improved pylint score

.pylintrc

@@ -347,7 +347,7 @@ module-naming-style=snake_case
 
 # Regular expression matching correct module names. Overrides module-naming-
 # style.
-module-rgx=^[A-Za-z0-9]+$
+module-rgx=^[A-Za-z0-9\_]+$
 
 # Colon-delimited sets of names that determine each other's naming style when
 # the name regexes allow several styles.

pycs/frontend/endpoints/results/ResultAsCrop.py

@@ -22,12 +22,13 @@ class ResultAsCrop(View):
         result = Result.get_or_404(result_id)
 
         if result.type != "bounding-box":
-            abort(400, f"The type of the queried result was not \"bounding-box\"! It was {result.type}")
+            msg = f"The type of the queried result was not \"bounding-box\"! It was {result.type}"
+            abort(400, msg)
 
         file = result.file
 
         if file.type != "image":
-            abort(400, f"Currently only supporting images!")
+            abort(400, "Currently only supporting images!")
 
 
         data = result.data
@@ -39,9 +40,8 @@ class ResultAsCrop(View):
         if -1 in xywh:
             abort(400, f"The data of the result is not correct: {data}!")
 
-        x, y, w, h = xywh
 
-        crop_path, crop_fname = file_ops.crop_file(file, file.project.root_folder, x, y, w, h)
+        crop_path, crop_fname = file_ops.crop_file(file, file.project.root_folder, *xywh)
 
         parts = os.path.splitext(crop_fname)
 

pycs/util/file_ops.py

@@ -0,0 +1,144 @@
+import os
+import typing as T
+
+import cv2
+
+from PIL import Image
+
+from pycs.database.File import File
+
+# pylint: disable=too-many-arguments, invalid-name, too-many-locals
+def crop_file(file: File, project_root: str, x: float, y: float, w: float, h: float) -> str:
+    """
+    gets a file for the given file_id, crops the according image to the
+    bounding box and saves the crops in the temp folder of the project.
+
+    :param file: file object
+    :param x: relative x-coordinate of the top left corner
+    :param y: relative y-coordinate of the top left corner
+    :param w: relative width of the bounding box
+    :param h: relative height of the bounding box
+
+    :return: directory and file name of the cropped patch
+    """
+
+    image = Image.open(file.absolute_path)
+    width, height = image.size
+
+    crop_width = int(width * w)
+    crop_height = int(height * h)
+
+    x0 = int(width * x)
+    y0 = int(height * y)
+    x1 = x0 + crop_width
+    y1 = y0 + crop_height
+
+    target_path = os.path.join(
+        os.getcwd(),
+        project_root,
+        'temp',
+        f'{file.uuid}_{x0}-{y0}_{x1}-{y1}.jpg',
+    )
+
+    if not os.path.exists(target_path):
+        crop = image.crop((x0, y0, x0+crop_width, y0+crop_height))
+        crop.save(target_path, quality=80)
+
+    return os.path.split(target_path)
+
+
+def resize_file(file: File,
+                project_root: str,
+                max_width: int,
+                max_height: int) -> T.Tuple[str, str]:
+    """
+    If file type equals video this function extracts a thumbnail first. It calls resize_image
+    to resize and returns the resized files directory and name.
+
+    :param file: file object
+    :param max_width: maximum image or thumbnail width
+    :param max_height: maximum image or thumbnail height
+    :return: resized file directory, resized file name
+    """
+
+    abs_file_path = file.absolute_path
+
+    # extract video thumbnail
+    if file.type == 'video':
+        abs_target_path = os.path.join(os.getcwd(), project_root, 'temp', f'{file.uuid}.jpg')
+        create_thumbnail(abs_file_path, abs_target_path)
+
+        abs_file_path = abs_target_path
+
+    # resize image file
+    abs_target_path = os.path.join(os.getcwd(), project_root,
+                                'temp', f'{file.uuid}_{max_width}_{max_height}.jpg')
+    result = resize_image(abs_file_path, abs_target_path, max_width, max_height)
+
+    # return path
+    if result is not None:
+        return os.path.split(abs_target_path)
+
+    return os.path.split(abs_file_path)
+
+def resize_image(file_path: str,
+                 target_path: str,
+                 max_width: int,
+                 max_height: int) -> T.Optional[bool]:
+    """
+    resize an image so width < max_width and height < max_height
+
+    :param file_path: path to source file
+    :param target_path: path to target file
+    :param max_width: maximum image width
+    :param max_height: maximum image height
+    :return:
+    """
+    # return if file exists
+    if os.path.exists(target_path):
+        return True
+
+    # load full size image
+    image = Image.open(file_path)
+    img_width, img_height = image.size
+
+    # abort if file is smaller than desired
+    if img_width < max_width and img_height < max_height:
+        return None
+
+    # calculate target size
+    target_width = int(max_width)
+    target_height = int(max_width * img_height / img_width)
+
+    if target_height > max_height:
+        target_height = int(max_height)
+        target_width = int(max_height * img_width / img_height)
+
+    # resize image
+    resized_image = image.resize((target_width, target_height))
+
+    # save to file
+    resized_image.save(target_path, quality=80)
+    return True
+
+def create_thumbnail(file_path: str, target_path: str) -> None:
+    """
+    extract a thumbnail from a video
+
+    :param file_path: path to source file
+    :param target_path: path to target file
+    :return:
+    """
+    # return if file exists
+    if os.path.exists(target_path):
+        return
+
+    # load video
+    video = cv2.VideoCapture(file_path)
+
+    # create thumbnail
+    _, image = video.read()
+    cv2.imwrite(target_path, image)
+
+    # close video file
+    video.release()