Guide to Porting Applications to KDE 2.0

Porting Applications to KDE 2.0

Last Modified on November 28, 2000

This document contains the changes you have to apply to programs written for KDE1.1 when you want to port them to KDE2.0.

As a start you should have a look at doc/porting.doc in the Qt package, or this page online.

Table of Contents

Getting started

The first step to get your KDE application to compile under KDE 2.0, is to detect KDE 2.0 and Qt 2.x at configure time. The easiest way to get a working autoconf/automake framework, is to either use KDevelop or kapptemplate (available in CVS under the module "kdesdk"), to generate a new application template. Replace the generated source files by yours and adapt Makefile.am accordingly.

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Global changes

We did our best to clean up the header files of kdelibs, so they do not include unnecessary bloat for your application. As a consequence, you may notice that some header files are missing from your source files as they have been included before by kapp.h for example. There is a script in kdesdk/scripts called "fixheaders" that takes care of most of these cases. Just call "make -k 2>&1 | perl .../fixheaders" and it will try to look after the error messages and add includes as it recognize the errors.

Also, if your code does not compile and complains about missing member functions, you should check for methods that started with get...(). These methods have been renamed to xy*() for consistency.

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automoc/am_edit, Makefile.am tags

On the subject of the compilation framework, automoc has been removed from the admin directory. It has been replaced by am_edit which provides a lot of additional features.

METASOURCES=AUTO still does the job of generating the appropriate moc files, but in addition, you should use KDE_ICON for the icons representing the application (and naming those icons conforming to lo16-app-<appname>.png), and install the application-specific icons under $(kde_datadir)/<appname>/pics.

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KApplication

doesn't hold any longer a KLocale instance. With this getLocale() and isLocaleInstantiated are now replaced by KGlobal::locale()

it also doesn't hold a KiconLoader instance. As this also getIconLoader() has been removed. Replace kapp->getIconLoader()->loadIcon() with BarIcon() or use KGlobal::iconLoader() instead of getIconLoader()

kde_*dir() have been removed as they require a unique top level directory for all applications (KDEDIR). This concept doesn't exist in KDE 2.0 any more, it has been replaced with "multiple levels of directories", set in KDEDIRS, so that it's possible to have global settings and group settings, applied before user settings.

Replace code that uses kde_*dir() + filename with calls to locate(filetype, filename) where filetype is what * used to be in kde_*dir(). locate is defined as function in kstddirs.h to call KGlobal::dirs()->findResource.

Use locateLocal to get the path of a writable file. For instance, KApplication::localconfigdir()+filename is now locateLocal( "config", filename ), but for most cases, simply using KGlobal::config() is enough, if you're happy with saving the application's configuration into appnamerc, or KSimpleConfig cfg("anothercfgfile") to create a config file with another name.

generalFont() and fixedFont() are deprecated and will be removed soon. Please use KGlobalSettings::generalFont() and KGlobalSettings::fixedFont() instead.

appName() is deprecated. Please use QApplication::name() or instanceName instead.

The methods tempSaveName() and checkRecoverFile() return QString now. The returned values must _not_ be free()d.

helpMenu() has been moved to KMainWindow. aboutKDE(), aboutApp() and appHelpActivated() have all been removed See section for KMainWindow for more info.

The KApplication constructor has changed. Command line arguments and program name should no longer be passed to KApplication but to KCmdLineArgs. KCmdLineArgs performs command line parsing and a command line help. See below for more info.

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KCmdLineArgs

KCmdLineArgs is a new class that handles command line parsing and command line help. It is now required that your application specifies at least:

Its name.
A short description what it does. (e.g. 1 line)
A version.
All command line options that it supports.

KCmdLineArgs itself will add the command line options supported by Qt and KApplication.

You can also use the KAboutData class to specify name, description and version.

In return for this information you can query KCmdLineArgs whether an certain option was specified on the command line and your application now automatically supports --help and --version. It aborts with a usefull error message when the command line contains a syntax error. See kdelibs/kdecore/kcmdlineargs.h for more info.

