diff options
Diffstat (limited to 'src/gui/text/qfont.cpp')
-rw-r--r-- | src/gui/text/qfont.cpp | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/src/gui/text/qfont.cpp b/src/gui/text/qfont.cpp index bff8af80b1c..8e515a79810 100644 --- a/src/gui/text/qfont.cpp +++ b/src/gui/text/qfont.cpp @@ -2502,6 +2502,35 @@ QDataStream &operator>>(QDataStream &s, QFont &font) info object is \e not updated. \endlist + \section1 Checking for the existence of a font + + Sometimes it can be useful to check if a font exists before attempting + to use it. The most thorough way of doing so is by using \l {exactMatch()}: + + \code + const QFont segoeFont(QLatin1String("Segoe UI")); + if (QFontInfo(segoeFont).exactMatch()) { + // Use the font... + } + \endcode + + However, this deep search of families can be expensive on some platforms. + \c QFontDatabase::families().contains() is a faster, but less thorough + alternative: + + \code + const QLatin1String segoeUiFamilyName("Segoe UI"); + if (QFontDatabase::families().contains(segoeUiFamilyName)) { + const QFont segoeFont(segoeUiFamilyName); + // Use the font... + } + \endcode + + It's less thorough because it's not a complete search: some font family + aliases may be missing from the list. However, this approach results in + faster application startup times, and so should always be preferred if + possible. + \sa QFont, QFontMetrics, QFontDatabase */ @@ -2518,6 +2547,8 @@ QDataStream &operator>>(QDataStream &s, QFont &font) Use QPainter::fontInfo() to get the font info when painting. This will give correct results also when painting on paint device that is not screen-compatible. + + \sa {Checking for the existence of a font} */ QFontInfo::QFontInfo(const QFont &font) : d(font.d) @@ -2559,7 +2590,7 @@ QFontInfo &QFontInfo::operator=(const QFontInfo &fi) /*! Returns the family name of the matched window system font. - \sa QFont::family() + \sa QFont::family(), {Checking for the existence of a font} */ QString QFontInfo::family() const { |