Generates a checksum for a region of pixels.
PixelChecksum ( left, top, right, bottom [, step = 1 [, hwnd [, mode = 0]]] )
|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. It is not recommended to use a step value greater than 1.|
|hwnd||[optional] Window handle to be used. Default is the desktop window.|
|mode||[optional] default 0 ADLER checksum, 1 CRC32 Checksum.|
|Success:||the checksum value of the region.|
A checksum only allows you to see if "something" has changed in a region - it does not tell you exactly what has changed.
CRC32 checksum is a little slower than ADLDER but detects better pixel variation.
PixelCoordMode (Option), PixelGetColor, PixelSearch
#include <MsgBoxConstants.au3> ; Wait until something changes in the region 0,0 to 50,50 ; Get initial checksum Local $iCheckSum = PixelChecksum(0, 0, 50, 50) ; Wait for the region to change, the region is checked every 100ms to reduce CPU load While $iCheckSum = PixelChecksum(0, 0, 50, 50) Sleep(100) WEnd MsgBox($MB_SYSTEMMODAL, "", "Something in the region has changed!")