Dynamic page content

mapp View

Many HMI applications are created so that they work with dynamic content – like modern smartphone user interfaces.

In these cases, pages with different layouts are created and content is dynamically loaded to these pages. These HMI applications make very heavy use of the visible/hidden setting for widgets.

At runtime, these types of HMI applications have a disadvantage – very slow image load times. mapp View is designed/optimized so that many areas on a page are static and unchanged. As a result, switching between mapp View pages on which little has changed takes place relatively quickly.

If a completely new layout is used, however, then a page must be completely redrawn, which takes correspondingly longer on a low-end device. The same applies when controlling the visibility of widgets. The browser has to wait with drawing the widgets until the visibility and therefore the position of all widgets is known. If widgets are changed from hidden to visible in the background, the browser must discard all of its data and begin reevaluating positions. This results in delayed image load times.

All configured widgets on a piece of content are provided with data regardless of their visibility and also saved to memory on the client. Corresponding resources are also needed on the OPC UA server for each active OPC UA variable.

Optimizing dynamic pages

It is generally recommended to use a static layout, i.e. all pages use the same layout.

Action LoadContentInArea can be used to create a dynamic page without overly affecting the screen load time.

With LoadContentInArea, it is possible to subsequently load a piece of content to an area dynamically when needed. If parts of the HMI application are not needed, then no time is wasted to load the image. This also works with content caching, which also further accelerates displaying subsequently loaded content.