Type Mappings

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

.slint Type	C++ Type	Note
int	int
float	float
bool	bool
string	slint::SharedString	A reference-counted string type that uses UTF-8 encoding and can be easily converted to a std::string_view or a const char *.
color	slint::Color
brush	slint::Brush
image	slint::Image
physical_length	float	The unit are physical pixels.
length	float	At run-time, logical lengths are automatically translated to physical pixels using the device pixel ratio.
duration	std::int64_t	At run-time, durations are always represented as signed 64-bit integers with millisecond precision.
angle	float	The value in degrees.
relative-font-size	float	Relative font size factor that is multiplied with the Window.default-font-size and can be converted to a length.
structure	A class of the same name	The order of the data member are in the same as in the slint declaration

Structures

The Slint compiler generates a class with all data members in lexicographic order for any user-defined, exported struct in the .slint code.

For example, this struct in a .slint file

export struct MyStruct := {
    foo: int,
    bar: string,
}

will generate the following type in C++:

class MyStruct {
public:
    int foo;
    slint::SharedString bar;
};