QChar ClassThe QChar class provides a 16-bit Unicode character. More... #include <QChar> Note: All functions in this class are reentrant. Public Types
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Detailed DescriptionThe QChar class provides a 16-bit Unicode character. In Qt, Unicode characters are 16-bit entities without any markup or structure. This class represents such an entity. It is lightweight, so it can be used everywhere. Most compilers treat it like a unsigned short. QChar provides a full complement of testing/classification functions, converting to and from other formats, converting from composed to decomposed Unicode, and trying to compare and case-convert if you ask it to. The classification functions include functions like those in the standard C++ header <cctype> (formerly <ctype.h>), but operating on the full range of Unicode characters, not just for the ASCII range. They all return true if the character is a certain type of character; otherwise they return false. These classification functions are isNull() (returns true if the character is '\0'), isPrint() (true if the character is any sort of printable character, including whitespace), isPunct() (any sort of punctation), isMark() (Unicode Mark), isLetter() (a letter), isNumber() (any sort of numeric character, not just 0-9), isLetterOrNumber(), and isDigit() (decimal digits). All of these are wrappers around category() which return the Unicode-defined category of each character. Some of these also calculate the derived properties (i.e. isSpace() returns true if the character is of category Separator_* or an exceptional code point from Other_Control category). QChar also provides direction(), which indicates the "natural" writing direction of this character. The joining() function indicates how the character joins with it's neighbors (needed mostly for Arabic) and finally hasMirrored(), which indicates whether the character needs to be mirrored when it is printed in it's "unnatural" writing direction. Composed Unicode characters (like ring) can be converted to decomposed Unicode ("a" followed by "ring above") by using decomposition(). In Unicode, comparison is not necessarily possible and case conversion is very difficult at best. Unicode, covering the "entire" world, also includes most of the world's case and sorting problems. operator==() and friends will do comparison based purely on the numeric Unicode value (code point) of the characters, and toUpper() and toLower() will do case changes when the character has a well-defined uppercase/lowercase equivalent. For locale-dependent comparisons, use QString::localeAwareCompare(). The conversion functions include unicode() (to a scalar), toLatin1() (to scalar, but converts all non-Latin-1 characters to 0), row() (gives the Unicode row), cell() (gives the Unicode cell), digitValue() (gives the integer value of any of the numerous digit characters), and a host of constructors. QChar provides constructors and cast operators that make it easy to convert to and from traditional 8-bit chars. If you defined QT_NO_CAST_FROM_ASCII and QT_NO_CAST_TO_ASCII, as explained in the QString documentation, you will need to explicitly call fromLatin1(), or use QLatin1Char, to construct a QChar from an 8-bit char, and you will need to call toLatin1() to get the 8-bit value back. For more information see "About the Unicode Character Database". See also Unicode, QString, and QLatin1Char. Member Type Documentation
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Constant | Value | Description |
---|---|---|
QChar::Mark_NonSpacing | 0 | Unicode class name Mn |
QChar::Mark_SpacingCombining | 1 | Unicode class name Mc |
QChar::Mark_Enclosing | 2 | Unicode class name Me |
QChar::Number_DecimalDigit | 3 | Unicode class name Nd |
QChar::Number_Letter | 4 | Unicode class name Nl |
QChar::Number_Other | 5 | Unicode class name No |
QChar::Separator_Space | 6 | Unicode class name Zs |
QChar::Separator_Line | 7 | Unicode class name Zl |
QChar::Separator_Paragraph | 8 | Unicode class name Zp |
QChar::Other_Control | 9 | Unicode class name Cc |
QChar::Other_Format | 10 | Unicode class name Cf |
QChar::Other_Surrogate | 11 | Unicode class name Cs |
QChar::Other_PrivateUse | 12 | Unicode class name Co |
QChar::Other_NotAssigned | 13 | Unicode class name Cn |
The following categories are informative in Unicode:
Constant | Value | Description |
---|---|---|
QChar::Letter_Uppercase | 14 | Unicode class name Lu |
QChar::Letter_Lowercase | 15 | Unicode class name Ll |
QChar::Letter_Titlecase | 16 | Unicode class name Lt |
QChar::Letter_Modifier | 17 | Unicode class name Lm |
QChar::Letter_Other | 18 | Unicode class name Lo |
QChar::Punctuation_Connector | 19 | Unicode class name Pc |
QChar::Punctuation_Dash | 20 | Unicode class name Pd |
QChar::Punctuation_Open | 21 | Unicode class name Ps |
QChar::Punctuation_Close | 22 | Unicode class name Pe |
QChar::Punctuation_InitialQuote | 23 | Unicode class name Pi |
QChar::Punctuation_FinalQuote | 24 | Unicode class name Pf |
QChar::Punctuation_Other | 25 | Unicode class name Po |
QChar::Symbol_Math | 26 | Unicode class name Sm |
QChar::Symbol_Currency | 27 | Unicode class name Sc |
QChar::Symbol_Modifier | 28 | Unicode class name Sk |
QChar::Symbol_Other | 29 | Unicode class name So |
See also category().
