Updating your Extension for 1.0

This is a preliminary and incomplete list of actions to take for updating Python extensions for Inkscape 1.0:

Adjusting folder structure

For easier extension 'installation' by users and for having a better overview about the installed extensions, you can now put extensions into their own subfolders of the extensions directory. This is optional.

When specifying the command in the .inx file, you can use the new parameter 'location'.

• If you set location="extensions" (de-facto default in 0.92.x), it will assume the path is relative to either user or system extensions folder.
• If it's location="inx" (new and recommended in 1.0), it will assume the path is relative to the .inx file location.

An extension that uses the following snippet:

<script>
    <command location="inx" interpreter="python">hello.py</command>
</script>

can be put into any subfolder in extensions or into the extensions folder itself, as long as the file hello.py is in that same folder, at the same hierarchy level.

The old parameter reldir is deprecated. It is recommended to use Unix style path separators (i.e. /), if your script file is located in a nested subdirectory (should be a very rare case).

Updating *.inx files

Remove dependency listings

Remove the dependency listings for the following modules:

• bezmisc.py
• coloreffect.py
• cspsubdiv.py
• cubicsuperpath.py
• ffgeom.py
• inkex.py (removal not strictly required)
• pathmodifier.py
• simplepath.py
• simplestyle.py
• simpletransform.py
• more?

This change is backwards compatible (as long as the user has a fully functioning Inkscape installation). Not removing these will result in the extension not being selectable (disabled and greyed out) in Inkscape 1.0 or higher.

Changes to parameter definitions

There are also some updates to the parameter definitions in .inx files. While these are intended to be backwards compatible to 0.92, you may wish to review the changes below:

• Underscores in inx parameter tags and attributes for translation can be dropped entirely. Use translatable="no" to make an item (e.g. a unit name) untranslatable.
• boolean can be renamed to bool
• <param type="enum" /> is deprecated, instead use optiongroups. Remember to rename <item> to <option> when replacing.
• In optiongroups appearance="minimal" is deprecated.
  • In optiongroups you can now define dropdown selections (comboboxes) and radio buttons.
  • i.e. <param type="optiongroup" appearance="combo" />, or <param type="optiongroup" appearance="radio" />.
• Choosing files / folders with <param type="path" /> (these return the path as a string to the Python script):
  • Files:
    • Choose a file, with file type restriction (optional): <param name="my_file" type="path" mode="file" filetypes="png,jpg" gui-text="A file:">my/path/to/file.png</param>
    • Choose multiple files (file type restriction possible, too): <param name="my_files" type="path" mode="files" gui-text="Multiple files:">my/path/to/file.png</param>
    • Create a new file: <param name="my_new_file" type="path" mode="file_new" filetypes="png" gui-text="A new file:">my/path/to/file.png</param>
  • Folders:
    • Choose a folder: <param name="my_folder" type="path" mode="folder" gui-text="A folder:">my/path/</param>
    • Choose multiple folders: <param name="my_folders" type="path" mode="folders" gui-text="Folders:">my/path/</param>
    • Create a new folder: <param name="my_new_folder" type="path" mode="folder_new" filetypes="png" gui-text="A new folder:">my/path/</param>
• Color choosers: make them more compact with appearance="colorbutton" for parameters of type color
• Multiline text entry fields are available with appearance="multiline" for parameters of type string
• The following new widgets (static, do not need to be read in by the .py file's option parser anymore):
  • label: (<label>Some text</label>), replaces parameters of type description (which never really were parameters in the actual sense), optionally with appearance="header".
  • hbox/vbox: for layouting purposes (allow to pack child widgets into horizontally/vertically oriented boxes)
  • <spacer/>/<separator/>: which add a variable space or separating line between child widgets.
  • <image>my_image.svg</image>: which allows to display an image in the extension UI

Example file with many of the new features (click on Expand on the right to show, requires an image in the extensions directory with the correct name):

<?xml version="1.0" encoding="UTF-8"?>
<inkscape-extension xmlns="http://www.inkscape.org/namespace/inkscape/extension">
    <name>Layout Demo</name>
    <id>org.inkscape.test.layout_demo</id>
    <dependency type="executable" location="extensions">pathmodifier.py</dependency>

