add imageResize.py to scripts

scripts/imageResize.py

@@ -0,0 +1,326 @@
+
+import math
+import re
+from dataclasses import dataclass
+from typing import Optional, Tuple
+from PIL import Image	
+
+_MARKER_RE = re.compile(r"[HhWwxX%]")		# Regex to find valid resize scaling markers
+_DIGIT_SPACE_RE = re.compile(r"^[\d\s]*$")	# Regex to ensure only digits and spaces are present
+
+def validate_scale(s: str) -> Tuple[bool, str, Optional[Tuple[str, ...]]]:
+	'''
+	Return (is_valid,kind, values) where
+	 	is_valid is True or False
+		str which is either the kind of resizing (H,W,X,%) or an error message
+		values which holds resize target as a tuple of (Width, Height) 
+	values is a tuple of numbers (floats).
+	'''	
+	'''Can be called just to check input for resize scaling 
+	Scaling factor must contain only numbers followed by one of: W w H h %
+	OR
+	A fixed dimension with X or x between numbers (e.g. 640x480 or 1000 X 1000)
+	Whitespace is ignored unless between digits.
+	All numeric values must be even, except for %.
+
+	Valid examples:	 	640w, 480h, 640x480, 640 x 480, 640W, 480 h , 640x 480, 75 %, 
+	Invalid examples: 	641w, 479x480, 45 0h, 640w x 480h, +50, -20, 150%
+	'''
+
+	# Helper to check if a cleaned string is an even number
+	def is_even_number(value: str) -> bool:
+		value = value.replace(" ", "")
+		return value.isdigit() and int(value) % 2 == 0
+
+	scale_err=""
+	# Check input type and if empty
+	if not isinstance(s, str):
+		scale_err="No input value"
+		return False,scale_err,None
+	s = s.strip()
+	if not s:
+		scale_err="Input value is only space(s)"
+		return False,scale_err,None
+	if s=="0":
+		scale_err= "Zero not allowed, enter 100% or leave blank for no resizing"
+		return False,scale_err,None	
+
+	# Check for valid scaling marker in the string
+	markers = _MARKER_RE.findall(s)
+	if len(markers) != 1:
+		scale_err="Scaling marker not found (H W X %)"
+		return False,scale_err,None
+	marker = markers[0]
+
+	# Split the string into parts around the marker
+	val1, sep, val2 = s.partition(marker)
+
+	# Validate HhWw% markers are at the end of string
+	if marker in "WwHh%":
+		if val2.strip():  # Nothing should follow the marker
+			scale_err="Characters not allowed after h,w,%"
+			return False,scale_err,None
+		if not _DIGIT_SPACE_RE.fullmatch(val1):  # Only digits and spaces allowed
+			scale_err="Invalid character entered"
+			return False,scale_err,None
+		if not re.search(r"\d", val1):  # Must contain at least one digit
+			scale_err="No number entered"
+			return False,scale_err,None
+		if re.search(r"\d\s+\d", val1):  # Digits separated by spaces are invalid
+			scale_err="Spaces found between digits"
+			return False,scale_err,None
+
+		# Made it this far, now check if even number for h or w
+		val1 = re.sub(r"\s+", "", (val1 or ""))
+
+		if marker in "WwHh" and not is_even_number(val1):
+			scale_err="Number is not even"
+			return False,scale_err,None
+
+		# Percentages must be <= 100
+		'''if marker == "%":
+			match = re.search(r"\d+", val1)
+			if match:
+				percent_value = int(match.group())
+				if percent_value >= 100:
+					return False, "Percentage must be <= 100%",None
+		target = (val1,)'''
+		target = (val1,)
+
+
+	# Validation for xX markers (must have digits on both sides)
+	if marker in "xX":
+		if not (_DIGIT_SPACE_RE.fullmatch(val1) and _DIGIT_SPACE_RE.fullmatch(val2)):
+			scale_err="Missing or invalid number before or after 'x'"
+			return False,scale_err,None
+		if re.search(r"\d\s+\d", val1) or re.search(r"\d\s+\d", val2):
+			scale_err="Numbers cannot contain spaces between digits."
+			return False,scale_err,None
+
+		val1 = re.sub(r"\s+", "", (val1 or ""))
+		val2 = re.sub(r"\s+", "", (val2 or ""))
+
+		if val1 == "0" or val2 =="0":
+			scale_err="Both dimensions must be greater than 0"
+			return False,scale_err,None
+		if not (re.search(r"\d", val1) and re.search(r"\d", val2)):
+			scale_err="Both sides of 'x' must contain at least one digit."
