Compatibility with PlantUML

[Oliver Kopp]

Short summary: `style="width:116px;height:131px;"` is not supported by inkscape. The SVG is rendered fine in IntelliJ, so I assume, inkscape could be improved.

How to produce such a PDF?

PlantUML file:

@startuml
Bob->Alice : hello
@enduml

Execute plantuml.jar to get the SVG:

    java -jar plantuml.jar -tsvg example.txt

Generated SVG:

```
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"
     contentScriptType="application/ecmascript" contentStyleType="text/css" height="131px" preserveAspectRatio="none"
     style="width:116px;height:131px;" version="1.1" viewBox="0 0 116 131" width="116px" zoomAndPan="magnify">
  <defs>
    <filter height="300%" id="f1bh39diomyks7" width="300%" x="-1" y="-1">
      <feGaussianBlur result="blurOut" stdDeviation="2.0"/>
      <feColorMatrix in="blurOut" result="blurOut2" type="matrix" values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 .4 0"/>
      <feOffset dx="4.0" dy="4.0" in="blurOut2" result="blurOut3"/>
      <feBlend in="SourceGraphic" in2="blurOut3" mode="normal"/>
    </filter>
  </defs>
  <g>
    <line style="stroke: #A80036; stroke-width: 1.0; stroke-dasharray: 5.0,5.0;" x1="29" x2="29" y1="39.6094"
          y2="89.9609"/>
    <line style="stroke: #A80036; stroke-width: 1.0; stroke-dasharray: 5.0,5.0;" x1="85" x2="85" y1="39.6094"
          y2="89.9609"/>
    <rect fill="#FEFECE" filter="url(#f1bh39diomyks7)" height="31.6094" style="stroke: #A80036; stroke-width: 1.5;"
          width="39" x="8" y="3"/>
    <text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacingAndGlyphs" textLength="25" x="15"
          y="24.5332">Bob
    </text>
    <rect fill="#FEFECE" filter="url(#f1bh39diomyks7)" height="31.6094" style="stroke: #A80036; stroke-width: 1.5;"
          width="39" x="8" y="88.9609"/>
    <text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacingAndGlyphs" textLength="25" x="15"
          y="110.4941">Bob
    </text>
    <rect fill="#FEFECE" filter="url(#f1bh39diomyks7)" height="31.6094" style="stroke: #A80036; stroke-width: 1.5;"
          width="44" x="61" y="3"/>
    <text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacingAndGlyphs" textLength="30" x="68"
          y="24.5332">Alice
    </text>
    <rect fill="#FEFECE" filter="url(#f1bh39diomyks7)" height="31.6094" style="stroke: #A80036; stroke-width: 1.5;"
          width="44" x="61" y="88.9609"/>
    <text fill="#000000" font-family="sans-serif" font-size="14" lengthAdjust="spacingAndGlyphs" textLength="30" x="68"
          y="110.4941">Alice
    </text>
    <polygon fill="#A80036" points="73,67.6094,83,71.6094,73,75.6094,77,71.6094"
             style="stroke: #A80036; stroke-width: 1.0;"/>
    <line style="stroke: #A80036; stroke-width: 1.0;" x1="29.5" x2="79" y1="71.6094" y2="71.6094"/>
    <text fill="#000000" font-family="sans-serif" font-size="13" lengthAdjust="spacingAndGlyphs" textLength="27"
          x="36.5" y="67.1045">hello
    </text><!--
@startuml
Bob->Alice : hello
@enduml

PlantUML version 1.2017.15(Mon Jul 03 18:45:34 CEST 2017)
(GPL source distribution)
Java Runtime: Java(TM) SE Runtime Environment
JVM: Java HotSpot(TM) 64-Bit Server VM
Java Version: 1.8.0_161-b12
Operating System: Windows 10
OS Version: 10.0
Default Encoding: Cp1252
Language: de
Country: DE
-->
  </g>
</svg>
```

Now use inkscape to convert it to PDF:

    inkscape -z -D --file=example.svg --export-pdf=example.pdf

Expected result: PDF with the correct page size

Got result: PDF with huge white border and following output:

```
** (inkscape.exe:14960): WARNING **: SPIStyle::readIfUnset(): Invalid style property id: 8 value: 131px

** (inkscape.exe:14960): WARNING **: SPIStyle::readIfUnset(): Invalid style property id: 7 value: 116px
```

[sk (skramm)]

Same issue when exporting to png.
Inkscape seems to ignore the drawing size when encountering this issue.
I checked, the code generated by Plantuml seems perfectly valid SVG 1.1

[Patrick Storz (ede123)]

The problem here does not actually seem to be the `style="width:116px;height:131px;"` - while I assume Inkscape just ignores it, the document width/height are set to the same dimensions via proper properties on the SVG root element.

What is causing the unexpected export size is the `filter="url(#f1bh39diomyks7)"` which uses a width/height of 300%.

Any reason for using "-D" switch here (which tells Inkscape to export the "whole drawing", including the invisible extens of this filter)?
When omitting the "-D" switch and exporting the "whole page" borders are as expected.

[Oliver Kopp (kopp-dev)]

No specific reason to use "-D" here. I just copied a command line from another inkscape call, where it used to be necessary to get the boundaries right.

[fuhrmanator (fuhrmanator)]

I'm running Inkscape 0.92.4 on Windows 10.

Removing the "-D" doesn't solve the problem for the SVG I have from PlantUML. I don't really mind the warnings normally:

** (inkscape.exe:22424): WARNING **: 11:49:08.629: SPIStyle::readIfUnset(): Invalid style property id: 8 value: 166px

** (inkscape.exe:22424): WARNING **: 11:49:08.629: SPIStyle::readIfUnset(): Invalid style property id: 7 value: 487px

The PDF that is generated is just fine, actually. The problem is the warnings, which cause the command processor I'm using to bail out. I have tried to suppress them per preferences.xml in #bug 437366 https://bugs.launchpad.net/ubuntu/+source/inkscape/+bug/437366/comments/3 but they still appear.

I verified the path of the preferences through the GUI, but the GUI changes don't seem to modify the XML. Do the GUI and CLI share the same preferences file?

[fuhrmanator (fuhrmanator)]

My workaround has been to redirect stderr (2>) to nul, e.g.,

    inkscape -z -D --file=mdd.svg --export-pdf=mdd.pdf 2> nul

which is not ideal, since it won't report ANY errors.