Android backend

.github/CODEOWNERS

@@ -1,3 +1,6 @@
+# Android
+/src/android.rs     @MarijnS95
+
 # Apple platforms
 /src/cg.rs          @madsmtm
 

CHANGELOG.md

@@ -73,38 +73,38 @@
 
 # 0.3.0
 
-* On MacOS, the contents scale is updated when set_buffer() is called, to adapt when the window is on a new screen (#68).
-* **Breaking:** Split the `GraphicsContext` type into `Context` and `Surface` (#64).
-* On Web, cache the document in the `Context` type (#66).
-* **Breaking:** Introduce a new "owned buffer" for no-copy presentation (#65).
-* Enable support for multi-threaded WASM (#77).
-* Fix buffer resizing on X11 (#69).
-* Add a set of functions for handling buffer damage (#99).
-* Add a `fetch()` function for getting the window contents (#104).
-* Bump MSRV to 1.64 (#81).
+- On MacOS, the contents scale is updated when set_buffer() is called, to adapt when the window is on a new screen (#68).
+- **Breaking:** Split the `GraphicsContext` type into `Context` and `Surface` (#64).
+- On Web, cache the document in the `Context` type (#66).
+- **Breaking:** Introduce a new "owned buffer" for no-copy presentation (#65).
+- Enable support for multi-threaded WASM (#77).
+- Fix buffer resizing on X11 (#69).
+- Add a set of functions for handling buffer damage (#99).
+- Add a `fetch()` function for getting the window contents (#104).
+- Bump MSRV to 1.64 (#81).
 
 # 0.2.1
 
-* Bump `windows-sys` to 0.48
+- Bump `windows-sys` to 0.48
 
 # 0.2.0
 
-* Add support for Redox/Orbital.
-* Add support for BSD distributions.
-* Ported Windows backend from `winapi` to `windows-sys`.
-* **Breaking:** Take a reference to a window instead of owning the window.
-* Add a `from_raw` function for directly using raw handles.
-* Improvements for Wayland support.
-* Support for HiDPI on macOS.
-* **Breaking:** Add feature flags for `x11` and `wayland` backends.
-* Use static dispatch instead of dynamic dispatch for the backends.
-* Add `libxcb` support to the X11 backend.
-* Use X11 MIT-SHM extension, if available.
+- Add support for Redox/Orbital.
+- Add support for BSD distributions.
+- Ported Windows backend from `winapi` to `windows-sys`.
+- **Breaking:** Take a reference to a window instead of owning the window.
+- Add a `from_raw` function for directly using raw handles.
+- Improvements for Wayland support.
+- Support for HiDPI on macOS.
+- **Breaking:** Add feature flags for `x11` and `wayland` backends.
+- Use static dispatch instead of dynamic dispatch for the backends.
+- Add `libxcb` support to the X11 backend.
+- Use X11 MIT-SHM extension, if available.
 
 # 0.1.1
 
-* Added WASM support (Thanks to [Liamolucko](https://github.com/Liamolucko)!)
-* CALayer is now used for Mac OS backend, which is more flexible about what happens in the windowing library (Thanks to [lunixbochs](https://github.com/lunixbochs)!)
+- Added WASM support (Thanks to [Liamolucko](https://github.com/Liamolucko)!)
+- CALayer is now used for Mac OS backend, which is more flexible about what happens in the windowing library (Thanks to [lunixbochs](https://github.com/lunixbochs)!)
 
