From 5fd868c46025509942793e9447f0811de00d56e8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Matheus=20T=2E=20Guimar=C3=A3es?= <matheusguimr@gmail.com>
Date: Tue, 22 Oct 2019 16:19:38 -0300
Subject: [PATCH] Add algorithm to rotate images (#1420)

* Add algorithm to rotate image

* Edit function to be compliant in Black and Flake8 formats

* Add type hints in get_rotation() and  enumerate() in loop
---
 digital_image_processing/rotation/__init__.py |  0
 digital_image_processing/rotation/rotation.py | 52 +++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 digital_image_processing/rotation/__init__.py
 create mode 100644 digital_image_processing/rotation/rotation.py

diff --git a/digital_image_processing/rotation/__init__.py b/digital_image_processing/rotation/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/digital_image_processing/rotation/rotation.py b/digital_image_processing/rotation/rotation.py
new file mode 100644
index 000000000..37b45ca39
--- /dev/null
+++ b/digital_image_processing/rotation/rotation.py
@@ -0,0 +1,52 @@
+from matplotlib import pyplot as plt
+import numpy as np
+import cv2
+
+
+def get_rotation(
+    img: np.array, pt1: np.float32, pt2: np.float32, rows: int, cols: int
+) -> np.array:
+    """
+    Get image rotation
+    :param img: np.array
+    :param pt1: 3x2 list
+    :param pt2: 3x2 list
+    :param rows: columns image shape
+    :param cols: rows image shape
+    :return: np.array
+    """
+    matrix = cv2.getAffineTransform(pt1, pt2)
+    return cv2.warpAffine(img, matrix, (rows, cols))
+
+
+if __name__ == "__main__":
+    # read original image
+    image = cv2.imread("lena.jpg")
+    # turn image in gray scale value
+    gray_img = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
+    # get image shape
+    img_rows, img_cols = gray_img.shape
+
+    # set different points to rotate image
+    pts1 = np.float32([[50, 50], [200, 50], [50, 200]])
+    pts2 = np.float32([[10, 100], [200, 50], [100, 250]])
+    pts3 = np.float32([[50, 50], [150, 50], [120, 200]])
+    pts4 = np.float32([[10, 100], [80, 50], [180, 250]])
+
+    # add all rotated images in a list
+    images = [
+        gray_img,
+        get_rotation(gray_img, pts1, pts2, img_rows, img_cols),
+        get_rotation(gray_img, pts2, pts3, img_rows, img_cols),
+        get_rotation(gray_img, pts2, pts4, img_rows, img_cols),
+    ]
+
+    # plot different image rotations
+    fig = plt.figure(1)
+    titles = ["Original", "Rotation 1", "Rotation 2", "Rotation 3"]
+    for i, image in enumerate(images):
+        plt.subplot(2, 2, i + 1), plt.imshow(image, "gray")
+        plt.title(titles[i])
+        plt.axis("off")
+        plt.subplots_adjust(left=0.0, bottom=0.05, right=1.0, top=0.95)
+    plt.show()