/**************************************************************************** ** ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). ** Contact: Nokia Corporation (qt-info@nokia.com) ** ** This file is part of the QtGui module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** No Commercial Usage ** This file contains pre-release code and may not be distributed. ** You may use this file in accordance with the terms and conditions ** contained in the Technology Preview License Agreement accompanying ** this package. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 2.1 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 2.1 requirements ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. ** ** In addition, as a special exception, Nokia gives you certain ** additional rights. These rights are described in the Nokia Qt LGPL ** Exception version 1.1, included in the file LGPL_EXCEPTION.txt in this ** package. ** ** If you have questions regarding the use of this file, please contact ** Nokia at qt-info@nokia.com. ** ** ** ** ** ** ** ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include "qpixmapcache.h" #include "qobject.h" #include "qdebug.h" #include "qpixmapcache_p.h" QT_BEGIN_NAMESPACE /*! \class QPixmapCache \brief The QPixmapCache class provides an application-wide cache for pixmaps. \ingroup painting This class is a tool for optimized drawing with QPixmap. You can use it to store temporary pixmaps that are expensive to generate without using more storage space than cacheLimit(). Use insert() to insert pixmaps, find() to find them, and clear() to empty the cache. QPixmapCache contains no member data, only static functions to access the global pixmap cache. It creates an internal QCache object for caching the pixmaps. 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) 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. The \e{Qt Quarterly} article \l{http://qt.nokia.com/doc/qq/qq12-qpixmapcache.html}{Optimizing with QPixmapCache} explains how to use QPixmapCache to speed up applications by caching the results of painting. \sa QCache, QPixmap */ #if defined(Q_OS_SYMBIAN) static int cache_limit = 1024; // 1048 KB cache limit for symbian #elif defined(Q_WS_QWS) || defined(Q_WS_WINCE) static int cache_limit = 2048; // 2048 KB cache limit for embedded #else 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) { } /*! \internal Constructs a copy of \a other. */ QPixmapCache::Key::Key(const Key &other) { if (other.d) ++(other.d->ref); d = other.d; } /*! Destroys the key. */ QPixmapCache::Key::~Key() { if (d && --(d->ref) == 0) delete d; } /*! \internal Returns true if this key is the same as the given \a key; otherwise returns false. */ bool QPixmapCache::Key::operator ==(const Key &key) const { return (d == key.d); } /*! \fn bool QPixmapCache::Key::operator !=(const Key &key) const \internal */ /*! \internal */ QPixmapCache::Key &QPixmapCache::Key::operator =(const Key &other) { if (d != other.d) { if (other.d) ++(other.d->ref); if (d && --(d->ref) == 0) delete d; d = other.d; } return *this; } class QPMCache : public QObject, public QCache { Q_OBJECT public: QPMCache(); ~QPMCache(); void timerEvent(QTimerEvent *); bool insert(const QString& key, const QPixmap &pixmap, int cost); QPixmapCache::Key insert(const QPixmap &pixmap, int cost); bool replace(const QPixmapCache::Key &key, const QPixmap &pixmap, int cost); bool remove(const QString &key); bool remove(const QPixmapCache::Key &key); void resizeKeyArray(int size); QPixmapCache::Key createKey(); void releaseKey(const QPixmapCache::Key &key); void clear(); QPixmap *object(const QString &key) const; QPixmap *object(const QPixmapCache::Key &key) const; static inline QPixmapCache::KeyData *get(const QPixmapCache::Key &key) {return key.d;} static QPixmapCache::KeyData* getKeyData(QPixmapCache::Key *key); private: int *keyArray; int theid; int ps; int keyArraySize; int freeKey; QHash cacheKeys; bool t; }; QT_BEGIN_INCLUDE_NAMESPACE #include "qpixmapcache.moc" QT_END_INCLUDE_NAMESPACE uint qHash(const QPixmapCache::Key &k) { return qHash(QPMCache::get(k)->key); } QPMCache::QPMCache() : QObject(0), QCache(cache_limit * 1024), keyArray(0), theid(0), ps(0), keyArraySize(0), freeKey(0), t(false) { } QPMCache::~QPMCache() { free(keyArray); } /* This is supposed to cut the cache size down by about 25% in a minute once the application becomes idle, to let any inserted pixmap remain in the cache for some time before it becomes a candidate for cleaning-up, and to not cut down the size of the cache while the cache is in active use. When the last pixmap has been deleted from the cache, kill the timer so Qt won't keep the CPU from going into sleep mode. */ void QPMCache::timerEvent(QTimerEvent *) { int mc = maxCost(); bool nt = totalCost() == ps; QList keys = QCache::keys(); setMaxCost(nt ? totalCost() * 3 / 4 : totalCost() -1); setMaxCost(mc); ps = totalCost(); QHash::iterator it = cacheKeys.begin(); while (it != cacheKeys.end()) { if (!contains(it.value())) { releaseKey(it.value()); it = cacheKeys.erase(it); } else { ++it; } } for (int i = 0; i < keys.size(); ++i) { if (!contains(keys.at(i))) releaseKey(keys.at(i)); } if (!size()) { killTimer(theid); theid = 0; } else if (nt != t) { killTimer(theid); theid = startTimer(nt ? 10000 : 30000); t = nt; } } QPixmap *QPMCache::object(const QString &key) const { QPixmapCache::Key cacheKey = cacheKeys.value(key); if (!cacheKey.d || !cacheKey.d->isValid) { const_cast(this)->cacheKeys.remove(key); return 0; } QPixmap *ptr = QCache::object(cacheKey); //We didn't find the pixmap in the cache, the key is not valid anymore if (!ptr) { const_cast(this)->cacheKeys.remove(key); const_cast(this)->releaseKey(cacheKey); } return ptr; } QPixmap *QPMCache::object(const QPixmapCache::Key &key) const { Q_ASSERT(key.d->isValid); QPixmap *ptr = QCache::object(key); //We didn't find the pixmap in the cache, the key is not valid anymore if (!ptr) const_cast(this)->releaseKey(key); return ptr; } bool QPMCache::insert(const QString& key, const QPixmap &pixmap, int cost) { QPixmapCache::Key cacheKey; QPixmapCache::Key oldCacheKey = cacheKeys.value(key); //If for the same key we add already a pixmap we should delete it if (oldCacheKey.d) { QCache::remove(oldCacheKey); cacheKey = oldCacheKey; } else { cacheKey = createKey(); } bool success = QCache::insert(cacheKey, new QDetachedPixmap(pixmap), cost); if (success) { cacheKeys.insert(key, cacheKey); if (!theid) { theid = startTimer(30000); t = false; } } else { //Insertion failed we released the new allocated key releaseKey(cacheKey); } return success; } QPixmapCache::Key QPMCache::insert(const QPixmap &pixmap, int cost) { QPixmapCache::Key cacheKey = createKey(); bool success = QCache::insert(cacheKey, new QDetachedPixmap(pixmap), cost); if (success) { if (!theid) { theid = startTimer(30000); t = false; } } else { //Insertion failed we released the key and return an invalid one releaseKey(cacheKey); } return cacheKey; } bool QPMCache::replace(const QPixmapCache::Key &key, const QPixmap &pixmap, int cost) { Q_ASSERT(key.d->isValid); //If for the same key we add already a pixmap we should delete it QCache::remove(key); bool success = QCache::insert(key, new QDetachedPixmap(pixmap), cost); if (success && !theid) { theid = startTimer(30000); t = false; } return success; } bool QPMCache::remove(const QString &key) { QPixmapCache::Key cacheKey = cacheKeys.value(key); //The key was not in the cache if (!cacheKey.d) return false; cacheKeys.remove(key); releaseKey(cacheKey); return QCache::remove(cacheKey); } bool QPMCache::remove(const QPixmapCache::Key &key) { bool result = QCache::remove(key); //We release the key after we removed it from the cache releaseKey(key); return result; } void QPMCache::resizeKeyArray(int size) { if (size <= keyArraySize || size == 0) return; keyArray = q_check_ptr(reinterpret_cast(realloc(keyArray, size * sizeof(int)))); for (int i = keyArraySize; i != size; ++i) keyArray[i] = i + 1; keyArraySize = size; } QPixmapCache::Key QPMCache::createKey() { if (freeKey == keyArraySize) resizeKeyArray(keyArraySize ? keyArraySize << 1 : 2); int id = freeKey; freeKey = keyArray[id]; QPixmapCache::Key key; QPixmapCache::KeyData *d = QPMCache::getKeyData(&key); d->key = ++id; return key; } void QPMCache::releaseKey(const