imaqGetMeterArc

Usage

MeterArc* imaqGetMeterArc(int lightNeedle, MeterArcMode mode, const ROI* roi, PointFloat base, PointFloat start, PointFloat end);

Purpose

Returns the arc information of a meter. imaqReadMeter() uses this information to read a meter.

Parameters

Name	Type	Description
lightNeedle	int	Set this parameter to TRUE to find a light-colored needle on a dark background. Set this parameter to FALSE to find a dark-colored needle on a light background.
mode	MeterArcMode	Describes how to determine the arc.
roi	const ROI*	A region consisting of two line contours, each drawn from the tip of the needle to its base. The first line contour represents the minimum position of the needle, and the second line contour represents the maximum position of the needle. If mode is IMAQ_METER_ARC_ROI, roi is required and cannot be NULL. If mode is IMAQ_METER_ARC_POINTS, the function ignores roi, and the parameter can be NULL.
base	PointFloat	The location of the base of the needle. If mode is IMAQ_METER_ARC_POINTS, base is required and cannot be NULL. If mode is IMAQ_METER_ARC_ROI, the function ignores base.
start	PointFloat	The location of the tip of the needle when the needle is at the minimum sweep position. If mode is IMAQ_METER_ARC_POINTS, start is required and cannot be NULL. If mode is IMAQ_METER_ARC_ROI, the function ignores start.
end	PointFloat	The location of the tip of the needle when the needle is at the maximum sweep position. If mode is IMAQ_METER_ARC_POINTS, end is required. If mode is IMAQ_METER_ARC_ROI, the function ignores end.

Return Value

Type	Description
MeterArc*	On success, this function returns a structure describing the arc across which a meter sweeps. On failure, this function returns NULL. To get extended error information, call imaqGetLastError(). When you are finished with the return value, dispose of it by calling imaqDispose().