/**************************************************************************** ** ** Copyright (C) 2016 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the QtGui module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 3 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL3 included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 3 requirements ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU ** General Public License version 2.0 or (at your option) the GNU General ** Public license version 3 or any later version approved by the KDE Free ** Qt Foundation. The licenses are as published by the Free Software ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 ** included in the packaging of this file. Please review the following ** information to ensure the GNU General Public License requirements will ** be met: https://www.gnu.org/licenses/gpl-2.0.html and ** https://www.gnu.org/licenses/gpl-3.0.html. ** ** $QT_END_LICENSE$ ** ****************************************************************************/ //#define QIMAGEREADER_DEBUG /*! \class QImageReader \brief The QImageReader class provides a format independent interface for reading images from files or other devices. \inmodule QtGui \reentrant \ingroup painting \ingroup io The most common way to read images is through QImage and QPixmap's constructors, or by calling QImage::load() and QPixmap::load(). QImageReader is a specialized class which gives you more control when reading images. For example, you can read an image into a specific size by calling setScaledSize(), and you can select a clip rect, effectively loading only parts of an image, by calling setClipRect(). Depending on the underlying support in the image format, this can save memory and speed up loading of images. To read an image, you start by constructing a QImageReader object. Pass either a file name or a device pointer, and the image format to QImageReader's constructor. You can then set several options, such as the clip rect (by calling setClipRect()) and scaled size (by calling setScaledSize()). canRead() returns the image if the QImageReader can read the image (i.e., the image format is supported and the device is open for reading). Call read() to read the image. If any error occurs when reading the image, read() will return a null QImage. You can then call error() to find the type of error that occurred, or errorString() to get a human readable description of what went wrong. \note QImageReader assumes exclusive control over the file or device that is assigned. Any attempts to modify the assigned file or device during the lifetime of the QImageReader object will yield undefined results. \section1 Formats Call supportedImageFormats() for a list of formats that QImageReader can read. QImageReader supports all built-in image formats, in addition to any image format plugins that support reading. Call supportedMimeTypes() to obtain a list of supported MIME types, which for example can be passed to QFileDialog::setMimeTypeFilters(). QImageReader autodetects the image format by default, by looking at the provided (optional) format string, the file name suffix, and the data stream contents. You can enable or disable this feature, by calling setAutoDetectImageFormat(). \section1 High Resolution Versions of Images It is possible to provide high resolution versions of images should a scaling between \e{device pixels} and \e{device independent pixels} be in effect. The high resolution version is marked by the suffix \c @2x on the base name. The image read will have its \e{device pixel ratio} set to a value of 2. This can be disabled by setting the environment variable \c QT_HIGHDPI_DISABLE_2X_IMAGE_LOADING. \sa QImageWriter, QImageIOHandler, QImageIOPlugin, QMimeDatabase \sa QImage::devicePixelRatio(), QPixmap::devicePixelRatio(), QIcon, QPainter::drawPixmap(), QPainter::drawImage(), Qt::AA_UseHighDpiPixmaps */ /*! \enum QImageReader::ImageReaderError This enum describes the different types of errors that can occur when reading images with QImageReader. \value FileNotFoundError QImageReader was used with a file name, but not file was found with that name. This can also happen if the file name contained no extension, and the file with the correct extension is not supported by Qt. \value DeviceError QImageReader encountered a device error when reading the image. You can consult your particular device for more details on what went wrong. \value UnsupportedFormatError Qt does not support the requested image format. \value InvalidDataError The image data was invalid, and QImageReader was unable to read an image from it. The can happen if the image file is damaged. \value UnknownError An unknown error occurred. If you get this value after calling read(), it is most likely caused by a bug in QImageReader. */ #include "qimagereader.h" #include #ifdef QIMAGEREADER_DEBUG #include #endif #include #include #include #include #include #include #include #include #include // factory loader #include #include #include // for qt_getImageText #include // image handlers #include #include #include #include #ifndef QT_NO_IMAGEFORMAT_PNG #include #endif #include QT_BEGIN_NAMESPACE #ifndef QT_NO_IMAGEFORMATPLUGIN Q_GLOBAL_STATIC_WITH_ARGS(QFactoryLoader, loader, (QImageIOHandlerFactoryInterface_iid, QLatin1String("/imageformats"))) #endif enum _qt_BuiltInFormatType { #ifndef QT_NO_IMAGEFORMAT_PNG _qt_PngFormat, #endif #ifndef QT_NO_IMAGEFORMAT_BMP _qt_BmpFormat, #endif #ifndef QT_NO_IMAGEFORMAT_PPM _qt_PpmFormat, _qt_PgmFormat, _qt_PbmFormat, #endif #ifndef QT_NO_IMAGEFORMAT_XBM _qt_XbmFormat, #endif #ifndef QT_NO_IMAGEFORMAT_XPM _qt_XpmFormat, #endif _qt_NumFormats, _qt_NoFormat = -1 }; #if !defined(QT_NO_IMAGEFORMAT_PPM) # define MAX_MT_SIZE 20 #elif !defined(QT_NO_IMAGEFORMAT_XBM) || !defined(QT_NO_IMAGEFORMAT_XPM) # define MAX_MT_SIZE 10 #else # define MAX_MT_SIZE 4 #endif struct _qt_BuiltInFormatStruct { char extension[4]; char mimeType[MAX_MT_SIZE]; }; #undef MAX_MT_SIZE static const _qt_BuiltInFormatStruct _qt_BuiltInFormats[] = { #ifndef QT_NO_IMAGEFORMAT_PNG {"png", "png"}, #endif #ifndef QT_NO_IMAGEFORMAT_BMP {"bmp", "bmp"}, #endif #ifndef QT_NO_IMAGEFORMAT_PPM {"ppm", "x-portable-pixmap"}, {"pgm", "x-portable-graymap"}, {"pbm", "x-portable-bitmap"}, #endif #ifndef QT_NO_IMAGEFORMAT_XBM {"xbm", "x-xbitmap"}, #endif #ifndef QT_NO_IMAGEFORMAT_XPM {"xpm", "x-xpixmap"}, #endif }; Q_STATIC_ASSERT(_qt_NumFormats == sizeof _qt_BuiltInFormats / sizeof *_qt_BuiltInFormats); static QImageIOHandler *createReadHandlerHelper(QIODevice *device, const QByteArray &format, bool autoDetectImageFormat, bool ignoresFormatAndExtension) { if (!autoDetectImageFormat && format.isEmpty()) return 0; QByteArray form = format.toLower(); QImageIOHandler *handler = 0; QByteArray suffix; #ifndef QT_NO_IMAGEFORMATPLUGIN static QMutex mutex; QMutexLocker locker(&mutex); typedef QMultiMap PluginKeyMap; // check if we have plugins that support the image format QFactoryLoader *l = loader(); const PluginKeyMap keyMap = l->keyMap(); #ifdef QIMAGEREADER_DEBUG qDebug() << "QImageReader::createReadHandler( device =" << (void *)device << ", format =" << format << ")," << keyMap.size() << "plugins available: " << keyMap.values(); #endif int suffixPluginIndex = -1; #endif // QT_NO_IMAGEFORMATPLUGIN if (device && format.isEmpty() && autoDetectImageFormat && !ignoresFormatAndExtension) { // if there's no format, see if \a device is a file, and if so, find // the file suffix and find support for that format among our plugins. // this allows plugins to override our built-in handlers. if (QFile *file = qobject_cast(device)) { #ifdef QIMAGEREADER_DEBUG qDebug() << "QImageReader::createReadHandler: device is a file:" << file->fileName(); #endif if (!(suffix = QFileInfo(file->fileName()).suffix().toLower().toLatin1()).isEmpty()) { #ifndef QT_NO_IMAGEFORMATPLUGIN const int index = keyMap.key(QString::fromLatin1(suffix), -1); if (index != -1) { #ifdef QIMAGEREADER_DEBUG qDebug() << "QImageReader::createReadHandler: suffix recognized; the" << suffix << "plugin might be able to read this"; #endif suffixPluginIndex = index; } #endif // QT_NO_IMAGEFORMATPLUGIN } } } QByteArray testFormat = !form.isEmpty() ? form : suffix; if (ignoresFormatAndExtension) testFormat = QByteArray(); #ifndef QT_NO_IMAGEFORMATPLUGIN if (suffixPluginIndex != -1) { // check if the plugin that claims support for this format can load // from this device with this format. const qint64 pos = device ? device->pos() : 0; const int index = keyMap.key(QString::fromLatin1(suffix), -1); if (index != -1) { QImageIOPlugin *plugin = qobject_cast(l->instance(index)); if (plugin && plugin->capabilities(device, testFormat) & QImageIOPlugin::CanRead) { handler = plugin->create(device, testFormat); #ifdef QIMAGEREADER_DEBUG qDebug() << "QImageReader::createReadHandler: using the" << suffix << "plugin"; #endif } } if (device && !device->isSequential()) device->seek(pos); } if (!handler && !testFormat.isEmpty() && !ignoresFormatAndExtension) { // check if any plugin supports the format (they are not allowed to // read from the device yet). const qint64 pos = device ? device->pos() : 0; if (autoDetectImageFormat) { const int keyCount = keyMap.size(); for (int i = 0; i < keyCount; ++i) { if (i != suffixPluginIndex) { QImageIOPlugin *plugin = qobject_cast(l->instance(i)); if (plugin && plugin->capabilities(device, testFormat) & QImageIOPlugin::CanRead) { #ifdef QIMAGEREADER_DEBUG qDebug() << "QImageReader::createReadHandler: the" << keyMap.keys().at(i) << "plugin can read this format"; #endif handler = plugin->create(device, testFormat); break; } } } } else { const int testIndex = keyMap.key(QLatin1String(testFormat), -1); if (testIndex != -1) { QImageIOPlugin *plugin = qobject_cast(l->instance(testIndex)); if (plugin && plugin->capabilities(device, testFormat) & QImageIOPlugin::CanRead) { #ifdef QIMAGEREADER_DEBUG qDebug() << "QImageReader::createReadHandler: the" << testFormat << "plugin can read this format"; #endif handler = plugin->create(device, testFormat); } } } if (device && !device->isSequential()) device->seek(pos); } #endif // QT_NO_IMAGEFORMATPLUGIN // if we don't have a handler yet, check if we have built-in support for // the format if (!handler && !testFormat.isEmpty()) { if (false) { #ifndef QT_NO_IMAGEFORMAT_PNG } else if (testFormat == "png") { handler = new QPngHandler; #endif #ifndef QT_NO_IMAGEFORMAT_BMP } else if (testFormat == "bmp") { handler = new QBmpHandler; } else if (testFormat == "dib") { handler = new QBmpHandler(QBmpHandler::DibFormat); #endif #ifndef QT_NO_IMAGEFORMAT_XPM } else if (testFormat == "xpm") { handler = new QXpmHandler; #endif #ifndef QT_NO_IMAGEFORMAT_XBM } else if (testFormat == "xbm") { handler = new QXbmHandler; handler->setOption(QImageIOHandler::SubType, testFormat); #endif #ifndef QT_NO_IMAGEFORMAT_PPM } else if (testFormat == "pbm" || testFormat == "pbmraw" || testFormat == "pgm" || testFormat == "pgmraw" || testFormat == "ppm" || testFormat == "ppmraw") { handler = new QPpmHandler; handler->setOption(QImageIOHandler::SubType, testFormat); #endif } #ifdef QIMAGEREADER_DEBUG if (handler) qDebug() << "QImageReader::createReadHandler: using the built-in handler for" << testFormat; #endif } #ifndef QT_NO_IMAGEFORMATPLUGIN if (!handler && (autoDetectImageFormat || ignoresFormatAndExtension)) { // check if any of our plugins recognize the file from its contents. const qint64 pos = device ? device->pos() : 0; const int keyCount = keyMap.size(); for (int i = 0; i < keyCount; ++i) { if (i != suffixPluginIndex) { QImageIOPlugin *plugin = qobject_cast(l->instance(i)); if (plugin && plugin->capabilities(device, QByteArray()) & QImageIOPlugin::CanRead) { handler = plugin->create(device, testFormat); #ifdef QIMAGEREADER_DEBUG qDebug() << "QImageReader::createReadHandler: the" << keyMap.keys().at(i) << "plugin can read this data"; #endif break; } } } if (device && !device->isSequential()) device->seek(pos); } #endif // QT_NO_IMAGEFORMATPLUGIN if (!handler && (autoDetectImageFormat || ignoresFormatAndExtension)) { // check if any of our built-in handlers recognize the file from its // contents. int currentFormat = 0; if (!suffix.isEmpty()) { // If reading from a file with a suffix, start testing our // built-in handler for that suffix first. for (int i = 0; i < _qt_NumFormats; ++i) { if (_qt_BuiltInFormats[i].extension == suffix) { currentFormat = i; break; } } } QByteArray subType; int numFormats = _qt_NumFormats; while (device && numFormats >= 0) { const qint64 pos = device->pos(); switch (currentFormat) { #ifndef QT_NO_IMAGEFORMAT_PNG case _qt_PngFormat: if (QPngHandler::canRead(device)) handler = new QPngHandler; break; #endif #ifndef QT_NO_IMAGEFORMAT_BMP case _qt_BmpFormat: if (QBmpHandler::canRead(device)) handler = new QBmpHandler; break; #endif #ifndef QT_NO_IMAGEFORMAT_XPM case _qt_XpmFormat: if (QXpmHandler::canRead(device)) handler = new QXpmHandler; break; #endif #ifndef QT_NO_IMAGEFORMAT_PPM case _qt_PbmFormat: case _qt_PgmFormat: case _qt_PpmFormat: if (QPpmHandler::canRead(device, &subType)) { handler = new QPpmHandler; handler->setOption(QImageIOHandler::SubType, subType); } break; #endif #ifndef QT_NO_IMAGEFORMAT_XBM case _qt_XbmFormat: if (QXbmHandler::canRead(device)) handler = new QXbmHandler; break; #endif default: break; } if (!device->isSequential()) device->seek(pos); if (handler) { #ifdef QIMAGEREADER_DEBUG qDebug("QImageReader::createReadHandler: the %s built-in handler can read this data", _qt_BuiltInFormats[currentFormat].extension); #endif break; } --numFormats; ++currentFormat; if (currentFormat >= _qt_NumFormats) currentFormat = 0; } } if (!handler) { #ifdef QIMAGEREADER_DEBUG qDebug("QImageReader::createReadHandler: no handlers found. giving up."); #endif // no handler: give up. return 0; } handler->setDevice(device); if (!form.isEmpty()) handler->setFormat(form); return handler; } class QImageReaderPrivate { public: QImageReaderPrivate(QImageReader *qq); ~QImageReaderPrivate(); // device QByteArray format; bool autoDetectImageFormat; bool ignoresFormatAndExtension; QIODevice *device; bool deleteDevice; QImageIOHandler *handler; bool initHandler(); // image options QRect clipRect; QSize scaledSize; QRect scaledClipRect; int quality; QMap text; void getText(); enum { UsePluginDefault, ApplyTransform, DoNotApplyTransform } autoTransform; // error QImageReader::ImageReaderError imageReaderError; QString errorString; QImageReader *q; }; /*! \internal */ QImageReaderPrivate::QImageReaderPrivate(QImageReader *qq) : autoDetectImageFormat(true), ignoresFormatAndExtension(false) { device = 0; deleteDevice = false; handler = 0; quality = -1; imageReaderError = QImageReader::UnknownError; autoTransform = UsePluginDefault; q = qq; } /*! \internal */ QImageReaderPrivate::~QImageReaderPrivate() { if (deleteDevice) delete device; delete handler; } /*! \internal */ bool QImageReaderPrivate::initHandler() { // check some preconditions if (!device || (!deleteDevice && !device->isOpen() && !device->open(QIODevice::ReadOnly))) { imageReaderError = QImageReader::DeviceError; errorString = QImageReader::tr("Invalid device"); return false; } // probe the file extension if (deleteDevice && !device->isOpen() && !device->open(QIODevice::ReadOnly) && autoDetectImageFormat) { QList extensions = QImageReader::supportedImageFormats(); if (!format.isEmpty()) { // Try the most probable extension first int currentFormatIndex = extensions.indexOf(format.toLower()); if (currentFormatIndex > 0) extensions.swap(0, currentFormatIndex); } int currentExtension = 0; QFile *file = static_cast(device); QString fileName = file->fileName(); do { file->setFileName(fileName + QLatin1Char('.') + QLatin1String(extensions.at(currentExtension++).constData())); file->open(QIODevice::ReadOnly); } while (!file->isOpen() && currentExtension < extensions.size()); if (!device->isOpen()) { imageReaderError = QImageReader::FileNotFoundError; errorString = QImageReader::tr("File not found"); file->setFileName(fileName); // restore the old file name return false; } } // assign a handler if (!handler && (handler = createReadHandlerHelper(device, format, autoDetectImageFormat, ignoresFormatAndExtension)) == 0) { imageReaderError = QImageReader::UnsupportedFormatError; errorString = QImageReader::tr("Unsupported image format"); return false; } return true; } /*! \internal */ void QImageReaderPrivate::getText() { if (text.isEmpty() && (handler || initHandler()) && handler->supportsOption(QImageIOHandler::Description)) text = qt_getImageTextFromDescription(handler->option(QImageIOHandler::Description).toString()); } /*! Constructs an empty QImageReader object. Before reading an image, call setDevice() or