From 7fc0f29536df804faaa7f1c8d7f1bd8a30081bee Mon Sep 17 00:00:00 2001
From: Apaar Raina <apaarraina@gmail.com>
Date: Wed, 27 May 2026 03:34:05 +0530
Subject: [PATCH 01/16] helper functions for moire synthesis

---
 src/PIL/_moire.py | 249 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 249 insertions(+)
 create mode 100644 src/PIL/_moire.py

diff --git a/src/PIL/_moire.py b/src/PIL/_moire.py
new file mode 100644
index 00000000000..2b4828922e6
--- /dev/null
+++ b/src/PIL/_moire.py
@@ -0,0 +1,249 @@
+from __future__ import annotations
+
+from . import Image, ImageFilter
+import random
+import math
+import io
+
+def _lcd_resampling(img: Image.Image) -> Image.Image:
+    """
+    Simulate an LCD display by mapping each pixel to a single RGB subpixel
+    in the repeating R-G-B stripe layout.
+
+    :param img:
+    :return: An image.
+    """
+    w, h = img.size
+    resampled_img = Image.new("RGB", (w, h))
+
+    for y in range(h):
+        num = 1
+        for x in range(w):
+            r, g, b = img.getpixel((x, y))
+            if num % 3 == 0:
+                resampled_img.putpixel((x, y), (0, 0, b))
+            elif num % 3 == 1:
+                resampled_img.putpixel((x, y), (r, 0, 0))
+            else:
+                resampled_img.putpixel((x, y), (0, g, 0))
+            num += 1
+
+    return resampled_img
+
+def _projective_transformation(img: Image.Image) -> Image.Image:
+    """
+    Apply a random projective transformation to simulate varying camera
+    position and orientation relative to the display.
+
+    :param img:
+    :return: An image.
+    """
+    w, h = img.size
+    theta = math.radians(random.uniform(-1,1))
+
+    #rotation
+    a = math.cos(theta)
+    b = -math.sin(theta)
+    d = math.sin(theta)
+    e = math.cos(theta)
+
+    # Translation
+    c = random.uniform(-0.01 * w, 0.01 * w)
+    f = random.uniform(-0.01 * h, 0.01 * h)
+
+    # Perspective distortion
+    g = random.uniform(-1e-5, 1e-5)
+    h_p = random.uniform(-1e-5, 1e-5)
+
+    # H
+    coeffs = (a, b, c,
+              d, e, f,
+              g, h_p)
+
+    return img.transform((w, h), Image.PERSPECTIVE, coeffs, resample=Image.BICUBIC)
+
+def _radial_distortion(img: Image.Image, k=-1e-7) -> Image.Image:
+    """
+    Use radial distortion function to simulate lens distortion
+
+    :param img:
+    :param k:
+    :return: An image
+    """
+    w, h = img.size
+    radial_distort = Image.new("RGB", (w, h))
+
+    cx = w / 2
+    cy = h / 2
+
+    for y in range(h):
+        for x in range(w):
+            r, g, b = img.getpixel((x, y))
+            xc = x - cx
+            yc = y - cy
+            radius2 = xc**2 + yc**2
+
+            factor = 1 + k * radius2
+            radial_x = int(xc * factor + cx)
+            radial_y = int(yc * factor + cy)
+
+            # Boundary check
+            if 0 <= radial_x < w and 0 <= radial_y < h:
+                radial_distort.putpixel((radial_x, radial_y),(r, g, b))
+
+    return radial_distort
+
+
+def _flat_top_kernel(size=5, sigma=1.0, n=2):
+    """
+    Generate a flat-top Gaussian kernel.
+
+    :param size: the size of the kernel to be produced
+    :param sigma: controls the broadness of the Gaussian kernel
+    :param n: controls the flatness of the kernel peak
+    :return: An Array
+    """
+    kernel = []
+    center = size // 2
+    total = 0
+
+    for y in range(size):
+        row = []
+        for x in range(size):
+            dx = x - center
+            dy = y - center
+            r2 = dx * dx + dy * dy
+            value = math.exp(-((r2 / (2 * sigma * sigma)) ** n))
+            row.append(value)
+            total += value
+        kernel.append(row)
+
+    for y in range(size):
+        for x in range(size):
+            kernel[y][x] /= total
+
+    return kernel
+
+def _flat_top_filtering(img, size=5, sigma=1.0, n=2):
+    """
+    Applying the flat top gaussian kernel on the image to simulate anti-aliasing fiter
+
+    :param img:
+    :param size:
+    :param sigma:
+    :param n:
+    :return: An image
+    """
+    kernel = _flat_top_kernel(size=size, sigma=sigma, n=n)
+    flat_kernel = []
+    for row in kernel:
+        flat_kernel.extend(row)
+
+    return img.filter(ImageFilter.Kernel((5,5), flat_kernel, scale=1))
+
+def _bayer_resampling(img: Image.Image) -> Image.Image:
+    """
+    Simulate a Bayer CFA (GRBG) where each pixel only captures one color channel
+
+    :param img:
+    :return: An image
+    """
+    w, h = img.size
+    resample = Image.new("RGB", (w, h))
+
+    for y in range(h):
+        for x in range(w):
+            r, g, b = img.getpixel((x, y))
+            if y % 2 == 0:
+                if x % 2 == 0:
+                    resample.putpixel((x, y), (0, g, 0))
+                else:
+                    resample.putpixel((x, y), (r, 0, 0))
+            else:
+                if x % 2 == 0:
+                    resample.putpixel((x, y), (0, 0, b))
+                else:
+                    resample.putpixel((x, y), (0, g, 0))
+
+    return resample
+
+def _add_noise(img: Image.Image) -> Image.Image:
+    """
+    Add standard normal noise to the image to simulate sensor noise
+
+    :param img:
+    :return: An image
+    """
+    w, h = img.size
+    noisy = Image.new("RGB", (w, h))
+    for y in range(h):
+        for x in range(w):
+            r, g, b = img.getpixel((x, y))
+            nr = int(r + random.gauss(0, 1))
+            ng = int(g + random.gauss(0, 1))
+            nb = int(b + random.gauss(0, 1))
+            noisy.putpixel((x, y), (nr, ng, nb))
+
+    return noisy
+
+def _clamp(v, lo, hi):
+    return lo if v < lo else (hi if v > hi else v)
+
+def _get_channel(img, x, y, ch, w, h):
+    x = _clamp(x, 0, w - 1)
+    y = _clamp(y, 0, h - 1)
+    return img.getpixel((x, y))[ch]
+
+def _demosaic_bilinear(img: Image.Image) -> Image.Image:
+    """
+    Reconstruct the full RGB image from the Bayer CFA image using bilinear interpolation
+    of the other 2 remaining channels from nearby pixels at each pixel
+
+    :param img:
+    :return: An image
+    """
+    w, h = img.size
+    out = Image.new("RGB", (w, h))
+
+    for y in range(h):
+        for x in range(w):
+            pixel = img.getpixel((x, y))
+
+            if y % 2 == 0 and x % 2 == 0:
+                new_r = (_get_channel(img, x-1, y, 0, w, h) + _get_channel(img, x+1, y, 0, w, h)) >> 1
+                new_g = pixel[1]
+                new_b = (_get_channel(img, x, y-1, 2, w, h) + _get_channel(img, x, y+1, 2, w, h)) >> 1
+
+            elif y % 2 == 0 and x % 2 == 1:
+                new_r = pixel[0]
+                new_g = (_get_channel(img, x-1, y, 1, w, h) + _get_channel(img, x+1, y, 1, w, h) +
+                         _get_channel(img, x, y-1, 1, w, h) + _get_channel(img, x, y+1, 1, w, h)) >> 2
+                new_b = (_get_channel(img, x-1, y-1, 2, w, h) + _get_channel(img, x+1, y-1, 2, w, h) +
+                         _get_channel(img, x-1, y+1, 2, w, h) + _get_channel(img, x+1, y+1, 2, w, h)) >> 2
+
+            elif y % 2 == 1 and x % 2 == 0:
+                new_r = (_get_channel(img, x-1, y-1, 0, w, h) + _get_channel(img, x+1, y-1, 0, w, h) +
+                         _get_channel(img, x-1, y+1, 0, w, h) + _get_channel(img, x+1, y+1, 0, w, h)) >> 2
+                new_g = (_get_channel(img, x-1, y, 1, w, h) + _get_channel(img, x+1, y, 1, w, h) +
+                         _get_channel(img, x, y-1, 1, w, h) + _get_channel(img, x, y+1, 1, w, h)) >> 2
+                new_b = pixel[2]
+
+            else:
+                new_r = (_get_channel(img, x, y-1, 0, w, h) + _get_channel(img, x, y+1, 0, w, h)) >> 1
+                new_g = pixel[1]
+                new_b = (_get_channel(img, x-1, y, 2, w, h) + _get_channel(img, x+1, y, 2, w, h)) >> 1
+
+            out.putpixel((x, y), (_clamp(new_r, 0, 255), _clamp(new_g, 0, 255), _clamp(new_b, 0, 255)))
+
+    return out
+
+def _denoise(img: Image.Image) -> Image.Image:
+    return img.filter(ImageFilter.GaussianBlur(radius=1))
+
+
+def _jpeg_compression(img: Image.Image) -> Image.Image:
+    buffer = io.BytesIO()
+    img.save(buffer, format='JPEG')
+    buffer.seek(0)
+
+    return Image.open(buffer).convert('RGB')

