Detailed Description
The QMimeSourceFactory class is an extensible provider of mime-typed data.
A QMimeSourceFactory provides an abstract interface to a
collection of information. Each piece of information is
represented by a QMimeSource object which can be examined and
converted to concrete data types by functions such as
QImageDrag::canDecode() and QImageDrag::decode().
The base QMimeSourceFactory can be used in two ways: as an
abstraction of a collection of files or as specifically stored
data. For it to access files, call setFilePath() before accessing
data. For stored data, call setData() for each item (there are
also convenience functions, e.g. setText(), setImage() and
setPixmap(), that simply call setData() with appropriate
parameters).
The rich text widgets, QTextEdit and QTextBrowser, use
QMimeSourceFactory to resolve references such as images or links
within rich text documents. They either access the default factory
(see defaultFactory()) or their own (see
QTextEdit::setMimeSourceFactory()). Other classes that are
capable of displaying rich text (such as QLabel, QWhatsThis or
QMessageBox) always use the default factory.
A factory can also be used as a container to store data associated
with a name. This technique is useful whenever rich text contains
images that are stored in the program itself, not loaded from the
hard disk. Your program may, for example, define some image data
as:
static const char* myimage_data[]={
"...",
...
"..."};
To be able to use this image within some rich text, for example
inside a QLabel, you must create a QImage from the raw data and
insert it into the factory with a unique name:
QMimeSourceFactory::defaultFactory()->setImage( "myimage", QImage(myimage_data) );
Now you can create a rich text QLabel with
QLabel* label = new QLabel(
"Rich text with embedded image:<img source=\"myimage\">"
"Isn't that <em>cute</em>?" );
When no longer needed, you can clear the data from the factory:
delete label;
QMimeSourceFactory::defaultFactory()->setData( "myimage", 0 );
See also Environment Classes and Input/Output and Networking.
Member Function Documentation
QMimeSourceFactory::QMimeSourceFactory ()
Constructs a QMimeSourceFactory that has no file path and no
stored content.
QMimeSourceFactory::~QMimeSourceFactory () [virtual]
Destroys the QMimeSourceFactory, deleting all stored content.
void QMimeSourceFactory::addFactory ( QMimeSourceFactory * f ) [static]
Adds the QMimeSourceFactory f to the list of available
mimesource factories. If the defaultFactory() can't resolve a
data() it iterates over the list of installed mimesource factories
until the data can be resolved.
See also removeFactory().
void QMimeSourceFactory::addFilePath ( const QString & p )
Adds another search path, p to the existing search paths.
See also setFilePath().
const QMimeSource * QMimeSourceFactory::data ( const QString & abs_name ) const [virtual]
Returns a reference to the data associated with abs_name. The
return value remains valid only until the next data() or setData()
call, so you should immediately decode the result.
If there is no data associated with abs_name in the factory's
store, the factory tries to access the local filesystem. If abs_name isn't an absolute file name, the factory will search for
it in all defined paths (see setFilePath()).
The factory understands all the image formats supported by
QImageIO. Any other mime types are determined by the file name
extension. The default settings are
setExtensionType("html", "text/html;charset=iso8859-1");
setExtensionType("htm", "text/html;charset=iso8859-1");
setExtensionType("txt", "text/plain");
setExtensionType("xml", "text/xml;charset=UTF-8");
The effect of these is that file names ending in "html" or "htm"
will be treated as text encoded in the iso8859-1 encoding, those
ending in "txt" will be treated as text encoded in the local
encoding; those ending in "xml" will be treated as text encoded in
Unicode UTF-8 encoding. The text subtype ("html", "plain", or
"xml") does not affect the factory, but users of the factory may
behave differently. We recommend creating "xml" files where
practical. These files can be viewed regardless of the runtime
encoding and can encode any Unicode characters without resorting
to encoding definitions inside the file.
Any file data that is not recognized will be retrieved as a
QMimeSource providing the "application/octet-stream" mime type,
meaning uninterpreted binary data.
You can add further extensions or change existing ones with
subsequent calls to setExtensionType(). If the extension mechanism
is not sufficient for your problem domain, you can inherit
QMimeSourceFactory and reimplement this function to perform some
more specialized mime-type detection. The same applies if you want
to use the mime source factory to access URL referenced data over
a network.
const QMimeSource * QMimeSourceFactory::data ( const QString & abs_or_rel_name, const QString & context ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
A convenience function. See data(const QString& abs_name). The
file name is given in abs_or_rel_name and the path is in context.
QMimeSourceFactory * QMimeSourceFactory::defaultFactory () [static]
Returns the application-wide default mime source factory. This
factory is used by rich text rendering classes such as
QSimpleRichText, QWhatsThis and QMessageBox to resolve named
references within rich text documents. It serves also as the
initial factory for the more complex render widgets, QTextEdit and
QTextBrowser.
See also setDefaultFactory().
Examples: action/application.cpp and application/application.cpp.
QStringList QMimeSourceFactory::filePath () const [virtual]
Returns the currently set search paths.
QString QMimeSourceFactory::makeAbsolute ( const QString & abs_or_rel_name, const QString & context ) const [virtual]
Converts the absolute or relative data item name abs_or_rel_name to an absolute name, interpreted within the
context (path) of the data item named context (this must be an
absolute name).
void QMimeSourceFactory::removeFactory ( QMimeSourceFactory * f ) [static]
Removes the mimesource factory f from the list of available
mimesource factories.
See also addFactory().
void QMimeSourceFactory::setData ( const QString & abs_name, QMimeSource * data ) [virtual]
Sets data to be the data item associated with
the absolute name abs_name. Note that the ownership of data is
transferred to the factory: do not delete or access the pointer after
passing it to this function.
Passing 0 for data removes previously stored data.
void QMimeSourceFactory::setDefaultFactory ( QMimeSourceFactory * factory ) [static]
Sets the default factory, destroying any previously set mime
source provider. The ownership of the factory is transferred to
Qt.
See also defaultFactory().
void QMimeSourceFactory::setExtensionType ( const QString & ext, const char * mimetype ) [virtual]
Sets the mime-type to be associated with the file name extension,
ext to mimetype. This determines the mime-type for files
found via the paths set by setFilePath().
void QMimeSourceFactory::setFilePath ( const QStringList & path ) [virtual]
Sets the list of directories that will be searched when named data
is requested to the those given in the string list path.
See also filePath().
void QMimeSourceFactory::setImage ( const QString & abs_name, const QImage & image ) [virtual]
Sets image to be the data item associated with the absolute
name abs_name.
Equivalent to setData(abs_name, new QImageDrag(image)).
void QMimeSourceFactory::setPixmap ( const QString & abs_name, const QPixmap & pixmap ) [virtual]
Sets pixmap to be the data item associated with the absolute
name abs_name.
void QMimeSourceFactory::setText ( const QString & abs_name, const QString & text ) [virtual]
Sets text to be the data item associated with the absolute name
abs_name.
Equivalent to setData(abs_name, new QTextDrag(text)).
QMimeSourceFactory * QMimeSourceFactory::takeDefaultFactory () [static]
Sets the defaultFactory() to 0 and returns the previous one.
This file is part of the Qt toolkit.
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