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authormread <qt-info@nokia.com>2009-08-07 13:34:12 (GMT)
committermread <qt-info@nokia.com>2009-08-07 13:34:12 (GMT)
commit5a72890b7ce12815f9567316da867006cff73f39 (patch)
tree46c8c793f19274f9ed19678d1732d2123adbdf34 /src/gui/image/qpixmapcache.cpp
parent0f6f1f841cea61cbb6905de92c2ca63bd369d55d (diff)
parentcc0a411e5e874aa224c26298a109973cb15ea291 (diff)
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Merge branch 'master' of git@scm.dev.nokia.troll.no:qt/qt-s60-public
Conflicts fixed: src/corelib/io/qdiriterator.cpp
Diffstat (limited to 'src/gui/image/qpixmapcache.cpp')
-rw-r--r--src/gui/image/qpixmapcache.cpp75
1 files changed, 43 insertions, 32 deletions
diff --git a/src/gui/image/qpixmapcache.cpp b/src/gui/image/qpixmapcache.cpp
index af13375..aedc90c 100644
--- a/src/gui/image/qpixmapcache.cpp
+++ b/src/gui/image/qpixmapcache.cpp
@@ -64,25 +64,24 @@ QT_BEGIN_NAMESPACE
access the global pixmap cache. It creates an internal QCache
object for caching the pixmaps.
- The cache associates a pixmap with a string as a key or with a QPixmapCache::Key.
- The QPixmapCache::Key is faster than using strings as key. The string API is
- very convenient for complex keys but the QPixmapCache::Key API will be very efficient
- and convenient for a 1 object <-> 1 pixmap mapping (then you can store the key as
- a member).
- If two pixmaps are inserted into the cache using equal keys, then the
- last pixmap will hide the first pixmap. The QHash and QCache classes do
- exactly the same.
+ The cache associates a pixmap with a user-provided string as a key,
+ or with a QPixmapCache::Key that the cache generates.
+ Using QPixmapCache::Key for keys is faster than using strings. The string API is
+ very convenient for complex keys but the QPixmapCache::Key API will be very
+ efficient and convenient for a one-to-one object-to-pixmap mapping \mdash in
+ this case, you can store the keys as members of an object.
+
+ If two pixmaps are inserted into the cache using equal keys then the
+ last pixmap will replace the first pixmap in the cache. This follows the
+ behavior of the QHash and QCache classes.
The cache becomes full when the total size of all pixmaps in the
cache exceeds cacheLimit(). The initial cache limit is
- 2048 KB(2 MB) for Embedded, 10240 KB (10
- MB) for Desktops; it is changed with setCacheLimit().
- A pixmap takes roughly (\e{width} * \e{height} * \e{depth})/8 bytes of memory.
-
- The \e{Qt Quarterly} article
- \l{http://doc.trolltech.com/qq/qq12-qpixmapcache.html}{Optimizing
- with QPixmapCache} explains how to use QPixmapCache to speed up
- applications by caching the results of painting.
+ 2048 KB (2 MB) on embedded platforms, 10240 KB (10 MB) on desktop
+ platforms; you can change this by calling setCacheLimit() with the
+ required value.
+ A pixmap takes roughly (\e{width} * \e{height} * \e{depth})/8 bytes of
+ memory.
\sa QCache, QPixmap
*/
@@ -96,6 +95,17 @@ static int cache_limit = 10240; // 10 MB cache limit for desktop
#endif
/*!
+ \class QPixmapCache::Key
+ \brief The QPixmapCache::Key class can be used for efficient access
+ to the QPixmapCache.
+ \since 4.6
+
+ Use QPixmapCache::insert() to receive an instance of Key generated
+ by the pixmap cache. You can store the key in your own objects for
+ a very efficient one-to-one object-to-pixmap mapping.
+*/
+
+/*!
Constructs an empty Key object.
*/
QPixmapCache::Key::Key() : d(0)
@@ -114,7 +124,7 @@ QPixmapCache::Key::Key(const Key &other)
}
/*!
- Destructor; called immediately before the object is deleted.
+ Destroys the key.
*/
QPixmapCache::Key::~Key()
{
@@ -125,7 +135,8 @@ QPixmapCache::Key::~Key()
/*!
\internal
- Returns true if this key is the same as the given \a key.
+ Returns true if this key is the same as the given \a key; otherwise returns
+ false.
*/
bool QPixmapCache::Key::operator ==(const Key &key) const
{
@@ -410,7 +421,7 @@ QPixmapCache::KeyData* QPMCache::getKeyData(QPixmapCache::Key *key)
Q_GLOBAL_STATIC(QPMCache, pm_cache)
/*!
- \obsolete
+ \obsolete
\overload
Returns the pixmap associated with the \a key in the cache, or
@@ -443,7 +454,7 @@ bool QPixmapCache::find(const QString &key, QPixmap& pixmap)
}
/*!
- Looks for a cached pixmap associated with the \a key in the cache.
+ Looks for a cached pixmap associated with the given \a key in the cache.
If the pixmap is found, the function sets \a pixmap to that pixmap and
returns true; otherwise it leaves \a pixmap alone and returns false.
@@ -462,10 +473,10 @@ bool QPixmapCache::find(const QString &key, QPixmap* pixmap)
}
/*!
- Looks for a cached pixmap associated with the \a key in the cache.
+ Looks for a cached pixmap associated with the given \a key in the cache.
If the pixmap is found, the function sets \a pixmap to that pixmap and
returns true; otherwise it leaves \a pixmap alone and returns false. If
- the pixmap is not found, it means that the \a key is not valid anymore,
+ the pixmap is not found, it means that the \a key is no longer valid,
so it will be released for the next insertion.
\since 4.6
@@ -507,8 +518,8 @@ bool QPixmapCache::insert(const QString &key, const QPixmap &pixmap)
}
/*!
- Inserts a copy of the pixmap \a pixmap into
- the cache and return you the key.
+ Inserts a copy of the given \a pixmap into the cache and returns a key
+ that can be used to retrieve it.
When a pixmap is inserted and the cache is about to exceed its
limit, it removes pixmaps until there is enough room for the
@@ -527,9 +538,9 @@ QPixmapCache::Key QPixmapCache::insert(const QPixmap &pixmap)
}
/*!
- Replace the pixmap associated to the \a key into
- the cache. It return true if the pixmap \a pixmap has been correctly
- inserted into the cache false otherwise.
+ Replaces the pixmap associated with the given \a key with the \a pixmap
+ specified. Returns true if the \a pixmap has been correctly inserted into
+ the cache; otherwise returns false.
\sa setCacheLimit(), insert()
@@ -546,8 +557,8 @@ bool QPixmapCache::replace(const Key &key, const QPixmap &pixmap)
/*!
Returns the cache limit (in kilobytes).
- The default cache limit is 2048 KB for Embedded, 10240 KB for
- Desktops.
+ The default cache limit is 2048 KB on embedded platforms, 10240 KB on
+ desktop platforms.
\sa setCacheLimit()
*/
@@ -560,8 +571,8 @@ int QPixmapCache::cacheLimit()
/*!
Sets the cache limit to \a n kilobytes.
- The default setting is 2048 KB for Embedded, 10240 KB for
- Desktops.
+ The default setting is 2048 KB on embedded platforms, 10240 KB on
+ desktop platforms.
\sa cacheLimit()
*/
@@ -581,7 +592,7 @@ void QPixmapCache::remove(const QString &key)
}
/*!
- Removes the pixmap associated with \a key from the cache and release
+ Removes the pixmap associated with \a key from the cache and releases
the key for a future insertion.
\since 4.6