Both element position and size are

Both element position and size are expressed in the parent referential taking into account that the parent element width is normalized. For instance, a child element which width, is one quarter of its parent width and which is also right aligned in its parent, will have a 0.25 width, and its x-axis position will be set to 0.75 (that is to say, 1.0-width). Conversely, height is not expressed explicitly but a width/height ratio has to be defined for each element.According to those simple rules, we can easily describefully scalable templates geometry. Furthermore, programmers can easily add new element types with special behavior, like we did for Spot type.Operator Definition In addition to geometry definition, Adaptive Templates contain also operators which can be linked to one or more elements. Those operators are algorithmic processes which take elements as inputs and return output values depending on their inner behavior. Therefore, adding operators to an adaptive template leads to more complex matching and consequently more efficient matching.