GetUtf16StringWidth

Short summary

This function returns the width of a given Utf-16 string.

A width of -1 means the string contains control characters, e.g. line feed or carriage return. If a string has for example a line break, the width cannot be calculated. A width 0 means the string is either empty or consists only of combining marks.

Attention: The actual width a character needs for displaying is always dependent on the used font, the fontsize and the rendering! The width this function returns is actually an estimation.

Example:

myString :WString(10) := "Test";
myWidth, charCount :UDINT;
------------------
GetUtf16StringLength(
	stringAddress := ADR(myString),
	width => myWidth,
	visibleCharacters => charCount
);

• Return type: DINT

Parameters

Name	Type	Comment	Kind
utf16StringBuffer	PVOID	adrress of the utf-8 encoded string or byte array (must be also null terminated!)	input
width	DINT	width of the given string	output
visibleCharacters	UDINT	count of visible characters	output

Code

Declaration

FUNCTION GetUtf16StringWidth :DINT;
VAR_INPUT
	(* adrress of the utf-8 encoded string or byte array (must be also null terminated!) *)
	utf16StringBuffer :PVOID;
END_VAR
VAR_OUTPUT
	(* width of the given string *)
	width :DINT := 0;
	(* count of visible characters *)
	visibleCharacters :UDINT;
END_VAR
VAR
	codepoints :POINTER TO UnicodeCodePoint;
	codepointCount :UDINT;
	stringLength :UDINT;
END_VAR

Implementation

GetUtf16StringWidth := 0;
stringLength := GetUtf16StringLength(utf16StringBuffer);
RETURN((utf16StringBuffer = 0) OR_ELSE (stringLength = 0));
codepoints := __NEW(UnicodeCodepoint, (stringLength+1));
RETURN(codepoints = 0);

GetCodepointsFromUtf16String(
	utf16StringAddress := utf16StringBuffer,
	utf16StringWordCount := stringLength,
	codepointBuffer := codepoints,
	bufferSize := (stringLength+1)*SIZEOF(UnicodeCodePoint),
	codePointCount => codepointCount);

width := GetWidthFromCodepointSequence(
			codepoints := codepoints,
			codepointCount := codepointCount, 
			visibleCharacters => visibleCharacters
		);
			
__DELETE(codepoints);

GetUtf16StringWidth := width;