Added WASM Support (#368)

* add: wasm support

* add: wasm-bindgen-rayon for multithreading

---------

Co-authored-by: Kornel <kornel@geekhood.net>

Author: ppmpreetham

Cargo.lock

@@ -42,6 +42,10 @@ ordered-channel = { version = "1.2.0", features = ["crossbeam-channel"] }
 wild = { version = "2.2.1", optional = true, features = ["glob-quoted-on-windows"] }
 y4m = { version = "0.8.0", optional = true }
 yuv = { version = "0.1.9", optional = true }
+wasm-bindgen = { version = "0.2.108", optional = true }
+web-sys = {version="0.3.85", features = ["console"], optional = true }
+console_error_panic_hook = {version = "0.1.7", optional = true}
+wasm-bindgen-rayon = "1.3.0"
 
 [dependencies.ffmpeg]
 package = "ffmpeg-next"
@@ -69,6 +73,7 @@ video-static = ["video", "ffmpeg/build"]
 video-prebuilt-static = ["video", "ffmpeg/static"]
 # Support lossy LZW encoding when lower quality is set
 gifsicle = []
+wasm = ["dep:wasm-bindgen", "dep:console_error_panic_hook", "dep:web-sys"]
 
 [lib]
 path = "src/lib.rs"
@@ -98,3 +103,9 @@ generation = false
 
 [package.metadata.capi.install.include]
 asset = [{from = "gifski.h"}]
+
+[package.metadata.wasm-pack.profile.release]
+wasm-opt = ["-O3", "--enable-bulk-memory", "--enable-nontrapping-float-to-int", "--enable-sign-ext", "--enable-mutable-globals"]
+
+[package.metadata.wasm-pack.profile.dev]
+wasm-opt = false

Cargo.toml

@@ -102,6 +102,15 @@ cargo cinstall --prefix=/usr --release --destdir=pkgroot
 
 The `cbuild` command can be omitted, since `cinstall` will trigger a build if it hasn't been done already.
 
+### For WASM
+To build the library for WebAssembly, you need to have [wasm-pack](https://rustwasm.github.io/wasm-pack/installer/) installed. Then run:
+
+```sh
+wasm-pack build --target web --features wasm --no-default-features
+```
+
+
+
 ## License
 
 AGPL 3 or later. I can offer alternative licensing options, including [commercial licenses](https://supso.org/projects/pngquant). Let [me](https://kornel.ski/contact) know if you'd like to use it in a product incompatible with this license.

README.md

@@ -69,6 +69,12 @@ use std::sync::atomic::Ordering::Relaxed;
 use std::sync::Mutex;
 use std::thread;
 
+#[cfg(feature = "wasm")]
+pub mod wasm;
+
+#[cfg(feature = "wasm")]
+pub use wasm::GifskiWasm;
+
 /// Number of repetitions
 pub type Repeat = gif::Repeat;
 

src/lib.rs

@@ -0,0 +1,103 @@
+use wasm_bindgen::prelude::*;
+use crate::{Settings, Repeat};
+use imgref::ImgVec;
+use rgb::RGBA8;
+use std::sync::Arc;
+use std::sync::Mutex;
+
+#[wasm_bindgen]
+pub struct GifskiWasm {
+    settings: Settings,
+    frames: Vec<(ImgVec<RGBA8>, f64)>,
+    width: u32,
+    height: u32,
+}
+
+#[wasm_bindgen]
+impl GifskiWasm {
+    #[wasm_bindgen(constructor)]
+    pub fn new(width: u32, height: u32, quality: u8) -> Result<GifskiWasm, JsValue> {
+        // Better panic messages in browser console
+        console_error_panic_hook::set_once();
+        
+        let settings = Settings {
+            width: if width > 0 { Some(width) } else { None },
+            height: if height > 0 { Some(height) } else { None },
+            quality,
+            fast: false,
+            repeat: Repeat::Infinite,
+        };
+        
+        Ok(GifskiWasm { 
+            settings,
+            frames: Vec::new(),
+            width,
+            height,
+        })
+    }
+    
+    pub fn add_frame_rgba(&mut self, rgba_data: &[u8], width: u32, height: u32, timestamp: f64) -> Result<(), JsValue> {
+        if rgba_data.len() != (width * height * 4) as usize {
+            return Err(JsValue::from_str("Invalid RGBA data size"));
+        }
+        
+        // flat RGBA bytes to RGBA8 pixels
+        if width != self.width || height != self.height {
+            return Err(JsValue::from_str("Frame dimensions don't match"));
+        }
+        
+        let pixels: Vec<RGBA8> = rgba_data
+            .chunks_exact(4)
+            .map(|chunk| RGBA8::new(chunk[0], chunk[1], chunk[2], chunk[3]))
+            .collect();
+        
+        let img = ImgVec::new(pixels, width as usize, height as usize);
+        
+        self.frames.push((img, timestamp));
+        
+        Ok(())
+    }
+    
+    pub fn finish(self) -> Result<Vec<u8>, JsValue> {
+        if self.frames.is_empty() {
+            return Err(JsValue::from_str("No frames added"));
+        }
+        
+        let (collector, writer) = crate::new(self.settings)
+            .map_err(|e| JsValue::from_str(&format!("Failed to create gifski: {:?}", e)))?;
+        
+        let frames = self.frames;
+        let output = Arc::new(Mutex::new(Vec::new()));
+        let output_clone = output.clone();
+        
+        let writer_handle = std::thread::spawn(move || {
+            let mut output_guard = output_clone.lock().unwrap();
+            writer.write(&mut *output_guard, &mut crate::progress::NoProgress {})
+        });
+        
+        for (frame_index, (img, timestamp)) in frames.into_iter().enumerate() {
+            collector.add_frame_rgba(frame_index, img, timestamp)
+                .map_err(|e| JsValue::from_str(&format!("Failed to add frame {}: {:?}", frame_index, e)))?;
+        }
+        
+        drop(collector);
+        
+        writer_handle.join()
+            .map_err(|_| JsValue::from_str("Writer thread panicked"))?
+            .map_err(|e| JsValue::from_str(&format!("Failed to write GIF: {:?}", e)))?;
+        
+        let output_vec = Arc::try_unwrap(output)
+            .map_err(|_| JsValue::from_str("Failed to unwrap output"))?
+            .into_inner()
+            .map_err(|_| JsValue::from_str("Failed to lock output"))?;
+        
+        Ok(output_vec)
+    }
+}
+
+// thread pool for wasm-bindgen-rayon
+#[wasm_bindgen]
+pub fn init_thread_pool(num_threads: usize) -> Result<(), JsValue> {
+    wasm_bindgen_rayon::init_thread_pool(num_threads);
+    Ok(())
+}

src/wasm.rs

@@ -0,0 +1,5 @@
+[package]
+name = "gifski-wasm"
+
+[profile.release]
+wasm-opt = ["-O3", "--enable-simd"]