This enum type defines the Unicode decomposition attributes. See the Unicode Standard for a description of the values.
Constant | Value |
---|---|
QChar::NoDecomposition | 0 |
QChar::Canonical | 1 |
QChar::Circle | 8 |
QChar::Compat | 16 |
QChar::Final | 6 |
QChar::Font | 2 |
QChar::Fraction | 17 |
QChar::Initial | 4 |
QChar::Isolated | 7 |
QChar::Medial | 5 |
QChar::Narrow | 13 |
QChar::NoBreak | 3 |
QChar::Small | 14 |
QChar::Square | 15 |
QChar::Sub | 10 |
QChar::Super | 9 |
QChar::Vertical | 11 |
QChar::Wide | 12 |
See also decomposition().
This enum type defines the Unicode direction attributes. See the Unicode Standard for a description of the values.
In order to conform to C/C++ naming conventions "Dir" is prepended to the codes used in the Unicode Standard.
Constant | Value |
---|---|
QChar::DirAL | 13 |
QChar::DirAN | 5 |
QChar::DirB | 7 |
QChar::DirBN | 18 |
QChar::DirCS | 6 |
QChar::DirEN | 2 |
QChar::DirES | 3 |
QChar::DirET | 4 |
QChar::DirL | 0 |
QChar::DirLRE | 11 |
QChar::DirLRO | 12 |
QChar::DirNSM | 17 |
QChar::DirON | 10 |
QChar::DirPDF | 16 |
QChar::DirR | 1 |
QChar::DirRLE | 14 |
QChar::DirRLO | 15 |
QChar::DirS | 8 |
QChar::DirWS | 9 |
See also direction().
This enum type defines the Unicode joining attributes. See the Unicode Standard for a description of the values.
Constant | Value |
---|---|
QChar::Center | 3 |
QChar::Dual | 1 |
QChar::OtherJoining | 0 |
QChar::Right | 2 |
See also joining().
Constant | Value | Description |
---|---|---|
QChar::Null | 0x0000 | A QChar with this value isNull(). |
QChar::Tabulation | 0x0009 | Character tabulation. |
QChar::LineFeed | 0x000a | |
QChar::CarriageReturn | 0x000d | |
QChar::Space | 0x0020 | |
QChar::Nbsp | 0x00a0 | Non-breaking space. |
QChar::ReplacementCharacter | 0xfffd | The character shown when a font has no glyph for a certain codepoint. A special question mark character is often used. Codecs use this codepoint when input data cannot be represented in Unicode. |
QChar::ObjectReplacementCharacter | 0xfffc | Used to represent an object such as an image when such objects cannot be presented. |
QChar::ByteOrderMark | 0xfeff | |
QChar::ByteOrderSwapped | 0xfffe | |
QChar::ParagraphSeparator | 0x2029 | |
QChar::LineSeparator | 0x2028 | |
QChar::LastValidCodePoint | 0x10ffff |
Specifies which version of the Unicode standard introduced a certain character.
