Add prototype invocation for running upscaling models with spandrel.

invokeai/app/invocations/spandrel_upscale.py

@@ -0,0 +1,94 @@
+import numpy as np
+import torch
+from PIL import Image
+from spandrel import ImageModelDescriptor, ModelLoader
+
+from invokeai.app.invocations.baseinvocation import BaseInvocation, invocation
+from invokeai.app.invocations.fields import ImageField, InputField, WithBoard, WithMetadata
+from invokeai.app.invocations.primitives import ImageOutput
+from invokeai.app.services.shared.invocation_context import InvocationContext
+from invokeai.backend.util.devices import TorchDevice
+
+
+def pil_to_tensor(image: Image.Image) -> torch.Tensor:
+    """Convert PIL Image to torch.Tensor.
+
+    Args:
+        image (Image.Image): A PIL Image with shape (H, W, C) and values in the range [0, 255].
+
+    Returns:
+        torch.Tensor: A torch.Tensor with shape (N, C, H, W) and values in the range [0, 1].
+    """
+    image_np = np.array(image)
+    # (H, W, C) -> (C, H, W)
+    image_np = np.transpose(image_np, (2, 0, 1))
+    image_np = image_np / 255
+    image_tensor = torch.from_numpy(image_np).float()
+    # (C, H, W) -> (N, C, H, W)
+    image_tensor = image_tensor.unsqueeze(0)
+    return image_tensor
+
+
+def tensor_to_pil(tensor: torch.Tensor) -> Image.Image:
+    """Convert torch.Tensor to PIL Image.
+
+    Args:
+        tensor (torch.Tensor): A torch.Tensor with shape (N, C, H, W) and values in the range [0, 1].
+
+    Returns:
+        Image.Image: A PIL Image with shape (H, W, C) and values in the range [0, 255].
+    """
+    # (N, C, H, W) -> (C, H, W)
+    tensor = tensor.squeeze(0)
+    # (C, H, W) -> (H, W, C)
+    tensor = tensor.permute(1, 2, 0)
+    tensor = tensor.clamp(0, 1)
+    tensor = (tensor * 255).cpu().detach().numpy().astype(np.uint8)
+    image = Image.fromarray(tensor)
+    return image
+
+
+@invocation("upscale_spandrel", title="Upscale (spandrel)", tags=["upscale"], category="upscale", version="1.0.0")
+class UpscaleSpandrelInvocation(BaseInvocation, WithMetadata, WithBoard):
+    """Upscales an image using any upscaler supported by spandrel (https://github.com/chaiNNer-org/spandrel)."""
+
+    image: ImageField = InputField(description="The input image")
+    # TODO(ryand): Figure out how to handle all the spandrel models so that you don't have to enter a string.
+    model_path: str = InputField(description="The path to the upscaling model to use.")
+
+    def invoke(self, context: InvocationContext) -> ImageOutput:
+        image = context.images.get_pil(self.image.image_name)
+
+        # Load the model.
+        # TODO(ryand): Integrate with the model manager.
+        model = ModelLoader().load_from_file(self.model_path)
+        if not isinstance(model, ImageModelDescriptor):
+            raise ValueError(
+                f"Loaded a spandrel model of type '{type(model)}'. Only image-to-image models are supported "
+                "('ImageModelDescriptor')."
+            )
+
+        # Select model device and dtype.
+        torch_dtype = TorchDevice.choose_torch_dtype()
+        torch_device = TorchDevice.choose_torch_device()
+        if (torch_dtype == torch.float16 and not model.supports_half) or (
+            torch_dtype == torch.bfloat16 and not model.supports_bfloat16
+        ):
+            context.logger.warning(
+                f"The configured dtype ('{torch_dtype}') is not supported by the {type(model.model)} model. Falling "
+                "back to 'float32'."
+            )
+            torch_dtype = torch.float32
+        model.to(device=torch_device, dtype=torch_dtype)
+
+        # Prepare input image for inference.
+        image_tensor = pil_to_tensor(image)
+        image_tensor = image_tensor.to(device=torch_device, dtype=torch_dtype)
+
+        # Run inference.
+        image_tensor = model(image_tensor)
+
+        # Convert the output tensor to a PIL image.
+        pil_image = tensor_to_pil(image_tensor)
+        image_dto = context.images.save(image=pil_image)
+        return ImageOutput.build(image_dto)

pyproject.toml

@@ -46,6 +46,7 @@ dependencies = [
   "opencv-python==4.9.0.80",
   "pytorch-lightning==2.1.3",
   "safetensors==0.4.3",
+  "spandrel==0.3.4",
   "timm==0.6.13",               # needed to override timm latest in controlnet_aux, see  https://github.com/isl-org/ZoeDepth/issues/26
   "torch==2.2.2",
   "torchmetrics==0.11.4",