Chapter 21. API compatibility definition

Table of Contents

What is in the API?
Regression test for backwards compatibility

This chapter presents the formal definition of what is considered to be in the PLplot library API. It is assumed that major new releases of PLplot will have substantial backwards incompatible changes in the API, but the PLplot developers commit to introducing as few as possible of such incompatibilities between minor releases such that stability across those minor releases is practically guaranteed. In all cases where backwards incompatible changes have been introduced, then the library soname will be changed (for operating systems such as Linux that support versioned shared libraries).

The information in this chapter regards version 5.10.0 of PLplot, released on 2014-02-12.

What is in the API?

The formal definition of the PLplot C API is everything that is defined in the include file plplot.h. This includes all the function prototypes, the defined structures and the semantics of the constants. The list of symbols currently exported by the shared library libplplot.h that are declared in plplot.h is the following:

plAlloc2dGrid           plgcolbg                plscmap1a
plClearOpts             plgcolbga               plscmap1l
plFindCommand           plgcompression          plscmap1la
plFindName              plgdev                  plscmap1n
plFree2dGrid            plgdidev                plscol0
plGetCursor             plgdiori                plscol0a
plGetFlt                plgdiplt                plscolbg
plGetInt                plgdrawmode             plscolbga
plGetName               plgesc                  plscolor
plMergeOpts             plgfam                  plscompression
plMinMax2dGrid          plgfci                  plsdev
plOptUsage              plgfile                 plsdidev
plResetOpts             plgfnam                 plsdimap
plSetOpt                plgfont                 plsdiori
plSetUsage              plglevel                plsdiplt
plTranslateCursor       plgpage                 plsdiplz
pl_cmd                  plgra                   plsdrawmode
pl_setcontlabelformat   plgradient              plseed
pl_setcontlabelparam    plgriddata              plseopH
pladv                   plgspa                  plsesc
plarc                   plgstrm                 plsetopt
plaxes                  plgver                  plsexit
plbin                   plgvpd                  plsfam
plbop                   plgvpw                  plsfci
plbox                   plgxax                  plsfile
plbox3                  plgyax                  plsfnam
plbtime                 plgzax                  plsfont
plcalc_world            plhist                  plshade
plclear                 plhls                   plshade1
plcol0                  plhlsrgb                plshades
plcol1                  plimage                 plslabelfunc
plcolorbar              plimagefr               plsmaj
plconfigtime            plinit                  plsmem
plcont                  pljoin                  plsmema
plcpstrm                pllab                   plsmin
plctime                 pllegend                plsori
pldid2pc                pllightsource           plspage
pldip2dc                plline                  plspal0
plend                   plline3                 plspal1
plend1                  pllsty                  plspause
plenv                   plmap                   plsstrm
plenv0                  plmapfill               plssub
pleop                   plmapline               plssym
plerrx                  plmapstring             plstar
plerry                  plmaptex                plstart
plf2eval                plmeridians             plstr
plf2eval1               plmesh                  plstransform
plf2eval2               plmeshc                 plstring
plf2evalr               plmkstrm                plstring3
plf2ops_c               plmtex                  plstripa
plf2ops_grid_c          plmtex3                 plstripc
plf2ops_grid_col_major  plot3d                  plstripd
plf2ops_grid_row_major  plot3dc                 plstyl
plfamadv                plot3dcl                plsurf3d
plfcont                 plparseopts             plsurf3dl
plfgriddata             plpat                   plsvect
plfill                  plpath                  plsvpa
plfill3                 plpoin                  plsxax
plfimage                plpoin3                 plsxwin
plfimagefr              plpoly3                 plsyax
plflush                 plprec                  plsym
plfmesh                 plpsty                  plszax
plfmeshc                plptex                  pltext
plfont                  plptex3                 pltimefmt
plfontld                plrandd                 pltr0
plfplot3d               plreplot                pltr1
plfplot3dc              plrgb                   pltr2
plfplot3dcl             plrgb1                  pltr2f
plfshade                plrgbhls                pltr2p
plfshade1               plsButtonEH             plvasp
plfshades               plsError                plvect
plfsurf3d               plsKeyEH                plvpas
plfsurf3dl              plsabort                plvpor
plfvect                 plsbopH                 plvsta
plgDevs                 plschr                  plw3d
plgFileDevs             plscmap0                plwid
plgchr                  plscmap0a               plwidth
plgcmap1_range          plscmap0n               plwind
plgcol0                 plscmap1                plxormod
plgcol0a                plscmap1_range          