Constant | Value | Description |
---|---|---|
QChar::Unicode_1_1 | 1 | Version 1.1 |
QChar::Unicode_2_0 | 2 | Version 2.0 |
QChar::Unicode_2_1_2 | 3 | Version 2.1.2 |
QChar::Unicode_3_0 | 4 | Version 3.0 |
QChar::Unicode_3_1 | 5 | Version 3.1 |
QChar::Unicode_3_2 | 6 | Version 3.2 |
QChar::Unicode_4_0 | 7 | Version 4.0 |
QChar::Unicode_4_1 | 8 | Version 4.1 |
QChar::Unicode_5_0 | 9 | Version 5.0 |
QChar::Unicode_Unassigned | 0 | The value is not assigned to any character in version 5.0 of Unicode. |
See also unicodeVersion() and currentUnicodeVersion().
Constructs a null QChar ('\0').
See also isNull().
Constructs a QChar for the character with Unicode code point code.
Constructs a QChar for Unicode cell cell in row row.
Constructs a QChar for the character with Unicode code point code.
Constructs a QChar for the character with Unicode code point code.
Constructs a QChar for the character with Unicode code point code.
Constructs a QChar for the predefined character value ch.
Constructs a QChar corresponding to ASCII/Latin-1 character ch.
Constructs a QChar corresponding to ASCII/Latin-1 character ch.
Constructs a QChar corresponding to ASCII/Latin-1 character ch.
Returns the character's category.
This is an overloaded function.
Returns the category of the UCS-4-encoded character specified by ucs4.
Returns the cell (least significant byte) of the Unicode character.
See also row().
Returns the combining class for the character as defined in the Unicode standard. This is mainly useful as a positioning hint for marks attached to a base character.
The Qt text rendering engine uses this information to correctly position non-spacing marks around a base character.
This is an overloaded function.
Returns the combining class for the UCS-4-encoded character specified by ucs4, as defined in the Unicode standard.
Returns the most recent supported Unicode version.
Decomposes a character into it's constituent parts. Returns an empty string if no decomposition exists.
This is an overloaded function.
Decomposes the UCS-4-encoded character specified by ucs4 into it's constituent parts. Returns an empty string if no decomposition exists.
Returns the tag defining the composition of the character. Returns QChar::NoDecomposition if no decomposition exists.
This is an overloaded function.
Returns the tag defining the composition of the UCS-4-encoded character specified by ucs4. Returns QChar::NoDecomposition if no decomposition exists.
Returns the numeric value of the digit, or -1 if the character is not a digit.
This is an overloaded function.
Returns the numeric value of the digit specified by the UCS-4-encoded character, ucs4, or -1 if the character is not a digit.
Returns the character's direction.
This is an overloaded function.
Returns the direction of the UCS-4-encoded character specified by ucs4.
This function is deprecated.
Converts the ASCII character c to it's equivalent QChar. This is mainly useful for non-internationalized software.
An alternative is to use QLatin1Char.
See also fromLatin1() and unicode().
Converts the Latin-1 character c to its equivalent QChar. This is mainly useful for non-internationalized software.
An alternative is to use QLatin1Char.
See also toLatin1() and unicode().
Returns true if the character should be reversed if the text direction is reversed; otherwise returns false.
A bit faster equivalent of (ch.mirroredChar() != ch).
See also mirroredChar().
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 should be reversed if the text direction is reversed; otherwise returns false.
A bit faster equivalent of (QChar::mirroredChar(ucs4) != ucs4).
This function was introduced in Qt 5.0.
See also mirroredChar().
Returns the high surrogate part of a UCS-4-encoded code point. The returned result is undefined if ucs4 is smaller than 0x10000.
Returns true if the character is a decimal digit (Number_DecimalDigit); otherwise returns false.
See also isNumber().
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is a decimal digit (Number_DecimalDigit); otherwise returns false.
This function was introduced in Qt 5.0.
