Add ConcatenateImagesInvocation.

invokeai/app/invocations/concatenate_images.py

@@ -0,0 +1,45 @@
+from typing import Literal
+
+import numpy as np
+from PIL import Image
+
+from invokeai.app.invocations.baseinvocation import BaseInvocation, invocation
+from invokeai.app.invocations.fields import ImageField, InputField
+from invokeai.app.invocations.primitives import ImageOutput
+from invokeai.app.services.shared.invocation_context import InvocationContext
+
+
+@invocation(
+    "concatenate_images",
+    title="Concatenate Images",
+    tags=["image", "concatenate"],
+    category="image",
+    version="1.0.0",
+)
+class ConcatenateImagesInvocation(BaseInvocation):
+    """Concatenate images horizontally or vertically."""
+
+    image_1: ImageField = InputField(description="The first image to concatenate.")
+    image_2: ImageField = InputField(description="The second image to concatenate.")
+    direction: Literal["horizontal", "vertical"] = InputField(
+        default="horizontal", description="The direction along which to concatenate the images."
+    )
+
+    def invoke(self, context: InvocationContext) -> ImageOutput:
+        # For now, we force the images to be RGB.
+        image_1 = np.array(context.images.get_pil(self.image_1.image_name, "RGB"))
+        image_2 = np.array(context.images.get_pil(self.image_2.image_name, "RGB"))
+
+        axis: int = 0
+        if self.direction == "horizontal":
+            axis = 1
+        elif self.direction == "vertical":
+            axis = 0
+        else:
+            raise ValueError(f"Invalid direction: {self.direction}")
+
+        concatenated_image = np.concatenate([image_1, image_2], axis=axis)
+
+        image_pil = Image.fromarray(concatenated_image, mode="RGB")
+        image_dto = context.images.save(image=image_pil)
+        return ImageOutput.build(image_dto)