Added support for lanczos scaling

comfy/utils.py

@@ -1,8 +1,10 @@
 import torch
+import torchvision
 import math
 import struct
 import comfy.checkpoint_pickle
 import safetensors.torch
+from PIL import Image
 
 def load_torch_file(ckpt, safe_load=False, device=None):
     if device is None:
@@ -346,6 +348,13 @@ def bislerp(samples, width, height):
     result = result.reshape(n, h_new, w_new, c).movedim(-1, 1)
     return result
 
+def lanczos(samples, width, height):
+    images = [torchvision.transforms.functional.to_pil_image(image) for image in samples]
+    images = [image.resize((width, height), resample=Image.Resampling.LANCZOS) for image in images]
+    images = [torchvision.transforms.functional.to_tensor(image) for image in images]
+    result = torch.stack(images)
+    return result
+
 def common_upscale(samples, width, height, upscale_method, crop):
         if crop == "center":
             old_width = samples.shape[3]
@@ -364,6 +373,8 @@ def common_upscale(samples, width, height, upscale_method, crop):
 
         if upscale_method == "bislerp":
             return bislerp(s, width, height)
+        elif upscale_method == "lanczos":
+            return lanczos(s, width, height)
         else:
             return torch.nn.functional.interpolate(s, size=(height, width), mode=upscale_method)