setFileName(). */ QImageReader::QImageReader() : d(new QImageReaderPrivate(this)) { } /*! Constructs a QImageReader object with the device \a device and the image format \a format. */ QImageReader::QImageReader(QIODevice *device, const QByteArray &format) : d(new QImageReaderPrivate(this)) { d->device = device; d->format = format; } /*! Constructs a QImageReader object with the file name \a fileName and the image format \a format. \sa setFileName() */ QImageReader::QImageReader(const QString &fileName, const QByteArray &format) : QImageReader(new QFile(fileName), format) { d->deleteDevice = true; } /*! Destructs the QImageReader object. */ QImageReader::~QImageReader() { delete d; } /*! Sets the format QImageReader will use when reading images, to \a format. \a format is a case insensitive text string. Example: \snippet code/src_gui_image_qimagereader.cpp 0 You can call supportedImageFormats() for the full list of formats QImageReader supports. \sa format() */ void QImageReader::setFormat(const QByteArray &format) { d->format = format; } /*! Returns the format QImageReader uses for reading images. You can call this function after assigning a device to the reader to determine the format of the device. For example: \snippet code/src_gui_image_qimagereader.cpp 1 If the reader cannot read any image from the device (e.g., there is no image there, or the image has already been read), or if the format is unsupported, this function returns an empty QByteArray(). \sa setFormat(), supportedImageFormats() */ QByteArray QImageReader::format() const { if (d->format.isEmpty()) { if (!d->initHandler()) return QByteArray(); return d->handler->canRead() ? d->handler->format() : QByteArray(); } return d->format; } /*! If \a enabled is true, image format autodetection is enabled; otherwise, it is disabled. By default, autodetection is enabled. QImageReader uses an extensive approach to detecting the image format; firstly, if you pass a file name to QImageReader, it will attempt to detect the file extension if the given file name does not point to an existing file, by appending supported default extensions to the given file name, one at a time. It then uses the following approach to detect the image format: \list \li Image plugins are queried first, based on either the optional format string, or the file name suffix (if the source device is a file). No content detection is done at this stage. QImageReader will choose the first plugin that supports reading for this format. \li If no plugin supports the image format, Qt's built-in handlers are checked based on either the optional format string, or the file name suffix. \li If no capable plugins or built-in handlers are found, each plugin is tested by inspecting the content of the data stream. \li If no plugins could detect the image format based on data contents, each built-in image handler is tested by inspecting the contents. \li Finally, if all above approaches fail, QImageReader will report failure when trying to read the image. \endlist By disabling image format autodetection, QImageReader will only query the plugins and built-in handlers based on the format string (i.e., no file name extensions are tested). \sa QImageIOHandler::canRead(), QImageIOPlugin::capabilities() */ void QImageReader::setAutoDetectImageFormat(bool enabled) { d->autoDetectImageFormat = enabled; } /*! Returns \c true if image format autodetection is enabled on this image reader; otherwise returns \c false. By default, autodetection is enabled. \sa setAutoDetectImageFormat() */ bool QImageReader::autoDetectImageFormat() const { return d->autoDetectImageFormat; } /*! If \a ignored is set to true, then the image reader will ignore specified formats or file extensions and decide which plugin to use only based on the contents in the datastream. Setting this flag means that all image plugins gets loaded. Each plugin will read the first bytes in the image data and decide if the plugin is compatible or not. This also disables auto detecting the image format. \sa decideFormatFromContent() */ void QImageReader::setDecideFormatFromContent(bool ignored) { d->ignoresFormatAndExtension = ignored; } /*! Returns whether the image reader should decide which plugin to use only based on the contents of the datastream rather than on the file extension. \sa setDecideFormatFromContent() */ bool QImageReader::decideFormatFromContent() const { return d->ignoresFormatAndExtension; } /*! Sets QImageReader's device to \a device. If a device has already been set, the old device is removed from QImageReader and is otherwise left unchanged. If the device is not already open, QImageReader will attempt to open the device in \l QIODevice::ReadOnly mode by calling open(). Note that this does not work for certain devices, such as QProcess, QTcpSocket and QUdpSocket, where more logic is required to open the device. \sa device(), setFileName() */ void QImageReader::setDevice(QIODevice *device) { if (d->device && d->deleteDevice) delete d->device; d->device = device; d->deleteDevice = false; delete d->handler; d->handler = 0; d->text.clear(); } /*! Returns the device currently assigned to QImageReader, or 0 if no device has been assigned. */ QIODevice *QImageReader::device() const { return d->device; } /*! Sets the file name of QImageReader to \a fileName. Internally, QImageReader will create a QFile object and open it in \l QIODevice::ReadOnly mode, and use this when reading images. If \a fileName does not include a file extension (e.g., .png or .bmp), QImageReader will cycle through all supported extensions