support jpeg encode

.gitignore

@@ -1,5 +1,7 @@
 /target
 Cargo.lock
+
+# for test
 *.ipynb
 *.jxl
 *.jpeg

pillow_jxl/JpegXLImagePlugin.py

@@ -89,7 +89,12 @@ def _save(im, fp, filename, save_all=False):
         decoding_speed=decoding_speed,
         use_container=use_container,
     )
-    data = enc(im.tobytes(), im.width, im.height)
+    # FIXME (Isotr0py): im.filename maybe None if parse stream
+    if im.format == "JPEG" and im.filename:
+        with open(im.filename, "rb") as f:
+            data = enc(f.read(), im.width, im.height, jpeg_encode=True)
+    else:
+        data = enc(im.tobytes(), im.width, im.height, jpeg_encode=False)
     fp.write(data)
 
 

pillow_jxl/__init__.pyi

@@ -17,7 +17,16 @@ class Encoder:
                  lossless: bool = True,
                  quality: float = 0.0): ...
 
-    def __call__(self, data: bytes, width: int, height: int) -> bytes: ...
+    def __call__(self, data: bytes, width: int, height: int, jpeg_encode: bool) -> bytes: ...
+    '''
+        Encode a jpeg-xl image.
+
+        Args:
+            data(`bytes`): raw image bytes
+
+        Return:
+            `bytes`: The encoded jpeg-xl image.
+    '''
 
 
 class Decoder:
@@ -30,14 +39,15 @@ class Decoder:
 
     def __init__(self, parallel: bool = True): ...
 
-    def __call__(self, data: bytes) -> (ImageInfo, bytes): ...
+    def __call__(self, data: bytes) -> (bool, ImageInfo, bytes): ...
     '''
         Decode a jpeg-xl image.
 
         Args:
             data(`bytes`): jpeg-xl image
 
         Return:
+            `bool`: If the jpeg is reconstructed
             `ImageInfo`: The metadata of decoded image
             `bytes`: The decoded image.
     '''

src/lib.rs

@@ -52,8 +52,8 @@ impl Encoder {
         }
     }
 
-    #[pyo3(signature = (data, width, height))]
-    fn __call__<'a>(&'a self, _py: Python<'a>, data: &[u8], width: u32, height: u32) -> &PyBytes {
+    #[pyo3(signature = (data, width, height, jpeg_encode))]
+    fn __call__<'a>(&'a self, _py: Python<'a>, data: &[u8], width: u32, height: u32, jpeg_encode: bool) -> &PyBytes {
         let parallel_runner: ThreadsRunner;
         let mut encoder = match self.parallel {
             true => {
@@ -71,7 +71,10 @@ impl Encoder {
         encoder.quality = self.quality;
         encoder.use_container = self.use_container;
         encoder.decoding_speed = self.decoding_speed;
-        let buffer: EncoderResult<u8> = encoder.encode(&data, width, height).unwrap();
+        let buffer: EncoderResult<u8> = match jpeg_encode {
+            true => encoder.encode_jpeg(&data).unwrap(),
+            false => encoder.encode(&data, width, height).unwrap(),
+        };
         PyBytes::new(_py, &buffer.data)
     }