Merge remote-tracking branch 'origin/master' into damage

src/lib.rs

@@ -1,6 +1,7 @@
 #![doc = include_str!("../README.md")]
 #![deny(unsafe_op_in_unsafe_fn)]
 #![warn(missing_docs)]
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
 
 #[cfg(target_os = "macos")]
 #[macro_use]
@@ -35,6 +36,9 @@ use raw_window_handle::{
     HasRawDisplayHandle, HasRawWindowHandle, RawDisplayHandle, RawWindowHandle,
 };
 
+#[cfg(target_arch = "wasm32")]
+pub use self::web::SurfaceExtWeb;
+
 /// An instance of this struct contains the platform-specific data that must be managed in order to
 /// write to a window on that platform.
 pub struct Context {

src/web.rs

@@ -11,6 +11,7 @@ use web_sys::ImageData;
 use crate::error::SwResultExt;
 use crate::{Rect, SoftBufferError};
 use std::convert::TryInto;
+use std::marker::PhantomData;
 use std::num::NonZeroU32;
 
 /// Display implementation for the web platform.
@@ -62,6 +63,10 @@ impl WebImpl {
             // We already made sure this was a canvas in `querySelector`.
             .unchecked_into();
 
+        Self::from_canvas(canvas)
+    }
+
+    fn from_canvas(canvas: HtmlCanvasElement) -> Result<Self, SoftBufferError> {
         let ctx = canvas
             .get_context("2d")
             .ok()
@@ -172,6 +177,23 @@ impl WebImpl {
     }
 }
 
+/// Extension methods for the Wasm target on [`Surface`](crate::Surface).
+pub trait SurfaceExtWeb: Sized {
+    /// Creates a new instance of this struct, using the provided [`HtmlCanvasElement`].
+    fn from_canvas(canvas: HtmlCanvasElement) -> Result<Self, SoftBufferError>;
+}
+
+impl SurfaceExtWeb for crate::Surface {
+    fn from_canvas(canvas: HtmlCanvasElement) -> Result<Self, SoftBufferError> {
+        let imple = crate::SurfaceDispatch::Web(WebImpl::from_canvas(canvas)?);
+
+        Ok(Self {
+            surface_impl: Box::new(imple),
+            _marker: PhantomData,
+        })
+    }
+}
+
 pub struct BufferImpl<'a> {
     imp: &'a mut WebImpl,
 }