From 2ef4858542630cc92e0fd91d540ad73d24740db4 Mon Sep 17 00:00:00 2001
From: Apaar Raina <apaarraina@gmail.com>
Date: Wed, 27 May 2026 03:34:27 +0530
Subject: [PATCH 02/16] test suite for moire synthesis

---
 Tests/test_moire_synthesis.py | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 Tests/test_moire_synthesis.py

diff --git a/Tests/test_moire_synthesis.py b/Tests/test_moire_synthesis.py
new file mode 100644
index 00000000000..74853820b52
--- /dev/null
+++ b/Tests/test_moire_synthesis.py
@@ -0,0 +1,17 @@
+import pytest
+from PIL import Image,ImageOps
+
+def test_moire_output_size():
+    img = Image.new("RGB", (100, 100), (128, 128, 128))
+    result = ImageOps.moire(img)
+    assert result.size == img.size
+
+def test_moire_output_mode():
+    img = Image.new("RGB", (100, 100), (128, 128, 128))
+    result = ImageOps.moire(img)
+    assert result.mode == "RGB"
+
+def test_moire_accepts_non_rgb():
+    img = Image.new("L", (100, 100), 128)
+    result = ImageOps.moire(img)
+    assert result.mode == "RGB"

From 2c57ab5dfc88a14488ae4da12fcb109885f3ccb2 Mon Sep 17 00:00:00 2001
From: Apaar Raina <apaarraina@gmail.com>
Date: Wed, 27 May 2026 03:34:53 +0530
Subject: [PATCH 03/16] added the moire synthesis function

---
 src/PIL/ImageOps.py | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/src/PIL/ImageOps.py b/src/PIL/ImageOps.py
index f0ae142b9ba..3e7c5229b11 100644
--- a/src/PIL/ImageOps.py
+++ b/src/PIL/ImageOps.py
@@ -24,6 +24,18 @@
 from collections.abc import Sequence
 from typing import Literal, Protocol, cast, overload
 
