/* CANVAS PREAMBLES AND POSTAMBLES */

void epswr_aux_write_canvas_header(FILE *psFile);
  /* Writes the preamble for a new canvas of an EPS file.
    May be called only once per EPS file. The preamble includes 
    commands that save the current Postscript state
    (with "save"), and open the "epsf$dict" dictionary. */
    
void epswr_aux_write_canvas_trailer(FILE *psFile);
  /* Writes the postamble for a canvas in an EPS file
    Must be matched to a preceding {epswr_aux_write_canvas_header}.
    The postamble includes commands that close the "epsf$dict"
    dictionary, and restore the Postcript state that was saved when
    the canvas was started. */

/* INTERNAL WINDOW SETUP */

void epswr_save_window_data
  ( epswr_figure_t *epsf,
    double xMin, double xMax,
    double yMin, double yMax,
    double hMin, double hMax,
    double vMin, double vMax
  )
  { /* Save the actual plot window: */
    epsf->hMin = hMin; epsf->hMax = hMax;
    epsf->vMin = vMin; epsf->vMax = vMax;
    /* Save the client scales: */
    epsf->xMin = xMin; epsf->xMax = xMax;
    epsf->yMin = yMin; epsf->yMax = yMax;
    /* Compute client-to-file scales: */
  }


    /* Caption cursor. */
    
    fprintf(wr, 
      "%% Parameters of text area:\n"
      "/dytext 10 pt mul def\n"
      "/xtext hMin def\n"
      "/ytext vMin def\n"
      "\n"
    );

    fprintf(wr, 
      "%% Caption font setup:\n"
      "/captionfont\n"
      "  /Courier findfont\n"
      "  dytext scalefont\n"
      "def\n"
      "\n"
    );


void epswr_def_set_grid(epswr_def_figure_t *epsf, int xn, int yn)
  { /* Save client grid size: */
    epsf->xGridN = xn; 
    epsf->yGridN = yn;
  }

void epswr_set_grid(epswr_figure_t *epsf, int nx, int ny)
  {
    /* Save the grid parameters in the {epswr_figure_t} record: */
    epswr_def_set_grid(epsf, nx, ny);
    
    /* Write the grid setup commands in the Postcript file: */
    FILE *wr = epsf->wr;
    epswr_aux_write_grid_set_cmds(wr, nx, ny);
    fflush(wr);
  }

void epswr_aux_write_grid_set_cmds(FILE *wr, int hGridN, int vGridN)
  { fprintf(wr, "/hGridN %d def     %% grid cells along x axis\n", hGridN);
    fprintf(wr, "/vGridN %d def     %% grid cells along y axis\n", vGridN);

    fprintf(wr, "/dhGrid hMax hMin sub hGridN div def  %% x-size of grid cell\n");
    fprintf(wr, "/dvGrid vMax vMin sub vGridN div def  %% y-size of grid cell\n");

    fflush(wr);
  }

    fprintf(wr, 
      "%% Draw all grid lines:\n"
      "%%  {nh} {nv} gridlines --> \n"
      "/gridlines\n"
      "{ gsave\n"
      "    initclip\n"
      "    dup 0 exch 1 exch \n"   /* --- {nh} {nv} 0 1 {nv} */
      "    {\n"                    /* --- {nh} {nv} {iv} */
      "      exch dup\n"           /* --- {nh} {iv} {nv} {nv} */
      "      3 2 roll\n"           /* --- {nh} {nv} {nv} {iv} */
      "      vMax vMin sub\n"      /* --- {nh} {nv} {nv} {iv} {dv} */
      "      mul div vMin add\n"   /* --- {nh} {nv} {v} */
      "      ygrd\n"               /* --- {nh} {nv} */
      "    } for\n"                /* --- {nh} {nv} */               
      "    pop\n"                  /* --- {nh} */ 
      "\n"
      "    dup 0 exch 1 exch \n"   /* --- {nh} 0 1 {nh} */
      "    {\n"                    /* --- {nh} {ih} */
      "      exch dup\n"           /* --- {ih} {nh} {nh} */
      "      3 2 roll\n"           /* --- {nh} {nh} {ih} */
      "      hMax hMin sub\n"      /* --- {nh} {nh} {ih} {dh} */
      "      mul div hMin add\n"   /* --- {nh} {h} */
      "      xgrd\n"               /* --- {nh} */
      "    } for\n"                /* --- {nh} */               
      "    pop\n"                  /* --- */                       
      "\n"
      "  grestore\n"
      "} bind def\n"
      "\n"
    );

    double pt_per_mm = (72.0/25.4); /* One mm in pt. */
    double hSize = 150.00*pt_per_mm; /* Figure X size excluding margin (pt). */
    double vSize = 150.00*pt_per_mm; /* Figure Y size excluding margin (pt). */
    double mrg = 4.0;  /* Figure margin width (pt). */
    double mrg_bot = mrg + nCap*fontHeight + mrg; /* Bottom margin (pt). */

    /* Add caption only if there is a user caption, or it is not EPS. */
    /* Select a good figure size: */
    epswr_figure_t *eps = epswr_new_named_figure
      ( NULL, prefix, NULL, -1, NULL,
        hSize, vSize, mrg, mrg, mrg_bot, mrg,
        eps_verbose
      );
      
    epswr_set_client_window(eps, xmin,xmax, ymin, ymax);
    
    /* Caption: */
    epswr_set_text_geomptry(eps, FALSE, 0,xSize, mrg-mrg_bot, -mrg, 0.0);
    epswr_set_text_font(eps, "Courier", fontHeight);