support drawio

Author: chrisfenner

Dockerfile

@@ -196,7 +196,17 @@ RUN tlmgr update --self && tlmgr install \
     zref
 
 RUN apt install -y \
-    imagemagick
+    dbus \
+    imagemagick \
+    libxss1 \
+    openbox \
+    wget \
+    xorg \
+    xvfb
+
+RUN wget https://github.com/jgraph/drawio-desktop/releases/download/v23.0.2/drawio-amd64-23.0.2.deb && \
+    dpkg -i drawio-amd64-23.0.2.deb && \
+    rm drawio-amd64-23.0.2.deb
 
 # https://stackoverflow.com/questions/52998331/imagemagick-security-policy-pdf-blocking-conversion
 RUN sed -i '/disable ghostscript format types/,+6d' /etc/ImageMagick-6/policy.xml
@@ -208,6 +218,7 @@ COPY ./filter/* /resources/filters/
 # mktexpk gets executed and needs a home dir, build one
 RUN mkdir -m 0777 /home/user
 ENV HOME="/home/user"
+ENV DBUS_SESSION_BUS_ADDRESS="unix:path=/var/run/dbus/system_bus_socket"
 
 COPY ./filter/pandoc-crossref.yaml /home/user/.pandoc-crossref/config.yaml
 

build.sh

@@ -12,6 +12,9 @@ pdflog_output=""
 table_rules="no"
 block_quotes_are_informative_text="no"
 
+# Start up the dbus daemon (drawio will use it later)
+dbus-daemon --system || echo "Failed to start dbus daemon"
+
 # Setup an EXIT handler
 on_exit() {
 	if [[ "${is_tmp}" == "yes" && -e "${build_dir}" ]]; then
@@ -321,10 +324,12 @@ cp "${input_file}" "${build_dir}/${input_file}"
 # \newpage is rendered as the string "\newpage" in GitHub markdown.
 # Transform horizontal rules into \newpages.
 # Exception: the YAML front matter of the document, so undo the instance on the first line.
+# TODO: Turn this into a Pandoc filter.
 sed -i.bak 's/^---$/\\newpage/g;1s/\\newpage/---/g' "${build_dir}/${input_file}"
 
 # Transform sections before the table of contents into section*, which does not number them.
 # While we're doing this, transform the case to all-caps.
+# TODO: Turn this into a Pandoc filter.
 sed -i.bak '0,/\\tableofcontents/s/^# \(.*\)/\\section*\{\U\1\}/g' "${build_dir}/${input_file}"
 
 if test "${do_gitversion}" == "yes"; then

filter/convert-images.lua

@@ -1,5 +1,31 @@
 -- Convert a variety of image formats to PDF
 
+
+-- Wrap calls to drawio in xvfb-run. Note that --no-sandbox has to be the last argument.
+-- https://github.com/jgraph/drawio-desktop/issues/249
+function drawio(source, dest)
+    if not os.execute(string.format("xvfb-run -a drawio -x -f pdf -o %s %s --no-sandbox", dest, source)) then
+        print(string.format('failed to convert %s to %s using drawio, falling back to letting latex try to pick it up', img.src, new_filename))
+        return false
+    end
+    return true
+end
+
+function imagemagick(source, dest)
+    if not os.execute(string.format("convert -density 300 %s %s", source, dest)) then
+        print(string.format('failed to convert %s to %s using imagemagick, falling back to letting latex try to pick it up', img.src, new_filename))
+        return false
+    end
+    return true
+end
+
+local converters = {
+    ['.jpg'] = imagemagick,
+    ['.png'] = imagemagick,
+    ['.svg'] = imagemagick,
+    ['.drawio'] = drawio
+}
+
 function string:hassuffix(suffix)
     return self:sub(-#suffix) == suffix
 end
@@ -9,15 +35,15 @@ if FORMAT:match 'latex' then
         -- Try to convert anything that is not a pdf, jpg, or png.
         -- This allows us to support file types that latex doesn't (e.g., SVG),
         -- as well as speed up the latex render iterations.
-        if not img.src or img.src:hassuffix('pdf') or img.src:hassuffix('jpg') or img.src:hassuffix('png') then
-            return img
-        end
-        local new_filename = pandoc.sha1(img.src) .. '.temp.pdf'
-        if not os.execute(string.format("convert -density 300 %s %s", img.src, new_filename)) then
-            print(string.format('failed to convert %s to %s, falling back to letting latex try to pick it up', img.src, new_filename))
-            return img
+        local file_ext = img.src:match("^.+(%..+)$")
+        if file_ext and converters[file_ext] then
+            local new_filename = pandoc.sha1(img.src) .. '.temp.pdf'
+            if converters[file_ext](img.src, new_filename) then
+                img.src = new_filename
+            end
+        else
+            print(string.format("not converting %s (extension %s)", img.src, file_ext))
         end
-        img.src = new_filename
         return img
     end
 end