+from ._moire import (
+    _lcd_resampling,
+    _projective_transformation,
+    _radial_distortion,
+    _flat_top_filtering,
+    _bayer_resampling,
+    _add_noise,
+    _demosaic_bilinear,
+    _denoise,
+    _jpeg_compression,
+)
+
 from . import ExifTags, Image, ImagePalette
 
 #
@@ -646,6 +658,26 @@ def mirror(image: Image.Image) -> Image.Image:
     """
     return image.transpose(Image.Transpose.FLIP_LEFT_RIGHT)
 
+def moire(image: Image.Image) -> Image.Image:
+    """
+    This is the applications of the helper functions defines in _moire.py to generate a synthetic moire image.
+    :param image:
+    :return: An image.
+    """
+    if len(image.getbands()) == 1:
+        image = image.convert("RGB")
+
+    resampled_img = _lcd_resampling(image)
+    projective_transform = _projective_transformation(resampled_img)
+    distorted_img = _radial_distortion(projective_transform)
+    filtered_img = _flat_top_filtering(distorted_img)
+    Bayer = _bayer_resampling(filtered_img)
+    Bayer_noise = _add_noise(Bayer)
+    rgb_img = _demosaic_bilinear(Bayer_noise)
+    rgb_denoised = _denoise(rgb_img)
+    compressed_img = _jpeg_compression(rgb_denoised)
+
+    return compressed_img
 
 def posterize(image: Image.Image, bits: int) -> Image.Image:
     """

From c52317340cf19b5a2710a78fc149ea16286d8a4e Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Tue, 26 May 2026 22:20:04 +0000
Subject: [PATCH 04/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 Tests/test_moire_synthesis.py |  8 +++-
 src/PIL/ImageOps.py           | 15 +++---
 src/PIL/_moire.py             | 90 +++++++++++++++++++++++++----------
 3 files changed, 79 insertions(+), 34 deletions(-)

diff --git a/Tests/test_moire_synthesis.py b/Tests/test_moire_synthesis.py
index 74853820b52..fcbac7b6058 100644
--- a/Tests/test_moire_synthesis.py
+++ b/Tests/test_moire_synthesis.py
@@ -1,16 +1,20 @@
-import pytest
-from PIL import Image,ImageOps
+from __future__ import annotations
+
+from PIL import Image, ImageOps
+
 
 def test_moire_output_size():
     img = Image.new("RGB", (100, 100), (128, 128, 128))
     result = ImageOps.moire(img)
     assert result.size == img.size
 
+
 def test_moire_output_mode():
     img = Image.new("RGB", (100, 100), (128, 128, 128))
     result = ImageOps.moire(img)
     assert result.mode == "RGB"
 
+
 def test_moire_accepts_non_rgb():
     img = Image.new("L", (100, 100), 128)
     result = ImageOps.moire(img)
diff --git a/src/PIL/ImageOps.py b/src/PIL/ImageOps.py
index 3e7c5229b11..2feb81535c3 100644
--- a/src/PIL/ImageOps.py
+++ b/src/PIL/ImageOps.py
@@ -24,20 +24,19 @@
 from collections.abc import Sequence
 from typing import Literal, Protocol, cast, overload
 
+from . import ExifTags, Image, ImagePalette
 from ._moire import (
-    _lcd_resampling,
-    _projective_transformation,
-    _radial_distortion,
-    _flat_top_filtering,
-    _bayer_resampling,
     _add_noise,
+    _bayer_resampling,
     _demosaic_bilinear,
     _denoise,
+    _flat_top_filtering,
     _jpeg_compression,
+    _lcd_resampling,
+    _projective_transformation,
+    _radial_distortion,
 )
 
-from . import ExifTags, Image, ImagePalette
-
 #
 # helpers
 
@@ -658,6 +657,7 @@ def mirror(image: Image.Image) -> Image.Image:
     """
     return image.transpose(Image.Transpose.FLIP_LEFT_RIGHT)
 
+
 def moire(image: Image.Image) -> Image.Image:
     """
     This is the applications of the helper functions defines in _moire.py to generate a synthetic moire image.
@@ -679,6 +679,7 @@ def moire(image: Image.Image) -> Image.Image:
 
     return compressed_img
 
+
 def posterize(image: Image.Image, bits: int) -> Image.Image:
     """
     Reduce the number of bits for each color channel.
diff --git a/src/PIL/_moire.py b/src/PIL/_moire.py
index 2b4828922e6..d348371ef4f 100644
--- a/src/PIL/_moire.py
+++ b/src/PIL/_moire.py
@@ -1,9 +1,11 @@
 from __future__ import annotations
 
-from . import Image, ImageFilter
-import random
-import math
 import io
+import math
+import random
+
+from . import Image, ImageFilter
+
 
 def _lcd_resampling(img: Image.Image) -> Image.Image:
     """
@@ -30,6 +32,7 @@ def _lcd_resampling(img: Image.Image) -> Image.Image:
 
     return resampled_img
 
+
 def _projective_transformation(img: Image.Image) -> Image.Image:
     """
     Apply a random projective transformation to simulate varying camera
@@ -39,9 +42,9 @@ def _projective_transformation(img: Image.Image) -> Image.Image:
     :return: An image.
     """
     w, h = img.size
-    theta = math.radians(random.uniform(-1,1))
+    theta = math.radians(random.uniform(-1, 1))
 
-    #rotation
+    # rotation
     a = math.cos(theta)
     b = -math.sin(theta)
     d = math.sin(theta)
@@ -56,12 +59,11 @@ def _projective_transformation(img: Image.Image) -> Image.Image:
     h_p = random.uniform(-1e-5, 1e-5)
 
