avoid a possible sign-extension for offsets/sizes in SGI

[imager.git] / polygon.c

diff --git a/polygon.c b/polygon.c
index da5d7beb1c8aa2f39fe1049e6e9bc5c111769c19..24b47e58d45b961c22dd41b268eaf7cc29af7b41 100644 (file)
--- a/polygon.c
+++ b/polygon.c
@@ -1,58 +1,50 @@
+#define IMAGER_NO_CONTEXT

 #include "imager.h"
 #include "draw.h"
 #include "log.h"
 #include "imrender.h"
 #include "imager.h"
 #include "draw.h"
 #include "log.h"
 #include "imrender.h"

+#include "imageri.h"

 
 #define IMTRUNC(x) ((int)((x)*16))
 
 #define coarse(x) ((x)/16)
 #define fine(x)   ((x)%16)
 
 
 #define IMTRUNC(x) ((int)((x)*16))
 
 #define coarse(x) ((x)/16)
 #define fine(x)   ((x)%16)
 

+/*#define DEBUG_POLY*/
+#ifdef DEBUG_POLY
+#define POLY_DEB(x) x
+#else

 #define POLY_DEB(x)
 #define POLY_DEB(x)

+#endif

 
 
 
 

-
-typedef int pcord;
+typedef i_img_dim pcord;

 
 typedef struct {
 
 typedef struct {

-  int n;
+  size_t n;

   pcord x,y;
 } p_point;
 
 typedef struct {
   pcord x,y;
 } p_point;
 
 typedef struct {

-  int n;
+  size_t n;

   pcord x1,y1;
   pcord x2,y2;
   pcord miny,maxy;
   pcord minx,maxx;
   int updown; /* -1 means down, 0 vertical, 1 up */
   pcord x1,y1;
   pcord x2,y2;
   pcord miny,maxy;
   pcord minx,maxx;
   int updown; /* -1 means down, 0 vertical, 1 up */

+  int dir; /* 1 for down, -1 for up */

 } p_line;
 
 typedef struct {
 } p_line;
 
 typedef struct {

-  int n;
+  size_t n;

   double x;
 } p_slice;
 
   double x;
 } p_slice;
 

-typedef struct {
-  int start;
-  int stop;
-} ss_pair;
-

 typedef struct {
   int *line;           /* temporary buffer for scanline */
 typedef struct {
   int *line;           /* temporary buffer for scanline */

-  int linelen;         /* length of scanline */
-  ss_pair *ss_list;    /* list of start stop linepairs */
-  int ssnext;          /* index of the next pair to use */
-  int sslen;           /* maximum number of start stop pairs */
+  i_img_dim linelen;   /* length of scanline */

 } ss_scanline;
 
 } ss_scanline;
 

-
-
-
-
-
-
-

 static
 int
 p_compy(const p_point *p1, const p_point *p2) {
 static
 int
 p_compy(const p_point *p1, const p_point *p2) {


@@ -91,61 +83,83 @@ p_eval_atx(p_line *l, pcord x) {
 
 static
 p_line *
 
 static
 p_line *

-line_set_new(const double *x, const double *y, int l) {
-  int i;
-  p_line *lset = mymalloc(sizeof(p_line) * l);
-
-  for(i=0; i<l; i++) {
-    lset[i].n=i;
-    lset[i].x1 = IMTRUNC(x[i]);
-    lset[i].y1 = IMTRUNC(y[i]);
-    lset[i].x2 = IMTRUNC(x[(i+1)%l]);
-    lset[i].y2 = IMTRUNC(y[(i+1)%l]);
-    lset[i].miny=i_min(lset[i].y1,lset[i].y2);
-    lset[i].maxy=i_max(lset[i].y1,lset[i].y2);
-    lset[i].minx=i_min(lset[i].x1,lset[i].x2);
-    lset[i].maxx=i_max(lset[i].x1,lset[i].x2);
+line_set_new(const i_polygon_t *polys, size_t count, size_t *line_count) {
+  size_t i, j, n;
+  p_line *lset, *line;
+  size_t lines = 0;
+  
+  for (i = 0; i < count; ++i)
+    lines += polys[i].count;
+
+  line = lset = mymalloc(sizeof(p_line) * lines);
+
+  n = 0;
+  for (i = 0; i < count; ++i) {
+    const i_polygon_t *p = polys + i;
+
+    for(j = 0; j < p->count; j++) {
+      line->x1 = IMTRUNC(p->x[j]);
+      line->y1 = IMTRUNC(p->y[j]);
+      line->x2 = IMTRUNC(p->x[(j + 1) % p->count]);
+      line->y2 = IMTRUNC(p->y[(j + 1) % p->count]);
+
+      /* don't include purely horizontal lines, we don't usefully
+        intersect with them. */
+      if (line->y1 == line->y2)
+       continue;
+
+      line->miny = i_min(line->y1, line->y2);
+      line->maxy = i_max(line->y1, line->y2);
+      line->minx = i_min(line->x1, line->x2);
+      line->maxx = i_max(line->x1, line->x2);
+      line->n = n++;
+      ++line;
+    }

