init commit

dither.py

@@ -0,0 +1,58 @@
+import torch
+
+class Dither:
+    def __init__(self):
+        pass
+    
+    @classmethod
+    def INPUT_TYPES(s):
+        return {
+            "required": {
+                "image": ("IMAGE",),
+                "bits": ("INT", {
+                    "default": 4, 
+                    "min": 0,
+                    "max": 8,
+                    "step": 1
+                }),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "dither"
+
+    CATEGORY = "postprocessing"
+
+    def dither(self, image, bits):
+        tensor_img = image[0]
+        height, width, _ = tensor_img.shape
+        out = tensor_img.clone()
+        levels = 2 ** bits - 1
+
+        for y in range(height):
+            for x in range(width):
+                old_pixel = out[y, x].clone()
+                new_pixel = torch.round(old_pixel * levels) / levels
+                out[y, x] = new_pixel
+
+                error = old_pixel - new_pixel
+
+                if x + 1 < width:
+                    out[y, x + 1] += error * (7 / 16)
+                if x - 1 >= 0 and y + 1 < height:
+                    out[y + 1, x - 1] += error * 3/16
+                if y + 1 < height:
+                    out[y + 1, x] += error * 5/16
+                if x + 1 < width and y + 1 < height:
+                    out[y + 1, x + 1] += error * 1/16
+
+        out = torch.clamp(out, 0, 1).unsqueeze(0)
+
+        return (out,)
+
+
+# A dictionary that contains all nodes you want to export with their names
+# NOTE: names should be globally unique
+NODE_CLASS_MAPPINGS = {
+    "Dither": Dither
+}