 # 0.1.0
 

Cargo.toml

@@ -28,6 +28,10 @@ x11-dlopen = ["tiny-xlib/dlopen", "x11rb/dl-libxcb"]
 log = "0.4.17"
 raw_window_handle = { package = "raw-window-handle", version = "0.6", features = ["std"] }
 
+[target.'cfg(target_os = "android")'.dependencies]
+bytemuck = "1.12.3"
+ndk = "0.9.0"
+
 [target.'cfg(all(unix, not(any(target_vendor = "apple", target_os = "android", target_os = "redox"))))'.dependencies]
 as-raw-xcb-connection = { version = "1.0.0", optional = true }
 bytemuck = { version = "1.12.3", optional = true }
@@ -89,6 +93,10 @@ criterion = { version = "0.4.0", default-features = false, features = ["cargo_be
 web-time = "1.0.0"
 winit = "0.30.0"
 
+[target.'cfg(target_os = "android")'.dev-dependencies]
+winit = { version = "0.30.0", features = ["android-native-activity"] }
+android-activity = "0.6"
+
 [dev-dependencies.image]
 version = "0.25.0"
 # Disable rayon on web
@@ -110,6 +118,16 @@ members = [
     "run-wasm",
 ]
 
+[[example]]
+# Run with `cargo apk r --example winit_android`
+name = "winit_android"
+crate-type = ["cdylib"]
+
+[[example]]
+# Run with `cargo apk r --example winit_multithread_android`
+name = "winit_multithread_android"
+crate-type = ["cdylib"]
+
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]

README.md

@@ -1,14 +1,12 @@
-Overview
-==
+# Softbuffer
 
 Enables software rendering via drawing an image straight to a window.
 
 Softbuffer integrates with the [`raw-window-handle`](https://crates.io/crates/raw-window-handle) crate
 to allow writing pixels to a window in a cross-platform way while using the very high quality dedicated window management
 libraries that are available in the Rust ecosystem.
 
-Alternatives
-==
+## Alternatives
 
 [minifb](https://crates.io/crates/minifb) also allows putting a 2D buffer/image on a window in a platform-independent way.
 Minifb's approach to doing window management itself, however, is problematic code duplication. We already have very high quality
@@ -24,27 +22,27 @@ hardware accelerated graphics stack in any way, and is thus more portable to ins
 hardware acceleration (e.g. VMs, older computers, computers with misconfigured drivers). Softbuffer should be used over
 pixels when its GPU-accelerated post-processing effects are not needed.
 
-License & Credits
-==
+## License & Credits
 
 This library is dual-licensed under MIT or Apache-2.0, just like minifb and rust. Significant portions of code were taken
 from the minifb library to do platform-specific work.
 
-Platform support:
-==
+## Platform support:
+
 Some, but not all, platforms supported in [raw-window-handle](https://crates.io/crates/raw-window-handle) are supported
 by Softbuffer. Pull requests are welcome to add new platforms! **Nonetheless, all major desktop platforms that winit uses
 on desktop are supported.**
 
 For now, the priority for new platforms is:
-1) to have at least one platform on each OS working (e.g. one of Win32 or WinRT, or one of Xlib, Xcb, and Wayland) and
-2) for that one platform on each OS to be the one that winit uses.
+
+1. to have at least one platform on each OS working (e.g. one of Win32 or WinRT, or one of Xlib, Xcb, and Wayland) and
+2. for that one platform on each OS to be the one that winit uses.
 
 (PRs will be accepted for any platform, even if it does not follow the above priority.)
 
 |  Platform ||
 |-----------|--|
-|Android NDK|❌|
+|Android NDK|✅|
 |   AppKit  |✅|
 |  Orbital  |✅|
 |    UIKit  |✅|
@@ -59,13 +57,16 @@ For now, the priority for new platforms is:
 ❔: Immature\
 ❌: Absent
 
-WebAssembly
------------
+## WebAssembly
 
 To run an example with the web backend: `cargo run-wasm --example winit`
 
-Example
-==
+## Android
+
+To run the Android-specific example on an Android phone: `cargo apk r --example winit_android` or `cargo apk r --example winit_multithread_android`.
+
+## Example
+
 ```rust,no_run
 use std::num::NonZeroU32;
 use std::rc::Rc;
@@ -138,8 +139,8 @@ fn main() {
 }
 ```
 
-MSRV Policy
-==
+## MSRV Policy
+
 This crate's Minimum Supported Rust Version (MSRV) is **1.70**. Changes to
 the MSRV will be accompanied by a minor version bump.
 