    <hbox>
        <vbox>
            <label appearance="header">Multiple vboxes packed into an hbox</label>
            <hbox>
                <vbox>
                    <label>Vertical stack</label>
                    <param name="param_bool" type="bool" gui-text="Boolean">true</param>
                    <param name="param_int" type="int" gui-text="Int:" >12345</param>
                    <param name="param_float" type="float" gui-text="Float:">1.2345</param>
                    <param name="param_color" type="color" appearance="colorbutton" gui-text="Color:">0x12345678</param>
                </vbox>
                <spacer />
                <vbox>
                    <label>Vertical stack with separators</label>
                    <param name="param_string" type="string" gui-text="Single line string:">a string value</param>
                    <separator></separator>
                    <param name="param_string_empty" type="string" gui-text="Empty single line:"></param>
                    <separator></separator>
                    <param name="param_string_multiline" type="string" appearance="multiline" gui-text="Multiline string:">a\nmultiline\nstring\nvalue</param>
                </vbox>
                <spacer />
                <vbox>
                    <label>Vertical stack with spacers</label>
                    <param name="param_file_new" type="path" mode="file_new"  filetypes="png" gui-text="A new file:">my/path/to/file.png</param>
                    <spacer />
                    <param name="param_file" type="path" mode="file" filetypes="png,jpg" gui-text="A file:">my/path/to/file.png</param>
                    <spacer />
                    <param name="param_files" type="path" mode="files" gui-text="Multiple files:">my/path/to/file.png</param>
                    <spacer />
                    
                </vbox>
                <spacer />
                <vbox>
                    <label>Vertical stack with expanding spacer</label>
                    <spacer size="expand"/>
                    <param name="param_folder" type="path" mode="folder" gui-text="A folder:">my/path/</param>
                    <param name="param_folders" type="path" mode="folders" gui-text="Folders:">my/path/to/file.png</param>
                    <param name="param_folder_new" type="path" mode="folder_new" gui-text="A new folder:">my/path/</param>
                </vbox>
                <spacer />
                <vbox>
                  <label appearance="header">An image!</label>
                  <image>ink_icon.svg</image>
                  <spacer />
                  <label appearance="header" indent="1">Indented header</label>
                  <spacer />
                  <label>For details please refer to</label>
                  <label appearance="url" indent="1">https://clickable.url</label>
                </vbox>
            </hbox>
        </vbox>
    </hbox>

    <effect needs-live-preview="false">
        <object-type>all</object-type>
        <effects-menu>
            <submenu _name="Test"/>
        </effects-menu>
    </effect>
    <script>
        <command reldir="extensions" interpreter="python">do_nothing.py</command>
    </script>
</inkscape-extension>

Updating *.py files

Collecting the options of the extension

1. Instead of inkex.Effect.OptionParser.add_option, your extension should now use inkex.Effect.arg_parser.add_argument.
2. The 'type' option now works with variables instead of strings. Use int instead of "int" (same for float,...).
3. The 'inkbool' type is now inkex.Boolean.
4. action="store" can be removed.

These changes are not backwards compatible. The old options will still work, but are deprecated and should no longer be used when you develop your extension for Inkscape 1.0 or higher.

Replace specific functions

When the .inx file is valid and not greyed out (meaning: a dependency is missing), you can start building the .py file up again.

In the Inkscape extensions refactoring process for Inkscape 1.0, many inkex functions have been removed, or renamed, or moved, or options have changed. Wherever possible, Inkscape will try to replace the old function by the new one, and will give you a deprecation warning, with instructions what to replace them by.

E.g. inkex.Effect.selected is replaced by inkex.Effect.svg.selected - however, most replacements do not follow this naming scheme translation.

These changes are not backwards compatible.

The full Python API documentation is available on GitLab.

Python 3 / Python 2 compatibility

Test your extension with both Python 2 and Python 3, if you want it to work for as many users as possible. With the updated extensions, Inkscape does no longer require Python 2, so some users will probably be using Python 3, and may no longer have Python 2 installed on their system. See Extension_Interpreters for how to set the Python version for your extension in the preferences file (for testing).

Getting your extension added to Inkscape's stock extensions

Inkscape now has a separate repository for its Python extensions, which is included into Inkscape proper by using a Git submodule.

Writing tests

Previously Inkscape didn't require any unit testing for code. You should now write test code, if you expect your module to be included into the Inkscape extensions repository and included in the shipped Inkscape release. In this case, a test suite file should be made in the tests directory for your extension. It should test each aspect of your extension and exercise all assumptions.

If you are writing a standalone extension that users will install themselves, there is no strict requirement for tests. But having them will greatly improve your code and your ability to upgrade the code later. You can have tests in your own folders and use the extension's setup.py as a harness to run them (a setup.py file is also useful for installing your python code as a non-inkscape related python module, which might be useful too). See Python documentation for creating packages.

Docstrings

Include docstrings in your extension, so documentation can be built from them automatically (see inkex API documentation) collects the inline documentation comments into a single document.

Submitting your extension for inclusion

Visit https://gitlab.com/inkscape/extensions, fork the repository, and create a merge request on GitLab.

External links

A script to perform some of the conversion steps automatically has been contributed: https://gitlab.com/inkscape/extensions/-/issues/380