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MeeGo Touch is a cross-platform application and UI framework library built on top of Qt. The framework library makes use of the very latest Qt features to implement a specific UI style which is primarily intended for touch screen devices.
Using MeeGo Touch makes it easy to implement good-looking, fully finger-optimised applications that automatically take advantage of multipoint touch, device sensors, animations and transitions to create an iconic user experience on a range of platforms from handhelds to the desktop.
The core of the MeeGo Touch style can be summarised as "direct manipulation of content". This places the focus of the applications squarely on the content that the users either create themselves (such as photos taken with the device itself) or is retrieved from the network. Therefore, in a typical MeeGo Touch application, the content occupies the major part of the view, and the rest of the UI elements are de-emphasised.
The MeeGo Touch style discards many well-known concepts from the desktop world such as file selection dialogs, scrollbars, tabs and so on. Due to the focus on touch, the user experience is highly tactile with panning, flicking, dragging and pinching being common operations on a wide variety of content. A MeeGo Touch application is typically divided into views and transitions between the views, instead of multiple windows as on a desktop.
The application canvas is the core of the MeeGo Touch style. It is a 2D pannable virtual area that extends beyond the physical borders of the screen. Using the canvas as the foundation on which everything else is built overcomes the limitations associated with traditional static UIs, be they Qt-based or created with some other framework. For instance, any object on the canvas can be arbitrarily transformed, including rotated, scaled or perspective-adjusted. Every object on the canvas exposes a set of properties, such as the current position, size, and opacity, that can be animated. Objects on the canvas can also freely overlap and be grouped into layers. These features enable highly fluid user interfaces where objects smoothly transition in and out of view, or where certain objects can detach from the rest of UI and stay pinned on the screen while all other content is replaced.
MeeGo Touch presents a programming interface that is similar to other UI frameworks such as Qt. Most of the time it is, therefore, not necessary to understand the workings of the underlying canvas itself. However, developers can also go beyond the ready-made components provided by the MeeGo Touch style and take direct advantage of the canvas in their applications. In such cases MeeGo Touch also offers a set of lower-level enablers to make an application themable and stylable for the scene.
Qt by itself is already a mature cross-platform framework, providing a full set of traditional widgets that have been used in a number of successful applications. In addition to this, Qt provides many essential functionalities for writing cross-platform applications in general, such as I/O, SQL & XML programming, threading, internationalisation and so on.
In addition to this, Qt has recently released a number of new subsystems:
These new technologies serve as the basic enablers for next-generation user interfaces. However, as of Qt 4.6, these elements by themselves are still fairly low-level and lack the ties to any ready-made UI components, including the existing Qt components. MeeGo Touch takes these cutting edge components and implements a particular UI style that is optimised for touch devices and then, combined with a number of additional enablers that makes creating scene based applications easier, packages it together as a coherent UI framework library.
MeeGo Touch, like Qt, is also a cross-platform framework, capable of running wherever Qt does. From the point of view of a developer that wants to create a touch optimised application in the MeeGo Touch style, both Qt and MeeGo Touch are typically directly used; Qt for the application logic and MeeGo Touch for the scene-based UI style.
Qt and MeeGo Touch, two complementary frameworks
The MeeGo Touch offering includes a set of ready-made widgets implementing the MeeGo Touch style that specifically target the Graphics View Framework, a set of pre-defined transitions and animations that can be themed and styled, and a set of features that makes writing scene based applications easier in general, such as automatic management of in-scene dialogs and windows, implicitly animated scene layouts and device orientation tracking. In addition to this MeeGo Touch exposes APIs necessary on mobile devices, such as power and memory management, that are not yet covered by either Qt or the Qt Mobility projects.
In the future, some of the functionality now provided through MeeGo Touch will migrate to Qt. In that sense, MeeGo Touch can be seen as the bleeding edge of Qt development, pushing the boundaries of next generation UI creation.
|Copyright © 2010 Nokia Corporation||Generated on Thu Feb 24 06:02:51 2011 (PDT)