🎉 Refactor memory managemnt for color linear gradient stops

render-wasm/src/main.rs

@@ -1,6 +1,7 @@
 mod debug;
 mod images;
 mod math;
+pub mod mem;
 mod render;
 mod shapes;
 mod state;
@@ -176,14 +177,34 @@ pub extern "C" fn add_shape_linear_fill(
     }
 }
 
+#[derive(Debug)]
+pub struct RawStopData {
+    color: [u8; 4],
+    offset: u8,
+}
+
 #[no_mangle]
-pub extern "C" fn add_shape_fill_stop(raw_color: u32, offset: f32) {
+pub extern "C" fn add_shape_fill_stops(ptr: *mut RawStopData, n_stops: i32) {
     let state = unsafe { STATE.as_mut() }.expect("got an invalid state pointer");
     if let Some(shape) = state.current_shape() {
-        let color = skia::Color::new(raw_color);
-        shape
-            .add_gradient_stop(color, offset)
-            .expect("got no fill or an invalid one");
+        unsafe {
+            let buf = Vec::<RawStopData>::from_raw_parts(ptr, n_stops as usize, n_stops as usize);
+            for raw_stop in buf.iter() {
+                let color = skia::Color::from_argb(
+                    raw_stop.color[3],
+                    raw_stop.color[0],
+                    raw_stop.color[1],
+                    raw_stop.color[2],
+                );
+                shape
+                    .add_gradient_stop(color, (raw_stop.offset as f32) / 100.)
+                    .expect("got no fill or an invalid one");
+            }
+            mem::free(
+                ptr as *mut u8,
+                n_stops as usize * std::mem::size_of::<RawStopData>(),
+            );
+        }
     }
 }
 

render-wasm/src/mem.rs

@@ -0,0 +1,17 @@
+#[no_mangle]
+pub extern "C" fn alloc_bytes(len: usize) -> *mut u8 {
+    // create a new mutable buffer with capacity `len`
+    let mut buf: Vec<u8> = Vec::with_capacity(len);
+    let ptr = buf.as_mut_ptr();
+    // take ownership of the memory block and ensure the its destructor is not
+    // called when the object goes out of scope at the end of the function
+    std::mem::forget(buf);
+    return ptr;
+}
+
+pub fn free(ptr: *mut u8, len: usize) {
+    unsafe {
+        let buf = Vec::<u8>::from_raw_parts(ptr, len, len);
+        std::mem::forget(buf);
+    }
+}