until it finds a matching file. \sa fileName(), setDevice(), supportedImageFormats() */ void QImageReader::setFileName(const QString &fileName) { setDevice(new QFile(fileName)); d->deleteDevice = true; } /*! If the currently assigned device is a QFile, or if setFileName() has been called, this function returns the name of the file QImageReader reads from. Otherwise (i.e., if no device has been assigned or the device is not a QFile), an empty QString is returned. \sa setFileName(), setDevice() */ QString QImageReader::fileName() const { QFile *file = qobject_cast(d->device); return file ? file->fileName() : QString(); } /*! \since 4.2 Sets the quality setting of the image format to \a quality. Some image formats, in particular lossy ones, entail a tradeoff between a) visual quality of the resulting image, and b) decoding execution time. This function sets the level of that tradeoff for image formats that support it. In case of scaled image reading, the quality setting may also influence the tradeoff level between visual quality and execution speed of the scaling algorithm. The value range of \a quality depends on the image format. For example, the "jpeg" format supports a quality range from 0 (low visual quality) to 100 (high visual quality). \sa quality() setScaledSize() */ void QImageReader::setQuality(int quality) { d->quality = quality; } /*! \since 4.2 Returns the quality setting of the image format. \sa setQuality() */ int QImageReader::quality() const { return d->quality; } /*! Returns the size of the image, without actually reading the image contents. If the image format does not support this feature, this function returns an invalid size. Qt's built-in image handlers all support this feature, but custom image format plugins are not required to do so. \sa QImageIOHandler::ImageOption, QImageIOHandler::option(), QImageIOHandler::supportsOption() */ QSize QImageReader::size() const { if (!d->initHandler()) return QSize(); if (d->handler->supportsOption(QImageIOHandler::Size)) return d->handler->option(QImageIOHandler::Size).toSize(); return QSize(); } /*! \since 4.5 Returns the format of the image, without actually reading the image contents. The format describes the image format \l QImageReader::read() returns, not the format of the actual image. If the image format does not support this feature, this function returns an invalid format. \sa QImageIOHandler::ImageOption, QImageIOHandler::option(), QImageIOHandler::supportsOption() */ QImage::Format QImageReader::imageFormat() const { if (!d->initHandler()) return QImage::Format_Invalid; if (d->handler->supportsOption(QImageIOHandler::ImageFormat)) return (QImage::Format)d->handler->option(QImageIOHandler::ImageFormat).toInt(); return QImage::Format_Invalid; } /*! \since 4.1 Returns the text keys for this image. You can use these keys with text() to list the image text for a certain key. Support for this option is implemented through QImageIOHandler::Description. \sa text(), QImageWriter::setText(), QImage::textKeys() */ QStringList QImageReader::textKeys() const { d->getText(); return d->text.keys(); } /*! \since 4.1 Returns the image text associated with \a key. Support for this option is implemented through QImageIOHandler::Description. \sa textKeys(), QImageWriter::setText() */ QString QImageReader::text(const QString &key) const { d->getText(); return d->text.value(key); } /*! Sets the image clip rect (also known as the ROI, or Region Of Interest) to \a rect. The coordinates of \a rect are relative to the untransformed image size, as returned by size(). \sa clipRect(), setScaledSize(), setScaledClipRect() */ void QImageReader::setClipRect(const QRect &rect) { d->clipRect = rect; } /*! Returns the clip rect (also known as the ROI, or Region Of Interest) of the image. If no clip rect has been set, an invalid QRect is returned. \sa setClipRect() */ QRect QImageReader::clipRect() const { return d->clipRect; } /*! Sets the scaled size of the image to \a size. The scaling is performed after the initial clip rect, but before the scaled clip rect is applied. The algorithm used for scaling depends on the image format. By default (i.e., if the image format does not support scaling), QImageReader will use QImage::scale() with Qt::SmoothScaling. \sa scaledSize(), setClipRect(), setScaledClipRect() */ void QImageReader::setScaledSize(const QSize &size) { d->scaledSize = size; } /*! Returns the scaled size of the image. \sa setScaledSize() */ QSize QImageReader::scaledSize() const { return d->scaledSize; } /*! Sets the scaled clip rect to \a rect. The scaled clip rect is the clip rect (also known as ROI, or Region Of Interest) that is applied after the image has been scaled. \sa scaledClipRect(), setScaledSize() */ void QImageReader::setScaledClipRect(const QRect &rect) { d->scaledClipRect = rect; } /*! Returns the scaled clip rect of the image. \sa setScaledClipRect() */ QRect QImageReader::scaledClipRect() const { return d->scaledClipRect; } /*! \since 4.1 Sets the background color to \a color. Image formats that support this operation are expected to initialize the background to \a color before reading an image. \sa backgroundColor(), read() */ void QImageReader::setBackgroundColor(const QColor &color) { if (!d->initHandler()) return; if (d->handler->supportsOption(QImageIOHandler::BackgroundColor)) d->handler->setOption(QImageIOHandler::BackgroundColor, color); } /*! \since 4.1 Returns the background color that's used when reading an image. If the image format does not support setting the background color an invalid color is