Using the display editor

Created by Stefan Rennick Egglestone 2006-02-15
Last updated by Stefan Rennick Egglestone 2006-06-29

Using the display editor
The tutorial


The display editor is an interface to ECT which has been designed to be as simple as possible to use, and which has also been optimised for use through a touchscreen. Figure 1 below shows a screenshot of the display editor.

Figure 1

Each of the icons in figure 1 represents either a source of data or a sink for data. Data sources appear to the left of the green dividing line, and data sinks to the right. In this case, the only data source is an email account, and the only data sink is an LCD screen. Blue links indicate how data should flow between sources and sinks, and in this case a link exists between a source of emails and an LCD screen which can be used to display them.

Note that in some cases, each icon will represent a single ECT component, and a link will represent a connection of one property on a source component to one property of a sink component. However, in other cases, data sources and sinks will be composed of multiple ECT components. In all cases, component have to be instantiated through the graph editor, as the display editor interface has been designed to be as simple as possible, and does not include component instantiation functionality. A detailed tutorial on how to use the graph editor in co-ordination with the display editor is included below.

Also note that, because the component properties to which a link can be connected cannot be defined in the display editor, only those components for which it is unambiguous as to which property should be used in a connection can actually be used in this editor. In practice, there are many ECT component for which this is the case. A list of such components can be found here. Any pair of sources and sinks from this list can be connected in the display editor, but this does not mean that the resultant installation will perform a sensible task. For example, connecting a VideoProcessor component to a StringConcatenation component is probably not a very useful thing to do!

Using the display editor

The rest of this document presents a simple tutorial on how to set up an ECT installation that can be configured using the display editor. The tutorial:

Instructions on how to construct the following types of data source are given in this tutorial:

The tutorial also includes instructions on how to construct the following data sinks:

With this particular set of sources and sinks, the data sources can be thought of as producing messages (eg a new email message, a message indicating the current temperature in a room) and the data sinks can be thought of as displays for these messages (eg the phidget lcd screen can be used to display a new email, or the email can be "displayed" by publishing it on a web-page or an RSS feed)

The tutorial

(Please note that this tutorial assumes familiarity with the graph editor and its use in requesting instances of components and adding connections between component properties. Remember that each of the components below will have documentation that is viewable in the graph editor (or on this website - eg see the alphabetical components list) which you should consult if you do not know how to use a component.)

Getting started

Creating an email data source

Creating an SMS data source

Creating an RSS data source

Creating an environmental information data source

Creating a PhidgetLCD data sink

Creating a web-publisher data sink

Making data sources and sinks available in the display editor

Starting up the display editor

Figure x - most recent email displayed on LCD screen, and all received emails exported by web-publisher

Figure x - temperature information displayed on nearby LCD screen, and published to the web

Figure 3 - items from BBC RSS feed displayed onto Phidget LCD screen