 Component THistograph
=======================

Author: Luis Iglesias <luis.iglesias@vigo.org>

THistograph displays historical graphic.
It's useful for monitoring integer values, such as free disk space, free or used resources, number of users connected, etc.
It maintains the last 300 values and uses the TTimer component to fire the OnTimer and redraw. I'll thank any suggestions about working with Threads with this component.

Properties:
------------
BackgroundColor:	color for the background
GridColor: 		color for the lines of the grid

GraphHighColor: 	color of data lines for higher values
GraphNormalColor: 	color of data lines for medium values
GraphLowColor: 		color of data lines for lower values
Transparent: 		TRUE: data lines transparent the grid
			FALSE: data lines are opaque. 

MaxValue: 		Max value for this graphic
HighValue: 		values >= HighValue are drawed with GraphHighColor
LowValue: 		values <= LowValue are drawed with GraphLowColor
MinValue: 		Min value for this graphic

Value (Integer): 

Interval (in seconds):	the interval for the timer to refresh the graphic

Active: 		TRUE for refresh the graphic
			FALSE for the graphic to be static

HorizLinesInterval: 	interval for horizontal lines

VertLinesInterval: 	interval for vertical lines (in seconds). It must be
			multiple of the value in <Interval>.

Methods:
--------
Clear: clear (reset to MinValue) the values of the graphic.