Storm includes a library for specifying layout of rectangles inside a container (perhaps Ui components on a screen). This library is written to be generic, and as such it is generally not usable without providing a small amount of code in order to hook it into whatever should be laid out.

The layout library is based around the Component class, which represents something that should be laid out in a container. These containers are represented by the Layout class, and are responsible for computing the position of all Components inside of them. Layout instances are also Components, which means that layout can be nested arbitrarily to produce the desired layout.

Each Layout provides two sets of properties: global properties and local properties. The global properties are set once for each instance of the Layout (eg. border), while local properties are specified for each child component. These properties are managed by the Layout using a nested class usually named Info. The syntax expects that the add function returns a subclass of Layout:Info that is associated with the newly added component. This object is expected to contain any local properties either in the form of member variables or functions.

Layout managers

The following layout managers are currently provided. For more detailed information, look up their documentation in the built-in documentation.

Layout DSL

The layout system provides a small language to specify layouts more conveniently. In Basic Storm, it looks like this (we expect that a, b, and c are declared elsewhere):

var x = layout Grid {
    wrapCols: 2;
    expandCol: 0, 1;
    a {}
    b {}
    c {
        row: 3;
        col: 3;

The example illustrates the overall structure: properties are specified using <name>: <value(s)>;, and components using <name> {...}. A property specified will first be applied as a global property for the component (such as wrapCols above). If no such global property exists, a local property is tried instead (such as row and col above). All properties are assigned in order, so if any property has side effects (such as nextLine inside a Grid), order may matter.

Components and values can be specified using any valid Basic Storm expression, but more complex expressions have to be enclosed in parentheses (such as a + b). If a component refers to something that does not inherit from Component, the grammar attempts to convert it to a component by calling a visible global function named component to do the job.