returned. \sa setBackgroundColor(), read() */ QColor QImageReader::backgroundColor() const { if (!d->initHandler()) return QColor(); if (d->handler->supportsOption(QImageIOHandler::BackgroundColor)) return qvariant_cast(d->handler->option(QImageIOHandler::BackgroundColor)); return QColor(); } /*! \since 4.1 Returns \c true if the image format supports animation; otherwise, false is returned. \sa QMovie::supportedFormats() */ bool QImageReader::supportsAnimation() const { if (!d->initHandler()) return false; if (d->handler->supportsOption(QImageIOHandler::Animation)) return d->handler->option(QImageIOHandler::Animation).toBool(); return false; } /*! \since 5.4 Returns the subtype of the image. */ QByteArray QImageReader::subType() const { if (!d->initHandler()) return QByteArray(); if (d->handler->supportsOption(QImageIOHandler::SubType)) return d->handler->option(QImageIOHandler::SubType).toByteArray(); return QByteArray(); } /*! \since 5.4 Returns the list of subtypes supported by an image. */ QList QImageReader::supportedSubTypes() const { if (!d->initHandler()) return QList(); if (d->handler->supportsOption(QImageIOHandler::SupportedSubTypes)) return d->handler->option(QImageIOHandler::SupportedSubTypes).value< QList >(); return QList(); } /*! \since 5.5 Returns the transformation metadata of the image, including image orientation. If the format does not support transformation metadata \c QImageIOHandler::Transformation_None is returned. \sa setAutoTransform(), autoTransform() */ QImageIOHandler::Transformations QImageReader::transformation() const { int option = QImageIOHandler::TransformationNone; if (d->initHandler() && d->handler->supportsOption(QImageIOHandler::ImageTransformation)) option = d->handler->option(QImageIOHandler::ImageTransformation).toInt(); return QImageIOHandler::Transformations(option); } /*! \since 5.5 Determines that images returned by read() should have transformation metadata automatically applied if \a enabled is \c true. \sa autoTransform(), transformation(), read() */ void QImageReader::setAutoTransform(bool enabled) { d->autoTransform = enabled ? QImageReaderPrivate::ApplyTransform : QImageReaderPrivate::DoNotApplyTransform; } /*! \since 5.5 Returns \c true if the image handler will apply transformation metadata on read(). \sa setAutoTransform(), transformation(), read() */ bool QImageReader::autoTransform() const { switch (d->autoTransform) { case QImageReaderPrivate::ApplyTransform: return true; case QImageReaderPrivate::DoNotApplyTransform: return false; case QImageReaderPrivate::UsePluginDefault: if (d->initHandler()) return d->handler->supportsOption(QImageIOHandler::TransformedByDefault); Q_FALLTHROUGH(); default: break; } return false; } /*! \since 5.6 This is an image format specific function that forces images with gamma information to be gamma corrected to \a gamma. For image formats that do not support gamma correction, this value is ignored. To gamma correct to a standard PC color-space, set gamma to \c 1/2.2. \sa gamma() */ void QImageReader::setGamma(float gamma) { if (d->initHandler() && d->handler->supportsOption(QImageIOHandler::Gamma)) d->handler->setOption(QImageIOHandler::Gamma, gamma); } /*! \since 5.6 Returns the gamma level of the decoded image. If setGamma() has been called and gamma correction is supported it will return the gamma set. If gamma level is not supported by the image format, \c 0.0 is returned. \sa setGamma() */ float QImageReader::gamma() const { if (d->initHandler() && d->handler->supportsOption(QImageIOHandler::Gamma)) return d->handler->option(QImageIOHandler::Gamma).toFloat(); return 0.0; } /*! Returns \c true if an image can be read for the device (i.e., the image format is supported, and the device seems to contain valid data); otherwise returns \c false. canRead() is a lightweight function that only does a quick test to see if the image data is valid. read() may still return false after canRead() returns \c true, if the image data is corrupt. \note A QMimeDatabase lookup is normally a better approach than this function for identifying potentially non-image files or data. For images that support animation, canRead() returns \c false when all frames have been read. \sa read(), supportedImageFormats(), QMimeDatabase */ bool QImageReader::canRead() const { if (!d->initHandler()) return false; return d->handler->canRead(); } /*! Reads an image from the device. On success, the image that was read is returned; otherwise, a null QImage is returned. You can then call error() to find the type of error that occurred, or errorString() to get a human readable description of the error. For image formats that support animation, calling read() repeatedly will return the next frame. When all frames have been read, a null image will be returned. \sa canRead(), supportedImageFormats(), supportsAnimation(), QMovie */ QImage QImageReader::read() { // Because failed image reading might have side effects, we explicitly // return a null image instead of the image we've just created. QImage image; return read(&image) ? image : QImage(); } extern void qt_imageTransform(QImage &src, QImageIOHandler::Transformations orient); /*! \overload Reads an image from the device into \a image, which must point to a QImage. Returns \c true on success; otherwise, returns \c false. If \a image has same format and size as the image data that is about to be read, this function may not need to allocate a new image before reading. Because of this, it can be faster than the other read() overload, which always constructs a new image; especially when