edouard@3936: Pre-made Widget Library
edouard@3936: =======================
edouard@3936: 
edouard@3936: Each widget type such as for example ``HMI:Meter`` can be applied to different
edouard@3936: SVG elements to make a new widget in an HMI.
edouard@3936: 
edouard@3936: +------------------------------------+---------------------------------+
edouard@3936: | Meter Widget Template (`HMI:Meter`)|      Voltmeter (`HMI:Meter`)    | 
edouard@3936: +====================================+=================================+
edouard@3936: | .. image:: svghmi_meter.svg        | .. image:: svghmi_voltmeter.svg |
edouard@3936: +------------------------------------+---------------------------------+
edouard@3936: 
edouard@3936: It is possible to collect customized widgets into libraries in order to re-use
edouard@3936: them in future HMI designs.
edouard@3936: 
edouard@3936: 
edouard@3936: Widget selection and configuration
edouard@3936: ----------------------------------
edouard@3936: 
edouard@3936: SVGHMI comes with a UI dedicated to:
edouard@3936: 
edouard@3936:     * Select SVG widget from a library
edouard@3936: 
edouard@3936:         Button on top of library tree opens a directory selector dialog to select another widget library.
edouard@3936:         When a widget is selected in library tree, a miniature of this widget is displayed in preview panel.
edouard@3936: 
edouard@3936:     * Set widget arguments
edouard@3936: 
edouard@3936:         Given values are checked against expected argument types and boundaries, and validity is shown as a 
edouard@3936:         check mark on the right side of each argument.
edouard@3936: 
edouard@3936:     * Bind widget to HMI Tree variables
edouard@3936: 
edouard@3936:         Variables are dragged from HMI Tree to text fields in "Widget's variables" section, and then a 
edouard@3936:         valid path corresponding to selected variable is assigned to this field.
edouard@3936: 
edouard@3936:         .. image:: svghmi_library_ui.svg
edouard@3936: 
edouard@3936:     * Place widget in HMI design
edouard@3936: 
edouard@3936:         Once configured, widget is placed in HMI design by dragging widget preview in Inkscape directly.
edouard@3936: 
edouard@3936:         .. image:: svghmi_dnd.svg
edouard@3936: 
edouard@3936: 
edouard@3936: How to create a widget library
edouard@3936: ------------------------------
edouard@3936: 
edouard@3936:     A widget library is a directory containing SVG files organized into arbitrarily nested subdirectories.
edouard@3936: 
edouard@3936:     Individual SVG file must only contain one widget, no nested widgets, and no pages.
edouard@3936:     It can be created by simply copying an existing widget into an empty SVG file.
edouard@3936:     Existing attributes are ignored when using widget from library and can be left as-is.