Layouts

Layout Target Resolution

The Player will be running in a layout.  The layout specifies the target screen resolution, for example 1920x1080 for a standard full HD landscape screen or 1080x1920 for portrait.  This target resolution defines the coordinate system for all layers in the layout, with (0,0) being in the upper left corner.  

Ideally, the layout's target resolution should match the actual physical resolution of the playback device and display.  However, there are cases where there is a mismatch and this is handled by automatic scaling in the player and/or in the display.  For example, the layout may specify a target resolution of 1920x1080 but the connected display may be 3840x2160.  In this example, there are two options:

1. The playback device may be set to run in 3840x2160 to match the display, in which case the player will automatically scale to match.
2. The playback device may be set to run in 1920x1080, in which case the display will do the scaling.

In both cases, the coordinate system remains 1920x1080.

Layers

The layout has to contain one or more Layers.  A layer is a rectangle of a certain width, height, and position - all relative to the layout's target resolution. Each layer also has a relative depth in relation to the other layers.  While the layers themselves are "invisible" or "transparent", any content in a layer in front will be appear as overlaying any content in a layer further in the back.  The player supports an alpha channel, meaning that a pixel may have an opacity ranging from 0% to 100%. This allows for semi-transparent content.

Note that two layers cannot be at the same depth.  Of any two layers, one will always be more in front than the other (though, of course, layers don't necessarily overlap).

Each layer will have a playlist connected to it.  The player runs the playlists of all layers simultaneously and independently from each other.  Each playlist has only access to, and only sees its layer.  The layer is the canvas on which the content is played out.

Template Target Resolution

The layer constitutes the coordinate system for the templates playing out within that layer.

For example a layout in 1920x1080 with three layers:

Templates for layer A should be designed for a target resolution of 1600x900.  (The player will scale to fit templates of different resolutions).

Templates for layer B should be designed for a target resolution of 1920x180; the coordinate 0,0 refers to the upper left pixel of layer B.

Template coordinates would not need changing if the position of layers are changed as the coordinates refer to the layer the template sits inside:

Special Layer Types

In addition to normal layers, as described above, the player supports a number of special layer types:

Hidden Layers

Hidden layers behave like normal layers, with one exception; they are never visible on the screen.  Hidden layers can be used for things like audio playback.  For example a playlist of mp3's playing out through an audio template would include a small audio player widget but shouldn't be visible.

Another use case for hidden layers is for background apps; these are "templates" which sit in the background and communicate with an external API.  Based on data fetched, these templates may store data in local storage for pickup by other templates, set triggers, invoke other external APIs etc.

Data Layers

In some advanced use cases the ability to publish and transport data objects from the CMS to the player, where the data is picked up by one or more templates may be needed.  In this case, the "template" used for the data objects will store the data in the local storage, allowing other templates to find it.

Data layers are hidden, just like the hidden layers described above, but in addition, the playlist in a data layer will just run once and not loop.  Only when the playlist is updated from the CMS will be run again.

Disabled Layers

A layer may be disabled, which means that the player will not invoke our play out any of the content and templates in its playlist.