+# For bibtex support
 import sphinxcontrib.bibtex
-except ImportError:
-    have_sphinxcontrib_bibtex = False
-
-# Import sphinxcontrib.yt
-have_sphinxcontrib_youtube = True
-try:
+# For embedded youtube
 import sphinxcontrib.yt
-except ImportError:
-    have_sphinxcontrib_youtube = False
-
-# Import sphinxcontrib.svg2pdfconverter
-have_sphinxcontrib_svg2pdfconverter = True
-try:
-    import sphinxcontrib.svg2pdfconverter
-except ImportError:
-    have_sphinxcontrib_svg2pdfconverter = False
+# For converting SVG to PNG using rsvg
+import sphinxcontrib.rsvgconverter
 
 # -- Project information -----------------------------------------------------
 
@@ -72,6 +58,7 @@ extensions = [
     'sphinxcontrib.bibtex',
     'sphinx.ext.autosectionlabel',
     'sphinxcontrib.yt',
+    'sphinxcontrib.rsvgconverter',
 ]
 
 # Add any paths that contain templates here, relative to this directory.

docs/source/manual/arch_lang/circuit_model_examples.rst

@@ -1160,7 +1160,7 @@ Template
 
 .. option:: <wire_param model_type="<string>" R="<float>" C="<float>" num_level="<int>"/>
 
-  - ``model_type="pi|T"`` Specify the type of RC models for this wire segement. Currently, OpenFPGA supports the π-type and T-type multi-level RC models.
+  - ``model_type="pi|T"`` Specify the type of RC models for this wire segement. Currently, OpenFPGA supports the :math:`\pi`-type and T-type multi-level RC models.
   - ``R="<float>"`` Specify the total resistance of the wire
   - ``C="<float>"`` Specify the total capacitance of the wire.
   - ``num_level="<int>"`` Specify the number of levels of the RC wire model.
@@ -1193,7 +1193,7 @@ The code describing this wire is:
 
 This example shows
   - A routing track wire has 1 input and output 
-  - The routing wire will be modelled as a 1-level π-type RC wire model with a total resistance of :math:`103.84\Omega` and a total capacitance of :math:`13.89fF`
+  - The routing wire will be modelled as a 1-level :math:`\pi`-type RC wire model with a total resistance of :math:`103.84\Omega` and a total capacitance of :math:`13.89fF`
 
 I/O pads
 ~~~~~~~~