     # H
-    coeffs = (a, b, c,
-              d, e, f,
-              g, h_p)
+    coeffs = (a, b, c, d, e, f, g, h_p)
 
     return img.transform((w, h), Image.PERSPECTIVE, coeffs, resample=Image.BICUBIC)
 
+
 def _radial_distortion(img: Image.Image, k=-1e-7) -> Image.Image:
     """
     Use radial distortion function to simulate lens distortion
@@ -89,7 +91,7 @@ def _radial_distortion(img: Image.Image, k=-1e-7) -> Image.Image:
 
             # Boundary check
             if 0 <= radial_x < w and 0 <= radial_y < h:
-                radial_distort.putpixel((radial_x, radial_y),(r, g, b))
+                radial_distort.putpixel((radial_x, radial_y), (r, g, b))
 
     return radial_distort
 
@@ -124,6 +126,7 @@ def _flat_top_kernel(size=5, sigma=1.0, n=2):
 
     return kernel
 
+
 def _flat_top_filtering(img, size=5, sigma=1.0, n=2):
     """
     Applying the flat top gaussian kernel on the image to simulate anti-aliasing fiter
@@ -139,7 +142,8 @@ def _flat_top_filtering(img, size=5, sigma=1.0, n=2):
     for row in kernel:
         flat_kernel.extend(row)
 
-    return img.filter(ImageFilter.Kernel((5,5), flat_kernel, scale=1))
+    return img.filter(ImageFilter.Kernel((5, 5), flat_kernel, scale=1))
+
 
 def _bayer_resampling(img: Image.Image) -> Image.Image:
     """
@@ -167,6 +171,7 @@ def _bayer_resampling(img: Image.Image) -> Image.Image:
 
     return resample
 
+
 def _add_noise(img: Image.Image) -> Image.Image:
     """
     Add standard normal noise to the image to simulate sensor noise
@@ -186,14 +191,17 @@ def _add_noise(img: Image.Image) -> Image.Image:
 
     return noisy
 
+
 def _clamp(v, lo, hi):
     return lo if v < lo else (hi if v > hi else v)
 
+
 def _get_channel(img, x, y, ch, w, h):
     x = _clamp(x, 0, w - 1)
     y = _clamp(y, 0, h - 1)
     return img.getpixel((x, y))[ch]
 
+
 def _demosaic_bilinear(img: Image.Image) -> Image.Image:
     """
     Reconstruct the full RGB image from the Bayer CFA image using bilinear interpolation
@@ -210,40 +218,72 @@ def _demosaic_bilinear(img: Image.Image) -> Image.Image:
             pixel = img.getpixel((x, y))
 
             if y % 2 == 0 and x % 2 == 0:
-                new_r = (_get_channel(img, x-1, y, 0, w, h) + _get_channel(img, x+1, y, 0, w, h)) >> 1
+                new_r = (
+                    _get_channel(img, x - 1, y, 0, w, h)
+                    + _get_channel(img, x + 1, y, 0, w, h)
+                ) >> 1
                 new_g = pixel[1]
-                new_b = (_get_channel(img, x, y-1, 2, w, h) + _get_channel(img, x, y+1, 2, w, h)) >> 1
+                new_b = (
+                    _get_channel(img, x, y - 1, 2, w, h)
+                    + _get_channel(img, x, y + 1, 2, w, h)
+                ) >> 1
 
             elif y % 2 == 0 and x % 2 == 1:
                 new_r = pixel[0]
-                new_g = (_get_channel(img, x-1, y, 1, w, h) + _get_channel(img, x+1, y, 1, w, h) +
-                         _get_channel(img, x, y-1, 1, w, h) + _get_channel(img, x, y+1, 1, w, h)) >> 2
-                new_b = (_get_channel(img, x-1, y-1, 2, w, h) + _get_channel(img, x+1, y-1, 2, w, h) +
-                         _get_channel(img, x-1, y+1, 2, w, h) + _get_channel(img, x+1, y+1, 2, w, h)) >> 2
+                new_g = (
+                    _get_channel(img, x - 1, y, 1, w, h)
+                    + _get_channel(img, x + 1, y, 1, w, h)
+                    + _get_channel(img, x, y - 1, 1, w, h)
+                    + _get_channel(img, x, y + 1, 1, w, h)
+                ) >> 2
+                new_b = (
+                    _get_channel(img, x - 1, y - 1, 2, w, h)
+                    + _get_channel(img, x + 1, y - 1, 2, w, h)
+                    + _get_channel(img, x - 1, y + 1, 2, w, h)
+                    + _get_channel(img, x + 1, y + 1, 2, w, h)
+                ) >> 2
 
             elif y % 2 == 1 and x % 2 == 0:
-                new_r = (_get_channel(img, x-1, y-1, 0, w, h) + _get_channel(img, x+1, y-1, 0, w, h) +
-                         _get_channel(img, x-1, y+1, 0, w, h) + _get_channel(img, x+1, y+1, 0, w, h)) >> 2
-                new_g = (_get_channel(img, x-1, y, 1, w, h) + _get_channel(img, x+1, y, 1, w, h) +
-                         _get_channel(img, x, y-1, 1, w, h) + _get_channel(img, x, y+1, 1, w, h)) >> 2
+                new_r = (
+                    _get_channel(img, x - 1, y - 1, 0, w, h)
+                    + _get_channel(img, x + 1, y - 1, 0, w, h)
+                    + _get_channel(img, x - 1, y + 1, 0, w, h)
+                    + _get_channel(img, x + 1, y + 1, 0, w, h)
+                ) >> 2
+                new_g = (
+                    _get_channel(img, x - 1, y, 1, w, h)
+                    + _get_channel(img, x + 1, y, 1, w, h)
+                    + _get_channel(img, x, y - 1, 1, w, h)
+                    + _get_channel(img, x, y + 1, 1, w, h)
+                ) >> 2
                 new_b = pixel[2]
 
             else:
-                new_r = (_get_channel(img, x, y-1, 0, w, h) + _get_channel(img, x, y+1, 0, w, h)) >> 1
+                new_r = (
+                    _get_channel(img, x, y - 1, 0, w, h)
+                    + _get_channel(img, x, y + 1, 0, w, h)
+                ) >> 1
                 new_g = pixel[1]
-                new_b = (_get_channel(img, x-1, y, 2, w, h) + _get_channel(img, x+1, y, 2, w, h)) >> 1
+                new_b = (
+                    _get_channel(img, x - 1, y, 2, w, h)
+                    + _get_channel(img, x + 1, y, 2, w, h)
+                ) >> 1
 