   }
   }

+  *line_count = n;
+

   return lset;
 }
 
 static
 p_point *
   return lset;
 }
 
 static
 p_point *

-point_set_new(const double *x, const double *y, int l) {
-  int i;
-  p_point *pset = mymalloc(sizeof(p_point) * l);
+point_set_new(const i_polygon_t *polys, size_t count, size_t *point_count) {
+  size_t i, j, n;
+  p_point *pset, *pt;
+  size_t points = 0;

   
   

-  for(i=0; i<l; i++) {
-    pset[i].n=i;
-    pset[i].x=IMTRUNC(x[i]);
-    pset[i].y=IMTRUNC(y[i]);
+  for (i = 0; i < count; ++i)
+    points += polys[i].count;
+
+  *point_count = points;
+
+  pt = pset = mymalloc(sizeof(p_point) * points);
+
+  n = 0;
+  for (i = 0; i < count; ++i) {
+    const i_polygon_t *p = polys + i;
+
+    for(j = 0; j < p->count; j++) {
+      pt->n = n++;
+      pt->x = IMTRUNC(p->x[j]);
+      pt->y = IMTRUNC(p->y[j]);
+      ++pt;
+    }

   }
   return pset;
 }
 
   }
   return pset;
 }
 

-#if 0
-static
-void
-p_line_dump(p_line *l) {
-  printf("%d (%d,%d)->(%d,%d) [%d-%d,%d-%d]\n", l->n, l->x1, l->y1, l->x2, l->y2, 
-        l->minx, l->maxx, l->miny, l->maxy);
-}
-#endif
-

 static
 void
 ss_scanline_reset(ss_scanline *ss) {
 static
 void
 ss_scanline_reset(ss_scanline *ss) {

-  ss->ssnext = 0;

   memset(ss->line, 0, sizeof(int) * ss->linelen);
 }
 
 static
 void
   memset(ss->line, 0, sizeof(int) * ss->linelen);
 }
 
 static
 void

-ss_scanline_init(ss_scanline *ss, int linelen, int linepairs) {
+ss_scanline_init(ss_scanline *ss, i_img_dim linelen, int linepairs) {

   ss->line    = mymalloc( sizeof(int) * linelen );
   ss->linelen = linelen;
   ss->line    = mymalloc( sizeof(int) * linelen );
   ss->linelen = linelen;

-  ss->ss_list = mymalloc( sizeof(ss_pair) * linepairs );
-  ss->sslen   = linepairs;

   ss_scanline_reset(ss);
 }
 
   ss_scanline_reset(ss);
 }
 


@@ -153,7 +167,6 @@ static
 void
 ss_scanline_exorcise(ss_scanline *ss) {
   myfree(ss->line);
 void
 ss_scanline_exorcise(ss_scanline *ss) {
   myfree(ss->line);

-  myfree(ss->ss_list);

 }
   
                     
 }
   
                     


@@ -180,40 +193,18 @@ lines_in_interval(p_line *lset, int l, p_slice *tllist, pcord minc, pcord maxc)
   return count;
 }
 
   return count;
 }
 

-#if 0
-static
-int
-lines_in_interval_old(p_line *lset, int l, p_slice *tllist, pcord cc) {
-  int k;
-  int count = 0;
-  for(k=0; k<l; k++) {
-    if (cc >= lset[k].miny && cc <=  lset[k].maxy) {
-      if (lset[k].miny == lset[k].maxy) {
-       POLY_DEB( printf(" HORIZONTAL - skipped\n") );
-      }
-      else {
-       tllist[count].x=p_eval_aty(&lset[k],cc);
-       tllist[count].n=k;
-       count++;
-      }
-    }
-  }
-  return count;
-}
-#endif
-

 /* marks the up variable for all lines in a slice */
 
 static
 void
 /* marks the up variable for all lines in a slice */
 
 static
 void

-mark_updown_slices(p_line *lset, p_slice *tllist, int count) {
+mark_updown_slices(pIMCTX, p_line *lset, p_slice *tllist, int count) {

   p_line *l, *r;
   int k;
   for(k=0; k<count; k+=2) {
     l = lset + tllist[k].n;
 
     if (l->y1 == l->y2) {
   p_line *l, *r;
   int k;
   for(k=0; k<count; k+=2) {
     l = lset + tllist[k].n;
 
     if (l->y1 == l->y2) {

-      mm_log((1, "mark_updown_slices: horizontal line being marked: internal error!\n"));
+      im_log((aIMCTX,1, "mark_updown_slices: horizontal line being marked: internal error!\n"));

       exit(3);
     }
 
       exit(3);
     }
 


@@ -224,19 +215,20 @@ mark_updown_slices(p_line *lset, p_slice *tllist, int count) {
       (l->y1 > l->y2) ? -1 : 1
       : 
       (l->y1 > l->y2) ? 1 : -1;
       (l->y1 > l->y2) ? -1 : 1
       : 
       (l->y1 > l->y2) ? 1 : -1;

+    l->dir = l->y1 < l->y2 ? 1 : -1;

 
     POLY_DEB( printf("marking left line %d as %s(%d)\n", l->n,
                     l->updown ?  l->updown == 1 ? "up" : "down" : "vert", l->updown, l->updown)
              );
 
     if (k+1 >= count) {
 
     POLY_DEB( printf("marking left line %d as %s(%d)\n", l->n,
                     l->updown ?  l->updown == 1 ? "up" : "down" : "vert", l->updown, l->updown)
              );
 
     if (k+1 >= count) {

-      mm_log((1, "Invalid polygon spec, odd number of line crossings.\n"));
+      im_log((aIMCTX, 1, "Invalid polygon spec, odd number of line crossings.\n"));

       return;
     }
 
     r = lset + tllist[k+1].n;
     if (r->y1 == r->y2) {
       return;
     }
 
     r = lset + tllist[k+1].n;
     if (r->y1 == r->y2) {

-      mm_log((1, "mark_updown_slices: horizontal line being marked: internal error!\n"));
+      im_log((aIMCTX, 1, "mark_updown_slices: horizontal line being marked: internal error!\n"));

       exit(3);
     }
 
       exit(3);
     }
 


@@ -247,6 +239,7 @@ mark_updown_slices(p_line *lset, p_slice *tllist, int count) {
       (r->y1 > r->y2) ? -1 : 1
       : 
       (r->y1 > r->y2) ? 1 : -1;
       (r->y1 > r->y2) ? -1 : 1
       : 
       (r->y1 > r->y2) ? 1 : -1;

+    r->dir = r->y1 < r->y2 ? 1 : -1;

     
     POLY_DEB( printf("marking right line %d as %s(%d)\n", r->n,
                     r->updown ?  r->updown == 1 ? "up" : "down" : "vert", r->updown, r->updown)
     
     POLY_DEB( printf("marking right line %d as %s(%d)\n", r->n,
                     r->updown ?  r->updown == 1 ? "up" : "down" : "vert", r->updown, r->updown)


@@ -254,8 +247,6 @@ mark_updown_slices(p_line *lset, p_slice *tllist, int count) {
   }
 }
 
   }
 }
 

-
-

 static
 unsigned char
 saturate(int in) {
 static
 unsigned char
 saturate(int in) {


@@ -264,15 +255,16 @@ saturate(int in) {
   return 0;
 }
 
   return 0;
 }
 

-typedef void (*scanline_flusher)(i_img *im, ss_scanline *ss, int y, const void *ctx);
+typedef void (*scanline_flusher)(i_img *im, ss_scanline *ss, int y, void *ctx);

 
 /* This function must be modified later to do proper blending */
 
 static void
 
 /* This function must be modified later to do proper blending */
 
 static void

-scanline_flush(i_img *im, ss_scanline *ss, int y, const void *ctx) {
+scanline_flush(i_img *im, ss_scanline *ss, int y, void *ctx) {

   int x, ch, tv;
   i_color t;
   i_color *val = (i_color *)ctx;
   int x, ch, tv;
   i_color t;
   i_color *val = (i_color *)ctx;

+  POLY_DEB( printf("Flushing line %d\n", y) );

   for(x=0; x<im->xsize; x++) {
     tv = saturate(ss->line[x]);
     i_gpix(im, x, y, &t);
   for(x=0; x<im->xsize; x++) {
     tv = saturate(ss->line[x]);
     i_gpix(im, x, y, &t);


@@ -305,6 +297,12 @@ pixel_coverage(p_line *line, pcord minx, pcord maxx, pcord  miny, pcord maxy) {
   double lycross, rycross;
   int l, r;
 
   double lycross, rycross;
   int l, r;
 

+  POLY_DEB
+    (
+     printf("    pixel_coverage(..., minx %g, maxx%g, miny %g, maxy %g)\n", 
+           minx/16.0, maxx/16.0, miny/16.0, maxy/16.0)
+     );
+

   if (!line->updown) {
     l = r = 0;
   } else {
   if (!line->updown) {
     l = r = 0;
   } else {


@@ -314,9 +312,9 @@ pixel_coverage(p_line *line, pcord minx, pcord maxx, pcord  miny, pcord maxy) {
     r = rycross <= maxy && rycross >= miny; /* true if it enters through left side */
   }
   POLY_DEB(
     r = rycross <= maxy && rycross >= miny; /* true if it enters through left side */
   }
   POLY_DEB(

-          printf("%4s(%+d): ", line->updown ?  line->updown == 1 ? "up" : "down" : "vert", line->updown);
-          printf("(%2d,%2d) [%3d-%3d, %3d-%3d] lycross=%.2f rycross=%.2f", coarse(minx), coarse(miny), minx, maxx, miny, maxy, lycross, rycross);
-          printf("    l=%d r=%d\n", l, r)
+          printf("    %4s(%+d): ", line->updown ?  line->updown == 1 ? "up" : "down" : "vert", line->updown);
+          printf(" (%2d,%2d) [%3d-%3d, %3d-%3d] lycross=%.2f rycross=%.2f", coarse(minx), coarse(miny), minx, maxx, miny, maxy, lycross, rycross);
+          printf(" l=%d r=%d\n", l, r)

           );
   
   if (l && r) 
           );
   
   if (l && r) 


@@ -340,6 +338,7 @@ pixel_coverage(p_line *line, pcord minx, pcord maxx, pcord  miny, pcord maxy) {
     return r;
   }
 
     return r;
   }
 

+  /* NOTREACHED */

   return 0; /* silence compiler warning */
 }
 
   return 0; /* silence compiler warning */
 }
 


@@ -358,34 +357,39 @@ pixel_coverage(p_line *line, pcord minx, pcord maxx, pcord  miny, pcord maxy) {
 
 static
 void
 
 static
 void

-render_slice_scanline(ss_scanline *ss, int y, p_line *l, p_line *r) {
+render_slice_scanline(ss_scanline *ss, int y, p_line *l, p_line *r, pcord miny, pcord maxy) {

   
   

-  pcord miny, maxy;    /* y bounds in fine coordinates */

   pcord lminx, lmaxx;  /* left line min/max within y bounds in fine coords */
   pcord rminx, rmaxx;  /* right line min/max within y bounds in fine coords */
   pcord lminx, lmaxx;  /* left line min/max within y bounds in fine coords */
   pcord rminx, rmaxx;  /* right line min/max within y bounds in fine coords */

-  int cpix;            /* x-coordinate of current pixel */
-  int thin;            /* boolean for thin/thick segment */
-  int startpix;                /* temporary variable for "start of this interval" */
-  int stoppix;         /* temporary variable for "end of this interval" */
+  i_img_dim cpix;      /* x-coordinate of current pixel */
+  i_img_dim startpix;  /* temporary variable for "start of this interval" */
+  i_img_dim stoppix;   /* temporary variable for "end of this interval" */

 
   /* Find the y bounds of scanline_slice */
 
 
   /* Find the y bounds of scanline_slice */
 

-  maxy = i_min( l->maxy, r->maxy );
-  miny = i_max( l->miny, r->miny );
-
-  maxy = i_min( maxy, (y+1)*16 );
-  miny = i_max( miny,  y*16 );
-
+  POLY_DEB
+    (
+     printf("render_slice_scanline(..., y=%d)\n");
+     printf("  left  n=%d p1(%.2g, %.2g) p2(%.2g,%.2g) min(%.2g, %.2g) max(%.2g,%.2g) updown(%d)\n",
+           l->n, l->x1/16.0, l->y1/16.0, l->x2/16.0, l->y2/16.0, 
+           l->minx/16.0, l->miny/16.0, l->maxx/16.0, l->maxy/16.0,
+           l->updown);
+     printf("  right n=%d p1(%.2g, %.2g) p2(%.2g,%.2g) min(%.2g, %.2g) max(%.2g,%.2g) updown(%d)\n",
+           r->n, r->x1/16.0, r->y1/16.0, r->x2/16.0, r->y2/16.0, 
+           r->minx/16.0, r->miny/16.0, r->maxx/16.0, r->maxy/16.0,
+           r->updown);
+     );
+  