QPixmapCache::Key &key) { if (key.d->key > keyArraySize || key.d->key <= 0) return; key.d->key--; keyArray[key.d->key] = freeKey; freeKey = key.d->key; key.d->isValid = false; key.d->key = 0; } void QPMCache::clear() { free(keyArray); keyArray = 0; freeKey = 0; keyArraySize = 0; //Mark all keys as invalid QList keys = QCache::keys(); for (int i = 0; i < keys.size(); ++i) keys.at(i).d->isValid = false; QCache::clear(); } QPixmapCache::KeyData* QPMCache::getKeyData(QPixmapCache::Key *key) { if (!key->d) key->d = new QPixmapCache::KeyData; return key->d; } Q_GLOBAL_STATIC(QPMCache, pm_cache) /*! \obsolete \overload Returns the pixmap associated with the \a key in the cache, or null if there is no such pixmap. \warning If valid, you should copy the pixmap immediately (this is fast). Subsequent insertions into the cache could cause the pointer to become invalid. For this reason, we recommend you use bool find(const QString&, QPixmap*) instead. Example: \snippet doc/src/snippets/code/src_gui_image_qpixmapcache.cpp 0 */ QPixmap *QPixmapCache::find(const QString &key) { return pm_cache()->object(key); } /*! \obsolete Use bool find(const QString&, QPixmap*) instead. */ bool QPixmapCache::find(const QString &key, QPixmap& pixmap) { return find(key, &pixmap); } /*! 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. \since 4.6 Example: \snippet doc/src/snippets/code/src_gui_image_qpixmapcache.cpp 1 */ bool QPixmapCache::find(const QString &key, QPixmap* pixmap) { QPixmap *ptr = pm_cache()->object(key); if (ptr && pixmap) *pixmap = *ptr; return ptr != 0; } /*! 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 no longer valid, so it will be released for the next insertion. \since 4.6 */ bool QPixmapCache::find(const Key &key, QPixmap* pixmap) { //The key is not valid anymore, a flush happened before probably if (!key.d || !key.d->isValid) return false; QPixmap *ptr = pm_cache()->object(key); if (ptr && pixmap) *pixmap = *ptr; return ptr != 0; } /*! Inserts a copy of the pixmap \a pixmap associated with the \a 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. \sa setCacheLimit() */ bool QPixmapCache::insert(const QString &key, const QPixmap &pixmap) { return pm_cache()->insert(key, pixmap, pixmap.width() * pixmap.height() * pixmap.depth() / 8); } /*! 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 pixmap to be inserted. The oldest pixmaps (least recently accessed in the cache) are deleted when more space is needed. \sa setCacheLimit(), replace() \since 4.6 */ QPixmapCache::Key QPixmapCache::insert(const QPixmap &pixmap) { return pm_cache()->insert(pixmap, pixmap.width() * pixmap.height() * pixmap.depth() / 8); } /*! 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() \since 4.6 */ bool QPixmapCache::replace(const Key &key, const QPixmap &pixmap) { //The key is not valid anymore, a flush happened before probably if (!key.d || !key.d->isValid) return false; return pm_cache()->replace(key, pixmap, pixmap.width() * pixmap.height() * pixmap.depth() / 8); } /*! Returns the cache limit (in kilobytes). The default cache limit is 2048 KB on embedded platforms, 10240 KB on desktop platforms. \sa setCacheLimit() */ int QPixmapCache::cacheLimit() { return cache_limit; } /*! Sets the cache limit to \a n kilobytes. The default setting is 2048 KB on embedded platforms, 10240 KB on desktop platforms. \sa cacheLimit() */ void QPixmapCache::setCacheLimit(int n) { cache_limit = n; pm_cache()->setMaxCost(1024 * cache_limit); } /*! Removes the pixmap associated with \a key from the cache. */ void QPixmapCache::remove(const QString &key) { pm_cache()->remove(key); } /*! Removes the pixmap associated with \a key from the cache and releases the key for a future insertion. \since 4.6 */ void QPixmapCache::remove(const Key &key) { //The key is not valid anymore, a flush happened before probably if (!key.d || !key.d->isValid) return; pm_cache()->remove(key); } /*! Removes all pixmaps from the cache. */ void QPixmapCache::clear() { QT_TRY { pm_cache()->clear(); } QT_CATCH(const std::bad_alloc &) { // if we ran out of memory during pm_cache(), it's no leak, // so just ignore it. } } QT_END_NAMESPACE