-            out.putpixel((x, y), (_clamp(new_r, 0, 255), _clamp(new_g, 0, 255), _clamp(new_b, 0, 255)))
+            out.putpixel(
+                (x, y),
+                (_clamp(new_r, 0, 255), _clamp(new_g, 0, 255), _clamp(new_b, 0, 255)),
+            )
 
     return out
 
+
 def _denoise(img: Image.Image) -> Image.Image:
     return img.filter(ImageFilter.GaussianBlur(radius=1))
 
 
 def _jpeg_compression(img: Image.Image) -> Image.Image:
     buffer = io.BytesIO()
-    img.save(buffer, format='JPEG')
+    img.save(buffer, format="JPEG")
     buffer.seek(0)
 
-    return Image.open(buffer).convert('RGB')
+    return Image.open(buffer).convert("RGB")

From 9bb24ad9aa1ad1b8b8951b38485f0b1fd5b55bd7 Mon Sep 17 00:00:00 2001
From: Apaar Raina <164377477+ApaarRaina@users.noreply.github.com>
Date: Wed, 27 May 2026 13:24:58 +0530
Subject: [PATCH 05/16] Updated docstring of the moire function

Co-authored-by: Andrew Murray <3112309+radarhere@users.noreply.github.com>
---
 src/PIL/ImageOps.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/PIL/ImageOps.py b/src/PIL/ImageOps.py
index 2feb81535c3..3e88672e792 100644
--- a/src/PIL/ImageOps.py
+++ b/src/PIL/ImageOps.py
@@ -660,7 +660,7 @@ def mirror(image: Image.Image) -> Image.Image:
 
 def moire(image: Image.Image) -> Image.Image:
     """
-    This is the applications of the helper functions defines in _moire.py to generate a synthetic moire image.
+    Generates a synthetic Moire image
     :param image:
     :return: An image.
     """

From 0711b7f7e993d8c4ac9c3b8948dd095152df0696 Mon Sep 17 00:00:00 2001
From: Apaar Raina <164377477+ApaarRaina@users.noreply.github.com>
Date: Wed, 27 May 2026 15:50:04 +0530
Subject: [PATCH 06/16] Add return type annotation to test_moire_synthesis

Co-authored-by: Andrew Murray <3112309+radarhere@users.noreply.github.com>
---
 Tests/test_moire_synthesis.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tests/test_moire_synthesis.py b/Tests/test_moire_synthesis.py
index fcbac7b6058..7183e999483 100644
--- a/Tests/test_moire_synthesis.py
+++ b/Tests/test_moire_synthesis.py
@@ -15,7 +15,7 @@ def test_moire_output_mode():
     assert result.mode == "RGB"
 
 
-def test_moire_accepts_non_rgb():
+def test_moire_accepts_non_rgb() -> None:
     img = Image.new("L", (100, 100), 128)
     result = ImageOps.moire(img)
     assert result.mode == "RGB"

From f621626f3cbdc2dc3f6bd8d19b2822037bb83fab Mon Sep 17 00:00:00 2001
From: Apaar Raina <apaarraina@gmail.com>
Date: Wed, 27 May 2026 13:31:28 +0530
Subject: [PATCH 07/16] Add return type annotation to test functions

---
 Tests/test_moire_synthesis.py | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/Tests/test_moire_synthesis.py b/Tests/test_moire_synthesis.py
index 7183e999483..b385882ffe6 100644
--- a/Tests/test_moire_synthesis.py
+++ b/Tests/test_moire_synthesis.py
@@ -1,21 +1,17 @@
-from __future__ import annotations
+import pytest
+from PIL import Image,ImageOps
 
-from PIL import Image, ImageOps
-
-
-def test_moire_output_size():
+def test_moire_output_size()->None:
     img = Image.new("RGB", (100, 100), (128, 128, 128))
     result = ImageOps.moire(img)
     assert result.size == img.size
 
-
-def test_moire_output_mode():
+def test_moire_output_mode()->None:
     img = Image.new("RGB", (100, 100), (128, 128, 128))
     result = ImageOps.moire(img)
     assert result.mode == "RGB"
 
-
-def test_moire_accepts_non_rgb() -> None:
+def test_moire_accepts_non_rgb()->None:
     img = Image.new("L", (100, 100), 128)
     result = ImageOps.moire(img)
     assert result.mode == "RGB"

From dd26167d38501f40d95a65fb3884bd0926a0a584 Mon Sep 17 00:00:00 2001
From: Apaar Raina <apaarraina@gmail.com>
Date: Wed, 27 May 2026 13:32:28 +0530
Subject: [PATCH 08/16] Updated the docstring for moire function

---
 src/PIL/ImageOps.py | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/src/PIL/ImageOps.py b/src/PIL/ImageOps.py
index 3e88672e792..a3a9bed3af6 100644
--- a/src/PIL/ImageOps.py
+++ b/src/PIL/ImageOps.py
@@ -24,19 +24,20 @@
 from collections.abc import Sequence
 from typing import Literal, Protocol, cast, overload
 
