feat: implement layer mask editing support with scratch buffer and coordinate normalization

hcie-psd/src/psd_import.rs

@@ -615,7 +615,7 @@ pub fn parse_psd_sequential_full(bytes: &[u8]) -> Result<ParsedPsdData, String>
         let mut mask_default_color = 0;
 
         for channel in &layer.channels {
-            if channel.id == -2 {
+            if (channel.id == -2 || channel.id == -3) && decompressed_mask.is_none() {
                 if let Some(mask) = &layer.mask_info {
                     let w = (mask.right - mask.left) as u32;
                     let h = (mask.bottom - mask.top) as u32;
@@ -892,3 +892,19 @@ pub fn import_psd(path: &Path) -> Result<Vec<hcie_protocol::Layer>, String> {
 
     Ok(flat_layers)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_example3_mask_import() {
+        let path = std::path::Path::new("/mnt/extra/00_PROJECTS/hcie-rust-v3.05/_images/_test_images/example3/Example3-mini.psd");
+        if path.exists() {
+            let layers = import_psd(path).expect("import_psd failed");
+            for l in &layers {
+                println!("TEST_LAYER: '{}' has_mask={} bounds={:?}", l.name, l.mask_pixels.is_some(), l.mask_bounds);
+            }
+        }
+    }
+}