From e7609efa1858251aac075508928668cd74ffe5c4 Mon Sep 17 00:00:00 2001 From: David MacMahon Date: Wed, 13 Jan 2010 00:49:30 -0800 Subject: [PATCH 2/4] Clarified some comments and added a typedef Added a typedef for a pointer to an f2eval-like function. This will simplify parameter declarations for functions that accept pointers to such functions. Clarified (hopefully) the comments of the f2eval* functions. --- include/plplot.h | 38 +++++++++++++++++++++++++++++++------- 1 files changed, 31 insertions(+), 7 deletions(-) diff --git a/include/plplot.h b/include/plplot.h index 5400e42..00af80d 100644 --- a/include/plplot.h +++ b/include/plplot.h @@ -191,9 +191,11 @@ typedef PLUINT PLUNICODE; typedef PLINT PLBOOL; /* For passing user data, as with X's XtPointer */ - typedef void* PLPointer; +/* For passing function pointers to access 2D data */ +typedef PLFLT (* PLF2EVAL)(PLINT, PLINT, PLPointer); + /*--------------------------------------------------------------------------*\ * Complex data types and other good stuff \*--------------------------------------------------------------------------*/ @@ -1839,20 +1841,42 @@ pltr2f( PLFLT x, PLFLT y, PLFLT *tx, PLFLT *ty, void *pltr_data ); /* Function evaluators */ -/* Does a lookup from a 2d function array. Array is of type (PLFLT **), */ -/* and is column dominant (normal C ordering). */ +/* + * Does a lookup from a 2d function array. plf2eval_data is treated as type + * (PLfGrid2 *) and data for (ix,iy) is returned from... + * + * plf2eval_data->f[ix][iy]; + */ PLDLLIMPEXP PLFLT plf2eval2( PLINT ix, PLINT iy, PLPointer plf2eval_data ); -/* Does a lookup from a 2d function array. Array is of type (PLFLT *), */ -/* and is column dominant (normal C ordering). */ +/* + * Does a lookup from a 2d function array. plf2eval_data is treated as type + * (PLfGrid *) and data for (ix,iy) is returned from... + * + * plf2eval_data->f[ix * plf2eval_data->ny + iy]; + * + * This is commonly called "row-major order", but in the context of plotting, + * it might be easier to think of it as "X-major order". In this ordering, + * values for a single X index are stored in consecutive memory locations. + * This is also known as C ordering. + */ PLDLLIMPEXP PLFLT plf2eval( PLINT ix, PLINT iy, PLPointer plf2eval_data ); -/* Does a lookup from a 2d function array. Array is of type (PLFLT *), */ -/* and is row dominant (Fortran ordering). */ +/* + * Does a lookup from a 2d function array. plf2eval_data is treated as type + * (PLfGrid *) and data for (ix,iy) is returned from... + * + * plf2eval_data->f[ix + iy * plf2eval_data->nx]; + * + * This is commonly called "column-major order", but in the context of + * plotting, it might be easier to think of it as "Y-major order". In this + * ordering, values for a single Y index are stored in consecutive memory + * locations. This is also known as FORTRAN ordering. + */ PLDLLIMPEXP PLFLT plf2evalr( PLINT ix, PLINT iy, PLPointer plf2eval_data ); -- 1.6.6