See also isNumber().
Returns true if the QChar is the high part of a UTF16 surrogate (i.e. if its code point is in range [0xd800..0xdbff]); false otherwise.
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is the high part of a UTF16 surrogate (i.e. if its code point is in range [0xd800..0xdbff]); false otherwise.
Returns true if the character is a letter (Letter_* categories); otherwise returns false.
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is a letter (Letter_* categories); otherwise returns false.
This function was introduced in Qt 5.0.
Returns true if the character is a letter or number (Letter_* or Number_* categories); otherwise returns false.
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is a letter or number (Letter_* or Number_* categories); otherwise returns false.
This function was introduced in Qt 5.0.
Returns true if the QChar is the low part of a UTF16 surrogate (i.e. if its code point is in range [0xdc00..0xdfff]); false otherwise.
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is the low part of a UTF16 surrogate (i.e. if its code point is in range [0xdc00..0xdfff]); false otherwise.
Returns true if the character is a lowercase letter, i.e. category() is Letter_Lowercase.
See also isUpper(), toLower(), and toUpper().
Returns true if the character is a mark (Mark_* categories); otherwise returns false.
See QChar::Category for more information regarding marks.
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is a mark (Mark_* categories); otherwise returns false.
This function was introduced in Qt 5.0.
Returns true if the QChar is a non-character; false otherwise.
Unicode has a certain number of code points that are classified as "non-characters:" that is, they can be used for internal purposes in applications but cannot be used for text interchange. Those are the last two entries each Unicode Plane ([0xfffe..0xffff], [0x1fffe..0x1ffff], etc.) as well as the entries in range [0xfdd0..0xfdef].
This function was introduced in Qt 5.0.
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is a non-character; false otherwise.
Unicode has a certain number of code points that are classified as "non-characters:" that is, they can be used for internal purposes in applications but cannot be used for text interchange. Those are the last two entries each Unicode Plane ([0xfffe..0xffff], [0x1fffe..0x1ffff], etc.) as well as the entries in range [0xfdd0..0xfdef].
This function was introduced in Qt 5.0.
Returns true if the character is the Unicode character 0x0000 ('\0'); otherwise returns false.
Returns true if the character is a number (Number_* categories, not just 0-9); otherwise returns false.
See also isDigit().
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is a number (Number_* categories, not just 0-9); otherwise returns false.
This function was introduced in Qt 5.0.
See also isDigit().
Returns true if the character is a printable character; otherwise returns false. This is any character not of category Other_*.
Note that this gives no indication of whether the character is available in a particular font.
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is a printable character; otherwise returns false. This is any character not of category Other_*.
Note that this gives no indication of whether the character is available in a particular font.
This function was introduced in Qt 5.0.
Returns true if the character is a punctuation mark (Punctuation_* categories); otherwise returns false.
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is a punctuation mark (Punctuation_* categories); otherwise returns false.
This function was introduced in Qt 5.0.
Returns true if the character is a separator character (Separator_* categories or certain code points from Other_Control category); otherwise returns false.
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is a separator character (Separator_* categories or certain code points from Other_Control category); otherwise returns false.
This function was introduced in Qt 5.0.
Returns true if the QChar contains a code point that is in either the high or the low part of the UTF-16 surrogate range (i.e. if its code point is in range [0xd800..0xdfff]); false otherwise.
This function was introduced in Qt 5.0.
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 contains a code point that is in either the high or the low part of the UTF-16 surrogate range (i.e. if its code point is in range [0xd800..0xdfff]); false otherwise.
This function was introduced in Qt 5.0.
Returns true if the character is a symbol (Symbol_* categories); otherwise returns false.
This is an overloaded function.
Returns true if the UCS-4-encoded character specified by ucs4 is a symbol (Symbol_* categories); otherwise returns false.
This function was introduced in Qt 5.0.
Returns true if the character is a titlecase letter, i.e. category() is Letter_Titlecase.
See also isLower(), toUpper(), toLower(), and toTitleCase().