-from . import ExifTags, Image, ImagePalette
 from ._moire import (
-    _add_noise,
+    _lcd_resampling,
+    _projective_transformation,
+    _radial_distortion,
+    _flat_top_filtering,
     _bayer_resampling,
+    _add_noise,
     _demosaic_bilinear,
     _denoise,
-    _flat_top_filtering,
     _jpeg_compression,
-    _lcd_resampling,
-    _projective_transformation,
-    _radial_distortion,
 )
 
+from . import ExifTags, Image, ImagePalette
+
 #
 # helpers
 
@@ -657,10 +658,9 @@ def mirror(image: Image.Image) -> Image.Image:
     """
     return image.transpose(Image.Transpose.FLIP_LEFT_RIGHT)
 
-
 def moire(image: Image.Image) -> Image.Image:
     """
-    Generates a synthetic Moire image
+    Generate a synthetic Moire image.
     :param image:
     :return: An image.
     """
@@ -679,7 +679,6 @@ def moire(image: Image.Image) -> Image.Image:
 
     return compressed_img
 
-
 def posterize(image: Image.Image, bits: int) -> Image.Image:
     """
     Reduce the number of bits for each color channel.

From 10cbfe085116c4b3bc4e41438b72d2ad24f3bbcb Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Wed, 27 May 2026 10:30:08 +0000
Subject: [PATCH 09/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 Tests/test_moire_synthesis.py | 14 +++++++++-----
 src/PIL/ImageOps.py           | 15 ++++++++-------
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/Tests/test_moire_synthesis.py b/Tests/test_moire_synthesis.py
index b385882ffe6..e57e20495b7 100644
--- a/Tests/test_moire_synthesis.py
+++ b/Tests/test_moire_synthesis.py
@@ -1,17 +1,21 @@
-import pytest
-from PIL import Image,ImageOps
+from __future__ import annotations
 
-def test_moire_output_size()->None:
+from PIL import Image, ImageOps
+
+
+def test_moire_output_size() -> None:
     img = Image.new("RGB", (100, 100), (128, 128, 128))
     result = ImageOps.moire(img)
     assert result.size == img.size
 
-def test_moire_output_mode()->None:
+
+def test_moire_output_mode() -> None:
     img = Image.new("RGB", (100, 100), (128, 128, 128))
     result = ImageOps.moire(img)
     assert result.mode == "RGB"
 
-def test_moire_accepts_non_rgb()->None:
+
+def test_moire_accepts_non_rgb() -> None:
     img = Image.new("L", (100, 100), 128)
     result = ImageOps.moire(img)
     assert result.mode == "RGB"
diff --git a/src/PIL/ImageOps.py b/src/PIL/ImageOps.py
index a3a9bed3af6..93bb3bae5f7 100644
--- a/src/PIL/ImageOps.py
+++ b/src/PIL/ImageOps.py
@@ -24,20 +24,19 @@
 from collections.abc import Sequence
 from typing import Literal, Protocol, cast, overload
 
+from . import ExifTags, Image, ImagePalette
 from ._moire import (
-    _lcd_resampling,
-    _projective_transformation,
-    _radial_distortion,
-    _flat_top_filtering,
-    _bayer_resampling,
     _add_noise,
+    _bayer_resampling,
     _demosaic_bilinear,
     _denoise,
+    _flat_top_filtering,
     _jpeg_compression,
+    _lcd_resampling,
+    _projective_transformation,
+    _radial_distortion,
 )
 
-from . import ExifTags, Image, ImagePalette
-
 #
 # helpers
 
@@ -658,6 +657,7 @@ def mirror(image: Image.Image) -> Image.Image:
     """
     return image.transpose(Image.Transpose.FLIP_LEFT_RIGHT)
 
+
 def moire(image: Image.Image) -> Image.Image:
     """
     Generate a synthetic Moire image.
@@ -679,6 +679,7 @@ def moire(image: Image.Image) -> Image.Image:
 
     return compressed_img
 
+
 def posterize(image: Image.Image, bits: int) -> Image.Image:
     """
     Reduce the number of bits for each color channel.

From f47c205761c10215ee0919e5fe3f75063410483e Mon Sep 17 00:00:00 2001
From: Apaar Raina <apaarraina@gmail.com>
Date: Wed, 27 May 2026 16:12:26 +0530
Subject: [PATCH 10/16] added remaining annotations

---
 src/PIL/_moire.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/PIL/_moire.py b/src/PIL/_moire.py
index d348371ef4f..6462442eb78 100644
--- a/src/PIL/_moire.py
+++ b/src/PIL/_moire.py
@@ -96,7 +96,7 @@ def _radial_distortion(img: Image.Image, k=-1e-7) -> Image.Image:
     return radial_distort
 
 
-def _flat_top_kernel(size=5, sigma=1.0, n=2):
+def _flat_top_kernel(size=5, sigma=1.0, n=2) -> list[list[float]]:
     """
     Generate a flat-top Gaussian kernel.
 
