Developing UI with Qt Safe Renderer

Safety-Critical QML Types

In Qt Safe Renderer, the safety-critical UI elements are implemented as QML Types. All the safety-critical QML types must be added to Qt Quick UI Forms (.ui.qml files). In Qt Quick Designer, you can use the safety-critical QML types just like any other QML types in Qt. Thus Qt Safe Renderer provides a seamless integration with the Qt toolchain.

With Qt Creator and Qt Quick Designer, you can easily design a UI that contains both safety-critical and non-safety information. After you have created the very first draft of the UI with Qt Quick Designer, you can deploy it right away to your target device via Qt Creator. Thus the Qt tools enable quick UI prototyping on a real hardware environment. Safety-Critical UI with Qt Quick Designer introduces the safety-critical UI related functionality in Qt Quick Designer.

Qt Quick Designer generates QML code into ui.qml files based on the UI form that contains the layout you have designed. If you do not want to use Qt Quick Designer, you can also write your safety-critical QML code yourself, in Qt Creator's edit mode. See Qt Safe Renderer QML Types for detailed information about the available safety-critical QML types and their properties and methods. Mandatory Properties for Safe QML Types lists the mandatory properties that are required for the safety-critical QML types.

When the developed Qt Quick UI forms are integrated into the safety-critical system, the Qt Safe Renderer messaging interface defines how non-safe parts of the system can communicate with safety-critical items on runtime. For example, it is possible to change the position of the safe elements. For more information, see Adapting Qt Safe Renderer for Systems, SafeRenderer::QSafeEvent, and QSafeMessageInterface.

UI Design Workflow with Qt Tools

In a high level, the following picture illustrates the UI design workflow with the Qt tools:

Qt Creator provides a cross-platform, complete integrated development environment (IDE) for application developers to create applications for multiple desktop and embedded targets. Qt Creator contains the Qt Quick Designer tool that enables designing and prototyping the UI without writing any code.

The UI designed with Qt Quick Designer can contain both non-safety and safety-critical UI elements. Qt comes with a comprehensive set of ISO standard icons that you can attach to safety-critical UI elements.

Qt Safe Renderer renders the safety-critical UI elements. For rendering, it needs the layout data in a safe, raw bitmap format. Qt Safe Layout Tool generates safe layout data on basis of the UI designed with Qt Quick Designer.

You can deploy your application to the target device directly from Qt Creator. In the target, Qt Safe Renderer takes care of rendering the safety-critical UI elements.

Building for INTEGRITYSafety-Critical UI with Qt Quick Designer

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