- Deleted constructors/functions/code for remasking existing QrCode object (due to doubtful real-world usefulness): C++, Java, JavaScript, Python, Rust.

- Tweaked code and comments due to feature removal: JavaScript, Python.
- Updated demo programs to reflect new API usage and add new example: C, C++, Java, Python, Rust.

python/qrcodegen-demo.py

@@ -35,6 +35,7 @@ def main():
 	do_basic_demo()
 	do_variety_demo()
 	do_segment_demo()
+	do_mask_demo()
 
 
 def do_basic_demo():
@@ -51,11 +52,6 @@ def do_basic_demo():
 def do_variety_demo():
 	"""Creates a variety of QR Codes that exercise different features of the library, and prints each one to the console."""
 	
-	# Project Nayuki URL
-	qr = qrcodegen.QrCode.encode_text("https://www.nayuki.io/", qrcodegen.QrCode.Ecc.HIGH)
-	qr = qrcodegen.QrCode(qrcode=qr, mask=3)  # Change mask, forcing to mask #3
-	print_qr(qr)
-	
 	# Numeric mode encoding (3.33 bits per digit)
 	qr = qrcodegen.QrCode.encode_text("314159265358979323846264338327950288419716939937510", qrcodegen.QrCode.Ecc.MEDIUM)
 	print_qr(qr)
@@ -64,12 +60,9 @@ def do_variety_demo():
 	qr = qrcodegen.QrCode.encode_text("DOLLAR-AMOUNT:$39.87 PERCENTAGE:100.00% OPERATIONS:+-*/", qrcodegen.QrCode.Ecc.HIGH)
 	print_qr(qr)
 	
-	# Unicode text as UTF-8, and different masks
+	# Unicode text as UTF-8
 	qr = qrcodegen.QrCode.encode_text(u"\u3053\u3093\u306B\u3061\u0077\u0061\u3001\u4E16\u754C\uFF01\u0020\u03B1\u03B2\u03B3\u03B4", qrcodegen.QrCode.Ecc.QUARTILE)
-	print_qr(qrcodegen.QrCode(qrcode=qr, mask=0))
-	print_qr(qrcodegen.QrCode(qrcode=qr, mask=1))
-	print_qr(qrcodegen.QrCode(qrcode=qr, mask=5))
-	print_qr(qrcodegen.QrCode(qrcode=qr, mask=7))
+	print_qr(qr)
 	
 	# Moderately large QR Code using longer text (from Lewis Carroll's Alice in Wonderland)
 	qr = qrcodegen.QrCode.encode_text(
@@ -153,6 +146,27 @@ def do_segment_demo():
 	print_qr(qr)
 
 
+def do_mask_demo():
+	"""Creates QR Codes with the same size and contents but different mask patterns."""
+	
+	# Project Nayuki URL
+	segs = qrcodegen.QrSegment.make_segments("https://www.nayuki.io/")
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.HIGH, mask=-1))  # Automatic mask
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.HIGH, mask=3))  # Force mask 3
+	
+	# Chinese text as UTF-8
+	segs = qrcodegen.QrSegment.make_segments(
+		u"\u7DAD\u57FA\u767E\u79D1\uFF08\u0057\u0069\u006B\u0069\u0070\u0065\u0064\u0069\u0061\uFF0C"
+		 "\u8046\u807D\u0069\u002F\u02CC\u0077\u026A\u006B\u1D7B\u02C8\u0070\u0069\u02D0\u0064\u0069"
+		 "\u002E\u0259\u002F\uFF09\u662F\u4E00\u500B\u81EA\u7531\u5167\u5BB9\u3001\u516C\u958B\u7DE8"
+		 "\u8F2F\u4E14\u591A\u8A9E\u8A00\u7684\u7DB2\u8DEF\u767E\u79D1\u5168\u66F8\u5354\u4F5C\u8A08"
+		 "\u756B")
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.MEDIUM, mask=0))  # Force mask 0
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.MEDIUM, mask=1))  # Force mask 1
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.MEDIUM, mask=5))  # Force mask 5
+	print_qr(qrcodegen.QrCode.encode_segments(segs, qrcodegen.QrCode.Ecc.MEDIUM, mask=7))  # Force mask 7
+
+
 
