F_VN_DrawContours

Syntax

Definition:

FUNCTION F_VN_DrawContours : HRESULT
VAR_INPUT
    ipContours    : ITcVnContainer;
    nContourIndex : DINT;
    ipDestImage   : ITcVnImage;
END_VAR
VAR_IN_OUT
    aColor        : TcVnVector4_LREAL;
END_VAR
VAR_INPUT
    nThickness    : DINT;
    hrPrev        : HRESULT;
END_VAR

Inputs

Name	Type	Description
ipContours	ITcVnContainer	Single contour (ContainerType_Vector_TcVnPoint2_DINT) or multiple contours (ContainerType_Vector_Vector_TcVnPoint2_DINT)
nContourIndex	DINT	Index of a specific contour to be drawn (if negative, all contours within the container are drawn)
ipDestImage	ITcVnImage	Destination image
nThickness	DINT	Line thickness (if negative, the contours are filled)
hrPrev	HRESULT	HRESULT indicating the result of previous operations (If SUCCEEDED(hrPrev) equals false, no operation is executed.)

In/Outputs

Name	Type	Description
aColor	TcVnVector4_LREAL	Color

Return value

HRESULT

Further information

The function F_VN_DrawContours draws contours in the destination image. A contour is described based on a set of points that are stored in a container. Please note that only integer contour points can be drawn, so that the container must be of type ContainerType_Vector_TcVnPoint2_DINT. If the points are described using floating point numbers, F_VN_ConvertContainerType can be used to convert the points.

In addition to a container with one contour, a container with several contours can be transferred to the function. This is of type ContainerType_Vector_Vector_TcVnPoint2_DINT. The input variable nContourIndex indicates which contour is to be drawn. If all contours are to be drawn, nContourIndex must be set to a negative value. It is more efficient to draw an entire container of contours at once (set nContourIndex to a negative value) than to draw them one after the other by repeatedly calling the function within a loop.

Expert parameters

The expert version F_VN_DrawContoursExp contains additional parameters.

Application

The painting of all contours in a contour list ipContours with a red line of 5 px in thickness looks like this, for example:

hr := F_VN_DrawContours(
    ipContours      :=  ipContours,
    nContourIndex   :=  -1,
    ipDestImage     :=  ipImageRes,
    aColor          :=  aColorRed,
    nThickness      :=  5,
    hrPrev          :=  hr
);

Typical functions that return contours of type ContainerType_Vector_Vector_TcVnPoint2_DINT

Samples

Blob Detection with watchdog monitoring

Required License

TC3 Vision Base

System Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT V3.1.4024.54 or later	PC or CX (x64) with PL50, e.g. Intel 4-core Atom CPU	Tc3_Vision