###Function###
PixelChecksum


###Description###
Generates a checksum for a region of pixels.


###Syntax###
PixelChecksum ( left, top, right, bottom [, step] )


###Parameters###
@@ParamTable@@
left
	left coordinate of rectangle.
top
	top coordinate of rectangle.
right
	right coordinate of rectangle.
bottom
	bottom coordinate of rectangle.
step
	[optional] Instead of checksumming each pixel use a value larger than 1 to skip pixels (for speed).  E.g. A value of 2 will only check every other pixel.  Default is 1.
@@End@@


###ReturnValue###
Returns the checksum value of the region.


###Remarks###
Performing a checksum of a region is time consuming, so use the smallest region you are able to reduce CPU load.  On some machines a checksum of the whole screen could take many seconds!

A checksum only allows you to see if "something" has changed in a region - it does not tell you exactly what has changed.

When using a step value greater than 1 you must bear in mind that the checksumming becomes less reliable for small changes as not every pixel is checked.


###Related###
PixelGetColor, PixelCoordMode (Option), PixelSearch


###Example###
@@IncludeExample@@