@@ -127,7 +127,7 @@ def _flat_top_kernel(size=5, sigma=1.0, n=2):
     return kernel
 
 
-def _flat_top_filtering(img, size=5, sigma=1.0, n=2):
+def _flat_top_filtering(img, size=5, sigma=1.0, n=2) -> Image.Image:
     """
     Applying the flat top gaussian kernel on the image to simulate anti-aliasing fiter
 
@@ -192,11 +192,11 @@ def _add_noise(img: Image.Image) -> Image.Image:
     return noisy
 
 
-def _clamp(v, lo, hi):
+def _clamp(v, lo, hi) -> int:
     return lo if v < lo else (hi if v > hi else v)
 
 
-def _get_channel(img, x, y, ch, w, h):
+def _get_channel(img, x, y, ch, w, h) -> int:
     x = _clamp(x, 0, w - 1)
     y = _clamp(y, 0, h - 1)
     return img.getpixel((x, y))[ch]

From 879564868834d98a427042939d5a126e68aee240 Mon Sep 17 00:00:00 2001
From: Apaar Raina <apaarraina@gmail.com>
Date: Wed, 27 May 2026 16:14:26 +0530
Subject: [PATCH 11/16] updated formating

---
 Tests/test_moire_synthesis.py | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/Tests/test_moire_synthesis.py b/Tests/test_moire_synthesis.py
index e57e20495b7..34fc6b1d9c2 100644
--- a/Tests/test_moire_synthesis.py
+++ b/Tests/test_moire_synthesis.py
@@ -1,20 +1,16 @@
-from __future__ import annotations
-
-from PIL import Image, ImageOps
-
+import pytest
+from PIL import Image,ImageOps
 
 def test_moire_output_size() -> None:
     img = Image.new("RGB", (100, 100), (128, 128, 128))
     result = ImageOps.moire(img)
     assert result.size == img.size
 
-
 def test_moire_output_mode() -> None:
     img = Image.new("RGB", (100, 100), (128, 128, 128))
     result = ImageOps.moire(img)
     assert result.mode == "RGB"
 
-
 def test_moire_accepts_non_rgb() -> None:
     img = Image.new("L", (100, 100), 128)
     result = ImageOps.moire(img)

From 0fd21177244f5c830a44ee8f8ad9308099c75108 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Wed, 27 May 2026 10:47:38 +0000
Subject: [PATCH 12/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 Tests/test_moire_synthesis.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Tests/test_moire_synthesis.py b/Tests/test_moire_synthesis.py
index 34fc6b1d9c2..e57e20495b7 100644
--- a/Tests/test_moire_synthesis.py
+++ b/Tests/test_moire_synthesis.py
@@ -1,16 +1,20 @@
-import pytest
-from PIL import Image,ImageOps
+from __future__ import annotations
+
+from PIL import Image, ImageOps
+
 
 def test_moire_output_size() -> None:
     img = Image.new("RGB", (100, 100), (128, 128, 128))
     result = ImageOps.moire(img)
     assert result.size == img.size
 
+
 def test_moire_output_mode() -> None:
     img = Image.new("RGB", (100, 100), (128, 128, 128))
     result = ImageOps.moire(img)
     assert result.mode == "RGB"
 
+
 def test_moire_accepts_non_rgb() -> None:
     img = Image.new("L", (100, 100), 128)
     result = ImageOps.moire(img)

From 95253e5339d8345508647b6dd9f59369dc50ddd3 Mon Sep 17 00:00:00 2001
From: Apaar Raina <apaarraina@gmail.com>
Date: Wed, 27 May 2026 16:32:17 +0530
Subject: [PATCH 13/16] fixed mypy errors

---
 src/PIL/_moire.py | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/PIL/_moire.py b/src/PIL/_moire.py
index 6462442eb78..e938a698d63 100644
--- a/src/PIL/_moire.py
+++ b/src/PIL/_moire.py
@@ -3,6 +3,7 @@
 import io
 import math
 import random
+from typing import cast
 
 from . import Image, ImageFilter
 
@@ -21,7 +22,7 @@ def _lcd_resampling(img: Image.Image) -> Image.Image:
     for y in range(h):
         num = 1
         for x in range(w):
-            r, g, b = img.getpixel((x, y))
+            r, g, b = cast(tuple[int, int, int], img.getpixel((x, y)))
             if num % 3 == 0:
                 resampled_img.putpixel((x, y), (0, 0, b))
             elif num % 3 == 1:
@@ -64,7 +65,7 @@ def _projective_transformation(img: Image.Image) -> Image.Image:
     return img.transform((w, h), Image.PERSPECTIVE, coeffs, resample=Image.BICUBIC)
 
 
-def _radial_distortion(img: Image.Image, k=-1e-7) -> Image.Image:
+def _radial_distortion(img: Image.Image, k: float=-1e-7) -> Image.Image:
     """
     Use radial distortion function to simulate lens distortion
 
@@ -80,7 +81,7 @@ def _radial_distortion(img: Image.Image, k=-1e-7) -> Image.Image:
 
     for y in range(h):
         for x in range(w):
-            r, g, b = img.getpixel((x, y))
+            r, g, b = cast(tuple[int, int, int], img.getpixel((x, y)))
             xc = x - cx
             yc = y - cy
             radius2 = xc**2 + yc**2
@@ -96,7 +97,7 @@ def _radial_distortion(img: Image.Image, k=-1e-7) -> Image.Image:
     return radial_distort
 
 
-def _flat_top_kernel(size=5, sigma=1.0, n=2) -> list[list[float]]:
+def _flat_top_kernel(size: int=5, sigma: float=1.0, n: int=2) -> list[list[float]]:
     """
     Generate a flat-top Gaussian kernel.
 