+			return False,scale_err,None
+		if not is_even_number(val1) or not is_even_number(val2):
+			return False, "Both dimensions must be even numbers",None
+		target = (val1,val2)
+
+	# All okay
+
+	factor = sep.upper()
+
+	#return True, factor, value to use (1000,) or (640,480), 
+	return True,factor,target
+
+def resize(input_path: str,						# if passing old size dimensions can be placeholder textresize"
+				 resize_target: str,			# target value for resizing basis
+				 *,
+				 start_size=None,				# Optional (w, h): compute plan only, no file I/O
+				 resample=None,					# Defaults to LANCZOS (set val2 import)
+				 return_image: bool = True):	# return an image file or not
+	""" Allsky Image resizer with even-dimension rounding for output files.
+
+	Behavior:
+		- Resize targets can be in several formats:
+			* '50%'				-> percent scale reduction
+			* '1000W' / '1000w'	-> target width
+			* '720H' / '720h'	-> target height
+			* '1280x720'		-> fixed target width x height (WxH)
+			* Zero-like: '0', '0%', '0H', '0W', '0x720', '1280x0' => will not be processed 
+
+		- NEW dimensions will be rounded up to even after calculating if required.
+
+	Returns:
+		(image, plan)
+
+	The 'image' is:
+		- The resized Image when a resize occurs (and return_image=True),
+		- A COPY of  original image if no-op (and return_image=True),
+		- None if return_image=False.
+	- If 'start_size' is provided, this tells the function to only compute new resized dimensions.
+		- image file is not opened or processed (can just be placeholder text)
+		- function returns (None or image depending on return_image) and with 'plan' computed from start_size dimensions provided.
+
+	The 'plan' is a dataclass-like object with attributes:
+		- start_size: (original width, original height)
+		- kind: one of 'height' | 'width' | 'fixed' | 'percent' | 'noop'
+		- target_values: tuple of floats (depending on kind)
+		- scale_factor: float or None (for single-side & percent)
+		- new_size_unrounded: (w_float, h_float) before even rounding
+		- new_size: (W, H) after even rounding
+		- will_resize: bool
+	"""	
+	#sys.path.append("/home/RazAdmin/allsky/scripts/modules")			
+	import allsky_shared as allsky_shared
+
+	# ************ Helper functions ************
+	# Round up Integers
+	def _ceil_even(x):
+		'''Round up to the next even integer (keeps even integers unchanged).'''
+		n = int(math.ceil(float(x)))
+		return n if n % 2 == 0 else n + 1
+
+	# Calculate Resize Dimensions 
+	@dataclass(frozen=True)
+	class RESIZEPLAN:
+		start_size: tuple
+		kind: str
+		target_values: tuple
+		scale_factor: Optional[float]
+		new_size_unrounded: tuple
+		new_size: tuple
+		will_resize: bool
+
+	def _calculate_resize(start_size_tuple, rt: str) -> RESIZEPLAN:
+		'''
+		Compute target dimensions from original size, final new dimensions are rounded up to even.
