qimagereader.cpp File Reference

#include "qimagereader.h"
#include <qbytearray.h>
#include <qfile.h>
#include <qfileinfo.h>
#include <qimage.h>
#include <qimageiohandler.h>
#include <qlist.h>
#include <qrect.h>
#include <qset.h>
#include <qsize.h>
#include <qcolor.h>
#include <qvariant.h>
#include <qcoreapplication.h>
#include <private/qfactoryloader_p.h>
#include <private/qbmphandler_p.h>
#include <private/qppmhandler_p.h>
#include <private/qxbmhandler_p.h>
#include <private/qxpmhandler_p.h>
#include <private/qpnghandler_p.h>
#include <private/qjpeghandler_p.h>
#include <private/qmnghandler_p.h>
#include <private/qtiffhandler_p.h>

Go to the source code of this file.

Classes
struct	_qt_BuiltInFormatStruct
class	QImageReaderPrivate

Functions
static QImageIOHandler *	createReadHandlerHelper (QIODevice *device, const QByteArray &format, bool autoDetectImageFormat, bool ignoresFormatAndExtension)
	Q_GLOBAL_STATIC_WITH_ARGS (QFactoryLoader, loader,(QImageIOHandlerFactoryInterface_iid, QLatin1String("/imageformats"))) enum _qt_BuiltInFormatType

Variables
static const _qt_BuiltInFormatStruct	_qt_BuiltInFormats []

Function Documentation

createReadHandlerHelper()

static QImageIOHandler* createReadHandlerHelper ( QIODevice *  device, const QByteArray &  format, bool  autoDetectImageFormat, bool  ignoresFormatAndExtension  )

static

Definition at line 239 of file qimagereader.cpp.

Referenced by QImageReader::imageFormat(), and QImageReaderPrivate::initHandler().

{
    if (!autoDetectImageFormat && format.isEmpty())
        return 0;

    QByteArray form = format.toLower();
    QImageIOHandler *handler = 0;

#ifndef QT_NO_LIBRARY
    // check if we have plugins that support the image format
    QFactoryLoader *l = loader();
    QStringList keys = l->keys();
#endif
    QByteArray suffix;

#ifdef QIMAGEREADER_DEBUG
    qDebug() << "QImageReader::createReadHandler( device =" << (void *)device << ", format =" << format << "),"
             << keys.size() << "plugins available: " << keys;
#endif

#ifndef QT_NO_LIBRARY
    int suffixPluginIndex = -1;
    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<QFile *>(device)) {
#ifdef QIMAGEREADER_DEBUG
            qDebug() << "QImageReader::createReadHandler: device is a file:" << file->fileName();
#endif
            if (!(suffix = QFileInfo(file->fileName()).suffix().toLower().toLatin1()).isEmpty()) {
                int index = keys.indexOf(QString::fromLatin1(suffix));
                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_LIBRARY

    QByteArray testFormat = !form.isEmpty() ? form : suffix;

    if (ignoresFormatAndExtension)
        testFormat = QByteArray();

#ifndef QT_NO_LIBRARY
    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;
        QImageIOPlugin *plugin = qobject_cast<QImageIOPlugin *>(l->instance(QString::fromLatin1(suffix)));
        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) {
            for (int i = 0; i < keys.size(); ++i) {
                if (i != suffixPluginIndex) {
                    QImageIOPlugin *plugin = qobject_cast<QImageIOPlugin *>(l->instance(keys.at(i)));
                    if (plugin && plugin->capabilities(device, testFormat) & QImageIOPlugin::CanRead) {
#ifdef QIMAGEREADER_DEBUG
                        qDebug() << "QImageReader::createReadHandler: the" << keys.at(i) << "plugin can read this format";
#endif
                        handler = plugin->create(device, testFormat);
                        break;
                    }
                }
            }
        } else {
            QImageIOPlugin *plugin = qobject_cast<QImageIOPlugin *>(l->instance(QLatin1String(testFormat)));
            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_LIBRARY

