QFontDatabase class provides information about the fonts available in the underlying window system. 更多...
| 头： | #include <QFontDatabase> |
| qmake: | QT += gui |
注意： 此类的所有函数 thread-safe .
| enum | SystemFont { GeneralFont, FixedFont, TitleFont, SmallestReadableFont } |
| enum | WritingSystem { Any, Latin, Greek, Cyrillic, ..., Nko } |
| QFontDatabase () | |
| bool | bold (const QString & family , const QString & style ) const |
| QStringList | families (WritingSystem writingSystem = Any) const |
| QFont | font (const QString & family , const QString & style , int pointSize ) const |
| bool | isBitmapScalable (const QString & family , const QString & style = QString()) const |
| bool | isFixedPitch (const QString & family , const QString & style = QString()) const |
| bool | isPrivateFamily (const QString & family ) const |
| bool | isScalable (const QString & family , const QString & style = QString()) const |
| bool | isSmoothlyScalable (const QString & family , const QString & style = QString()) const |
| bool | italic (const QString & family , const QString & style ) const |
| QList<int> | pointSizes (const QString & family , const QString & styleName = QString()) |
| QList<int> | smoothSizes (const QString & family , const QString & styleName ) |
| QString | styleString (const QFont & font ) |
| QString | styleString (const QFontInfo & fontInfo ) |
| QStringList | styles (const QString & family ) const |
| int | weight (const QString & family , const QString & style ) const |
| QList<WritingSystem> | writingSystems () const |
| QList<WritingSystem> | writingSystems (const QString & family ) const |
| int | addApplicationFont (const QString & fileName ) |
| int | addApplicationFontFromData (const QByteArray & fontData ) |
| QStringList | applicationFontFamilies (int id ) |
| bool | removeAllApplicationFonts () |
| bool | removeApplicationFont (int id ) |
| QList<int> | standardSizes () |
| QFont | systemFont (SystemFont type ) |
| QString | writingSystemName (WritingSystem writingSystem ) |
| QString | writingSystemSample (WritingSystem writingSystem ) |
QFontDatabase class provides information about the fonts available in the underlying window system.
The most common uses of this class are to query the database for the list of font families () and for the pointSizes () 和 styles () that are available for each family. An alternative to pointSizes () 是 smoothSizes () which returns the sizes at which a given family and style will look attractive.
If the font family is available from two or more foundries the foundry name is included in the family name; for example: "Helvetica [Adobe]" and "Helvetica [Cronyx]". When you specify a family, you can either use the old hyphenated "foundry-family" format or the bracketed "family [foundry]" format; for example: "Cronyx-Helvetica" or "Helvetica [Cronyx]". If the family has a foundry it is always returned using the bracketed format, as is the case with the value returned by families ().
font () 函数返回 QFont 给定系列、样式及点大小。
A family and style combination can be checked to see if it is italic () 或 bold (), and to retrieve its weight (). Similarly we can call isBitmapScalable (), isSmoothlyScalable (), isScalable () 和 isFixedPitch ().
使用 styleString () 以获取样式的文本版本。
QFontDatabase class also supports some static functions, for example, standardSizes (). You can retrieve the description of a writing system using writingSystemName (), and a sample of characters in a writing system with writingSystemSample ().
范例：
QFontDatabase database;
QTreeWidget fontTree;
fontTree.setColumnCount(2);
fontTree.setHeaderLabels(QStringList() << "Font" << "Smooth Sizes");
foreach (const QString &family, database.families()) {
QTreeWidgetItem *familyItem = new QTreeWidgetItem(&fontTree);
familyItem->setText(0, family);
foreach (const QString &style, database.styles(family)) {
QTreeWidgetItem *styleItem = new QTreeWidgetItem(familyItem);
styleItem->setText(0, style);
QString sizes;
foreach (int points, database.smoothSizes(family, style))
sizes += QString::number(points) + ' ';
styleItem->setText(1, sizes.trimmed());
}
}
This example gets the list of font families, the list of styles for each family, and the point sizes that are available for each combination of family and style, displaying this information in a tree view.
另请参阅 QFont , QFontInfo , QFontMetrics ，和 字符映射范例 .
| 常量 | 值 | 描述 |
|---|---|---|
QFontDatabase::GeneralFont
|
0
|
The default system font. |
QFontDatabase::FixedFont
|
1
|
The fixed font that the system recommends. |
QFontDatabase::TitleFont
|
2
|
The system standard font for titles. |
QFontDatabase::SmallestReadableFont
|
3
|
The smallest readable system font. |
该枚举在 Qt 5.2 引入或被修改。
| 常量 | 值 | 描述 |
|---|---|---|
QFontDatabase::Any
|
0
|
|
QFontDatabase::Latin
|
1
|
|
QFontDatabase::Greek
|
2
|
|
QFontDatabase::Cyrillic
|
3
|
|
QFontDatabase::Armenian
|
4
|
|
QFontDatabase::Hebrew
|
5
|
|
QFontDatabase::Arabic
|
6
|
|
QFontDatabase::Syriac
|
7
|
|
QFontDatabase::Thaana
|
8
|
|
QFontDatabase::Devanagari
|
9
|
|
QFontDatabase::Bengali
|
10
|
|
QFontDatabase::Gurmukhi
|
11
|
|
QFontDatabase::Gujarati
|
12
|
|
QFontDatabase::Oriya
|
13
|
|
QFontDatabase::Tamil
|
14
|
|
QFontDatabase::Telugu
|
15
|
|
QFontDatabase::Kannada
|
16
|
|
QFontDatabase::Malayalam
|
17
|
|
QFontDatabase::Sinhala
|
18
|
|
QFontDatabase::Thai
|
19
|
|
QFontDatabase::Lao
|
20
|
|
QFontDatabase::Tibetan
|
21
|
|
QFontDatabase::Myanmar
|
22
|
|
QFontDatabase::Georgian
|
23
|
|
QFontDatabase::Khmer
|
24
|
|
QFontDatabase::SimplifiedChinese
|
25
|
|
QFontDatabase::TraditionalChinese
|
26
|
|
QFontDatabase::Japanese
|
27
|
|
QFontDatabase::Korean
|
28
|
|
QFontDatabase::Vietnamese
|
29
|
|
QFontDatabase::Symbol
|
30
|
|
QFontDatabase::Other
|
Symbol
|
(the same as Symbol) |
QFontDatabase::Ogham
|
? | |
QFontDatabase::Runic
|
? | |
QFontDatabase::Nko
|
? |
Creates a font database object.
[static]
int
QFontDatabase::
addApplicationFont
(const
QString
&
fileName
)
Loads the font from the file specified by fileName and makes it available to the application. An ID is returned that can be used to remove the font again with removeApplicationFont () or to retrieve the list of family names contained in the font.
The function returns -1 if the font could not be loaded.
Currently only TrueType fonts, TrueType font collections, and OpenType fonts are supported.
注意： Adding application fonts on Unix/X11 platforms without fontconfig is currently not supported.
该函数在 Qt 4.2 引入。
另请参阅 addApplicationFontFromData (), applicationFontFamilies ()，和 removeApplicationFont ().
[static]
int
QFontDatabase::
addApplicationFontFromData
(const
QByteArray
&
fontData
)
Loads the font from binary data specified by fontData and makes it available to the application. An ID is returned that can be used to remove the font again with removeApplicationFont () or to retrieve the list of family names contained in the font.
The function returns -1 if the font could not be loaded.
Currently only TrueType fonts and TrueType font collections are supported.
注意： Adding application fonts on Unix/X11 platforms without fontconfig is currently not supported.
该函数在 Qt 4.2 引入。
另请参阅 addApplicationFont (), applicationFontFamilies ()，和 removeApplicationFont ().
[static]
QStringList
QFontDatabase::
applicationFontFamilies
(
int
id
)
Returns a list of font families for the given application font identified by id .
该函数在 Qt 4.2 引入。
另请参阅 addApplicationFont () 和 addApplicationFontFromData ().
返回
true
若字体拥有系列
family
和样式
style
is bold; otherwise returns
false
.
返回可用字体系列的排序列表，支持 writingSystem .
If a family exists in several foundries, the returned name for that font is in the form "family [foundry]". Examples: "Times [Adobe]", "Times [Cronyx]", "Palatino".
