Graphite/gui

GUI system

This directory contains the XML files describing the components which make up Graphite's GUI.

Principles

The framework is inspired by Vue.js. Each component's layout is defined in an XML, and recursively made out of lower-level components.

Interactivity is provided by script files which expose reactive variables. As these variables are mutated, the component is updated to match the current state.

Layout

The layout engine does a top-down pass through the component tree in order to determine what to render.

Layout is controlled using predefined attributes, such as width, height, x-align, y-align, spacing or padding.

Component lifetime

The children of a component are passed to it as a content attribute. For example, looking at the row component:

<row content="INNER_XML: (Layout) = [[]]">
    {{INNER_XML}}
</row>

The content attribute defines a new variable INNER_XML of type Layout which can contain more XML layout structure. It has a default value of [[]] which refers to an empty layout— XML syntax (for the Layout data type) written in a tag's attribute is wrapped in [[ (opening) and ]] (closing) symbols. In this case the INNER_XML variable defaults to empty XML, however it is not stricly useful here because the content attribute will always have its value replaced by whatever exists between opening and closing tags when this component is called from elsewhere.

This is then expanded in the body of the row: {{INNER_XML}}.

Defining new components

Component files

To define a new component, create a new .xml file in this directory. Subdirectories become namespaces for the components (e.g. the file window/main.xml defines a component <window:main>).

Parameters

User-defined parameters start with a colon (:).

They are created by adding attributes to a component source file: :parameter="VARIABLE_NAME: (VariableType) = defaultValue"