The QFontDatabase class provides information about the fonts available in the underlying window system. 更多...
The 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 () function 返回 QFont given a family, style and point size.
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 () to obtain a text version of a style.
The QFontDatabase class also supports some static functions, for example, standardSizes (). You can retrieve the description of a writing system using writingSystemName ()，和 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.
| 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.
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.
注意： On Symbian, the font family names get truncated to a length of 20 characters.
该函数在 Qt 4.2 引入。
另请参阅 addApplicationFontFromData (), applicationFontFamilies (), and removeApplicationFont ().
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.
注意： On Symbian, the font family names get truncated to a length of 20 characters.
该函数在 Qt 4.2 引入。
另请参阅 addApplicationFont (), applicationFontFamilies (), and removeApplicationFont ().
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 () and addApplicationFontFromData ().
Returns true if the font that has family family and style style is bold; otherwise returns false.
Returns a sorted list of the available font families which support the 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.
Returns true if the font that has family family and style 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 ().
Returns true if the font that has family family and style style is fixed pitch; otherwise returns false.
Returns true if the font that has family family and style style is scalable; otherwise returns false.
另请参阅 isBitmapScalable () 和 isSmoothlyScalable ().
Returns true if the font that has family family and style style is smoothly scalable; otherwise returns false. If this function returns 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 ().
Returns true if the font that has family family and style style is italic; otherwise returns false.
Returns a list of the point sizes available for the font with the given family and style . The list may be empty.
另请参阅 smoothSizes () 和 standardSizes ().
Removes all application-local fonts previously added using addApplicationFont () and addApplicationFontFromData ().
Returns true if unloading of the fonts succeeded; otherwise returns false.
该函数在 Qt 4.2 引入。
另请参阅 removeApplicationFont (), addApplicationFont (), and addApplicationFontFromData ().
Removes the previously loaded application font identified by id . Returns 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 (), and addApplicationFontFromData ().
Returns the point sizes of a font with the given family and style 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 ().
Returns a list of standard font sizes.
另请参阅 smoothSizes () 和 pointSizes ().
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 ().
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 true if font rendering is supported outside the GUI thread, false otherwise. In other words, a return value of false means that all QPainter.drawText () calls outside the GUI thread will not produce readable output.
该函数在 Qt 4.4 引入。
另请参阅 Painting In Threads .
Returns the weight of the font that has family family and style style . If there is no such family and style combination, returns -1.
Returns the names the writingSystem (e.g. for displaying to the user in a dialog).
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 ().
Returns a string with sample characters from writingSystem .