The Instrument is a compound object with a hierarchical structure. Any elements can be included in the instrument. The elements can be structurally divided into two groups:
- compound (elements that can include any other elements).
The elements can be functionally divided into:
- visual (are intended for instrument appearance assigning);
- non-visual (intended for elements’ binding and grouping, as well as for assigning instrument functionality).
The elements can be included in the instrument in different combinations. However, for practical use the instruments, specifically intended for displaying and assigning some certain values, are utilized.
Such elements are built according to the following scheme. One or several scales assigning and displaying value range are included in the instrument. Several sliders displaying (assigning) the current value are included. The elements, displaying the value in some other form, for example in the form of text line, can also be included.
For example, to build a simple instrument the following structure is used: