MgraArc

This function draws an arc destructively (raster-based) in the specified image. Alternatively, this function can add a vector-based version of an arc to the specified graphics list, allowing you to, for example, non-destructively annotate a display without pixelation effects upon scaling.

The arc is based on an ellipse centered at XCenter and YCenter, with radii XRad and YRad. The arc is the part of the ellipse between the start angle (StartAngle) and the end angle (EndAngle), both measured with respect to the X-axis. The arc inherits all the relevant settings of the specified graphics context, such as the foreground color (MgraControl() with M_COLOR). If part of the arc falls outside of the specified area (image or display), that part is clipped off. The following image shows how the parameters are used to define an arc:

An arc's center position, radii, and angle values are interpreted with respect to the input coordinate system, specified using MgraControl() or MgraControlList() with M_INPUT_UNITS. An angle interpreted with respect to the pixel coordinate system is always measured counter-clockwise. For information on the angle's direction of rotation when interpreting the angle with respect to the relative coordinate system, see the Angle convention in MIL subsection of the Working with real-world units section of Chapter 25: Calibrating your camera setup. Note that if you set your input coordinate system to M_WORLD and you pass MgraArc() an uncalibrated image or the drawing target of the graphics list is uncalibrated, the function will generate an error.

To modify or inquire graphics context settings, use MgraControl() or MgraInquire(). To modify or inquire graphics list settings, use MgraControlList() or MgraInquireList().

To create a filled arc, use MgraArcFill(). To create an arc that can be optionally filled and rotated, use MgraArcAngle().

Unlike most other functions that modify a MIL object, you can call this function concurrently from multiple threads on the same MIL graphics list (DstImageBufOrListGraId) without using an M_MUTEX object, as long as all the other parameters of the concurrent calls do not also share data.