Copyright © 1998-1999
A Simple Chart (or Single Layer) is represented by a sequence of triplets. A triplet consists of a label (or name), a numerical value and a color code. The label corresponds to 'X' of X-Y graphs. All the X values are assumed to be equidistant. The numerical value correspond to 'Y' of X-Y graphs. The numeric value represents value of attribute represented by label. (The numerical values must be integral; if not, multiply them by suitable scaling factor.)
The set of triplets has a name (title) and represents one chart, a single layer in multilayer charts.
e.g. The quarterly sales of a company could be reprsented as:
Sales for 1998, 1st Qtr,76,1,2nd Qtr,85,1,3rd Qtr, 70,2,4th Qtr,86, 2
Here "Sales for 1998" is name of chart/layer and is followd by '4 points'. The color code could 0-7 (3 bit RGB representation) or 24 bit integers.
A DrillDown Chart is a multilayer chart each layer having above format. The whole set of layers has name representing multilayer chart.
The hierarchical relationship among the layers is determined by the DrillDown Bean using the following algorithm.
The Bean looks for a layer named "DATASET". If not found it rejects entire data. If found, it displays the top layer represented by DATASET. (An API allows to change names). When the user clicks on the chart, the Bean finds out the data element on which click occured, and looks of layer having that name. If found, it displays that layer. If not, the click is ignored. When a layer other than top layer is displayed the Bean listens to Up arrow key press. (You can also add an UP button and click on it). If either Up arrow is clicked or Up button is clicked the parent layer is displayed.