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KLocale

i18n is no longer a macro

KApplication::getApplication()->getLocale()->translate

but a function on its own. klocale is obsolete and replace every call to klocale->translate with i18n.

The return value of i18n is also no longer a const char*, but a unicode QString.

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KGlobal: access to KDE global objects.

KGlobal allows centralized access to KDE global objects without including extraneous headers. object creation is deferred if possible.

All methods are static and headers for returned types are not included. You must have created a KApplication object before the methods can be used.

#include <kglobal.h> #include <kconfig.h> // Needed to use KConfig #include <klocale.h> // Needed to use KLocale #include <kiconloader.h> // Needed to use KIconLoader

... KConfig *appcfg = KGlobal::config(); QString mystr = i18n( "This is a string" ); KIconLoader *loader = KGlobal::iconLoader();

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KIconLoader

KIconLoader in 1.1 used to mix icons for applications and for toolbars. This has changed, so you may notice that your application doesn't find the right icons. loadIcon (used by BarIcon) returns only toolbar icons.

If you need icons for applications, use loadApplicationIcon.

loadMiniIcon and loadApplicationMiniIcon have been removed, instead loadApplicationIcon now takes a "size" argument where you can specify the size of the icon (small, medium, large).

The other big change you may notice, is that ICON and Icon have been removed as they caused big confusion for not loading application icons (see above). For this we added BarIcon which does the same as ICON before. The third change in this row is that loadIcon doesn't need the extension anymore, but looks for standard extensions (png, xpm) itself. If you hard- coded .xpm, loadIcon will issue a warning at runtime, but will still work in stripping off the .xpm part

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KTMainWindow

KTMainWindow has been replaced with KMainWindow.

The KMainWindow constructor needs a parent widget as first argument. You can use 0 for this.

setView() has been replaced with setCentralWidget().

view() has been replaced with centralWidget().

addToolBar() has been removed, it is not needed any more.

setMenu(...) has been removed, it is not needed any more.

setStatusBar(...) has been removed, it is not needed any more.

updateRects() has been removed, it is not needed any more.

enableStatusBar(...) has been removed, use statusBar()->show() and/or statusBar()->hide() instead.

enableToolBar(...) has been removed, use toolBar()->show() and/or toolBar()->hide() instead.

view_* public variables do no longer exist. There is really no reason for an app to use this information. If you do need it anyway, use mainViewGeometry() instead.

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KHelpMenu

helpMenu() has been moved to KMainWindow from KApplication (kapp).

Both the "About KDE" and the "About <Application>" dialog boxes are now modeless. "About KDE" is a completely new widget.

If you used in the toplevel window (that is derived from KMainWindow) "kapp->helpMenu( bool, QString )" to get the help menu you must now change this to "helpMenu( QString )". The QString defaults to QString::null so it is sufficient to write helpMenu().

The old aboutKDE(), aboutApp() and appHelpActivated() of KApplication have all been removed. If you need direct access to these or need access to a help menu in a class that is not derived from KMainWindow then allocate an instance of the new class KHelpMenu. See KDE 2.0 API reference or khelpmenu.h (kdeui) for additional info.

Espen Sand <espen@kde.org>

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KToolBar

enable(...) is depreciated, use show()/hide() instead.

enableFloating(...) has been removed, use enableMoving() instead.

setMaxHeight() is depreciated, use setMaximumHeight() instead.

maxHeight() is depreciated, use maximumHeight() instead.

setMaxWidth() is depreciated, use setMaximumWidth() instead.

maxWidth() is depreciated, use maximumWidth() instead.

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Starting other programs

In KDE 2.0 there are several ways to start other programs from within your application. Here is a short summary of your options with reasons why you should or should not use them.

1. fork + exec

You never want to use this unless you have a very good reason why it is impossible to use KProcess.

2. KProcess

You want to use this if you need to start a new process which needs to be a child of your process, e.g. because you want to catch stdout/stderr or need to send it data via stdin. You should never use this to start other KDE applications unless your application is called kgdb :-) If you need to send/receive text like data to/from the process, you are probably better off with KProcIO

3. KProcIO

Like KProcess. Unlike KProcess, this class actually makes it easy to send data to and receive data from the process.

4. startServiceByDesktopPath

Preferred way to launch desktop (KDE/Gnome/X) applications or KDE services. The application/service must have a .desktop file. It will make use of KDEinit for increased startup performance and lower memory usage. These benefits only apply to applications available as KDEinit loadable module (KLM)

5. KRun

Generic way to open documents/applications/shell commands. Uses startServiceBy.... where applicable. Offers the additional benefit of startup-notification.
KRun can start any application, from the binary or the desktop file, it will determine the mimetype of a file before running the preferred handler for it, and it can also start shell commands. This makes KRun the recommended way to run another program in KDE 2.

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khtmlw

khtmlw has been replaced with khtml.

KHTMLView has vanished. Just use KHTMLWidget, which does scrollbar managing for free.
A lot of the API has changed. If you just want to open a file/URL, you just need to do:
```
	KHTMLWidget *w = new KHTMLWidget();
	w->openURL(myURL);
  
```
khtml uses QString's instead of char *'s now. This means, that most of the api has changed. In all functions:
```
     const char * -> QString
     QStrList -> QStringList
  
```
The only exception for the moment is KHTMLWidget::write(), which does also exist in a const char * version.
you won't need the getKHTMLWiget function anymore. Just replace getKHTMLWidget->xxx() with xxx()
xxx(QString) -> xxx(const QString &)
consistent naming. All getXyz() functions are renamed to xyz()

replaced/changed functions:

KHTMLWidget::setDefaultFontBase() -> setFontSizes()

x/yOffset() -> contentsX/Y()

getSelectedText(QString &) -> QString selectedText()

findTextEnd() has vanished. just remove the call from your code

gotoXY(x, y) -> setContentsPos(x, y)

docWidth() -> contentsWidth()

docHeight() -> contentsHeight()

Don't forget to change the link-flags! (-lkhtml -lkjava instead of -lkhtmlw)

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KIntegerLine, KIntLineEdit

KIntegerLine and KIntLineEdit have been replaced by KIntNumInput. The new header file is called knuminput.h.

The new KIntNumInput can have an optional slider attached, ensures that the entered value is in a given range (use MAX_INT or similar if you don't care about the range) and can maintain a descriptive label and also a unit for the edited value.

The API is almost the same and it simplifies existing code a bit, so give it a try. If you need more functionality, please contact me, Dirk A. Mueller <mueller@kde.org>.

The additional class KDoubleNumInput gives you the same look & feel, but allows you to edit floating point numbers.

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KDNDIcon, KDNDDropZone, KDNDWidget, kdecore/drag.h

KDE Drag and Drop is Dead. Long live Qt Xdnd.

Xdnd is better anyway, because it has been adopted by all the other major GUI toolkits still under active development (this precludes Motif, but maybe we can convince the lesstif guys!). Some changes are necessary to convert your old KDND-based stuff to Qt DND.

Remove drag.h from all of your sources / header files.
Remove KDNDDropZone object creations. Instead of creating an object of this type and then connecting it to some arbitrary slot to handle drops, call "setAcceptDrops(true)" in your widget constructor and then override the protected methods dragEnterEvent, dragMoveEvent, dragLeaveEvent, and dropEvent.
You should be aware that to handle drops, you will either have to inherit a widget and then override the methods mentioned above, or install an event handler for the widget in that widget's parent, and then handle QEvent::DragMove or QEvent::Drop inside there (if you want to avoid inheritance).
You can emulate the old DndURL drop-type behaviour with the Qt Drag Object type QUriList.
You can start a drag from inside your widget's mouseMoveEvent method if you wish.
Qt includes a Drag and Drop tutorial. We suggest you read that now if you are confused.
QMultiLineEdit has already a DnD interface that accepts text/* If you want to add support for other mimetypes, you need to re-implement all DnD-methods (also dragMoveEvent()) and pass QTextDrag's to the parent methods.
QTextDrag also accepts text/uri-list, which means that you always need to check for QUriDrag first if you want to get both working.
The mimetype for Uri's is now text/uri-list. If you've used the proprietary Qt 1.x url/url, you need to adjust that.

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KConfigBase, KConfig, KSimpleConfig

These classes have been largely re-implemented. The external API remains mostly the same, with the single notable change that the groupIterator and entryIterator methods have been removed and instead replaced by groupList (which returns a QStringList of groups) and entryMap(const QString &group) (which returns a QMap of entries in the specified group). This is due to internal changes in KConfig which would make providing iterators possibly rather difficult.

Much more extensive documentation on the KConfig and friends API can be found in the kdoc generated documentation from the header files, and in kdecore/KCONFIG_DESIGN.

To use the new iterator, you will probably want to do something like this:


  QMap<QString, QString> tmpMap = config-<entryMap(myGroup);
  QMap<QString, QString>::Iterator aIt(tmpMap.begin());

  for (; aIt != tmpMap.end(); ++aIt) {
   // body here.  Access iterator key as aIt.key(),
   // data as *aIt.
  }

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libkfm has disappeared

Lots of other functionalities have been taken out of kfm, some being now in libkio, some in libkonq.

Replacement table :

KFM::download -> KIO::NetAccess::download (kdelibs/kio/netaccess.h)

KFM::removeTempFile -> KIO::NetAccess::removeTempFile

refreshDesktop, sortDesktop, selectRootIcons : removed; kdesktop handles it

KFM::configure -> see konqueror DCOP interface

KFM::openURL -> "(void) new KRun (url)" (kdelibs/kio/krun.h)

KFM::refreshDirectory -> not needed anymore since konqy/kdesktop use KDirWatch

KFM::openProperties -> "(void) new KPropertiesDialog (url)" (kdelibs/kfile/kpropsdlg.h)

KFM::exec -> "(void) new KRun (url)" (kdelibs/kio/krun.h)

KFM::copy, KFM::move -> KIO::Job (async, see kio/job.h)
or KIO::NetAccess (sync, see kio/netaccess.h)

DlgLocation -> Use KLineEditDlg (kdeui/klineeditdlg.h) instead

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KDialog

KDialog is no longer defined in kwizard.h. Include kdialog.h instead.

Note that the best way to write new dialogs is to use KDialogBase (see kdialogbase.h)

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kcharsets

The kcharsets class has been completely rewritten, and most of it has vanished, since support for it moved to Qt.

Most applications will only need to replace kapp->getKCharsets() with KGlobal::charsets().

For conversion of various input formats to QStrings, please have a look at QTextCodec and classes derived from it.

Character entities are now converted from and to QChars. The name has changed from convertTag to fromEntity and toEntity.

To get a font, which can display a certain charset (if such a font exists), you can use the KCharsets::setQFont methods. Input is a font and a charset. Kcharsets tries to find an output font, which matches the input font most closely, but can display the given charset.

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KWizard, KNoteBook

KWizard is based on QWizard now. The API has changed. Consult Qt's documentation and kdelibs/kdetest/kwizardtest.cpp for an example use.

KNoteBook (deeply entwined with the former KWizard) has been removed until someone is willing to port it to work with the new wizard. If you want to use it you'll find the necessary files in kdegraphics/kiconedit.

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KSpinBox, KNumericSpinBox

These classes have been replaced by QSpinBox. API is almost the same HINTS:

valueincreased()/valuedecreased -> valueChanged()
getValue() -> value()

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KClipboard

KClipboard has been removed. In case you've been using KClipboard, QClipboard is the way to go now, as it has all the functionality the K version had, and more.

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KPanner, KNewPanner

KPanner and KNewPanner have been removed. QSplitter does everything KPanner did and more. The api is similar, but not compatible. Basically to set it up so that you have a vertical splitter between a listbox, a listview and multi line editor, you would do something like this:

QSplitter *split = new QSplitter( parent );
QListBox *lb = new QListBox( split );
KListView *lv = new KListView( split );
QMultiLineEdit *ed = new QMultiLineEdit( split );
As you can see you are not limited to two children. Additionally, you do not have to call activate when you are done, and opaque resizing is possible if you call setOpaqueResize(true).

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KTreeList, KTreeListItem

Use KListView, QListViewItem instead. API is almost the same, you only need to add a Column (KListView::addColum) before KListView is useable.

