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CanvasDrawLine

LabWindows/CVI

CanvasDrawLine

int CanvasDrawLine (int panelHandle, int controlID, Point start, Point end);

Purpose

Draws a line between two specified points.

CanvasDrawLine draws the line using the current value of the following attributes:

ATTR_PEN_COLOR
ATTR_PEN_MODE
ATTR_PEN_WIDTH
ATTR_PEN_STYLE
(ignored when pen width is greater than one)

Supported Controls

You can use CanvasDrawLine with canvas controls.

Parameters

Input
Name Type Description
panelHandle int Specifier for a particular panel that is currently in memory. You can obtain this handle from functions such as LoadPanel and NewPanel.
controlID int The defined constant, located in the .uir header file, that you assigned to the control in the User Interface Editor, or the ID returned by functions such as NewCtrl and DuplicateCtrl.
start Point Point structure specifying the location at which the line begins.

The Point structure is defined as follows:

typedef struct
   {
   int x;
   int y;
   } Point;
You can create a Point without having to declare a variable by using the following function:

Point MakePoint (int x, int y);

Example

CanvasDrawLine (panelHandle, controlID, MakePoint (20, 30), endPoint);

end Point Point structure specifying the location at which the line ends. The Point structure is defined as follows:

typedef struct
   {
   int x;
   int y;
   } Point;
You can create a Point without having to declare a variable by using the following function:

Point MakePoint (int x, int y);

Example

CanvasDrawLine (panelHandle, controlID, startPoint, MakePoint (90, 80));

Return Value

Name Type Description
status int Return value indicating whether the function was successful. A negative number indicates that an error occurred.

Additional Information

Library: User Interface Library

Include file: userint.h

LabWindows/CVI compatibility: LabWindows/CVI 4.0 and later

Example

Refer to userint\canvas.cws for an example of using the CanvasDrawLine function.