AltFrequencies

Purpose

This property array is used to define meaningful frequencies to place point labels and tabled data.

Comments

The Graph Object has a mechanism to produce legible point labels and tabled data when many points are being graphed. This mechanism is implemented with the following properties: AltFrequencies, AltFrequencies, and TargetPointsToTable.

PEP_naALTFREQUENCIES is used to trigger this mechanism.

TargetPointsToTable represents the number of point labels which will be attempted to be displayed.

AltFrequencies holds an array of meaningful frequencies.

*Note: You are not required to define alternate frequencies for this mechanism to function. Only define alternate frequencies if you want the frequency selection process to pick a frequency which seems logical with respect to the type of data being displayed. If no alt frequencies are defined, the Graph Object can pick any frequency which produces a number of point labels closest to TargetPointsToTable.

Example:

You are displaying point information as seconds and have 2400 seconds worth of data. You could define alternate frequencies of 5, 15, 30, 60,and 120, or 5 seconds, 15 seconds, 1/2 minute, 1 minute, and 2 minutes. As the user utilizes the Customization Dialog and changes the PointsToGraph property, the Graph Object would select the closest frequency to the result of dividing PointsToGraph by TargetPointsToTable.

C / C++ Example

OCX Example

VCL Example

See Also: Chapter 7, Question 20.