float GetContour (size, x, y, level) CNTPLT.C Level 3
int *size A pointer to the size of the returned x and y vectors.
float **x 
float **y
Pointers to the addresses of the returned x and y vectors. The memory will be allocated by GetContour() and must be freed by the user using gpcfree()
float level The value of the function at the contour level desired.
GetContour() allows you to obtain the x, y coordinate pairs for any single contour in a contour plot. You must make the call to GetContour() before calling any of the contour-plotting functions (e.g., contour(), lconmat(),..). When the contours are being calculated by the contour-plotting routine you call, your x and y arrays will be filled, and their dimension placed into the size variable. The coordinates will be returned in user units. The routine returns 0.0f when called by the user. Other return values are used internally by GraphiC.