.. _inx-widgets: INX widgets and parameters ========================== This page contains the reference documentation for INX widgets and parameters. Their primary goal is to make it easy to design GUIs for `Inkscape Extensions `__ using the built-in `INX extension descriptor format `__, although (invisible) parameters can also be used for extensions that don't need to show a user interface. Introduction ------------ Extension GUIs consists of an arbitrary number of GUI elements, so-called `Widgets <#Widgets>`__. These can be simple text labels, boxes and spacers to control layout or more complex UI elements like images. A special class of Widgets are `Parameters <#Parameters>`__. They differ from other Widgets in that they have a user-settable value, for example a boolean (implemented as checkbox) or integer (implemented as number entry). The value of each Parameter is passed to the extension on execution and can be used to control its behavior. All Widgets are described using an easy-to-learn XML schema with predefined tags and attributes which are described in detail below. .. _available_widgets: Available Widgets ~~~~~~~~~~~~~~~~~ A general Widget takes the form .. code:: value where ``widget_name`` specifies the name of the widget and is one of the following: - ``label``:sup:`since 1.0`\ - ``hbox``:sup:`since 1.0`\ /``vbox``:sup:`since 1.0`\ - ``separator``:sup:`since 1.0`\ /``spacer``:sup:`since 1.0`\ - ``image``:sup:`since 1.0`\ - ``param`` (for all Parameter types) .. _apt: Available Parameter types ~~~~~~~~~~~~~~~~~~~~~~~~~ A general Parameter takes the form .. code:: value where ``parameter_type`` specifies the type of the parameter and is one of the following: - ``bool``:sup:`since 1.0`\ - ``int`` - ``float`` - ``string`` - ``path``:sup:`since 1.0`\ - ``optiongroup`` - ``notebook`` - ``color`` If a parameter is made invisible (see ``gui-hidden`` attribute in the `next section <#common-attributes>`__) it will not be shown in the GUI but it's value is still passed to an extension. This is useful if you want to hardcode parameter value the user should not be able to change. If all parameters (and potential widgets) are invisible, Inkscape will not show a GUI and execute the extension immediately instead, but will still pass the values of the invisible parameters. .. _common_attributes: Common attributes ----------------- For all widgets ~~~~~~~~~~~~~~~ +------------------+------------------+------------------+------------------+ | Attribute | Allowed | Default | Required? | | name | value(s) | value | | +==================+==================+==================+==================+ | ``gui-hidden`` | ``true``, | | | | | ``false`` | ``false`` | optional | +------------------+------------------+------------------+------------------+ | If set to ``true`` the Widget is hidden from the GUI (primarily used to | | add hidden parameters that are passed to the extension but are not | | supposed to be editable by the user.) | | | | *Note: If there are* **no** *visible parameters defined in a GUI, the | | extension is executed immediately without showing a dialog.* | +------------------+------------------+------------------+------------------+ | ``indent`` | ``0,1,2,…`` | ``0`` | optional | +------------------+------------------+------------------+------------------+ | Sets indentation level of the parameter. Increasing indentation adds | | padding to the start of the line. | +------------------+------------------+------------------+------------------+ Only for Parameters ~~~~~~~~~~~~~~~~~~~ +------------------------+------------------------+------------------------+------------------------+ | Attribute name | Allowed value(s) | Default value | Required? | +========================+========================+========================+========================+ | ``name`` | *(text)* | -- | required | +------------------------+------------------------+------------------------+------------------------+ | Used as an identifier of the parameter. It has to be unique since the value of this attribute is | | used to save and transmit parameter values internally! | +------------------------+------------------------+------------------------+------------------------+ | ``type`` | see `above <#apt>`__ | -- | required | +------------------------+------------------------+------------------------+------------------------+ | Determines the type of the parameter, see the extensive description of | | `Parameters <#parameters>`__ below. | +------------------------+------------------------+------------------------+------------------------+ | ``gui-text`` | *(text)* | -- | required *(visible | | | | | parameters)*, optional | | | | | *(hidden parameters* + | | | | | ``notebooks`` *)* | +------------------------+------------------------+------------------------+------------------------+ | Label shown for the parameter in the GUI. | +------------------------+------------------------+------------------------+------------------------+ | ``gui-description`` | *(text)* | -- | optional | +------------------------+------------------------+------------------------+------------------------+ | Tooltip shown for the parameter when the user hovers the mouse cursor over the active area of the | | parameter in question. | +------------------------+------------------------+------------------------+------------------------+ Widgets ------- ``hbox`` / ``vbox`` ~~~~~~~~~~~~~~~~~~~ Creates a container for other widgets. No visual rendering but provides a possibility to align and layout other widgets. Child widgets are either added in horizontal (``hbox``) or vertical (``vbox``) direction. .. code:: xml … … A box can contain an arbitrary number of other widgets and parameters (including other boxes) to fine-tune the layout of the GUI. *Note*: When you start with an empty extension GUI, you're basically starting with a ``vbox``. Also ``notebook`` pages behave like vertically oriented boxes. .. figure:: widgets/separator.png :alt: Rendering of hbox/vbox ``hbox`` and ``vbox`` ``image`` ~~~~~~~~~ Creates a widget displaying an image. The content of the node specifies the path of the image file (ideally specify a path relative to the .inx file itself). .. code:: xml path/to/image.svg By default the image will be rendered at it's actual size. Use attributes ``width/heigth`` to override the default size (in this case *both* attributes need to be supplied; units are pixels). Images are aligned in the horizontal center of the current box; different alignment can be realized by wrapping the image in a `hbox <#hbox-vbox>`__ and adding a `spacer <#spacer>`__ with ``size=expand`` before (for right alignment) or after (for left alignment) of the image. *Implementation note: Loadable image formats are determined by GdkPixbuf and therefore system-specific. PNG should always work and is the safe choice. SVG should mostly work and is the preferred choice for obvious reasons.* .. figure:: widgets/image.png :alt: Rendering of image An ``image`` ``label`` ~~~~~~~~~ Creates a widget showing text. The content of the node corresponds to the text content that will be rendered. .. code:: xml *Note: Labels are intended to provide additional information / help. For labeling parameters use the ``gui-text`` attribute; for short help texts that are specific to a single parameter prefer ``gui-description`` which will render as a tooltip.* - When setting the attribute ``appearance="header"`` the text is styled as a heading and can be used as another possibility to group parameters. - | When setting the attribute ``appearance="url"`` the text is rendered as a clickable link. | *Note: The text is escaped and used as the link target as-is. Creating a link text that differs from the URL is prevented for security reasons.* - When setting the attribute ``xml:space="preserve"`` any white-space (spaces, tabs, line-breaks, etc.) in the label will be preserved, allowing to format the label accordingly. By default all leading/tailing and intermediary whitespace is collapsed into a single space character. .. figure:: widgets/label.png :alt: Rendering of different labels Different label types (in order): default | ``appearance="header"`` | ``appearance="url"`` | ``xml:space="preserve"`` ``separator`` ~~~~~~~~~~~~~ Creates a separator for visual separation of other widgets. Renders as a horizontal/vertical line. .. code:: xml The direction of the separator will automatically adjust depending on direction of the current container (vertical for "empty" extension GUIs and ``notebook`` pages; vertical/horizontal for ``vbox`` and ``hbox`` respectively). .. figure:: widgets/separator.png :alt: Rendering of separators Separators can be used in `hbox` and `vbox` environments. ``spacer`` ~~~~~~~~~~ Creates a spacer for visual separation of other widgets. No visual rendering but provides variable spacing. .. code:: xml The direction of the spacer will automatically adjust depending on direction of the current container (vertical for "empty" extension GUIs and ``notebook`` pages; vertical/horizontal for ``vbox`` and ``hbox`` respectively). Use the ``size`` attribute to set the spacing in pixels (default: ``size="10"``). The special value ``expand`` results in a spacer that grows dynamically and always uses up as much space as possible (useful for aligning content). .. figure:: widgets/spacer.png :alt: Rendering of spacers Different spacer types: (1) default, (2) ``size="30"``, (3) ``size="expand"`` Parameters ---------- ``bool`` ~~~~~~~~ .. versionadded:: 1.0 Creates a checkbox to set a **boolean value**. Allowed values are ``true`` or ``false`` (default value: ``true``). .. code:: xml false .. figure:: widgets/bool.png :alt: Checkbox Rendering of ``boolean`` values ``color`` ~~~~~~~~~ Creates a control to select an **RGBA color value**. Values should be given in hexadecimal notation, e.g. ``0xff0000ff`` for red with full opacity (default value: ``0x000000ff``) .. code:: xml 0x000000ff Use ``appearance="colorbutton"`` for a simple button that opens a simplified color picker. Otherwise a full ColorNotebook will be rendered. .. figure:: widgets/color.png :alt: Rendering of color parameter Rendering of a full ColorNotebook for a ``color`` parameter .. versionchanged:: 1.0 *Implementation note:* colors values are internally treated as 32-bit unsigned integers (unsigned long). Acceptable default values include everything the standard library function ``strtoul`` [#]_ understands (since Inkscape 1.0). Earlier Inkscape version only handled decimal numbers. The value passed to the extension script will also be a decimal number. ``float`` ~~~~~~~~~ Creates a input to enter a **floating point number**. Limit the input range with the ``min`` and ``max`` attributes; set the number of decimal places with the ``precision`` attribute. (defaults: ``min="0"``, ``max="10"`` and ``precision="1"``; default value: 0) .. code:: xml 1.234 Use the attribute ``appearance="full"`` to create a slider with which the value can be adjusted dynamically over the full range. .. figure:: widgets/float.png :alt: Rendering of float parameter Rendering of ``float`` parameters: default and with ``appearance="full"`` ``int`` ~~~~~~~ Creates a textbox input to enter an **integer number**. Limit the input range with the ``min`` and ``max`` attributes. (defaults: ``min="0"`` and ``max="10"``; default value: 0) .. code:: xml 1 Use the attribute ``appearance="full"`` to create a slider with which the value can be adjusted dynamically over the full range. .. figure:: widgets/integer.png :alt: Rendering of integer parameter Rendering of ``int`` parameters: default and with ``appearance="full"`` ``notebook`` ~~~~~~~~~~~~ Creates a set of pages (aka tab control). The user can switch between individual pages. Each page can contain an arbitrary set of other Widgets and Parameters. Individual pages are created with the element. The **returned value** for ``notebook`` parameters is the value of the ``name`` attribute of the selected . By default the first page is selected. Notebooks can be used to show widgets based on an option; that option would be implemented as notebook. .. code:: xml … … .. figure:: widgets/notebook.png :alt: Rendering of notebook parameter Rendering of a ``notebook`` ``optiongroup`` ~~~~~~~~~~~~~~~ Creates a control that allows to select one option **one option** from a set of multiple choices. The different choices are created with elements. The **returned value** for ``optiongroup`` type parameters is the value of the ``value`` attribute of the selected . By default the first is selected. .. code:: xml .. versionadded:: 1.0 Set the attribute ``appearance="radio"``\ to render radio buttons (default). Set the attribute ``appearance="combo"``\ to display a drop-down list instead. .. figure:: widgets/optiongroup.png :alt: Rendering of float parameter Rendering of ``optionsgroup`` parameters: ``appearance="radio"`` and ``appearance="combo"``. On the bottom parameter, ``precision="1"`` has been set. ``path`` ~~~~~~~~ .. versionadded:: 1.0 Creates a control to choose a **path**. Paths can either be entered manually or by using the file chooser that can be opened using the ellipsis button. The ``mode`` attribute allows to set behavior of the file chooser (i.e. if files or folders can be selected, if they need to exist previously and if multiple selections are possible). The ``filetypes`` attribute holds a comma-separated list of file extensions and restricts the selectable file types in file picker mode. .. code:: Possible values for the ``mode`` attribute: - ``file`` - select a single existing file - ``files`` - select multiple existing files - ``folder`` - select a single existing folder - ``folders`` - select multiple existing folders - ``file_new`` - select a single new file name - ``file_new`` - select a single new folder name Examples - Files: - Choose a file, with file type restriction (optional): .. code:: xml my/path/to/file.png - Choose multiple files (file type restriction possible, too): .. code:: xml my/path/to/file.png - Create a new file: .. code:: xml my/path/to/file.png - Folders: - Choose a folder: .. code:: xml my/path/ - Choose multiple folders: .. code:: xml my/path/ - Create a new folder: .. code:: xml my/path/ .. figure:: widgets/path.png :alt: Rendering of path parameter Rendering of ``path`` parameters *Implementation note:* Existence of paths are not checked before passing them to the extension, so extension authors need to implement suitable error handling, especially in case of manual path entry. For multiple selections the individual paths are joined using the pipe character ("|") and passed to the extension as a single string. ``string`` ~~~~~~~~~~ Creates a input to enter a **string**. Limit the number of characters the user is allowed to enter with the ``max-length`` attribute. (defaults: no character limit; default value: empty string) .. code:: xml Some default text .. versionadded:: 1.0 Set the attribute ``appearance="multiline"``\ to render a multi-line input. Line-breaks will be encoded as literal ``\n`` in the value passed to the extension. .. figure:: widgets/string.png :alt: Rendering of string parameters Rendering of ``string`` parameters: default and ``appearance="multiline"`` .. [#] https://en.cppreference.com/w/cpp/string/byte/strtoul