Pixel Blur (#1777)

* Create pixel_blur.py

Add pixel blur node similar to "Pixelize" in gimp.

* Update pixel_blur.py

* Update pixel_blur.py

* Update pixel_blur.py

added padding

* Update pixel_blur.py

fix greyscale image

* change name & category

---------

Co-authored-by: Joey Ballentine <34788790+joeyballentine@users.noreply.github.com>
Co-authored-by: Michael Schmidt <mitchi5000.ms@googlemail.com>

backend/src/packages/chaiNNer_standard/image_filter/miscellaneous/pixelate.py

@@ -0,0 +1,56 @@
+from __future__ import annotations
+
+import cv2
+import numpy as np
+
+from nodes.properties.inputs import ImageInput, NumberInput
+from nodes.properties.outputs import ImageOutput
+
+from .. import miscellaneous_group
+
+
+@miscellaneous_group.register(
+    schema_id="chainner:image:pixelate",
+    name="Pixelate",
+    description="Pixelate an image.",
+    icon="MdOutlineAutoFixHigh",
+    inputs=[
+        ImageInput(),
+        NumberInput("Size X", default=10, precision=0, minimum=1, controls_step=1),
+        NumberInput("Size Y", default=10, precision=0, minimum=1, controls_step=1),
+    ],
+    outputs=[ImageOutput(image_type="Input0")],
+)
+def pixelate_node(
+    img: np.ndarray,
+    size_x: int,
+    size_y: int,
+) -> np.ndarray:
+    block_sizes = (size_x, size_y)
+    height, width = img.shape[:2]
+
+    pad_x = (block_sizes[0] - width % block_sizes[0]) % block_sizes[0]
+    pad_y = (block_sizes[1] - height % block_sizes[1]) % block_sizes[1]
+    img = cv2.copyMakeBorder(img, 0, pad_y, 0, pad_x, cv2.BORDER_REFLECT_101)
+
+    num_blocks_x = width // block_sizes[0]
+    num_blocks_y = height // block_sizes[1]
+
+    blocks = img[: num_blocks_y * block_sizes[1], : num_blocks_x * block_sizes[0]]
+    blocks = (
+        blocks.reshape(
+            (num_blocks_y, block_sizes[1], num_blocks_x, block_sizes[0], img.shape[-1])
+        )
+        if len(img.shape) > 2
+        else blocks.reshape(
+            (num_blocks_y, block_sizes[1], num_blocks_x, block_sizes[0])
+        )
+    )
+
+    average_colors = np.mean(np.mean(blocks, axis=1), axis=2)
+
+    repeated_colors = np.repeat(
+        np.repeat(average_colors, block_sizes[0], axis=1), block_sizes[1], axis=0
+    )
+
+    return repeated_colors[:height, :width]