    // 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_JPEG
        } else if (testFormat == "jpg" || testFormat == "jpeg") {
            handler = new QJpegHandler;
#endif
#ifndef QT_NO_IMAGEFORMAT_MNG
        } else if (testFormat == "mng") {
            handler = new QMngHandler;
#endif
#ifndef QT_NO_IMAGEFORMAT_TIFF
        } else if (testFormat == "tif" || testFormat == "tiff") {
            handler = new QTiffHandler;
#endif
#ifdef QT_BUILTIN_GIF_READER
        } else if (testFormat == "gif") {
            handler = new QGifHandler;
#endif
#ifndef QT_NO_IMAGEFORMAT_BMP
        } else if (testFormat == "bmp") {
            handler = new QBmpHandler;
#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_LIBRARY
    if (!handler && (autoDetectImageFormat || ignoresFormatAndExtension)) {
        // check if any of our plugins recognize the file from its contents.
        const qint64 pos = device ? device->pos() : 0;
        for (int i = 0; i < keys.size(); ++i) {
            if (i != suffixPluginIndex) {
                QImageIOPlugin *plugin = qobject_cast<QImageIOPlugin *>(l->instance(keys.at(i)));
                if (plugin && plugin->capabilities(device, QByteArray()) & QImageIOPlugin::CanRead) {
                    handler = plugin->create(device, testFormat);
#ifdef QIMAGEREADER_DEBUG
                    qDebug() << "QImageReader::createReadHandler: the" << keys.at(i) << "plugin can read this data";
#endif
                    break;
                }
            }
        }
        if (device && !device->isSequential())
            device->seek(pos);
    }
#endif // QT_NO_LIBRARY

    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 _qt_BuiltInFormatStruct *formatStruct = &_qt_BuiltInFormats[currentFormat];

            const qint64 pos = device->pos();
            switch (formatStruct->type) {
#ifndef QT_NO_IMAGEFORMAT_PNG
            case _qt_PngFormat:
                if (QPngHandler::canRead(device))
                    handler = new QPngHandler;
                break;
#endif
#ifndef QT_NO_IMAGEFORMAT_JPEG
            case _qt_JpgFormat:
                if (QJpegHandler::canRead(device))
                    handler = new QJpegHandler;
                break;
#endif
#ifndef QT_NO_IMAGEFORMAT_MNG
            case _qt_MngFormat:
                if (QMngHandler::canRead(device))
                    handler = new QMngHandler;
                break;
#endif
#ifndef QT_NO_IMAGEFORMAT_TIFF
            case _qt_TifFormat:
                if (QTiffHandler::canRead(device))
                    handler = new QTiffHandler;
                break;
#endif
#ifdef QT_BUILTIN_GIF_READER
            case _qt_GifFormat:
                if (QGifHandler::canRead(device))
                    handler = new QGifHandler;
                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" << formatStruct->extension
                         << "built-in handler can read this data";
#endif
                break;
            }

            --numFormats;
            ++currentFormat;
            currentFormat %= _qt_NumFormats;
        }
    }

    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;
}

Q_GLOBAL_STATIC_WITH_ARGS()

Q_GLOBAL_STATIC_WITH_ARGS	(	QFactoryLoader	,
		loader	,
		(QImageIOHandlerFactoryInterface_iid, QLatin1String("/imageformats"))
	)

Definition at line 166 of file qimagereader.cpp.

                           {
#ifndef QT_NO_IMAGEFORMAT_PNG
    _qt_PngFormat,
#endif
#ifndef QT_NO_IMAGEFORMAT_JPEG
    _qt_JpgFormat,
#endif
#ifndef QT_NO_IMAGEFORMAT_MNG
    _qt_MngFormat,
#endif
#ifndef QT_NO_IMAGEFORMAT_TIFF
    _qt_TifFormat,
#endif
#ifdef QT_BUILTIN_GIF_READER
    _qt_GifFormat,
#endif
    _qt_BmpFormat,
#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
};

Variable Documentation

_qt_BuiltInFormats

const _qt_BuiltInFormatStruct _qt_BuiltInFormats[]

static

Initial value:

= {

    {_qt_PngFormat, "png"},


    {_qt_JpgFormat, "jpg"},


    {_qt_MngFormat, "mng"},


    {_qt_TifFormat, "tif"},




    {_qt_BmpFormat, "bmp"},

    {_qt_PpmFormat, "ppm"},
    {_qt_PgmFormat, "pgm"},
    {_qt_PbmFormat, "pbm"},


    {_qt_XbmFormat, "xbm"},


    {_qt_XpmFormat, "xpm"},

    {_qt_NoFormat, ""}
}

Definition at line 208 of file qimagereader.cpp.