iOS support

[wusyong]

Perhaps it's possible with the help of this crate: https://github.com/ryanmcgrath/cacao

[wusyong]

Here are some good news and bad news.
The good news is it can be built. I use cargo mobile to set up a basic winit workplace to explore it.
Once the project is generated. Enter cargo apple open can open it via xcode.
Be sure to add WebKit framework as follows:

Connect your device and run it on xcode or cargo apple run will run the app on your phone.

The bad news is it will crash whenever I touch the screen. The error message is like below:

2021-02-12 21:53:58.252035+0800 wryyyyyyyyy[38573:2578915] *** Assertion failure in -[UIGestureGraphEdge initWithLabel:sourceNode:targetNode:directed:], UIGestureGraphEdge.m:24
fatal runtime error: Rust cannot catch foreign exceptions
Process 38573 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGABRT
    frame #0: 0x00000001bcb0a414 libsystem_kernel.dylib`__pthread_kill + 8
libsystem_kernel.dylib`__pthread_kill:
->  0x1bcb0a414 <+8>:  b.lo   0x1bcb0a434               ; <+40>
    0x1bcb0a418 <+12>: pacibsp
    0x1bcb0a41c <+16>: stp    x29, x30, [sp, #-0x10]!
    0x1bcb0a420 <+20>: mov    x29, sp
Target 0: (wryyyyyyyyy) stopped.

Here's my minimum example for anyone who want to try it:

#[macro_use]
extern crate objc;

use mobile_entry_point::mobile_entry_point;
use winit::{
    event::{Event, WindowEvent},
    event_loop::{ControlFlow, EventLoop},
    platform::ios::{WindowBuilderExtIOS, WindowExtIOS, ScreenEdge},
    window::WindowBuilder,
};
use std::ffi::CString;
use cocoa::base::id;
use core_graphics::geometry::{CGPoint, CGRect, CGSize};

#[cfg(not(target_os = "android"))]
fn init_logging() {
    simple_logger::SimpleLogger::new().init().unwrap();
}

#[mobile_entry_point]
fn main() {
    unsafe {
        init_logging();
        let event_loop = EventLoop::new();
        let window = WindowBuilder::new()
            .with_preferred_screen_edges_deferring_system_gestures(ScreenEdge::ALL)
            .build(&event_loop)
            .unwrap();
        
        let wkwebview = class!(WKWebView);
        let webview: id = msg_send![wkwebview, alloc];

        let rect = CGRect::new(&CGPoint::new(0., 0.), &CGSize::new(400., 900.));
        let () = msg_send![webview, initWithFrame:rect];

        let view = window.ui_view() as id;
        let () = msg_send![view, addSubview:webview];
        
        event_loop.run(move |event, _, control_flow| {
            *control_flow = ControlFlow::Wait;
            println!("{:?}", event);

            match event {
                Event::WindowEvent {
                    event: WindowEvent::CloseRequested,
                    window_id,
                } if window_id == window.id() => *control_flow = ControlFlow::Exit,
                _ => (),
            }
        });
    }
}

[lemarier]

I got it to works ;)

#[macro_use]
extern crate objc;

use std::{slice, str, os::raw::c_char};
use core_graphics::geometry::{CGPoint, CGRect, CGSize};
use cocoa::base::id;
use mobile_entry_point::mobile_entry_point;
use winit::{
    event::{Event, WindowEvent},
    event_loop::{ControlFlow, EventLoop},
    platform::ios::{WindowBuilderExtIOS, WindowExtIOS, ScreenEdge},
    window::WindowBuilder,
};
use objc::runtime::Object;
use objc_id::Id;

#[cfg(target_os = "android")]
fn init_logging() {
    android_logger::init_once(
        android_logger::Config::default()
            .with_min_level(log::Level::Trace)
            .with_tag("Test"),
    );
}

#[cfg(not(target_os = "android"))]
fn init_logging() {
    simple_logger::SimpleLogger::new().init().unwrap();
}

#[mobile_entry_point]
fn main() {
    init_logging();
    let event_loop = EventLoop::new();

    let wkwebview = class!(WKWebView);
    let webview: id = unsafe { msg_send![wkwebview, alloc] };
    

    let window = WindowBuilder::new()
        .with_preferred_screen_edges_deferring_system_gestures(ScreenEdge::ALL)
        .build(&event_loop)
        .unwrap();

    let rect = CGRect::new(&CGPoint::new(0., 0.), &CGSize::new(400., 900.));
    let () = unsafe { msg_send![webview, initWithFrame:rect] };

    let view = window.ui_view() as id;
    let () = unsafe { msg_send![view, addSubview:webview] };

    let sample_html_to_load = r#"
    <!DOCTYPE html>
    <html lang="en">
      <head>
        <meta charset="UTF-8" />
        <meta http-equiv="X-UA-Compatible" content="IE=edge" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
      </head>
      <body>
        <h1>Welcome to WRY!</h1>
        <a href="/hello.html">Link</a>
        <script type="text/javascript" src="/hello.js"></script>
      </body>
    </html>"#;

    // load content
    let empty: id = unsafe { msg_send![class!(NSURL), URLWithString: NSString::new("")] };
    let () = unsafe { msg_send![webview, loadHTMLString:NSString::new(sample_html_to_load) baseURL:empty] };

    event_loop.run(move |event, _, control_flow| {
        *control_flow = ControlFlow::Wait;
        println!("{:?}", event);

        match event {
            Event::WindowEvent {
                event: WindowEvent::CloseRequested,
                window_id,
            } if window_id == window.id() => *control_flow = ControlFlow::Exit,
            Event::MainEventsCleared => {
                window.request_redraw();
            }
            _ => (),
        }
    });
}

const UTF8_ENCODING: usize = 4;

struct NSString(Id<Object>);

impl NSString {
  fn new(s: &str) -> Self {
    // Safety: objc runtime calls are unsafe
    NSString(unsafe {
      let nsstring: id = msg_send![class!(NSString), alloc];
      Id::from_ptr(
        msg_send![nsstring, initWithBytes:s.as_ptr() length:s.len() encoding:UTF8_ENCODING],
      )
    })
  }

  fn to_str(&self) -> &str {
    unsafe {
      let bytes: *const c_char = msg_send![self.0, UTF8String];
      let len = msg_send![self.0, lengthOfBytesUsingEncoding: UTF8_ENCODING];
      let bytes = slice::from_raw_parts(bytes as *const u8, len);
      str::from_utf8_unchecked(bytes)
    }
  }
}

[simlay]

Note:

    let rect = CGRect::new(&CGPoint::new(0., 0.), &CGSize::new(400., 900.));
    let () = unsafe { msg_send![webview, initWithFrame:rect] };

To make this fullscreen, you'll want something like UIScreen::mainScreen().bounds(); but without the uikit-sys crate because I never finished a last rust-bindgen PR. I'd link to the docs src but it kinda crashes my browser due to how long the file is haha.

I think you want like:

let screen = unsafe { msg_send![UIScreen, mainScreen] };
let rect = unsafe { msg_send![rect bounds] };
let () = unsafe { msg_send![webview, initWithFrame:rect] };

[wusyong]

Closed by #238