QPixmapCache Class Reference

Member Function Documentation

int QPixmapCache::cacheLimit () [static]

Returns the cache limit (in kilobytes).

The default cache limit is 2048 KB on embedded platforms, 10240 KB on desktop platforms.

See also setCacheLimit().

void QPixmapCache::clear () [static]

Removes all pixmaps from the cache.

bool QPixmapCache::find ( const QString & key, QPixmap * pixmap ) [static]

Looks for a cached pixmap associated with the given key in the cache. If the pixmap is found, the function sets pixmap to that pixmap and returns true; otherwise it leaves pixmap alone and returns false.

Example:

 QPixmap pm;
 if (!QPixmapCache::find("my_big_image", &pm)) {
     pm.load("bigimage.png");
     QPixmapCache::insert("my_big_image", pm);
 }
 painter->drawPixmap(0, 0, pm);

This function was introduced in Qt 4.6.

bool QPixmapCache::find ( const Key & key, QPixmap * pixmap ) [static]

Looks for a cached pixmap associated with the given key in the cache. If the pixmap is found, the function sets pixmap to that pixmap and returns true; otherwise it leaves pixmap alone and returns false. If the pixmap is not found, it means that the key is no longer valid, so it will be released for the next insertion.

This function was introduced in Qt 4.6.

bool QPixmapCache::insert ( const QString & key, const QPixmap & pixmap ) [static]

Inserts a copy of the pixmap pixmap associated with the key into the cache.

All pixmaps inserted by the Qt library have a key starting with "$qt", so your own pixmap keys should never begin "$qt".

When a pixmap is inserted and the cache is about to exceed its limit, it removes pixmaps until there is enough room for the pixmap to be inserted.

The oldest pixmaps (least recently accessed in the cache) are deleted when more space is needed.

The function returns true if the object was inserted into the cache; otherwise it returns false.

See also setCacheLimit().

Key QPixmapCache::insert ( const QPixmap & pixmap ) [static]

Inserts a copy of the given 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 pixmap to be inserted.

The oldest pixmaps (least recently accessed in the cache) are deleted when more space is needed.

This function was introduced in Qt 4.6.

See also setCacheLimit() and replace().

void QPixmapCache::remove ( const QString & key ) [static]

Removes the pixmap associated with key from the cache.

void QPixmapCache::remove ( const Key & key ) [static]

Removes the pixmap associated with key from the cache and releases the key for a future insertion.

This function was introduced in Qt 4.6.

bool QPixmapCache::replace ( const Key & key, const QPixmap & pixmap ) [static]

Replaces the pixmap associated with the given key with the pixmap specified. Returns true if the pixmap has been correctly inserted into the cache; otherwise returns false.

This function was introduced in Qt 4.6.

See also setCacheLimit() and insert().

void QPixmapCache::setCacheLimit ( int n ) [static]

Sets the cache limit to n kilobytes.

The default setting is 2048 KB on embedded platforms, 10240 KB on desktop platforms.

See also cacheLimit().