pltr2: Linear interpolation for grid to world mapping using doubly dimensioned coord arrays (column dominant, as per normal C 2d arrays)

Linear interpolation for grid to world mapping using doubly dimensioned coord arrays (column dominant, as per normal C 2d arrays). This routine can be used both for plcont and plshade. See also the Section called Contour Plots from C in Chapter 3 and the Section called Shade Plots from C in Chapter 3.

x (PLFLT, input) X-position in grid coordinates. y (PLFLT, input) Y-position in grid coordinates. tx (PLFLT *, output) X-position in world coordinates. ty (PLFLT *, output) Y-position in world coordinates. pltr_data (PLPointer, input) Pointer to additional input data that is passed as an argument to plcont or plshade and then on to the grid to world transformation routine.

This function is currently available in C, C++, Ocaml, Perl, Python and Tcl.

This function is used in example 22.