KListView has no addChild(), insertItem() and removeItem() calls. Inserting a root item is done by constructing a QListViewItem with the KListView passed as the parent widget. adding a child item is done by constructing a QListViewItem with the parent item as parameter. removeItem() should be replaced by delete <pointer to item>.

The root items are not shown in a tree fashion by default. to get this, use KListView::setDecorativeRoot(true).

Expanding and collapsing can by done by using QListViewItem::setOpen(bool).

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KMsgBox

KMsgBox has been superseded by QMessageBox. Which has been superseded by KMessageBox.

KMsgBox had return codes starting with 1 for the first button, 2 for the second, and so on. KMessageBox defines an enum which you should use instead.
Please note that you shouldn't add the name of your application to the caption argument. It is already added automatically.

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KCombo

KCombo has been removed. Use KComboBox instead, it is completely compatible with the old KCombo API. The method that you may have problems with is the old KCombo::setText. This has been renamed to KComboBox::setEditText.

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KQuickHelp

KQuickHelp, the "super-tooltip" widget, has been replaced by QWhatsThis. It provides a compatible API and almost the same look and feel, in addition to some new functionality.

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KPixmap::gradientFill

Instead of old KPixmap::gradientFill, use:

KPixmapEffect::gradient(KPixmap&, QColor, QColor, enum KPixmapEffect::GradientType, int)

Hence:

pix.gradientFill(ca, cb, direction, ncols)

becomes, for direction == true :

KPixmapEffect::gradient(pix, ca, cb, KPixmapEffect::VerticalGradient, ncols)

There are now:

KPixmapEffect::
[Vertical,
Horizontal,
Diagonal,
CrossDiagonal,
Rectangle,
Pyramid,
PipeCross,
Elliptic]
Gradients. See kdelibs/kdetest/kgradienttest & kunbalancedgradienttest for information on how they actually look.

Look further in this document for other info about pixmap effect code reorganization (essentially, all effects are now in libkdeui.so: gradient(), unbalancedGradient(), hash(), desaturate(), pattern(), fade(), blend() etc.

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KTabListBox

This widget has been replaced by the almighty KListView. Everything said about KTreeList could be repeated here. The good thing is, that you now can combine TreeView's and normal Tablists without problems.

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KToolBarButton & KRadioGroup

If you need to do anything with KToolBarButton you now need to include <ktoolbarbutton.h> KRadioGroup has been renamed to KToolBarRadioGroup and requires you to include <ktoolbarradiogroup.h>

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KAccel

The functions keyToString() and stringToKey() which were previously declared globally in kaccel.h are now static methods in KAccel.

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kstring.h / KString

The KString class is obsolete and is not defined in kstring.h anymore. The header file only existed for compatibility reasons. The file has been removed completely, use QString instead. (mirko@kde.org)

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ktopwidget.h / KTopWidget

KMainWindow replaces this class completly. ktopwidget.h does not exist in KDE 2. (mirko@kde.org)

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kbutton.h / KButton

Since Qt 2.0, the class QToolButton provides the functionality of buttons that raise when the mouse is moved over them, so there is no reason to have a class providing the same feature in KDE libs. All occurrences of KButton in the KDE CVS have been replaced by QToolButtons, but for applications not in the CVS it has to be done by the respective developer. (mirko@kde.org)

kbuttonbox.h / KButtonBox

KButtonBox::Orientation has been removed in favor of Qt::Orientation.

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kcolorgroup.h / KColorGroup

KColorGroup was not used in sources in the KDE CVS, and its functionality is provided by Qt. It has been removed. (mirko@kde.org)

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kled.h, kledlamp.h / KLed, KLedLamp

There where two different classes for showing an LED lamp. Both are merged to the KLed class, but THE USER INTERFACE IS DIFFERENT, as both where more or less broken.

Please adjust your code accordingly.

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KDockWidget

KDockWidget inherits form KMainWindow instead of KTMainWindow now. See KTMainWindow for more details.