+		'''
+		ow, oh = start_size_tuple
+		if ow <= 0 or oh <= 0:
+			raise ValueError("Original image dimensions must be > 0")
+
+		#kind, target_values = _parse_resize_target(rt)
+		do_resize, scale_by, target_values = validate_scale(rt)
+
+		if do_resize == False:
+			# this means ther was an error and text is in scale_by
+			# message logged by validate_scale	
+			pass
+
+		# Defaults (same values if no scaling required)
+		new_w_unrounded = float(ow)
+		new_h_unrounded = float(oh)
+		scale_factor = None
+
+		if scale_by == "X":
+			kind = "Fixed"
+			target_w_raw, target_h_raw = target_values  # (w, h)
+			new_w_unrounded = float(target_w_raw)
+			new_h_unrounded = float(target_h_raw)
+
+		elif scale_by == "W":
+			kind = "Width"
+			(target_w_raw,) = target_values
+			scale_factor = float(target_w_raw) / float(ow)
+			new_w_unrounded = float(target_w_raw)
+			new_h_unrounded = float(oh) * scale_factor
+
+		elif scale_by == "H":
+			kind = "Height"
+			(target_h_raw,) = target_values
+			scale_factor = float(target_h_raw) / float(oh)
+			new_h_unrounded = float(target_h_raw)
+			new_w_unrounded = float(ow) * scale_factor
+
+		elif scale_by == "%":
+			kind = "Percent"
+			(pct,) = target_values
+			scale_factor = float(pct) / 100.0
+			new_w_unrounded = float(ow) * scale_factor
+			new_h_unrounded = float(oh) * scale_factor
+
+		else:
+			kind = f"Error: {scale_by}"	# no scaling will be done
+
+
+		# Round final result up to even
+		proposed_nw = _ceil_even(new_w_unrounded)
+		proposed_nh = _ceil_even(new_h_unrounded)
+
+		#check final to compare new and old sizes
+		final_new_size = (proposed_nw, proposed_nh)
+		will_resize = final_new_size != (ow, oh)		# True if new dimensions <> old dimensions
+
+		return RESIZEPLAN(
+			start_size=(ow, oh),
+			kind=kind,
+			target_values=target_values,
+			scale_factor=scale_factor,
+			new_size_unrounded=(new_w_unrounded, new_h_unrounded),
+			new_size=final_new_size,
+			will_resize=will_resize,
+		)
+
+	# ********** Main Function **********
+	#first validate the scaling factor
+	good_scale,kind,target1 = validate_scale(resize_target)
+	if not good_scale:
+		# log scaling error and return
+		allsky_shared.log(1, f"WARNING: Image will not be resized. Invalid parameter: {resize_target} - {kind}")
+
+	# Only calculate output dimensions
+	if start_size is not None:
+		# dimesions were passed, which means to just calcluate a new_Size.  (no image operations)
+		plan = _calculate_resize(start_size, resize_target)
+		if not plan.will_resize or not return_image:
+			return (None, plan)
+		# If asked for an image, they didn't give us pixels; return None + plan
+		return (None, plan)				# <----------  THIS MIGHT BE REDUNDANT????
+
+	# Open image, determine new dimensions, and resize
+	with Image.open(input_path) as original_image:
+		orig_width, orig_height = original_image.size
+		plan = _calculate_resize((orig_width, orig_height), resize_target)
+
+		if not plan.will_resize:
+			return (original_image.copy() if return_image else None, plan)			# no resizing so return image and plan
+
+		if resample is None:
+			try:
+				resample = Image.Resampling.LANCZOS
+			except AttributeError:
+				resample = Image.LANCZOS  # older Pillow support
+
+		resized_image = original_image.resize(plan.new_size, resample=resample)		# resize image
+		return (resized_image if return_image else None, plan)
+
+
+if __name__ == "__main__":
+	import argparse
+
+	parser = argparse.ArgumentParser(
+		description="""
+		Validate a resize target string or calculate resized dimensions of an image.
+
+		Functions:
+		  - validate: Check if a resize target string is valid (e.g. '640x480', '720h', '50%')
+		  - resize: Calculate new dimensions based on input Width x Height or an image file
+		    (optionally resize and return an image)
+
+		Examples:
+		  python3 imageResize_test.py validate -t "640x480"
+		  python3 imageResize_test.py resize -t "640x480" -s 1920 1080
+		""",
+		formatter_class=argparse.RawTextHelpFormatter
+	)
+	parser.add_argument("function", choices=["resize", "validate"], help="Function to run. 'validate ' to check a resize parameter, 'resize' to calculate resized dimensions")
+	parser.add_argument("-t", "--resize_target", required=True, help="Resize target string. (e.g. '640x480', '720h', '50%%')")
+	parser.add_argument("-i", "--input_path", required=False, help="Path to input image file. (Dimensions read from file)")
+	parser.add_argument("-s", "--start_size", nargs=2, type=int, help="Image dimensions as width and height.  (eg -s 1920 1080)")
+	parser.add_argument("-r", "--return_image", action="store_true", help="Return image object (when resizing an image file)")
+	# -r wont work with bash
+
+	args = parser.parse_args()
+
+	if args.function == "validate":
+		result = validate_scale(args.resize_target)
+		print(result)
+
+	elif args.function == "resize":
+		if args.start_size:
+			start_size = tuple(args.start_size)
+		else:
+			start_size = None
+
+		result = resize(
+			input_path=args.input_path,
+			resize_target=args.resize_target,
+			start_size=start_size,
+			return_image=args.return_image
+		)
+		print(result)