@@ -127,7 +128,7 @@ def _flat_top_kernel(size=5, sigma=1.0, n=2) -> list[list[float]]:
     return kernel
 
 
-def _flat_top_filtering(img, size=5, sigma=1.0, n=2) -> Image.Image:
+def _flat_top_filtering(img: Image.Image, size: int=5, sigma: float=1.0, n: int=2) -> Image.Image:
     """
     Applying the flat top gaussian kernel on the image to simulate anti-aliasing fiter
 
@@ -157,7 +158,7 @@ def _bayer_resampling(img: Image.Image) -> Image.Image:
 
     for y in range(h):
         for x in range(w):
-            r, g, b = img.getpixel((x, y))
+            r, g, b = cast(tuple[int, int, int], img.getpixel((x, y)))
             if y % 2 == 0:
                 if x % 2 == 0:
                     resample.putpixel((x, y), (0, g, 0))
@@ -183,7 +184,7 @@ def _add_noise(img: Image.Image) -> Image.Image:
     noisy = Image.new("RGB", (w, h))
     for y in range(h):
         for x in range(w):
-            r, g, b = img.getpixel((x, y))
+            r, g, b = cast(tuple[int, int, int], img.getpixel((x, y)))
             nr = int(r + random.gauss(0, 1))
             ng = int(g + random.gauss(0, 1))
             nb = int(b + random.gauss(0, 1))
@@ -192,14 +193,14 @@ def _add_noise(img: Image.Image) -> Image.Image:
     return noisy
 
 
-def _clamp(v, lo, hi) -> int:
+def _clamp(v: int, lo: int, hi: int) -> int:
     return lo if v < lo else (hi if v > hi else v)
 
 
-def _get_channel(img, x, y, ch, w, h) -> int:
+def _get_channel(img: Image.Image, x: int, y: int, ch: int, w: int, h: int) -> int:
     x = _clamp(x, 0, w - 1)
     y = _clamp(y, 0, h - 1)
-    return img.getpixel((x, y))[ch]
+    return cast(tuple[int, int, int], img.getpixel((x, y)))[ch]
 
 
 def _demosaic_bilinear(img: Image.Image) -> Image.Image:
@@ -215,7 +216,7 @@ def _demosaic_bilinear(img: Image.Image) -> Image.Image:
 
     for y in range(h):
         for x in range(w):
-            pixel = img.getpixel((x, y))
+            pixel = cast(tuple[int, int, int], img.getpixel((x, y)))
 
             if y % 2 == 0 and x % 2 == 0:
                 new_r = (

From 51ce8e3eb2037e138a5b066fe1fa345de6c5ddce Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Wed, 27 May 2026 11:04:19 +0000
Subject: [PATCH 14/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 src/PIL/_moire.py | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/PIL/_moire.py b/src/PIL/_moire.py
index e938a698d63..af2e1866ca4 100644
--- a/src/PIL/_moire.py
+++ b/src/PIL/_moire.py
@@ -65,7 +65,7 @@ def _projective_transformation(img: Image.Image) -> Image.Image:
     return img.transform((w, h), Image.PERSPECTIVE, coeffs, resample=Image.BICUBIC)
 
 
-def _radial_distortion(img: Image.Image, k: float=-1e-7) -> Image.Image:
+def _radial_distortion(img: Image.Image, k: float = -1e-7) -> Image.Image:
     """
     Use radial distortion function to simulate lens distortion
 
@@ -97,7 +97,9 @@ def _radial_distortion(img: Image.Image, k: float=-1e-7) -> Image.Image:
     return radial_distort
 
 
-def _flat_top_kernel(size: int=5, sigma: float=1.0, n: int=2) -> list[list[float]]:
+def _flat_top_kernel(
+    size: int = 5, sigma: float = 1.0, n: int = 2
+) -> list[list[float]]:
     """
     Generate a flat-top Gaussian kernel.
 
@@ -128,7 +130,9 @@ def _flat_top_kernel(size: int=5, sigma: float=1.0, n: int=2) -> list[list[float
     return kernel
 
 
-def _flat_top_filtering(img: Image.Image, size: int=5, sigma: float=1.0, n: int=2) -> Image.Image:
+def _flat_top_filtering(
+    img: Image.Image, size: int = 5, sigma: float = 1.0, n: int = 2
+) -> Image.Image:
     """
     Applying the flat top gaussian kernel on the image to simulate anti-aliasing fiter
 

From 0443e94b6bf28a06614c62da5e4d6558c80aa3c9 Mon Sep 17 00:00:00 2001
From: Apaar Raina <apaarraina@gmail.com>
Date: Wed, 27 May 2026 16:50:30 +0530
Subject: [PATCH 15/16] fixed formating

---
 src/PIL/_moire.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/PIL/_moire.py b/src/PIL/_moire.py
index af2e1866ca4..ba710e17e0b 100644
--- a/src/PIL/_moire.py
+++ b/src/PIL/_moire.py
@@ -62,7 +62,7 @@ def _projective_transformation(img: Image.Image) -> Image.Image:
     # H
     coeffs = (a, b, c, d, e, f, g, h_p)
 
-    return img.transform((w, h), Image.PERSPECTIVE, coeffs, resample=Image.BICUBIC)
+    return img.transform((w, h), Image.Transform.PERSPECTIVE, coeffs, resample=Image.Resampling.BICUBIC)
 
 
 def _radial_distortion(img: Image.Image, k: float = -1e-7) -> Image.Image:
@@ -110,7 +110,7 @@ def _flat_top_kernel(
     """
     kernel = []
     center = size // 2
-    total = 0
+    total = 0.0
 
     for y in range(size):
         row = []

From 8d85aab6b966769a6e7e6aa42b6e9b8234415f07 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Wed, 27 May 2026 11:21:56 +0000
Subject: [PATCH 16/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 src/PIL/_moire.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/PIL/_moire.py b/src/PIL/_moire.py
index ba710e17e0b..97635c13366 100644
--- a/src/PIL/_moire.py
+++ b/src/PIL/_moire.py
@@ -62,7 +62,9 @@ def _projective_transformation(img: Image.Image) -> Image.Image:
     # H
     coeffs = (a, b, c, d, e, f, g, h_p)
 
-    return img.transform((w, h), Image.Transform.PERSPECTIVE, coeffs, resample=Image.Resampling.BICUBIC)
+    return img.transform(
+        (w, h), Image.Transform.PERSPECTIVE, coeffs, resample=Image.Resampling.BICUBIC
+    )
 
 
 def _radial_distortion(img: Image.Image, k: float = -1e-7) -> Image.Image: