Qt 3.0 adds a wide range of major new features as well as substantial improvements over the Qt 2.x series. Some internals have undergone major redesign and new classes and methods have been added. The Qt version 3.x series is not binary compatible with the 2.x series. This means programs compiled with Qt version 2.x must be recompiled to work with Qt 3.0. In addition to the traditional Qt platforms Linux, Unix and the various flavours of MS-Windows. Qt 3.0 for the first time introduces a native port to MacOS X. Like all Qt versions, Qt/Mac is source compatible with the other editions and follows closely the platform's native look and feel guidelines. We have tried to keep the API of Qt 3.0 as compatible as possible with the Qt 2.x series. For most applications, only minor changes will be needed to compile and run them successfully using Qt 3.0. One of the major new features that has been added in the 3.0 release is a module allowing you to easily work with databases. The API is platform independent and database neutral. This module is seamlessly integrated into Qt Designer, greatly simplifying the process of building database applications and using data aware widgets. Other major new features include a plugin architecture to extend Qt's functionality, for styles, text encodings, image formats and database drivers. The Unicode support of Qt 2.x has been greatly enhanced, it now includes full support for scripts written from right to left (e.g. Arabic and Hebrew) and also provides improved support for Asian languages. Many new classes have been added to the Qt Library. Amongst them are classes that provide a docking architecture (QDockArea/QDockWindow), a powerful rich text editor (QTextEdit), a class to store and access application settings (QSettings) and a class to create and communicate with processes (QProcess). Apart from the changes in the library itself a lot has been done to make the development of Qt applications with Qt 3.0 even easier than before. Two new applications have been added: Qt Linguist is a tool to help you translate your application into different languages; Qt Assistant is an easy to use help browser for the Qt documentation that supports bookmarks and can search by keyword. Another change concerns the Qt build system, which has been reworked to make it a lot easier to port Qt to new platforms. You can use this platform independent build system - called qmake - for your own applications. And last but not least we hope you will enjoy the revisited and widely extended documentation. Qt/Embedded ---------- Qt/Embedded 3.0 provides the same features as Qt 3.0, but currently lacks some of the memory optimizations and fine-tuning capabilities of Qt/Embedded 2.3.x. We will add these in the upcoming maintainance releases. If you develop a new product based on Qt/Embedded, we recommend switching to 3.0 because of the greatly improved functionality. However, if you are planning a release within the next two months and require memory optimizations not available with Qt/Embedded 3.0, we suggest using Qt/Embedded 2.3.x. The Qt Library ======================================== A large number of new features has been added to Qt 3.0. The following list gives an overview of the most important new and changed aspects of the Qt library. Database support ---------------- One of the major new features in Qt 3.0 is the SQL module that provides cross-platform access to SQL databases, making database application programming with Qt seamless and portable. The API, built with standard SQL, is database-neutral and software development is independent of the underlying database. A collection of tightly focused C++ classes are provided to give the programmer direct access to SQL databases. Developers can send raw SQL to the database server or have the Qt SQL classes generate SQL queries automatically. Drivers for Oracle, PostgreSQL, MySQL and ODBC are available and writing new drivers is straightforward. Tying the results of SQL queries to GUI components is fully supported by Qt's SQL widgets. These classes include a tabular data widget (for spreadsheet-like data presentation with in-place editing), a form-based data browser (which provides data navigation and edit functions) and a form-based data viewer (which provides read-only forms). This framework can be extended by using custom field editors, allowing for example, a data table to use custom widgets for in-place editing. The SQL module fully supports Qt's signals/slots mechanism, making it easy for developers to include their own data validation and auditing code. Qt Designer fully supports Qt's SQL module. All SQL widgets can be laid out within Qt Designer, and relationships can be established between controls visually. Many interactions can be defined purely in terms of Qt's signals/slots mechanism directly in Qt Designer. Explicit linking and plugins ------------------------- The QLibrary class provides a platform independent wrapper for runtime loading of shared libraries. Specialized classes that make it possible to extend Qt's functionality with plugins: QStylePlugin for user interface styles, QTextCodecPlugin for text encodings, QImageFormatPlugin for image formats and QSqlDriverPlugin for database drivers. It is possible to remove unused components from the Qt library, and easy to extend any application with 3rd party styles, database drivers or text codecs. Qt Designer supports custom widgets in plugins, and will use the widgets both when designing and previewing forms (QWidgetPlugin). Rich text engine and editor --------------------------- The rich text engine originally introduced in Qt 2.0 has been further optimized and extended to support editing. It allows editing formatted text with different fonts, colors, paragraph styles, tables and images. The editor supports different word wrap modes, command-based undo/redo, multiple selections, drag and drop, and many other features. The engine is highly optimized for proccesing and displaying large documents quickly and efficiently. Unicode ------- Apart from the rich text engine, another new feature of Qt 3.0 that relates to text handling is the greatly improved Unicode support. Qt 3.0 includes an implementation of the bidirectional algorithm (BiDi) as defined in the Unicode standard and a shaping engine for Arabic, which gives full native language support to Arabic and Hebrew speaking people. At the same time the support for Asian languages has been greatly enhanced. The support is almost transparent for the developer using Qt to develop their applications. This means that developers who developed applications using Qt 2.x will automatically gain the full support for these languages when switching to Qt 3.0. Developers can rely on their application to work for people using writing systems different from Latin1, without having to worry about the complexities involved with these scripts, as Qt takes care of this automatically. Docked and Floating Windows --------------------------- Qt 3.0 introduces the concept of dock windows and dock areas. Dock windows are widgets, that can be attached to, and detached from, dock areas. The most common kind of dock window is a tool bar. Any number of dock windows may be placed in a dock area. A main window can have dock areas, for example, QMainWindow provides four dock areas (top, left, bottom, right) by default. The user can freely move dock windows and place them at a convenient place in a dock area, or drag them out of the application and have them float freely as top level windows in their own right. Dock windows can also be minimized or hidden. For developers, dock windows behave just like ordinary widgets. QToolbar for example is now a specialized subclass of a dock window. The API of QMainWindow and QToolBar is source compatible with Qt 2.x, so existing code which uses these classes will continue to work. Regular Expressions ------------------- Qt has always provided regular expression support, but that support was pretty much limited to what was required in common GUI control elements such as file dialogs. Qt 3.0 introduces a new regular expression engine that supports most of Perl's regex features and is Unicode based. The most useful additions are support for parentheses (capturing and non-capturing) and backreferences. Storing application settings ---------------------------- Most programs will need to store some settings between runs, for example, user selected fonts, colors and other preferences, or a list of recently used files. The new QSettings class provides a platform independent way to achieve this goal. The API makes it easy to store and retrieve most of the basic data types used in Qt (such as basic C++ types, strings, lists, colors, etc). The class uses the registry on the Windows platform and traditional resource files on Unix. Creating and controlling other processes ---------------------------------------- QProcess is a class that allows you to start other programs from within a Qt application in a platform independent manner. It gives you full control over the started program. For example you can redirect the input and output of console applications. Accessibility --------------- Accessibility means making software usable and accessible to a wide range of users, including those with disabilities. In Qt 3.0, most widgets provide accessibility information for assistive tools that can be used by a wide range of disabled users. Qt standard widgets like buttons or range controls are fully supported. Support for complex widgets, like e.g. QListView, is in development. Existing applications that make use of standard widgets will become accessible just by using Qt 3.0. Qt uses the Active Accessibility infrastructure on Windows, and needs the MSAA SDK, which is part of most platform SDKs. With improving standardization of accessibility on other platforms, Qt will support assistive technologies on other systems too. XML Improvements ---------------- The XML framework introduced in Qt 2.2 has been vastly improved. Qt 2.2 already supported level 1 of the Document Object Model (DOM), a W3C standard for accessing and modifying XML documents. Qt 3.0 has added support for DOM Level 2 and XML namespaces. The XML parser has been extended to allow incremental parsing of XML documents. This allows you to start parsing the document directly after the first parts of the data have arrived, and to continue whenever new data is available. This is especially useful if the XML document is read from a slow source, e.g. over the network, as it allows the application to start working on the data at a very early stage. SVG support ----------- SVG is a W3C standard for "Scalable Vector Graphics". Qt 3.0's SVG support means that QPicture can optionally generate and import static SVG documents. All the SVG features that have an equivalent in QPainter are supported. Multihead support ----------------- Many professional applications, such as DTP and CAD software, are able to display data on two or more monitors. In Qt 3.0 the QDesktopWidget class provides the application with runtime information about the number and geometry of the desktops on the different monitors and such allows applications to efficiently use a multi-monitor setup. The virtual desktop of Windows 98 and 2000 is supported, as well as the traditional multi-screen and the newer Xinerama multihead setups on X11. X11 specific enhancements ------------------------- Qt 3.0 now complies with the NET WM Specification, recently adopted by KDE 2.0. This allows easy integration and proper execution with desktop environments that support the NET WM specification. The font handling on X11 has undergone major changes. QFont no longer has a one-to-one relation with window system fonts. QFont is now a logical font that can load multiple window system fonts to simplify Unicode text display. This completely removes the burden of changing/setting fonts for a specific locale/language from the programmer. For end-users, any font can be used in any locale. For example, a user in Norway will be able to see Korean text without having to set their locale to Korean. Qt 3.0 also supports the new render extension recently added to XFree86. This adds support for anti-aliased text and pixmaps with alpha channel (semi transparency) on the systems that support the rendering extension (at the moment XFree 4.0.3 and later). Printing -------- Printing support has been enhanced on all platforms. The QPrinter class now supports setting a virtual resolution for the painting process. This makes WYSIWYG printing trivial, and also allows you to take full advantage of the high resolution of a printer when painting on it. The postscript driver built into Qt and used on Unix has been greatly enhanced. It supports the embedding of true/open type and type1 fonts into the document, and can correctly handle and display Unicode. Support for fonts built into the printer has been enhanced and Qt now knows about the most common printer fonts used for Asian languages. Networking ----------- A new class QHttp provides a simple interface for HTTP downloads and uploads. Compatibility with the Standard Template Library (STL) ------------------------------------------------------ Support for the C++ Standard Template Library has been added to the Qt Template Library (QTL). The QTL classes now contain appropriate copy constructors and typedefs so that they can be freely mixed with other STL containers and algorithms. In addition, new member functions have been added to QTL template classes which correspond to STL-style naming conventions (e.g., push_back()). Qt Designer ======================================== Qt Designer was a pure dialog editor in Qt 2.2 but has now been extended to provide the full functionality of a GUI design tool. This includes the ability to lay out main windows with menus and toolbars. Actions can be edited within Qt Designer and then plugged into toolbars and menu bars via drag and drop. Splitters can now be used in a way similar to layouts to group widgets horizontally or vertically. In Qt 2.2, many of the dialogs created by Qt Designer had to be subclassed to implement functionality beyond the predefined signal and slot connections. Whilst the subclassing approach is still fully supported, Qt Designer now offers an alternative: a plugin for editing code. The editor offers features such as syntax highlighting, completion, parentheses matching and incremental search. The functionality of Qt Designer can now be extended via plugins. Using Qt Designer's interface or by implementing one of the provided interfaces in a plugin, a two way communication between plugin and Qt Designer can be established. This functionality is used to implement plugins for custom widgets, so that they can be used as real widgets inside the designer. Basic support for project management has been added. This allows you to read and edit *.pro files, add and remove files to/from the project and do some global operations on the project. You can now open the project file and have one-click access to all the *.ui forms in the project. In addition to generating code via uic, Qt Designer now supports the dynamic creation of widgets directly from XML user interface description files (*.ui files) at runtime. This eliminates the need of recompiling your application when the GUI changes, and could be used to enable your customers to do their own customizations. Technically, the feature is provided by a new class, QWidgetFactory in the UI-library. Qt Linguist ======================================== Qt Linguist is a GUI utility to support translating the user-visible text in applications written with Qt. It comes with two command-line tools: lupdate and lrelease. Translation of a Qt application is a three-step process: 1) Run lupdate to extract user-visible text from the C++ source code of the Qt application, resulting in a translation source file (a *.ts file). 2) Provide translations for the source texts in the *.ts file using Qt Linguist. 3) Run lrelease to obtain a light-weight message file (a *.qm file) from the *.ts file, which provides very fast lookup for released applications. Qt Linguist is a tool suitable for use by translators. Each user-visible (source) text is characterized by the text itself, a context (usually the name of the C++ class containing the text), and an optional comment to help the translator. The C++ class name will usually be the name of the relevant dialog, and the comment will often contain instructions that describe how to navigate to the relevant dialog. You can create phrase books for Qt Linguist to provide common translations to help ensure consistency and to speed up the translation process. Whenever a translator navigates to a new text to translate, Qt Linguist uses an intelligent algorithm to provide a list of possible translations: the list is composed of relevant text from any open phrase books and also from identical or similar text that has already been translated. Once a translation is complete it can be marked as "done"; such translations are included in the *.qm file. Text that has not been "done" is included in the *.qm file in its original form. Although Qt Linguist is a GUI application with dock windows and mouse control, toolbars, etc., it has a full set of keyboard shortcuts to make translation as fast and efficient as possible. When the Qt application that you're developing evolves (e.g. from version 1.0 to version 1.1), the utility lupdate merges the source texts from the new version with the previous translation source file, reusing existing translations. In some typical cases, lupdate may suggest translations. These translations are marked as unfinished, so you can easily find and check them. Qt Assistant ======================================== Due to the positive feedback we received about the help system built into Qt Designer, we decided to offer this part as a separate application called Qt Assistant. Qt Assistant can be used to browse the Qt class documentation as well as the manuals for Qt Designer and Qt Linguist. It offers index searching, a contents overview, bookmarks history and incremental search. Qt Assistant is used by both Qt Designer and Qt Linguist for browsing their help documentation. qmake ======================================== qmake is a cross-platform make utility that makes it possible to build the Qt library and Qt-based applications on various target platforms from one single project description. It is the C++ successor of 'tmake' which required Perl. qmake offers additional functionallity that is difficult to reproduce in tmake. Qt uses qmake in its build system and we have released it as free software. Detailed changes ============= Qt 3.0 went through 6 beta releases. These are the detailed changes since Beta 6 only. For other changes, please see the changes notes of the respective beta releases. Qt 3.0 final is not binary compatible with Beta6; any programs linked against Beta6 must be recompiled. Below you will find a description of general changes in the Qt Library, Qt Designer and Qt Assistant. Followed by a detailed list of changes in the API. **************************************************************************** * General * **************************************************************************** **************************************************************************** * Library * **************************************************************************** - QApplication make sure we process deferred deletes before leaving the event loop. This fixes some ocassions of memory leaks on exit. win32: some improvements for modality and dockwindow handling x11 only: read non-gui QSettings when running without GUI. - QCheckListItem Make the checkboxes respect the AlignCenter flag. Also make the boxes look better in case they are not placed in the first column. - QComboBox if we have a currentItem and then we set the combobox to be editable then set the text in the lineedit to be of the current item. - QCommonStyle QToolButton: spacing between a toolbutton's icon and its label. QProgressBar: text color fixed. - QCursor added the What's This? cursor to the collection. - QDataTable fixed broken context menus. - QDate fixed addMonth() overflow. - QDesktopWidget win32 only: works now also for cases where the card handles multiple monitors and GetSystemMetrics returns a single screen only. - QDomAttr fixed a memory leak in setNodeValue() - QDomNodeMap added count() as a Qt-style alias for length() - QDragObject default to the middle of the pixmap as a hot spot, this looks nicer. - QFileDialog (internal dialog) make viewMode() return the correct value even after the dialog is finished. Fixed getOpenFileName and getSaveFileName for non-existant directories. Make sure that when it's in directory mode that the filters reflect this, and change the label from file name to directory. win32 only: Improved modality when using the native file dialog. - QFont x11 only: speed up fontloading with even more clever caching. Make sure we can match scaled bitmap fonts by default. Do not load a backup font for a script that is not default. Make sure the pixel size is correct, even for fonts that are unavailable. Try even harder to find a fontname that is not understood. Some RENDER performance optimizations. - QFontDialog make sure the content