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KPixmap, KPixmapEffect

KPixmap::gradientFill, KPixmap::patternFill, KPixmap::tile and KPixmap::mapFill have been moved to KPixmapEffect, which is now part of libkdeui.

KPixmap::tile() has been renamed to KPixmapEffects::createTile().

Dirk A. Mueller <mueller@kde.org>

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KDE Control Center

The format for modules for the KDE Control Center has changed quite a bit. If you want to port your module to the new schema, please consult

kdebase/kcontrol/README

which explains what needs to be done.

Matthias Hoelzer-Kluepfel <hoelzer@kde.org>

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KWMModuleApplication libkdeui/kwmmapp.h

The KWMModuleApplication has been removed. Instead, use the class KWinModule in libkdecore. The API is a bit cleaner but very similar, so you will feel comfortable immediately. One of the advantages of KWinModule is that it doesn't require a special KApplication subclass. This lead to many problems and misunderstandings in the past. KWinModule is now just an object that emits fancy signals (and provides some useful lists, like the list of all managed windows). (ettrich@kde.org)

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kDebug

Use kdDebug, kdWarning, kdError, kdFatal to log debug output, warnings and errors in a very flexible way. kdebug has been improved, and the API simplified. kdesdk/scripts/kDebug2kdDebug.sh provides a script for automating the conversion. Note that enabling/disabling debug output can now be done with kdebugdialog, which can be found in kdebase. The hidden dialog on C+S+F12 no longer exists.

Also, note that qDebug and fprintf aren't disabled by -DNDEBUG, whereas kdDebug is. One more reason to use kdDebug ! (faure@kde.org)

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KFileDialog - General Stuff

The new (rewritten) KFileDialog (KFD) is a lot more like the new QFileDialog but still looks quite different. Normally you may want to use the static methods provided for convenience (getOpenFileName and getSaveFileName). If you need special features you can configure the dialog extensively. Just create an object and use the different methods.

Werner Trobin <wtrobin@carinthia.com>

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KFileDialog - Preview Mode

There is also a new preview mode which is quite different to the one we had in the KDE 1.x KFD. There are no preview modules you have to register but there is a single method you can use to set a preview widget. This widget has to inherit QWidget and you have to implement a slot (showPreview(const KURL &)) in this class. This slot is called each time the selected file/dir changes. In this slot you have to react appropriate (i.e. show the preview :). The easiest way this can be done is to derive your class from QWidgetStack and add a Object (derived from QWidget) for each file type. In the showPreview method you just raise the matching widget. If you can't find an appropriate widget just hide() the widget stack.

If you need some "inspiration" on how that could be done, please have a look at koffice/lib/kofficecore/koFilterManager.cc (PreviewStack).

Werner Trobin <wtrobin@carinthia.com>

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Image effects

The kFSDither class is now gone. Its functionality was moved to KImageEffect::dither(). Whereas before, you would done:

kFSDither dither(palette, ncols); image = dither.dither(image);

Now do:

KImageEffect::dither(image, palette, ncols);

Kurt Granroth <granroth@kde.org>

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KAudio (kaudio.h)

The KAudio class no longer exists. Here are your options for porting.

notifications like "you have got new mail"
The way to go for this one is to use the KNotify API, which will allow users to reconfigure how your application should sound. On the other hand, they will also be able to disable specific sounds, rather let the events log to a file, and so on. You can provide an rc file with the default configuration. (Include "knotifyclient.h" and use the KNotifyClient class).
very simple cases
On the other hand, if you just want a really small solution, there is the KAudioPlayer class (declared kaudioplayer.h), which has a static member function for playing, like
```
   KAudioPlayer::play("/var/samples/foo.wav");
```
multimedia apps
If you are writing "real multimedia apps", you may also have a look at the even more advanced sound/multimedia support, that using the aRts/MCOP libraries directly can offer you.

Stefan Westerfeld stefan@space.twc.de

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KImageIO (kimgio.h)

KImageIO has moved from 'kimgio.h' to 'kimageio.h'. LIB_KIMGIO does no longer exists, you need to link against LIB_KSYCOCA instead.

kimgioRegister() has been replaced by KImageIO::registerFormats().

Waldo Bastian bastian@kde.org

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