 # ---- Utilities ----
 

python/qrcodegen.py

@@ -31,7 +31,6 @@ This module "qrcodegen", public members:
   - Function encode_binary(bytes data, QrCode.Ecc ecl) -> QrCode
   - Function encode_segments(list<QrSegment> segs, QrCode.Ecc ecl,
         int minversion=1, int maxversion=40, mask=-1, boostecl=true) -> QrCode
-  - Constructor QrCode(QrCode qr, int mask)
   - Constructor QrCode(bytes datacodewords, int mask, int version, QrCode.Ecc ecl)
   - Method get_version() -> int
   - Method get_size() -> int
@@ -135,56 +134,36 @@ class QrCode(object):
 		assert len(bb) % 8 == 0
 		
 		# Create the QR Code symbol
-		return QrCode(None, bb.get_bytes(), mask, version, ecl)
+		return QrCode(bb.get_bytes(), mask, version, ecl)
 	
 	
 	# ---- Constructor ----
 	
-	def __init__(self, qrcode=None, datacodewords=None, mask=None, version=None, errcorlvl=None):
-		"""This constructor can be called in one of two ways:
-		- QrCode(datacodewords=list<int>, mask=int, version=int, errcorlvl=QrCode.Ecc):
-		      Creates a new QR Code symbol with the given version number, error correction level, binary data array,
-		      and mask number. This is a cumbersome low-level constructor that should not be invoked directly by the user.
-		      To go one level up, see the QrCode.encode_segments() function.
-		- QrCode(qrcode=QrCode, mask=int):
-		      Creates a new QR Code symbol based on the given existing object, but with a potentially different
-		      mask pattern. The version, error correction level, codewords, etc. of the newly created object are
-		      all identical to the argument object; only the mask may differ.
-		In both cases, mask = -1 is for automatic choice or 0 to 7 for fixed choice."""
+	def __init__(self, datacodewords, mask, version, errcorlvl):
+		"""Creates a new QR Code symbol with the given version number, error correction level, binary data array,
+		and mask number. mask = -1 is for automatic choice, or 0 to 7 for fixed choice. This is a cumbersome low-level constructor
+		that should not be invoked directly by the user. To go one level up, see the QrCode.encode_segments() function."""
 		
 		# Check arguments and handle simple scalar fields
 		if not (-1 <= mask <= 7):
 			raise ValueError("Mask value out of range")
-		if datacodewords is not None and qrcode is None:
-			if not (1 <= version <= 40):
-				raise ValueError("Version value out of range")
-			if not isinstance(errcorlvl, QrCode.Ecc):
-				raise TypeError("QrCode.Ecc expected")
-		elif qrcode is not None and datacodewords is None:
-			if version is not None or errcorlvl is not None:
-				raise ValueError("Values must be None")
-			version = qrcode._version
-			errcorlvl = qrcode._errcorlvl
-		else:
-			raise ValueError("Exactly one of datacodewords or qrcode must be not None")
+		if not (1 <= version <= 40):
+			raise ValueError("Version value out of range")
+		if not isinstance(errcorlvl, QrCode.Ecc):
+			raise TypeError("QrCode.Ecc expected")
 		self._version = version
 		self._errcorlvl = errcorlvl
 		self._size = version * 4 + 17
 		
-		if datacodewords is not None:  # Render from scratch a QR Code based on data codewords
-			if len(datacodewords) != QrCode._get_num_data_codewords(version, errcorlvl):
-				raise ValueError("Invalid array length")
-			# Initialize grids of modules
-			self._modules    = [[False] * self._size for _ in range(self._size)]  # The modules of the QR symbol; start with entirely white grid
-			self._isfunction = [[False] * self._size for _ in range(self._size)]  # Indicates function modules that are not subjected to masking
-			# Draw function patterns, draw all codewords
-			self._draw_function_patterns()
-			allcodewords = self._append_error_correction(datacodewords)
-			self._draw_codewords(allcodewords)
-		elif qrcode is not None:  # Modify the mask of an existing QR Code
-			self._modules = [list(row) for row in qrcode._modules]  # Deep copy
-			self._isfunction = qrcode._isfunction  # Shallow copy because the data is read-only
-			self._apply_mask(qrcode._mask)  # Undo existing mask
+		if len(datacodewords) != QrCode._get_num_data_codewords(version, errcorlvl):
+			raise ValueError("Invalid array length")
+		# Initialize grids of modules
+		self._modules    = [[False] * self._size for _ in range(self._size)]  # The modules of the QR symbol; start with entirely white grid
+		self._isfunction = [[False] * self._size for _ in range(self._size)]  # Indicates function modules that are not subjected to masking
+		# Draw function patterns, draw all codewords
+		self._draw_function_patterns()
+		allcodewords = self._append_error_correction(datacodewords)
+		self._draw_codewords(allcodewords)
 		
 		# Handle masking
 		if mask == -1:  # Automatically choose best mask