From c64de3a8fd8e08c12b1e51d6d6d059f809e739cb Mon Sep 17 00:00:00 2001
From: dAxpeDDa <daxpedda@gmail.com>
Date: Mon, 29 May 2023 19:59:59 +0200
Subject: [PATCH] Document possible errors for Web

---
 src/lib.rs | 2 ++
 src/web.rs | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/src/lib.rs b/src/lib.rs
index 98084704..e1365c52 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -321,6 +321,8 @@ impl Surface {
     ///
     /// - On X11, the window must be visible.
     /// - On macOS, Redox and Wayland, this function is unimplemented.
+    /// - On Web, this will fail if the content was supplied by
+    ///   a different origin depending on the sites CORS rules.
     pub fn fetch(&mut self) -> Result<Vec<u32>, SoftBufferError> {
         self.surface_impl.fetch()
     }
diff --git a/src/web.rs b/src/web.rs
index d6c84174..95bcfa72 100644
--- a/src/web.rs
+++ b/src/web.rs
@@ -126,6 +126,10 @@ 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`].
+    ///
+    /// # Errors
+    /// - If the canvas was already controlled by an `OffscreenCanvas`.
+    /// - If a another context then "2d" was already created for this canvas.
     fn from_canvas(canvas: HtmlCanvasElement) -> Result<Self, SoftBufferError>;
 }