@@ -163,7 +164,6 @@ same MSRV policy.
 
 [`rust-windowing`]: https://github.com/rust-windowing
 
-Changelog
----------
+## Changelog
 
 See the [changelog](CHANGELOG.md) for a list of this package's versions and the changes made in each version.

examples/winit.rs

@@ -6,9 +6,12 @@ use winit::keyboard::{Key, NamedKey};
 #[path = "utils/winit_app.rs"]
 mod winit_app;
 
+#[cfg(not(target_os = "android"))]
 fn main() {
-    let event_loop = EventLoop::new().unwrap();
+    entry(EventLoop::new().unwrap())
+}
 
+pub(crate) fn entry(event_loop: EventLoop<()>) {
     let app = winit_app::WinitAppBuilder::with_init(
         |elwt| {
             let window = winit_app::make_window(elwt, |w| w);

examples/winit_android.rs

@@ -0,0 +1,18 @@
+#![cfg(target_os = "android")]
+
+use winit::event_loop::EventLoop;
+pub use winit::platform::android::{activity::AndroidApp, EventLoopBuilderExtAndroid};
+
+#[path = "winit.rs"]
+mod desktop_example;
+
+/// Run with `cargo apk r --example winit_android`
+#[no_mangle]
+fn android_main(app: AndroidApp) {
+    let mut builder = EventLoop::builder();
+
+    // Install the Android event loop extension if necessary.
+    builder.with_android_app(app);
+
+    desktop_example::entry(builder.build().unwrap())
+}

examples/winit_multithread.rs

@@ -5,7 +5,7 @@
 mod winit_app;
 
 #[cfg(not(target_family = "wasm"))]
-mod ex {
+pub mod ex {
     use std::num::NonZeroU32;
     use std::sync::{mpsc, Arc, Mutex};
     use winit::event::{Event, KeyEvent, WindowEvent};
@@ -59,9 +59,7 @@ mod ex {
         }
     }
 
-    pub(super) fn entry() {
-        let event_loop = EventLoop::new().unwrap();
-
+    pub fn entry(event_loop: EventLoop<()>) {
         let app = winit_app::WinitAppBuilder::with_init(
             |elwt| {
                 let attributes = Window::default_attributes();
@@ -135,11 +133,14 @@ mod ex {
 
 #[cfg(target_family = "wasm")]
 mod ex {
-    pub(crate) fn entry() {
+    use winit::event_loop::EventLoop;
+    pub(crate) fn entry(_event_loop: EventLoop<()>) {
         eprintln!("winit_multithreaded doesn't work on WASM");
     }
 }
 
+#[cfg(not(target_os = "android"))]
 fn main() {
-    ex::entry();
+    use winit::event_loop::EventLoop;
+    ex::entry(EventLoop::new().unwrap())
 }

examples/winit_multithread_android.rs

@@ -0,0 +1,18 @@
+#![cfg(target_os = "android")]
+
+use winit::event_loop::EventLoop;
+pub use winit::platform::android::{activity::AndroidApp, EventLoopBuilderExtAndroid};
+
+#[path = "winit_multithread.rs"]
+mod desktop_example;
+
+/// Run with `cargo apk r --example winit_android`
+#[no_mangle]
+fn android_main(app: AndroidApp) {
+    let mut builder = EventLoop::builder();
+
+    // Install the Android event loop extension if necessary.
+    builder.with_android_app(app);
+
+    desktop_example::ex::entry(builder.build().unwrap())
+}

src/backend_dispatch.rs

@@ -178,6 +178,8 @@ macro_rules! make_dispatch {
 
 make_dispatch! {
     <D, W> =>
+    #[cfg(target_os = "android")]
+    Android(D, backends::android::AndroidImpl<D, W>, backends::android::BufferImpl<'a, D, W>),
     #[cfg(x11_platform)]
     X11(Arc<backends::x11::X11DisplayImpl<D>>, backends::x11::X11Impl<D, W>, backends::x11::BufferImpl<'a, D, W>),
     #[cfg(wayland_platform)]