SDK:TXString

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What is this?

TXString is one of the SDK generic types. It is used to represent a string in Vectorworks. TXString is Unicode-compliant since Vectorworks 2018.

TXChar

TXString uses UTF-16 encoding since this encoding is natively used on Windows and Mac. There is a new typedef called TXChar, which is wchar_t on Windows and UniChar on Mac. Thus, TXChar uses UTF-16 encoding on both platforms.

TXString uses std::basic_string<TXChar> internally to store Unicode characters. There are two new macros for creating Unicode character or string literal. The following are two examples.

TXString txStr1 = txuc('♥');              // Unicode character
TXString txStr2 = txu("1文本2テキ3ßÜü4");  // Unicode string literal

Conversion to and from OS Native String Types

Using OS dependent components (e.g. types, functions, classes, etc.) should be avoided. If the code has the need to handle OS native string types, the following are examples to achieve that.

Windows

// You can use the following code if MFC is used.
// CString → TXString
TXString txStr = cStr;

// TXString → CString
CString cStr = txStr.GetData();

Mac

// CFString
// CFStringRef → TXString
TXString txStr = cfStr;

// TXString → CFStringRef
CFStringRef cfStr = txStr.GetCFStringRef()
if(cfStr)
{
    ... // Do something with cfStr;
    CFRelease(cfStr);
}

// NSString
// NSString → TXString
TXString txStr = [nsStr toTXString];

// TXString → NSString
NSString* nsStr = [NSString stringWithTXString:txStr];

Precomposed and Decomposed Forms

Some Unicode characters can be represented in two forms, which are decomposed form and precomposed form (precomposed form is also called composite form or composed form). For example, ' パ ' can be represented by one Unicode character (U+30D1, precomposed form) or by two Unicode characters (U+30CF( ハ ) + U+309A('°'), decomposed form). Internally, Vectorworks uses Unicode characters in precomposed form. Client code using VW SDK doesn't need to worry about the difference.

Developers need to pay attention to the difference when calling some native Mac functions. In most cases, characters from OS APIs (Mac or Windows) are in the precomposed form. There are some exceptions on Mac. Two of them are APIs handling URLs and plist files. When TXString objects are initiated from objects returned by OS in these areas, ToPrecomposed() can be called to convert decomposed form to precomposed form. If the code needs to return a string in decomposed form, ToDecomposed() can be called to do the conversion before sending it to the OS. For example, SDK file/folder classes convert decomposed strings from Mac APIs to precomposed form right after these calls. Thus, all strings processed and manipulated internally are in precomposed form, and the client code using VW SDK doesn't need to worry about this. (If strings are in different forms, string comparison won't work. In addition, methods like element access operator[] and GetLength() may return different results if strings are in decomposed form.)

Surrogate Pairs

Most Unicode characters can be represented by one UTF-16 character. However, Unicode characters greater than U+FFFF need two UTF-16 characters, called surrogate pairs. For example, Unicode character 'SMILING FACE WITH SMILING EYES' ( 😊, U+1F60A) is represented by 0xD83D and 0xDE0A in UTF-16. Thus, it is possible to have a TXString with invalid UTF-16 characters at the edges after some manipulations, such as Truncate(...). TXString automatically removes invalid UTF-16 characters at the edges during the call to Mid(...), Left(...), Right(...), or Truncate(...). The client code can also call TrimLeftInvalidCharacter(), TrimRightInvalidCharacter(), or TrimInvalidCharacters() manually to remove invalid UTF-16 characters at the edges.

Definition

TXString class is defined in "GSString.X.h".

Iterators

TConstForwardIterator

class TConstForwardIterator
{
public:
	TConstForwardIterator(const TXString &str, int nStart=0);
	TConstForwardIterator& operator++();
	TConstForwardIterator& operator--();
	operator bool() const;
	bool operator==(char ch) const;
	int GetPosition() const;
	char GetChar() const;
	char GetNextChar() const;
	char GetPrevChar() const;
};

TConstReverseIterator

class TConstReverseIterator
{
public:
	TConstReverseIterator(const TXString &str);
	TConstReverseIterator& operator++();
	TConstReverseIterator& operator--();
	operator bool() const;
	bool operator==(char ch) const;
	int GetPosition() const;
	char GetChar() const;
	char GetNextChar() const;
	char GetPrevChar() const;
};

TForwardIterator

class TForwardIterator : public TConstForwardIterator
{
public:
	TForwardIterator(const TXString &str, int nStart=0);
	TXString& operator*() const;
	TXString* operator->() const;
};

TReverseIterator

class TReverseIterator : public TConstReverseIterator
{
public:
	TReverseIterator(const TXString &str);
	TXString& operator*() const;	
	TXString* operator->() const;
};

Displaying String Content in Xcode Debug Area

#=========================================================================================
# The following code is for displaying TXString content in Xcode debug area.
# Add the following code to "~/.lldbinit".
# These code will take effect after Xcode restarts.

#=========================================================================================
import sys
import lldb
import lldb.formatters.Logger

CATEGORY_NAME = "vectorworks"

#=========================================================================================
# For displaying StdUStr summary in Xcode
def StdUStrSummary(valobj,internal_dict):
	middle = valobj.GetChildAtIndex(0).GetChildAtIndex(0).GetChildAtIndex(0).GetChildAtIndex(0)
	__s = middle.GetChildAtIndex(1)
	modeAndSize = __s.GetChildAtIndex(0).GetChildAtIndex(0).GetValueAsUnsigned(0)
	
	# String to be returned later.
	retStr = u'u"'
	
	if (modeAndSize & 1) == 0:  # Short/static form
		size = (modeAndSize >> 1)
		
		# Current max array size is 11. If size is greater than 11, this object is not 
		# initialized and the content should be empty.
		if size < 12:	
			txCharBuf = __s.GetChildAtIndex(1).GetPointeeData(0, size).uint16
		
			for i in range(size):
				if txCharBuf[i] == 0:
					break;
				retStr = retStr + unichr(txCharBuf[i])
			
	else:  # Long/dynamic form
		__l = middle.GetChildAtIndex(0)
		
		# We only show the first 1000 characters.
		size = __l.GetChildAtIndex(1).GetValueAsUnsigned(0)
		if size > 1000:
			size = 1000
		txCharBuf = __l.GetChildAtIndex(2).GetPointeeData(0, size).uint16
		
		for i in range(size):
			if txCharBuf[i] == 0:
				break;
			retStr = retStr + unichr(txCharBuf[i])
			
	retStr = retStr + u'"'
	
	return retStr.encode('utf-8')

#=========================================================================================
# For displaying TXString summary in Xcode
def TXStringSummary(valobj,internal_dict):
	return StdUStrSummary(valobj.GetChildMemberWithName('stdUStr'), internal_dict)

#=========================================================================================
def __lldb_init_module(debugger, dict):
	reload(sys)
	sys.setdefaultencoding('utf-8')

	# StdUStr and TXString
	debugger.HandleCommand('type summary add -F lldb_vectorworks.StdUStrSummary StdUStr --category %s' % CATEGORY_NAME)
	debugger.HandleCommand('type summary add -F lldb_vectorworks.TXStringSummary TXString --category %s' % CATEGORY_NAME)

	# Enable the vectorworks category
	debugger.HandleCommand("type category enable %s" % CATEGORY_NAME)
	
#=========================================================================================