另请参阅 writingSystems ().
返回 QFont object that has family family , style style and point size pointSize . If no matching font could be created, a QFont object that uses the application's default font is returned.
返回
true
若字体拥有系列
family
和样式
style
is a scalable bitmap font; otherwise returns
false
. Scaling a bitmap font usually produces an unattractive hardly readable result, because the pixels of the font are scaled. If you need to scale a bitmap font it is better to scale it to one of the fixed sizes returned by
smoothSizes
().
另请参阅 isScalable () 和 isSmoothlyScalable ().
返回
true
若字体拥有系列
family
和样式
style
is fixed pitch; otherwise returns
false
.
返回
true
if and only if the
family
font family is private.
This happens, for instance, on macOS and iOS, where the system UI fonts are not accessible to the user. For completeness, QFontDatabase::families () returns all font families, including the private ones. You should use this function if you are developing a font selection control in order to keep private fonts hidden.
该函数在 Qt 5.5 引入。
另请参阅 families ().
返回
true
若字体拥有系列
family
和样式
style
is scalable; otherwise returns
false
.
另请参阅 isBitmapScalable () 和 isSmoothlyScalable ().
返回
true
若字体拥有系列
family
和样式
style
is smoothly scalable; otherwise returns
false
。若此函数返回
true
, it's safe to scale this font to any size, and the result will always look attractive.
另请参阅 isScalable () 和 isBitmapScalable ().
返回
true
若字体拥有系列
family
和样式
style
为斜体；否则返回
false
.
Returns a list of the point sizes available for the font that has family family 和样式 styleName . The list may be empty.
另请参阅 smoothSizes () 和 standardSizes ().
[static]
bool
QFontDatabase::
removeAllApplicationFonts
()
Removes all application-local fonts previously added using addApplicationFont () 和 addApplicationFontFromData ().
返回
true
若字体卸载成功；否则返回
false
.
该函数在 Qt 4.2 引入。
另请参阅 removeApplicationFont (), addApplicationFont ()，和 addApplicationFontFromData ().
[static]
bool
QFontDatabase::
removeApplicationFont
(
int
id
)
Removes the previously loaded application font identified by
id
。返回
true
if unloading of the font succeeded; otherwise returns
false
.
该函数在 Qt 4.2 引入。
另请参阅 removeAllApplicationFonts (), addApplicationFont ()，和 addApplicationFontFromData ().
Returns the point sizes of a font that has family family 和样式 styleName that will look attractive. The list may be empty. For non-scalable fonts and bitmap scalable fonts, this function is equivalent to pointSizes ().
另请参阅 pointSizes () 和 standardSizes ().
[static]
QList
<
int
> QFontDatabase::
standardSizes
()
返回标准字体大小的列表。
另请参阅 smoothSizes () 和 pointSizes ().
Returns a string that describes the style of the font . For example, "Bold Italic", "Bold", "Italic" or "Normal". An empty string may be returned.
Returns a string that describes the style of the fontInfo . For example, "Bold Italic", "Bold", "Italic" or "Normal". An empty string may be returned.
Returns a list of the styles available for the font family family . Some example styles: "Light", "Light Italic", "Bold", "Oblique", "Demi". The list may be empty.
另请参阅 families ().
[static]
QFont
QFontDatabase::
systemFont
(
SystemFont
type
)
Returns the most adequate font for a given type case for proper integration with the system's look and feel.
该函数在 Qt 5.2 引入。
另请参阅 QGuiApplication::font ().
Returns the weight of the font that has family family 和样式 style . If there is no such family and style combination, returns -1.
[static]
QString
QFontDatabase::
writingSystemName
(
WritingSystem
writingSystem
)
Returns the names the writingSystem (e.g. for displaying to the user in a dialog).
[static]
QString
QFontDatabase::
writingSystemSample
(
WritingSystem
writingSystem
)
Returns a string with sample characters from writingSystem .
Returns a sorted list of the available writing systems. This is list generated from information about all installed fonts on the system.
另请参阅 families ().
Returns a sorted list of the writing systems supported by a given font family .
另请参阅 families ().