Presentation engines
Presentation engines provide runtime display and session management for HMI
applications, supporting both native and web-based user interfaces.
Overview
Presentation engines display UI elements at runtime and manage user sessions. There
are two types: native and web.
- Native presentation engine
- Use for HMI applications with an operator panel. Only one native engine per project. Sessions are interactive and can change based on user and logic.
- Web presentation engine
- Use for web access to HMI applications. Only one web engine per project. Supports multiple users, automation IDs for testing, and Progressive Web Apps (workstation clients).
For details, see Native presentation engine and Web presentation engine.
SVGs in presentation engines
To use an SVG image that displays consistently between the web and native
presentation engines, define a height and width attribute for the SVG element within
the image file.
For
example:
<svg xmlns:xlink="http://www.w3.org/1999/xlink" height="100" width="100" xmlns="http://www.w3.org/2000/svg"> <rect width="100" height="100" style="fill:rgb(0,0,255)"/> </svg>
Session in presentation engines
Both the web presentation engine and native presentation engine expose a session type
pointer. To read or change session nodes, use the
{Session}
alias instead. For more information, see Built-in aliases.SVG
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