is set up correctly when initializing the dialog. - QGLWidget IRIX only: fixed reparent/resize bug, QGLContext::setContext() is incredibly sensitive on different X servers. - QHeader fixed missing updates on height resp. width changes like the occur when changing the application font. - QIconView fixed updates of non-auto-arranged views. - QImage no gamma correction by default. x11 only: some alignment issue with the alpha masked fixed. - QIODevice fixed return value of QIODevice::readLine() for sequential access. - QKeyEvent win32 only: generate Direction_R/L events for bidirectional input. - QLabel handle setPixmap( *pixmap() ) gracefully. Apply the WordBreak alignment flag to both plaintext and richtext. Improved alignment of richtext labels. Removed some sizepolicy magic, QLabel now works fine with Preferred/Preferred in all modes. - QLineEdit fixed a crash when doing undo and a validator is set. Emit textChanged() also if the text changed because of undo or redo. - QListBox fixed RMB context-menu offset. - QListView do not start renaming an item is CTRL or SHIFT is pressed. Start renaming on mouse release, not mouse press, so click + click + move on the same item does not start a rename operation. - QMainWindow show dock-menu also when clicking on the menubar. - QPainter win32 only: improved printing performance through printer font caching. boundingRect(): ignore 0-width in the constrain rectangle. - QPicture added overload for load() that takes a QIODevice. - QPrintDialog (internal dialog) fixed enabling of the first page and last page labels. - QPrinter win32 only: make setColorMode() work, some unicode fixes. Make collate the default. Enable the collate checkbox without losing the page selection if you want to print multiple pages. Make the collateCopies property work that it knows checks/unchecks the collate checkbox in the printing dialog. Make settings also work when the print dialog is not shown at all. - QProcess added a new communication mode that duplicates stderr to stdout (i.e. the equivalent of the shell's 2>&1). - QPSPrinter (unix) fixed collate. - QRangeControl simplified code. - QRichText Propagate WhiteSpaceMode to subitems with WhiteSpaceModeNormal. Hide DisplayModeNone items without additional newline. Fixed links inside non-left aligned tables. Fixed some bidi layout problems. Fixed last line layout in right-aligned paragraphs. For plain text, always use the palette's text color. - QScrollView safer destruction. - QSettings win32 only: fixed a dead lock situation when writing to LOCAL_MACHINE, but reading from CURRENT_USER. - QSGIStyle fixed drawing of checkable menu items. - QSimpleRichText use the specified default font. - QSlider optimized drawing in the new style engine. - QString QString::replace() with a regular expression requires a QRegExp object, passing a plain string will cause a compile error. - QStyleSheet additional parameter 'whitespacemode' for QStyleSheet::convertFromPlainText(). Support for superscript ('sup') and subscript ( 'sub' ). - QTabBar react properly on runtime font changes, less flicker. - QTable take the pixmap of a header section into account when adjusting the size. - QTabWidget use the embedded tabbar as focus proxy. - QThread win32 only: possible crash with the thread dictionary fixed. - QValidator In Q{Int,Double}Validator, consider '-' as Invalid rather than Intermediate if bottom() >= 0. - QWidget made showFullScreen() multihead aware. win32 only: Better size and position restoring when switching between fullscreen, maximized and minimized. x11 only: improvements to XIM, overthespot works correctly now. - QWorkspace smarter placement of the minimize button when there is no maximize button. Make titlebars of tool windows a bit smaller. Improved styleability. Do not maximize a widget that has a maximum size that is smaller than the workspace. **************************************************************************** * Other * **************************************************************************** - moc fixed generation of uncompilable code in conjunction with Q_ENUMS and signal/slots. - unicode allow keyboard switching of paragraph directionality. - installation install $QTDIR/doc/html/ instead of $QTDIR/doc/ install Qt Designer templates as well. - improved build on HP-UX with cc. Solaris 8 with gcc 3.0.1. AIX with xlC and aCC. - inputmethods x11 only: do not reset the input context on focus changes. - uic smaller improvements, handle additional form signals. - Qt Designer make it possible to add new signals to a form without subclassing. Minor fixes. - Qt Assistant fixed Shift-LMB selection bug. Fixed new window and window restoration on restart. - Qt Linguist change fourth parameter of QApplication::translate() from bool to enum type. This affects MOC (new revision) and lupdate (new syntax to parse). Change Qt Linguist's XML file format (.ts) to be consistent with QApplication: (rather than ) to match QApp::defaultCodec(); encoding="UTF-8" (rather than utf8="true") to match QApp::translate(). Fixed window decoration on restart. Use 'finished', 'unfinished' and 'unresolved' instead of the (!), (?) symbols on printouts. - QMsDev merge "Add UIC" and "New Dialog". Better user interface and general cleanup. Wwrite (and merge) qmake pro file with active project. Load qmake pro files into Visual Studio.