Legacy Syntax

To maintain compatibility with earlier version of Slint, the pre-1.0 syntax that declared components and named structs with := remains supported:

export MyApp := Window {
    //...
}

This syntax change also effects property lookup rules and default element placement.

In components defined in the new syntax, only properties declared within the component are in scope. By default parent elements render their children centered and will apply all layout constraints.

In components defined using old systax, all properties of bases of self and root were in scope in addition to all properties defined inside the component itself. Elements are placed at position x: 0 and y: 0 and their constraints aren’t applied.