prj/tech/libsrc/g2/g2ring.c

   1 /*
   2  * $Source: x:/prj/tech/libsrc/g2/RCS/g2ring.c $
   3  * $Revision: 1.2 $
   4  * $Author: buzzard $
   5  * $Date: 1997/10/31 17:49:41 $
   6  */
   7
   8 #include <dev2d.h>
   9 #include <buffer.h>
  10 #include <rastel.h>
  11
  12 bool gd_secret_hack_nest_rings;
  13
  14 int g2_ring (fix x0, fix y0, fix co, fix ci)
  15 {
  16    grs_raster *r0, *r, *r0i, *ri;
  17    int y, y_max;
  18    int y_in_min, y_in_max;
  19    fix a_o, b_o, a_i, b_i;
  20    gdulin_func *uhline_func;
  21
  22    if (co < ci) {
  23       fix foo=co;
  24       co=ci;
  25       ci=foo;
  26    }
  27
  28    a_o = co*grd_bm.w;
  29    a_i = ci*grd_bm.w;
  30    b_o = fix_div(a_o, grd_cap->aspect);
  31    b_i = fix_div(a_i, grd_cap->aspect);
  32
  33    r0 = gr_rasterize_fix_elipse(x0, y0, a_o, b_o);
  34    if (r0==NULL)
  35       return CLIP_ALL;
  36    uhline_func=gd_uhline_expose(0,0,0);
  37    y = r0->top;
  38    y_max = r0->bot;
  39    r = r0+1;
  40    r0i = gr_rasterize_fix_elipse(x0, y0, a_i, b_i);
  41    if (r0i!=NULL) {
  42       y_in_min = r0i->top;
  43       y_in_max = r0i->bot;
  44       ri = r0i+1;
  45       while (y < y_in_min) {
  46          gd_hline_opt(r->left, y, r->right, uhline_func);
  47          y++;
  48          r++;
  49       }
  50       if (gd_secret_hack_nest_rings) {
  51          while (y < y_in_max) {
  52             gd_hline_opt(r->left, y, ri->left-1, uhline_func);
  53             gd_hline_opt(ri->right+1, y, r->right, uhline_func);
  54             ++y;
  55             ++r;
  56             ++ri;
  57          }
  58       } else {
  59          // make sure we don't have any dropouts/gaps in the ring,
  60          // since while that might be "correct" it will show our
  61          // horizontal scan bias
  62
  63          int xl,xll,xln,xli;
  64          int xr,xrl,xrn,xri;
  65          xl=r->left;
  66          xr=r->right;
  67          if (r==r0+1) {
  68             xll=xr+1;
  69             xrl=xl-1;
  70          } else {
  71             xll=(r-1)->left;
  72             xrl=(r-1)->right;
  73          }
  74          if (y_in_max == y_max)
  75             y_in_max--;
  76          while (y < y_in_max) {
  77             xln = (r+1)->left;
  78             xrn = (r+1)->right;
  79             xli = ri->left;
  80             xri = ri->right;
  81             if (xli < xln)
  82                xli = xln-1;
  83             if (xli < xll)
  84                xli = xll-1;
  85             if (xri > xrn)
  86                xri = xrn+1;
  87             if (xri > xrl)
  88                xri = xrl+1;
  89             if (xri <= xli) {
  90                gd_hline_opt(r->left, y, r->right, uhline_func);
  91             } else {
  92                gd_hline_opt(r->left, y, xli, uhline_func);
  93                gd_hline_opt(xri, y, r->right, uhline_func);
  94             }
  95             xll = xl;
  96             xrl = xr;
  97             xl = xln;
  98             xr = xrn;
  99             y++;
 100             r++;
 101             ri++;
 102          }
 103       }
 104       gr_free_temp(r0i);
 105    }
 106    while (y < y_max) {
 107       gd_hline_opt(r->left, y, r->right, uhline_func);
 108       y++;
 109       r++;
 110    }
 111    gr_free_temp(r0);
 112    return CLIP_NONE;
 113 }
 114