Returns true if the character is an uppercase letter, i.e. category() is Letter_Uppercase.
See also isLower(), toUpper(), and toLower().
Returns information about the joining properties of the character (needed for certain languages such as Arabic).
This is an overloaded function.
Returns information about the joining properties of the UCS-4-encoded character specified by ucs4 (needed for certain languages such as Arabic).
Returns the low surrogate part of a UCS-4-encoded code point. The returned result is undefined if ucs4 is smaller than 0x10000.
Returns the mirrored character if this character is a mirrored character; otherwise returns the character itself.
See also hasMirrored().
This is an overloaded function.
Returns the mirrored character if the UCS-4-encoded character specified by ucs4 is a mirrored character; otherwise returns the character itself.
See also hasMirrored().
Returns true if the UCS-4-encoded character specified by ucs4 can be split into the high and low parts of a UTF16 surrogate (i.e. if its code point is greater than or equals to 0x10000); false otherwise.
Returns the row (most significant byte) of the Unicode character.
See also cell().
Converts a UTF16 surrogate pair with the given high and low values to it's UCS-4-encoded code point.
This is an overloaded function.
Converts a UTF16 surrogate pair (high, low) to it's UCS-4-encoded code point.
This function is deprecated.
Returns the Latin-1 character value of the QChar, or 0 if the character is not representable.
The main purpose of this function is to preserve ASCII characters used in C strings. This is mainly useful for developers of non-internationalized software.
Note: It is not possible to distinguish a non-Latin 1 character from an ASCII 0 (NUL) character. Prefer to use unicode(), which does not have this ambiguity.
Note: This function does not check whether the character value is inside the valid range of US-ASCII.
See also toLatin1() and unicode().
Returns the case folded equivalent of the character. For most Unicode characters this is the same as toLowerCase().
This is an overloaded function.
Returns the case folded equivalent of the UCS-4-encoded character specified by ucs4. For most Unicode characters this is the same as toLowerCase().
Returns the Latin-1 character equivalent to the QChar, or 0. This is mainly useful for non-internationalized software.
Note: It is not possible to distinguish a non-Latin-1 character from a Latin-1 0 (NUL) character. Prefer to use unicode(), which does not have this ambiguity.
See also unicode().
Returns the lowercase equivalent if the character is uppercase or titlecase; otherwise returns the character itself.
This is an overloaded function.
Returns the lowercase equivalent of the UCS-4-encoded character specified by ucs4 if the character is uppercase or titlecase; otherwise returns the character itself.
Returns the title case equivalent if the character is lowercase or uppercase; otherwise returns the character itself.
This is an overloaded function.
Returns the title case equivalent of the UCS-4-encoded character specified by ucs4 if the character is lowercase or uppercase; otherwise returns the character itself.
Returns the uppercase equivalent if the character is lowercase or titlecase; otherwise returns the character itself.
This is an overloaded function.
Returns the uppercase equivalent of the UCS-4-encoded character specified by ucs4 if the character is lowercase or titlecase; otherwise returns the character itself.
Returns the numeric Unicode value of the QChar.
Returns a reference to the numeric Unicode value of the QChar.
Returns the Unicode version that introduced this character.
This is an overloaded function.
Returns the Unicode version that introduced the character specified in its UCS-4-encoded form as ucs4.
Returns true if c1 and c2 are not the same Unicode character; otherwise returns false.
Returns true if the numeric Unicode value of c1 is less than that of c2; otherwise returns false.
Writes the char chr to the stream out.
See also Serializing Qt Data Types.
Returns true if the numeric Unicode value of c1 is less than or equal to that of c2; otherwise returns false.
Returns true if c1 and c2 are the same Unicode character; otherwise returns false.
Returns true if the numeric Unicode value of c1 is greater than that of c2; otherwise returns false.
Returns true if the numeric Unicode value of c1 is greater than or equal to that of c2; otherwise returns false.
Reads a char from the stream in into char chr.
See also Serializing Qt Data Types.