Another important aspect of compatibility regard the Application Binary Interface (ABI). Backwards compatibility can be broken by changes in the C structures made public through plplot.h. Currently, they are:

typedef struct
{
    const char *opt;
    int ( *handler )( const char *, const char *, void * );
    void       *client_data;
    void       *var;
    long       mode;
    const char *syntax;
    const char *desc;
} PLOptionTable;

typedef struct
{
    int          type;              // of event (CURRENTLY UNUSED)
    unsigned int state;             // key or button mask
    unsigned int keysym;            // key selected
    unsigned int button;            // mouse button selected
    PLINT        subwindow;         // subwindow (alias subpage, alias subplot) number
    char         string[PL_MAXKEY]; // translated string
    int          pX, pY;            // absolute device coordinates of pointer
    PLFLT        dX, dY;            // relative device coordinates of pointer
    PLFLT        wX, wY;            // world coordinates of pointer
} PLGraphicsIn;

typedef struct
{
    PLFLT dxmi, dxma, dymi, dyma;       // min, max window rel dev coords
    PLFLT wxmi, wxma, wymi, wyma;       // min, max window world coords
} PLWindow;

typedef struct
{
    unsigned int x, y;                  // upper left hand corner
    unsigned int width, height;         // window dimensions
} PLDisplay;

typedef struct
{
    const PLFLT *f;
    PLINT       nx, ny, nz;
} PLfGrid;

typedef struct
{
    PLFLT **f;
    PLINT nx, ny;
} PLfGrid2;

typedef struct
{
    PLFLT *xg, *yg, *zg;
    PLINT nx, ny, nz;
} PLcGrid;

typedef struct
{
    PLFLT **xg, **yg, **zg;
    PLINT nx, ny;
} PLcGrid2;

typedef struct
{
    unsigned char r;            // red
    unsigned char g;            // green
    unsigned char b;            // blue
    PLFLT         a;            // alpha (or transparency)
    const char    *name;
} PLColor;

typedef struct
{
    PLFLT h;                    // hue
    PLFLT l;                    // lightness
    PLFLT s;                    // saturation
    PLFLT p;                    // position
    PLFLT a;                    // alpha (or transparency)
    int   alt_hue_path;         // if set, interpolate through h=0
} PLControlPt;

typedef struct
{
    PLINT cmd;
    PLINT result;
} PLBufferingCB;

typedef struct
{
    PLFLT exp_label_disp;
    PLFLT exp_label_pos;
    PLFLT exp_label_just;
} PLLabelDefaults;

typedef struct
{
    PLFLT ( *get )( PLPointer p, PLINT ix, PLINT iy );
    PLFLT ( *set )( PLPointer p, PLINT ix, PLINT iy, PLFLT z );
    PLFLT ( *add )( PLPointer p, PLINT ix, PLINT iy, PLFLT z );
    PLFLT ( *sub )( PLPointer p, PLINT ix, PLINT iy, PLFLT z );
    PLFLT ( *mul )( PLPointer p, PLINT ix, PLINT iy, PLFLT z );
    PLFLT ( *div )( PLPointer p, PLINT ix, PLINT iy, PLFLT z );
    PLINT ( *is_nan )( PLPointer p, PLINT ix, PLINT iy );
    void ( *minmax )( PLPointer p, PLINT nx, PLINT ny, PLFLT *zmim, PLFLT *zmax );
    //
    // f2eval is backwards compatible signature for "f2eval" functions that
    // existed before plf2ops "operator function families" were used.
    //
    PLFLT ( *f2eval )( PLINT ix, PLINT iy, PLPointer p );
} plf2ops_t;