reading several images with the same format and size. \snippet code/src_gui_image_qimagereader.cpp 2 For image formats that support animation, calling read() repeatedly will return the next frame. When all frames have been read, a null image will be returned. \sa canRead(), supportedImageFormats(), supportsAnimation(), QMovie */ bool QImageReader::read(QImage *image) { if (!image) { qWarning("QImageReader::read: cannot read into null pointer"); return false; } if (!d->handler && !d->initHandler()) return false; // set the handler specific options. if (d->handler->supportsOption(QImageIOHandler::ScaledSize) && d->scaledSize.isValid()) { if ((d->handler->supportsOption(QImageIOHandler::ClipRect) && !d->clipRect.isNull()) || d->clipRect.isNull()) { // Only enable the ScaledSize option if there is no clip rect, or // if the handler also supports ClipRect. d->handler->setOption(QImageIOHandler::ScaledSize, d->scaledSize); } } if (d->handler->supportsOption(QImageIOHandler::ClipRect) && !d->clipRect.isNull()) d->handler->setOption(QImageIOHandler::ClipRect, d->clipRect); if (d->handler->supportsOption(QImageIOHandler::ScaledClipRect) && !d->scaledClipRect.isNull()) d->handler->setOption(QImageIOHandler::ScaledClipRect, d->scaledClipRect); if (d->handler->supportsOption(QImageIOHandler::Quality)) d->handler->setOption(QImageIOHandler::Quality, d->quality); // read the image if (!d->handler->read(image)) { d->imageReaderError = InvalidDataError; d->errorString = QImageReader::tr("Unable to read image data"); return false; } // provide default implementations for any unsupported image // options if (d->handler->supportsOption(QImageIOHandler::ClipRect) && !d->clipRect.isNull()) { if (d->handler->supportsOption(QImageIOHandler::ScaledSize) && d->scaledSize.isValid()) { if (d->handler->supportsOption(QImageIOHandler::ScaledClipRect) && !d->scaledClipRect.isNull()) { // all features are supported by the handler; nothing to do. } else { // the image is already scaled, so apply scaled clipping. if (!d->scaledClipRect.isNull()) *image = image->copy(d->scaledClipRect); } } else { if (d->handler->supportsOption(QImageIOHandler::ScaledClipRect) && !d->scaledClipRect.isNull()) { // supports scaled clipping but not scaling, most // likely a broken handler. } else { if (d->scaledSize.isValid()) { *image = image->scaled(d->scaledSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation); } if (d->scaledClipRect.isValid()) { *image = image->copy(d->scaledClipRect); } } } } else { if (d->handler->supportsOption(QImageIOHandler::ScaledSize) && d->scaledSize.isValid() && d->clipRect.isNull()) { if (d->handler->supportsOption(QImageIOHandler::ScaledClipRect) && !d->scaledClipRect.isNull()) { // nothing to do (ClipRect is ignored!) } else { // provide all workarounds. if (d->scaledClipRect.isValid()) { *image = image->copy(d->scaledClipRect); } } } else { if (d->handler->supportsOption(QImageIOHandler::ScaledClipRect) && !d->scaledClipRect.isNull()) { // this makes no sense; a handler that supports // ScaledClipRect but not ScaledSize is broken, and we // can't work around it. } else { // provide all workarounds. if (d->clipRect.isValid()) *image = image->copy(d->clipRect); if (d->scaledSize.isValid()) *image = image->scaled(d->scaledSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation); if (d->scaledClipRect.isValid()) *image = image->copy(d->scaledClipRect); } } } // successful read; check for "@2x" file name suffix and set device pixel ratio. static bool disable2xImageLoading = !qEnvironmentVariableIsEmpty("QT_HIGHDPI_DISABLE_2X_IMAGE_LOADING"); if (!disable2xImageLoading && QFileInfo(fileName()).baseName().endsWith(QLatin1String("@2x"))) { image->setDevicePixelRatio(2.0); } if (autoTransform()) qt_imageTransform(*image, transformation()); return true; } /*! For image formats that support animation, this function steps over the current image, returning true if successful or false if there is no following image in the animation. The default implementation calls read(), then discards the resulting image, but the image handler may have a more efficient way of implementing this operation. \sa jumpToImage(), QImageIOHandler::jumpToNextImage() */ bool QImageReader::jumpToNextImage() { if (!d->initHandler()) return false; return d->handler->jumpToNextImage(); } /*! For image formats that support animation, this function skips to the image whose sequence number is \a imageNumber, returning true if successful or false if the corresponding image cannot be found. The next call to read() will attempt to read this image. \sa jumpToNextImage(), QImageIOHandler::jumpToImage() */ bool QImageReader::jumpToImage(int imageNumber) { if (!d->initHandler()) return false; return d->handler->jumpToImage(imageNumber); } /*! For image formats that support animation, this function returns the number of times the animation should loop. If this function returns -1, it can either mean the animation should loop forever, or that an error occurred. If an error occurred, canRead() will return false. \sa supportsAnimation(), QImageIOHandler::loopCount(), canRead() */ int QImageReader::loopCount() const { if (!d->initHandler()) return -1; return d->handler->loopCount(); } /*! For image formats that support animation, this function returns the total number of images in the animation. If the format does not support animation, 0 is returned. This function returns -1 if an error occurred. \sa supportsAnimation(), QImageIOHandler::imageCount(), canRead() */ int QImageReader::imageCount() const { if (!d->initHandler()) return -1; return