Layout
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.
- Border: Adds a border around another component.
- Grid: Places components inside a grid that resizes automatically.
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.