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TQMimeSourceFactory Class Reference

The TQMimeSourceFactory class is an extensible provider of mime-typed data. More...

#include <ntqmime.h>

List of all member functions.

Public Members

Static Public Members

Detailed Description

The TQMimeSourceFactory class is an extensible provider of mime-typed data.

A TQMimeSourceFactory provides an abstract interface to a collection of information. Each piece of information is represented by a TQMimeSource object which can be examined and converted to concrete data types by functions such as TQImageDrag::canDecode() and TQImageDrag::decode().

The base TQMimeSourceFactory 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, TQTextEdit and TQTextBrowser, use TQMimeSourceFactory to resolve references such as images or links within rich text documents. They either access the default factory (see defaultFactory()) or their own (see TQTextEdit::setMimeSourceFactory()). Other classes that are capable of displaying rich text (such as TQLabel, TQWhatsThis or TQMessageBox) 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 TQLabel, you must create a TQImage from the raw data and insert it into the factory with a unique name: 

    TQMimeSourceFactory::defaultFactory()->setImage( "myimage", TQImage(myimage_data) );

Now you can create a rich text TQLabel with 

    TQLabel* label = new TQLabel(
        "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;
    TQMimeSourceFactory::defaultFactory()->setData( "myimage", 0 );

See also Environment Classes and Input/Output and Networking.

Member Function Documentation

TQMimeSourceFactory::TQMimeSourceFactory ()

Constructs a TQMimeSourceFactory that has no file path and no stored content.

TQMimeSourceFactory::~TQMimeSourceFactory () [virtual]

Destroys the TQMimeSourceFactory, deleting all stored content.

void TQMimeSourceFactory::addFactory ( TQMimeSourceFactory * f ) [static]

Adds the TQMimeSourceFactory 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 TQMimeSourceFactory::addFilePath ( const TQString & p )

Adds another search path, p to the existing search paths.

See also setFilePath().

const TQMimeSource * TQMimeSourceFactory::data ( const TQString & 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 TQImageIO. 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 "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/html type is treated specially, since the encoding can be specified in the html file itself. "html" or "htm" will be treated as text encoded in the encoding specified by the html meta tag, if none could be found, the charset of the mime type will be used. 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 TQMimeSource 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 TQMimeSourceFactory 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 TQMimeSource * TQMimeSourceFactory::data ( const TQString & abs_or_rel_name, const TQString & context ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

A convenience function. See data(const TQString& abs_name). The file name is given in abs_or_rel_name and the path is in context.

TQMimeSourceFactory * TQMimeSourceFactory::defaultFactory () [static]

Returns the application-wide default mime source factory. This factory is used by rich text rendering classes such as TQSimpleRichText, TQWhatsThis and TQMessageBox to resolve named references within rich text documents. It serves also as the initial factory for the more complex render widgets, TQTextEdit and TQTextBrowser.

See also setDefaultFactory().

Examples: action/application.cpp and application/application.cpp.

TQStringList TQMimeSourceFactory::filePath () const [virtual]

Returns the currently set search paths.

TQString TQMimeSourceFactory::makeAbsolute ( const TQString & abs_or_rel_name, const TQString & 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 TQMimeSourceFactory::removeFactory ( TQMimeSourceFactory * f ) [static]

Removes the mimesource factory f from the list of available mimesource factories.

See also addFactory().

void TQMimeSourceFactory::setData ( const TQString & abs_name, TQMimeSource * 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 TQMimeSourceFactory::setDefaultFactory ( TQMimeSourceFactory * factory ) [static]

Sets the default factory, destroying any previously set mime source provider. The ownership of the factory is transferred to TQt.

See also defaultFactory().

void TQMimeSourceFactory::setExtensionType ( const TQString & 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 TQMimeSourceFactory::setFilePath ( const TQStringList & 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 TQMimeSourceFactory::setImage ( const TQString & abs_name, const TQImage & image ) [virtual]

Sets image to be the data item associated with the absolute name abs_name.

Equivalent to setData(abs_name, new TQImageDrag(image)).

void TQMimeSourceFactory::setPixmap ( const TQString & abs_name, const TQPixmap & pixmap ) [virtual]

Sets pixmap to be the data item associated with the absolute name abs_name.

void TQMimeSourceFactory::setText ( const TQString & abs_name, const TQString & text ) [virtual]

Sets text to be the data item associated with the absolute name abs_name.

Equivalent to setData(abs_name, new TQTextDrag(text)).

TQMimeSourceFactory * TQMimeSourceFactory::takeDefaultFactory () [static]

Sets the defaultFactory() to 0 and returns the previous one.

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TQt 3.3.8