d->handler->imageCount(); } /*! For image formats that support animation, this function returns the number of milliseconds to wait until displaying the next frame in the animation. If the image format doesn't support animation, 0 is returned. This function returns -1 if an error occurred. \sa supportsAnimation(), QImageIOHandler::nextImageDelay(), canRead() */ int QImageReader::nextImageDelay() const { if (!d->initHandler()) return -1; return d->handler->nextImageDelay(); } /*! For image formats that support animation, this function returns the sequence number of the current frame. If the image format doesn't support animation, 0 is returned. This function returns -1 if an error occurred. \sa supportsAnimation(), QImageIOHandler::currentImageNumber(), canRead() */ int QImageReader::currentImageNumber() const { if (!d->initHandler()) return -1; return d->handler->currentImageNumber(); } /*! For image formats that support animation, this function returns the rect for the current frame. Otherwise, a null rect is returned. \sa supportsAnimation(), QImageIOHandler::currentImageRect() */ QRect QImageReader::currentImageRect() const { if (!d->initHandler()) return QRect(); return d->handler->currentImageRect(); } /*! Returns the type of error that occurred last. \sa ImageReaderError, errorString() */ QImageReader::ImageReaderError QImageReader::error() const { return d->imageReaderError; } /*! Returns a human readable description of the last error that occurred. \sa error() */ QString QImageReader::errorString() const { if (d->errorString.isEmpty()) return QImageReader::tr("Unknown error"); return d->errorString; } /*! \since 4.2 Returns \c true if the reader supports \a option; otherwise returns false. Different image formats support different options. Call this function to determine whether a certain option is supported by the current format. For example, the PNG format allows you to embed text into the image's metadata (see text()), and the BMP format allows you to determine the image's size without loading the whole image into memory (see size()). \snippet code/src_gui_image_qimagereader.cpp 3 \sa QImageWriter::supportsOption() */ bool QImageReader::supportsOption(QImageIOHandler::ImageOption option) const { if (!d->initHandler()) return false; return d->handler->supportsOption(option); } /*! If supported, this function returns the image format of the file \a fileName. Otherwise, an empty string is returned. */ QByteArray QImageReader::imageFormat(const QString &fileName) { QFile file(fileName); if (!file.open(QFile::ReadOnly)) return QByteArray(); return imageFormat(&file); } /*! If supported, this function returns the image format of the device \a device. Otherwise, an empty string is returned. \sa QImageReader::autoDetectImageFormat() */ QByteArray QImageReader::imageFormat(QIODevice *device) { QByteArray format; QImageIOHandler *handler = createReadHandlerHelper(device, format, /* autoDetectImageFormat = */ true, false); if (handler) { if (handler->canRead()) format = handler->format(); delete handler; } return format; } #ifndef QT_NO_IMAGEFORMATPLUGIN void supportedImageHandlerFormats(QFactoryLoader *loader, QImageIOPlugin::Capability cap, QList *result); void supportedImageHandlerMimeTypes(QFactoryLoader *loader, QImageIOPlugin::Capability cap, QList *result); #endif /*! Returns the list of image formats supported by QImageReader. By default, Qt can read the following formats: \table \header \li Format \li MIME type \li Description \row \li BMP \li image/bmp \li Windows Bitmap \row \li GIF \li image/gif \li Graphic Interchange Format (optional) \row \li JPG \li image/jpeg \li Joint Photographic Experts Group \row \li PNG \li image/png \li Portable Network Graphics \row \li PBM \li image/x-portable-bitmap \li Portable Bitmap \row \li PGM \li image/x-portable-graymap \li Portable Graymap \row \li PPM \li image/x-portable-pixmap \li Portable Pixmap \row \li XBM \li image/x-xbitmap \li X11 Bitmap \row \li XPM \li image/x-xpixmap \li X11 Pixmap \row \li SVG \li image/svg+xml \li Scalable Vector Graphics \endtable Reading and writing SVG files is supported through the \l{Qt SVG} module. The \l{Qt Image Formats} module provides support for additional image formats. Note that the QApplication instance must be created before this function is called. \sa setFormat(), QImageWriter::supportedImageFormats(), QImageIOPlugin */ QList QImageReader::supportedImageFormats() { QList formats; formats.reserve(_qt_NumFormats); for (int i = 0; i < _qt_NumFormats; ++i) formats << _qt_BuiltInFormats[i].extension; #ifndef QT_NO_IMAGEFORMATPLUGIN supportedImageHandlerFormats(loader(), QImageIOPlugin::CanRead, &formats); #endif // QT_NO_IMAGEFORMATPLUGIN std::sort(formats.begin(), formats.end()); formats.erase(std::unique(formats.begin(), formats.end()), formats.end()); return formats; } /*! Returns the list of MIME types supported by QImageReader. Note that the QApplication instance must be created before this function is called. \sa supportedImageFormats(), QImageWriter::supportedMimeTypes() */ QList QImageReader::supportedMimeTypes() { QList mimeTypes; mimeTypes.reserve(_qt_NumFormats); for (const auto &fmt : _qt_BuiltInFormats) mimeTypes.append(QByteArrayLiteral("image/") + fmt.mimeType); #ifndef QT_NO_IMAGEFORMATPLUGIN supportedImageHandlerMimeTypes(loader(), QImageIOPlugin::CanRead, &mimeTypes); #endif // QT_NO_IMAGEFORMATPLUGIN std::sort(mimeTypes.begin(), mimeTypes.end()); mimeTypes.erase(std::unique(mimeTypes.begin(), mimeTypes.end()), mimeTypes.end()); return mimeTypes; } QT_END_NAMESPACE