Module type_mappings 

Type Mappings

The types used for properties in .slint design markup each translate to specific types in Rust. The follow table summarizes the entire mapping:

.slint Type	Rust Type	Note
angle	f32	The angle in degrees
array	ModelRc	Arrays are represented as models, so that their contents can change dynamically.
bool	bool
brush	Brush
color	Color
duration	i64	At run-time, durations are always represented as signed 64-bit integers with millisecond precision.
float	f32
image	Image
int	i32
length	f32	At run-time, logical lengths are automatically translated to physical pixels using the device pixel ratio.
physical_length	f32	The unit are physical pixels.
Point	LogicalPosition	A struct with x and y fields, representing logical coordinates.
relative-font-size	f32	Relative font size factor that is multiplied with the Window.default-font-size and can be converted to a length.
string	SharedString	A reference-counted string type that can be easily converted to a str reference.
anonymous object	anonymous tuple	The fields are in alphabetical order.
enumeration	enum of the same name	The values are converted to CamelCase
structure	struct of the same name

For user defined structures in the .slint, an extra struct is generated. For example, if the .slint contains

export struct MyStruct {
    foo: int,
    bar: string,
    names: [string],
}

The following struct would be generated:

#[derive(Default, Clone, Debug, PartialEq)]
struct MyStruct {
    foo: i32,
    bar: slint::SharedString,
    names: slint::ModelRc<slint::SharedString>,
}

The .slint file allows you to utilize Rust attributes and features for defining structures using the @rust-attr() directive. This enables you to customize the generated code by applying additional traits, derivations, or annotations. Consider the following structure defined in the .slint file with Rust attributes:

@rust-attr(derive(serde::Serialize, serde::Deserialize))
struct MyStruct {
    foo: int,
}

Based on this structure, the following Rust code would be generated:

#[derive(serde::Serialize, serde::Deserialize)]
#[derive(Default, Clone, Debug, PartialEq)]
struct MyStruct {
    foo: i32,
}