guide.tcg

@@ -615,9 +615,6 @@ Host->>TPM: TPM2_Quote
 TPM->>Host: <quoted PCRs>
 ```
 
-Crossreferences to Mermaid diagrams are supported by providing both `caption`
-and `#fig:xxxxx` classes in curly braces.
-
 ### Flow Charts
 
 Mermaid supports flow-charts like @fig:flowchart with the following notation:
@@ -640,6 +637,24 @@ graph TD;
     C-->D;
 ```
 
+Crossreferences to Mermaid diagrams are supported by providing both `caption`
+and `#fig:xxxxx` classes in curly braces.
+
+## DrawIO Diagrams
+
+Some diagrams can't easily be represented in (human-maintained) code.
+
+[Draw.io](https://app.diagrams.net/) is a tool for creating sophisticated
+diagrams. There is a Visual Studio Code extension for it.
+
+Check in and add draw.io diagrams to your document like in @fig:sample-drawio:
+
+```md
+![Sample DrawIO Diagram](sample.drawio){#fig:sample-drawio width=50%}
+```
+
+![Sample DrawIO Diagram](sample.drawio){#fig:sample-drawio width=50%}
+
 # Tables {#sec:tables}
 
 We support several notation styles for tables.

sample.drawio

@@ -0,0 +1,28 @@
+<mxfile host="65bd71144e">
+    <diagram id="ZsT7yVSXCH5zRSQvvg-b" name="Page-1">
+        <mxGraphModel dx="1441" dy="1380" grid="1" gridSize="10" guides="1" tooltips="1" connect="1" arrows="1" fold="1" page="0" pageScale="1" pageWidth="850" pageHeight="1100" math="0" shadow="0">
+            <root>
+                <mxCell id="0"/>
+                <mxCell id="1" parent="0"/>
+                <mxCell id="2" value="Process?" style="shape=process;whiteSpace=wrap;html=1;backgroundOutline=1;" vertex="1" parent="1">
+                    <mxGeometry x="20" y="150" width="120" height="60" as="geometry"/>
+                </mxCell>
+                <mxCell id="3" value="&lt;b&gt;DB&lt;/b&gt;" style="shape=cylinder3;whiteSpace=wrap;html=1;boundedLbl=1;backgroundOutline=1;size=15;" vertex="1" parent="1">
+                    <mxGeometry x="190" y="140" width="60" height="80" as="geometry"/>
+                </mxCell>
+                <mxCell id="4" value="" style="endArrow=classic;startArrow=classic;html=1;exitX=1;exitY=0.5;exitDx=0;exitDy=0;entryX=0;entryY=0.5;entryDx=0;entryDy=0;entryPerimeter=0;" edge="1" parent="1" source="2" target="3">
+                    <mxGeometry width="50" height="50" relative="1" as="geometry">
+                        <mxPoint x="350" y="500" as="sourcePoint"/>
+                        <mxPoint x="400" y="450" as="targetPoint"/>
+                    </mxGeometry>
+                </mxCell>
+                <mxCell id="5" value="Test&lt;br&gt;&lt;ol&gt;&lt;li&gt;One&lt;/li&gt;&lt;li&gt;Two&lt;/li&gt;&lt;li&gt;Three&lt;/li&gt;&lt;/ol&gt;" style="whiteSpace=wrap;html=1;aspect=fixed;" vertex="1" parent="1">
+                    <mxGeometry x="30" y="-10" width="120" height="120" as="geometry"/>
+                </mxCell>
+                <mxCell id="7" value="Text" style="text;html=1;align=center;verticalAlign=middle;resizable=0;points=[];autosize=1;strokeColor=none;fillColor=none;" vertex="1" parent="1">
+                    <mxGeometry x="170" y="50" width="50" height="30" as="geometry"/>
+                </mxCell>
+            </root>
+        </mxGraphModel>
+    </diagram>
+</mxfile>