slint/internal/backends/selector/lib.rs
2022-02-02 16:16:55 +01:00

94 lines
3.5 KiB
Rust

// Copyright © SixtyFPS GmbH <info@sixtyfps.io>
// SPDX-License-Identifier: (GPL-3.0-only OR LicenseRef-SixtyFPS-commercial)
/*!
**NOTE**: This library is an **internal** crate for the [Slint project](https://sixtyfps.io).
This crate should **not be used directly** by applications using Slint.
You should use the `slint` crate instead.
**WARNING**: This crate does not follow the semver convention for versioning and can
only be used with `version = "=x.y.z"` in Cargo.toml.
The purpose of this crate is to select the default backend for [Slint](https://sixtyfps.io)
The backend can either be a runtime or a build time decision. The runtime decision is decided
by the `SLINT_BACKEND` environment variable. The built time default depends on the platform.
In order for the crate to be available at runtime, they need to be added as feature
*/
#![doc(html_logo_url = "https://sixtyfps.io/resources/logo.drawio.svg")]
#![cfg_attr(
not(any(feature = "slint-backend-qt-internal", feature = "slint-backend-gl-internal")),
no_std
)]
cfg_if::cfg_if! {
if #[cfg(feature = "slint-backend-qt-internal")] {
use slint_backend_qt_internal as default_backend;
} else if #[cfg(feature = "slint-backend-gl-internal")] {
use slint_backend_gl_internal as default_backend;
}
}
cfg_if::cfg_if! {
if #[cfg(any(
feature = "slint-backend-qt-internal",
feature = "slint-backend-gl-internal"
))] {
pub fn backend() -> &'static dyn slint_core_internal::backend::Backend {
slint_core_internal::backend::instance_or_init(|| {
let backend_config = std::env::var("SLINT_BACKEND").unwrap_or_default();
#[cfg(feature = "slint-backend-qt-internal")]
if backend_config == "Qt" {
return Box::new(slint_backend_qt_internal::Backend);
}
#[cfg(feature = "slint-backend-gl-internal")]
if backend_config == "GL" {
return Box::new(slint_backend_gl_internal::Backend);
}
#[cfg(any(
feature = "slint-backend-qt-internal",
feature = "slint-backend-gl-internal"
))]
if !backend_config.is_empty() {
eprintln!("Could not load rendering backend {}, fallback to default", backend_config)
}
#[cfg(feature = "slint-backend-gl-internal")]
if !default_backend::IS_AVAILABLE {
// If Qt is not available always fallback to Gl
return Box::new(slint_backend_gl_internal::Backend);
}
Box::new(default_backend::Backend)
})
}
pub use default_backend::{
native_widgets, Backend, NativeGlobals, NativeWidgets, HAS_NATIVE_STYLE,
};
} else {
pub fn backend() -> &'static dyn slint_core_internal::backend::Backend {
slint_core_internal::backend::instance().expect("no default backend configured, the backend must be initialized manually")
}
pub type NativeWidgets = ();
pub type NativeGlobals = ();
pub mod native_widgets {}
pub const HAS_NATIVE_STYLE: bool = false;
}
}
#[doc(hidden)]
#[cold]
#[cfg(not(target_arch = "wasm32"))]
pub fn use_modules() {
slint_core_internal::use_modules();
#[cfg(feature = "slint-backend-qt-internal")]
slint_backend_qt_internal::use_modules();
#[cfg(feature = "slint-backend-gl-internal")]
slint_backend_gl_internal::use_modules();
}