Add new node to split image channels

comfy_extras/nodes_compositing.py

@@ -185,6 +185,36 @@ class SplitImageWithAlpha(io.ComfyNode):
         return io.NodeOutput(torch.stack(out_images), 1.0 - torch.stack(out_alphas))
 
 
+class SplitImageChannels(io.ComfyNode):
+    @classmethod
+    def define_schema(cls):
+        return io.Schema(
+            node_id="SplitImageChannels",
+            search_aliases=["extract alpha", "extract channels", "separate transparency", "split channels", "remove alpha"],
+            display_name="Split Image Channels",
+            category="mask/compositing",
+            inputs=[
+                io.Image.Input("image"),
+            ],
+            outputs=[
+                io.Image.Output(display_name="red"),
+                io.Image.Output(display_name="green"),
+                io.Image.Output(display_name="blue"),
+                io.Mask.Output(display_name="alpha")
+            ],
+        )
+
+    @classmethod
+    def execute(cls, image: torch.Tensor) -> io.NodeOutput:
+        images = [i[:,:,:3] for i in image]
+        stacked = torch.stack(images)
+        reds = stacked[:, :, :, 0:1].repeat(1, 1, 1, 3)
+        greens = stacked[:, :, :, 1:2].repeat(1, 1, 1, 3)
+        blues = stacked[:, :, :, 2:3].repeat(1, 1, 1, 3)
+        alphas = [i[:,:,3] if i.shape[2] > 3 else torch.ones_like(i[:,:,0]) for i in image]
+        return io.NodeOutput(reds, greens, blues, 1.0 - torch.stack(alphas))
+
+
 class JoinImageWithAlpha(io.ComfyNode):
     @classmethod
     def define_schema(cls):
@@ -217,6 +247,7 @@ class CompositingExtension(ComfyExtension):
     async def get_node_list(self) -> list[type[io.ComfyNode]]:
         return [
             PorterDuffImageComposite,
+            SplitImageChannels,
             SplitImageWithAlpha,
             JoinImageWithAlpha,
         ]