diff options
Diffstat (limited to 'src/gui/text/qfont.cpp')
| -rw-r--r-- | src/gui/text/qfont.cpp | 69 |
1 files changed, 32 insertions, 37 deletions
diff --git a/src/gui/text/qfont.cpp b/src/gui/text/qfont.cpp index 580a09427c..a23ef95fde 100644 --- a/src/gui/text/qfont.cpp +++ b/src/gui/text/qfont.cpp @@ -340,7 +340,7 @@ QFontEngineData::~QFontEngineData() \class QFont \reentrant - \brief The QFont class specifies a font used for drawing text. + \brief The QFont class specifies a query for a font used for drawing text. \ingroup painting \ingroup appearance @@ -348,6 +348,7 @@ QFontEngineData::~QFontEngineData() \ingroup richtext-processing \inmodule QtGui + QFont can be regarded as a query for one or more fonts on the system. When you create a QFont object you specify various attributes that you want the font to have. Qt will use the font with the specified @@ -355,9 +356,15 @@ QFontEngineData::~QFontEngineData() matching installed font. The attributes of the font that is actually used are retrievable from a QFontInfo object. If the window system provides an exact match exactMatch() returns \c true. - Use QFontMetrics to get measurements, e.g. the pixel length of a + Use QFontMetricsF to get measurements, e.g. the pixel length of a string using QFontMetrics::width(). + Attributes which are not specifically set will not affect the font + selection algorithm, and default values will be preferred instead. + + To load a specific physical font, typically represented by a single file, + use QRawFont instead. + Note that a QGuiApplication instance must exist before a QFont can be used. You can set the application's default font with QGuiApplication::setFont(). @@ -390,8 +397,6 @@ QFontEngineData::~QFontEngineData() setStyleHint(). The default family (corresponding to the current style hint) is returned by defaultFamily(). - The font-matching algorithm has a lastResortFamily() and - lastResortFont() in cases where a suitable match cannot be found. You can provide substitutions for font family names using insertSubstitution() and insertSubstitutions(). Substitutions can be removed with removeSubstitutions(). Use substitute() to retrieve @@ -419,18 +424,20 @@ QFontEngineData::~QFontEngineData() \target fontmatching The font matching algorithm works as follows: \list 1 - \li The specified font family is searched for. - \li If not found, the styleHint() is used to select a replacement - family. - \li Each replacement font family is searched for. - \li If none of these are found or there was no styleHint(), "helvetica" - will be searched for. - \li If "helvetica" isn't found Qt will try the lastResortFamily(). - \li If the lastResortFamily() isn't found Qt will try the - lastResortFont() which will always return a name of some kind. + \li If the specified font family exists and can be used to represent + the writing system in use, it will be selected. + \li If not, a replacement font that supports the writing system is + selected. The font matching algorithm will try to find the + best match for all the properties set in the QFont. How this is + done varies from platform to platform. + \li If no font exists on the system that can support the text, + then special "missing character" boxes will be shown in its place. \endlist - Note that the actual font matching algorithm varies from platform to platform. + \note If the selected font, though supporting the writing system in general, + is missing glyphs for one or more specific characters, then Qt will try to + find a fallback font for this or these particular characters. This feature + can be disabled using QFont::NoFontMerging style strategy. In Windows a request for the "Courier" font is automatically changed to "Courier New", an improved version of Courier that allows for smooth scaling. @@ -2133,14 +2140,14 @@ void QFont::cacheStatistics() { } +#if QT_DEPRECATED_SINCE(5, 13) /*! \fn QString QFont::lastResortFamily() const - Returns the "last resort" font family name. + \obsolete - The current implementation tries a wide variety of common fonts, - returning the first one it finds. Is is possible that no family is - found in which case an empty string is returned. + This function is deprecated and is not in use by the font + selection algorithm in Qt 5. It always returns "helvetica". \sa lastResortFont() */ @@ -2148,6 +2155,7 @@ QString QFont::lastResortFamily() const { return QString::fromLatin1("helvetica"); } +#endif extern QStringList qt_fallbacksForFamily(const QString &family, QFont::Style style, QFont::StyleHint styleHint, QChar::Script script); @@ -2169,33 +2177,20 @@ QString QFont::defaultFamily() const return QString(); } +#if QT_DEPRECATED_SINCE(5, 13) /*! \fn QString QFont::lastResortFont() const - Returns a "last resort" font name for the font matching algorithm. - This is used if the last resort family is not available. It will - always return a name, if necessary returning something like - "fixed" or "system". - - The current implementation tries a wide variety of common fonts, - returning the first one it finds. The implementation may change - at any time, but this function will always return a string - containing something. - - It is theoretically possible that there really isn't a - lastResortFont() in which case Qt will abort with an error - message. We have not been able to identify a case where this - happens. Please \l{bughowto.html}{report it as a bug} if - it does, preferably with a list of the fonts you have installed. + \obsolete - \sa lastResortFamily() + Deprecated function. Since Qt 5.0, this is not used by the font selection algorithm. For + compatibility it remains in the API, but will always return the same value as lastResortFamily(). */ QString QFont::lastResortFont() const { - qFatal("QFont::lastResortFont: Cannot find any reasonable font"); - // Shut compiler up - return QString(); + return lastResortFamily(); } +#endif /***************************************************************************** QFont stream functions |