From 83ad2068e0c188c947f1e3dd178e474e2bed8084 Mon Sep 17 00:00:00 2001
From: Joakim Hulthe <joakim@hulthe.net>
Date: Thu, 12 Jun 2025 20:38:33 +0200
Subject: [PATCH] Make it run in wasm

---
 .cargo/config.toml |  2 ++
 Cargo.lock         |  4 ++++
 Cargo.toml         |  3 +++
 src/app.rs         |  5 +++--
 src/painting.rs    | 11 +++++++----
 5 files changed, 19 insertions(+), 6 deletions(-)
 create mode 100644 .cargo/config.toml

diff --git a/.cargo/config.toml b/.cargo/config.toml
new file mode 100644
index 0000000..2e07606
--- /dev/null
+++ b/.cargo/config.toml
@@ -0,0 +1,2 @@
+[target.wasm32-unknown-unknown]
+rustflags = ['--cfg', 'getrandom_backend="wasm_js"']
diff --git a/Cargo.lock b/Cargo.lock
index 81c139c..7b2cb7d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -953,9 +953,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "73fea8450eea4bac3940448fb7ae50d91f034f941199fcd9d909a5a07aa455f0"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
  "r-efi",
  "wasi 0.14.2+wasi-0.2.4",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -1350,6 +1352,7 @@ dependencies = [
  "egui_glow 0.31.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger",
  "eyre",
+ "getrandom 0.3.2",
  "half",
  "insta",
  "log",
@@ -1357,6 +1360,7 @@ dependencies = [
  "rfd",
  "serde",
  "wasm-bindgen-futures",
+ "web-sys",
  "zerocopy 0.8.25",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 5bcbf74..d38fa8c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -30,9 +30,12 @@ base64 = "0.22.1"
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 env_logger = "0.11.8"
+rand = "0.9.1"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
+getrandom = { version = "0.3", features = ["wasm_js"] }
 wasm-bindgen-futures = "0.4.50"
+web-sys = "0.3.77"
 
 [patch.crates-io]
 egui =   { git = "https://github.com/emilk/egui", rev = "f2ce6424f3a32f47308fb9871d540c01377b2cd9" }
diff --git a/src/app.rs b/src/app.rs
index 80431f9..ca8d386 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -2,7 +2,6 @@ use std::{
     fs,
     path::PathBuf,
     sync::{Arc, mpsc},
-    thread,
 };
 
 use crate::{file_editor::FileEditor, preferences::Preferences, util::GuiSender};
@@ -204,9 +203,10 @@ impl eframe::App for App {
                         self.open_tab(Tab::File(file));
                     }
 
+                    #[cfg(not(target_arch = "wasm32"))]
                     if ui.button("Open File").clicked() {
                         let actions_tx = self.actions_tx(ui.ctx());
-                        thread::spawn(move || {
+                        std::thread::spawn(move || {
                             let file = rfd::FileDialog::new().pick_file();
 
                             let Some(file_path) = file else { return };
@@ -263,6 +263,7 @@ impl eframe::App for App {
                         }
                     }
 
+                    #[cfg(not(target_arch = "wasm32"))]
                     if ui
                         .add_enabled(open_file.is_some(), Button::new("Save As"))
                         .clicked()
diff --git a/src/painting.rs b/src/painting.rs
index 3080d7a..83ea913 100644
--- a/src/painting.rs
+++ b/src/painting.rs
@@ -3,7 +3,6 @@ use std::{
     iter, mem,
     str::FromStr,
     sync::Arc,
-    time::Instant,
 };
 
 use base64::{Engine, prelude::BASE64_STANDARD};
@@ -436,7 +435,8 @@ impl Handwriting {
 
         self.refresh_texture = false;
 
-        let start_time = Instant::now();
+        #[cfg(not(target_arch = "wasm32"))]
+        let start_time = std::time::Instant::now();
 
         let mut tesselator = Tessellator::new(
             mesh_context.pixels_per_point,
@@ -468,8 +468,11 @@ impl Handwriting {
         self.image = rasterize::<StrokeBlendMode>(px_x, px_y, point_to_pixel, triangles);
         texture.set(self.image.clone(), Default::default());
 
-        let elapsed = start_time.elapsed();
-        println!("refreshed mesh in {:.3}s", elapsed.as_secs_f32());
+        #[cfg(not(target_arch = "wasm32"))]
+        {
+            let elapsed = start_time.elapsed();
+            println!("refreshed mesh in {:.3}s", elapsed.as_secs_f32());
+        }
     }
 
     pub fn ui(&mut self, style: &HandwritingStyle, ui: &mut Ui) {