code-paul-creator · Nov 11, 2026
diff --git a/digital_image_processing/morphological_operations/dilation_operation.py b/digital_image_processing/morphological_operations/dilation_operation.py
@@ -1,3 +1,13 @@
+"""
+Dilation, a morphological operation on binary images.
+
+Dilation grows the white (True) regions of a binary image: a pixel becomes True if
+the structuring element, placed over it, overlaps at least one True pixel. The
+functions here convert an RGB image to gray, threshold it to binary, and dilate it.
+
+Reference: https://en.wikipedia.org/wiki/Dilation_(morphology)
+"""
+
 from pathlib import Path
 
 import numpy as np
@@ -6,7 +16,8 @@
 
 def rgb_to_gray(rgb: np.ndarray) -> np.ndarray:
     """
-    Return gray image from rgb image
+    Return gray image from rgb image.
+
     >>> rgb_to_gray(np.array([[[127, 255, 0]]]))
     array([[187.6453]])
     >>> rgb_to_gray(np.array([[[0, 0, 0]]]))
@@ -22,7 +33,8 @@ def rgb_to_gray(rgb: np.ndarray) -> np.ndarray:
 
 def gray_to_binary(gray: np.ndarray) -> np.ndarray:
     """
-    Return binary image from gray image
+    Return binary image from gray image.
+
     >>> gray_to_binary(np.array([[127, 255, 0]]))
     array([[False,  True, False]])
     >>> gray_to_binary(np.array([[0]]))
@@ -39,7 +51,8 @@ def gray_to_binary(gray: np.ndarray) -> np.ndarray:
 
 def dilation(image: np.ndarray, kernel: np.ndarray) -> np.ndarray:
     """
-    Return dilated image
+    Return dilated image.
+
     >>> dilation(np.array([[True, False, True]]), np.array([[0, 1, 0]]))
     array([[False, False, False]])
     >>> dilation(np.array([[False, False, True]]), np.array([[1, 0, 1]]))

diff --git a/work/R23-T057/REVIEW.md b/work/R23-T057/REVIEW.md
@@ -0,0 +1,47 @@
+# R23-T057: strict Ruff review of `digital_image_processing/morphological_operations/dilation_operation.py`
+
+Tool: `ruff 0.16.9`. Commands (from the repo root):
+
+    ruff check digital_image_processing/morphological_operations/dilation_operation.py              # repo config
+    ruff check --select ALL --output-format concise digital_image_processing/morphological_operations/dilation_operation.py
+
+Raw outputs are saved next to this file (`ruff_*_before.txt`, `ruff_*_after.txt`).
+
+## Result
+| | repo config | `--select ALL` |
+|---|---|---|
+| before | All checks passed | **15 findings**, 7 codes |
+| after | All checks passed | **6 findings**, 3 codes |
+
+## `--select ALL` findings and decisions
+| Code | Name | Count | Decision | Reason |
+|---|---|---|---|---|
+| D100 | undocumented-public-module | 1 | **Fixed** | CONTRIBUTING.md asks for docstrings with a source URL. Added a module docstring with a summary and the Wikipedia reference for dilation. |
+| D205 | missing-blank-line-after-summary | 3 | **Fixed** | A blank line between the summary and the `>>>` examples makes the docstring easier to read; no behaviour change. |
+| D400 | missing-trailing-period | 3 | **Fixed** | Summary lines now end with a period. |
+| D415 | missing-terminal-punctuation | 3 | **Fixed** | Same lines as D400 (this rule also accepts `?`/`!`); fixed by the same edit. |
+| D212 | multi-line-summary-first-line | 4 | **Not fixed** | Wants the summary on the first line (`"""Return ...`). CONTRIBUTING.md's own docstring example starts the text on the second line, which is the opposite rule (D213). Following D212 would contradict the contributing guide and the style used across the repo. (The count went from 3 to 4 because the new module docstring follows the same second-line style.) |
+| COM812 | missing-trailing-comma | 1 | **Not fixed** | `pyproject.toml` lists `"COM"` as `-- DO NOT FIX`, and Ruff documents that COM812 can conflict with the formatter. The repo formatter already accepts the current code. |
+| CPY001 | missing-copyright-notice | 1 | **Not fixed** | The repo uses no per-file copyright headers (the licence lives at the repository root), so adding one here would be inconsistent. |
+
+4 codes fixed (D100, D205, D400, D415; 10 findings). No logic was changed, only documentation.
+
+## Checks after the changes
+- `ruff check` (repo config): All checks passed
+- `ruff format --check`: already formatted
+- `python -m pytest --doctest-modules digital_image_processing/morphological_operations/dilation_operation.py`: passed (10 doctests)
+- The file uses CRLF line endings in the repo; they were kept so the diff only shows the real changes.
+
+## Observation (not changed; outside the Ruff task)
+`dilation()` only works for 3x3 kernels. It copies the image into the padded array with
+`image_padded[kernel.shape[0] - 2 : -1, kernel.shape[1] - 2 : -1] = image`, which assumes a kernel
+size of 3. For other sizes the slice can be empty and the copy silently does nothing.
+Two existing doctests record the resulting all-False output:
+
+    dilation(np.array([[True, False, True]]), np.array([[0, 1, 0]]))   # shown as [[False, False, False]]
+    dilation(np.array([[False, False, True]]), np.array([[1, 0, 1]]))  # shown as [[False, False, False]]
+
+A 1x3 kernel `[0, 1, 0]` is the identity for dilation, so the first result should be
+`[[True, False, True]]`. With the normal 3x3 plus-shaped kernel the function is correct
+(one True pixel grows into a plus shape). Left as is so the 10 existing doctests stay
+unchanged; worth a separate fix.
diff --git a/work/R23-T057/ruff_all_after.txt b/work/R23-T057/ruff_all_after.txt
@@ -0,0 +1,10 @@
+warning: `incorrect-blank-line-before-class` (D203) and `blank-line-before-class` (D211) are incompatible. Ignoring `incorrect-blank-line-before-class`.
+warning: `multi-line-summary-first-line` (D212) and `multi-line-summary-second-line` (D213) are incompatible. Ignoring `multi-line-summary-second-line`.
+digital_image_processing/morphological_operations/dilation_operation.py:1:1: D212 [*] Multi-line docstring summary should start at the first line
+digital_image_processing/morphological_operations/dilation_operation.py:1:1: CPY001 Missing copyright notice at top of file
+digital_image_processing/morphological_operations/dilation_operation.py:18:5: D212 [*] Multi-line docstring summary should start at the first line
+digital_image_processing/morphological_operations/dilation_operation.py:35:5: D212 [*] Multi-line docstring summary should start at the first line
+digital_image_processing/morphological_operations/dilation_operation.py:53:5: D212 [*] Multi-line docstring summary should start at the first line
+digital_image_processing/morphological_operations/dilation_operation.py:63:85: COM812 [*] Trailing comma missing
+Found 6 errors.
+[*] 5 fixable with `--fix`.
diff --git a/work/R23-T057/ruff_all_before.txt b/work/R23-T057/ruff_all_before.txt
@@ -0,0 +1,19 @@
+warning: `incorrect-blank-line-before-class` (D203) and `blank-line-before-class` (D211) are incompatible. Ignoring `incorrect-blank-line-before-class`.
+warning: `multi-line-summary-first-line` (D212) and `multi-line-summary-second-line` (D213) are incompatible. Ignoring `multi-line-summary-second-line`.
+digital_image_processing/morphological_operations/dilation_operation.py:1:1: D100 Missing docstring in public module
+digital_image_processing/morphological_operations/dilation_operation.py:1:1: CPY001 Missing copyright notice at top of file
+digital_image_processing/morphological_operations/dilation_operation.py:8:5: D205 1 blank line required between summary line and description
+digital_image_processing/morphological_operations/dilation_operation.py:8:5: D212 [*] Multi-line docstring summary should start at the first line
+digital_image_processing/morphological_operations/dilation_operation.py:8:5: D400 First line should end with a period
+digital_image_processing/morphological_operations/dilation_operation.py:8:5: D415 First line should end with a period, question mark, or exclamation point
+digital_image_processing/morphological_operations/dilation_operation.py:24:5: D205 1 blank line required between summary line and description
+digital_image_processing/morphological_operations/dilation_operation.py:24:5: D212 [*] Multi-line docstring summary should start at the first line
+digital_image_processing/morphological_operations/dilation_operation.py:24:5: D400 First line should end with a period
+digital_image_processing/morphological_operations/dilation_operation.py:24:5: D415 First line should end with a period, question mark, or exclamation point
+digital_image_processing/morphological_operations/dilation_operation.py:41:5: D205 1 blank line required between summary line and description
+digital_image_processing/morphological_operations/dilation_operation.py:41:5: D212 [*] Multi-line docstring summary should start at the first line
+digital_image_processing/morphological_operations/dilation_operation.py:41:5: D400 First line should end with a period
+digital_image_processing/morphological_operations/dilation_operation.py:41:5: D415 First line should end with a period, question mark, or exclamation point
+digital_image_processing/morphological_operations/dilation_operation.py:50:85: COM812 [*] Trailing comma missing
+Found 15 errors.
+[*] 4 fixable with `--fix` (6 unsafe fixes available with `--fix --unsafe-fixes`).
diff --git a/work/R23-T057/ruff_repo_config_after.txt b/work/R23-T057/ruff_repo_config_after.txt
@@ -0,0 +1 @@
+All checks passed!
diff --git a/work/R23-T057/ruff_repo_config_before.txt b/work/R23-T057/ruff_repo_config_before.txt
@@ -0,0 +1 @@
+All checks passed!