   lminx = i_min( p_eval_aty(l, maxy), p_eval_aty(l, miny) );
   lmaxx = i_max( p_eval_aty(l, maxy), p_eval_aty(l, miny) );
 
   rminx = i_min( p_eval_aty(r, maxy), p_eval_aty(r, miny) );
   rmaxx = i_max( p_eval_aty(r, maxy), p_eval_aty(r, miny) );
 
   lminx = i_min( p_eval_aty(l, maxy), p_eval_aty(l, miny) );
   lmaxx = i_max( p_eval_aty(l, maxy), p_eval_aty(l, miny) );
 
   rminx = i_min( p_eval_aty(r, maxy), p_eval_aty(r, miny) );
   rmaxx = i_max( p_eval_aty(r, maxy), p_eval_aty(r, miny) );
 

-  thin = coarse(lmaxx) >= coarse(rminx);
-

   startpix = i_max( coarse(lminx), 0 );
   stoppix  = i_min( coarse(rmaxx-1), ss->linelen-1 );
   startpix = i_max( coarse(lminx), 0 );
   stoppix  = i_min( coarse(rmaxx-1), ss->linelen-1 );

+
+  POLY_DEB(  printf("  miny=%g maxy=%g\n", miny/16.0, maxy/16.0)  );

   
   for(cpix=startpix; cpix<=stoppix; cpix++) {
     int lt = coarse(lmaxx-1) >= cpix;
   
   for(cpix=startpix; cpix<=stoppix; cpix++) {
     int lt = coarse(lmaxx-1) >= cpix;


@@ -393,112 +397,19 @@ render_slice_scanline(ss_scanline *ss, int y, p_line *l, p_line *r) {
     
     int A, B, C;
     
     
     int A, B, C;
     

-    POLY_DEB( printf("(%d,%d) lt=%d rt=%d\n", cpix, y, lt, rt) );
+    POLY_DEB( printf("  (%d,%d) lt=%d rt=%d\n", cpix, y, lt, rt) );

 
     A = lt ? pixel_coverage(l, cpix*16, cpix*16+16, miny, maxy) : 0;
     B = lt ? 0 : 16*(maxy-miny);
     C = rt ? pixel_coverage(r, cpix*16, cpix*16+16, miny, maxy) : 0;
 
 
     A = lt ? pixel_coverage(l, cpix*16, cpix*16+16, miny, maxy) : 0;
     B = lt ? 0 : 16*(maxy-miny);
     C = rt ? pixel_coverage(r, cpix*16, cpix*16+16, miny, maxy) : 0;
 

-    POLY_DEB( printf("A=%d B=%d C=%d\n", A, B, C) );
+    POLY_DEB( printf("  A=%d B=%d C=%d\n", A, B, C) );

 
     ss->line[cpix] += A+B-C;
 
   }
 
     ss->line[cpix] += A+B-C;
 
   }

-  
-}
-
-
-#if 0
-static
-void
-render_slice_scanline_old(ss_scanline *ss, int y, p_line *l, p_line *r) {
-  
-  pcord miny, maxy;    /* y bounds in fine coordinates */
-  pcord lminx, lmaxx;  /* left line min/max within y bounds in fine coords */
-  pcord rminx, rmaxx;  /* right line min/max within y bounds in fine coords */
-  int cpix;            /* x-coordinate of current pixel */
-  int thin;            /* boolean for thin/thick segment */
-  int startpix;                /* temporary variable for "start of this interval" */
-  int stoppix;         /* temporary variable for "end of this interval" */
-
-  /* Find the y bounds of scanline_slice */
-
-  maxy = i_min( l->maxy, r->maxy );
-  miny = i_max( l->miny, r->miny );
-
-  maxy = i_min( maxy, (y+1)*16 );
-  miny = i_max( miny,  y*16 );
-
-  lminx = i_min( p_eval_aty(l, maxy), p_eval_aty(l, miny) );
-  lmaxx = i_max( p_eval_aty(l, maxy), p_eval_aty(l, miny) );
-
-  rminx = i_min( p_eval_aty(r, maxy), p_eval_aty(r, miny) );
-  rmaxx = i_max( p_eval_aty(r, maxy), p_eval_aty(r, miny) );
-
-  thin = coarse(lmaxx) >= coarse(rminx);
-
-
-  /* First step */
-  startpix = coarse(lminx);                            /* includes tricky starting pixel */
-  stoppix  = i_min(coarse(lmaxx), coarse(rminx) );     /* last pixel is tricky */
-  
-  /* handle start pixel */
-
-  cpix = startpix;
-  if (cpix < stoppix) {
-    ss->line[cpix] += pixel_coverage(l, cpix*16, cpix*16+16, miny, maxy);
-    printf("%2d: step1 - start pixel\n", cpix);
-  }
-  
-  for(cpix=startpix+1; cpix<stoppix; cpix++) {
-    printf("%2d: step1 pixel\n", cpix);
-    ss->line[cpix] += l->updown == 1 ? 
-      8.0 * (2*maxy-p_eval_atx(l, 16*cpix)-p_eval_atx(l, 16*cpix+16))  /* up case */
-      :
-      8.0 * (p_eval_atx(l, 16*cpix)+p_eval_atx(l, 16*cpix+16)-2*miny); /* down case */
-  }
-  
-  
-  /* handle stop pixel */
-
-  if (thin) { /* step 2a */
-    startpix = coarse(rminx);
-    stoppix = coarse(lmaxx+15); /* one more than needed */
-    
-    for(cpix=startpix; cpix<stoppix; cpix++) {
-      printf("%2d: step2a pixel\n", cpix);
-      ss->line[cpix] += 
-       pixel_coverage(l, cpix*16, cpix*16+16, miny, maxy)
-       +(cpix*16+16-i_min(cpix*16+16, l->maxx))*(maxy-miny)
-       -pixel_coverage(r, cpix*16, cpix*16+16, miny, maxy);
-    }
-  } else { /* step 2b */
-    stoppix = coarse(rminx);
-    for(/* cpix already correct */; cpix<stoppix; cpix++) {
-      printf("%2d: step2b pixel\n", cpix);
-      ss->line[cpix] += 16.0*(maxy-miny);
-    }
-  }
-  
-  /* step 3 */
-
-  cpix = i_max(coarse(rminx), coarse(lmaxx+15));
-  stoppix = coarse(rmaxx-15);
-  
-  printf("step3 from %d to %d\n", cpix, stoppix);
-
-  for(; cpix<stoppix; cpix++) {
-    printf("%2d: step3 pixel\n", cpix);
-    ss->line[cpix] += 0+ 
-      (l->updown == 1 ?
-       8.0 * (2*maxy-p_eval_atx(r, 16*cpix)-p_eval_atx(r, 16*cpix+16))  /* up case */
-       :
-       8.0 * (p_eval_atx(r, 16*cpix)+p_eval_atx(r, 16*cpix+16)-2*miny));  /* down case */
-  }
-  
-  ss->line[cpix] += (16.0)*(maxy-miny) - pixel_coverage(r, cpix*16, cpix*16+16, miny, maxy);
+  POLY_DEB( printf("end render_slice_scanline()\n") );

 }
 }

-#endif

 
 /* Antialiasing polygon algorithm 
    specs:
 
 /* Antialiasing polygon algorithm 
    specs:


@@ -530,23 +441,45 @@ render_slice_scanline_old(ss_scanline *ss, int y, p_line *l, p_line *r) {
  */
 
 
  */
 
 

-static void
-i_poly_aa_low(i_img *im, int l, const double *x, const double *y, void const *ctx, scanline_flusher flusher) {
+static int
+i_poly_poly_aa_low(i_img *im, int count, const i_polygon_t *polys,
+                  i_poly_fill_mode_t mode, void *ctx,
+                  scanline_flusher flusher) {

   int i ,k;                    /* Index variables */
   int i ,k;                    /* Index variables */

-  int clc;                     /* Lines inside current interval */
+  i_img_dim clc;               /* Lines inside current interval */

   /* initialize to avoid compiler warnings */
   pcord tempy = 0;
   /* initialize to avoid compiler warnings */
   pcord tempy = 0;

-  int cscl = 0;                        /* Current scanline */
+  i_img_dim cscl = 0;                  /* Current scanline */

 
   ss_scanline templine;                /* scanline accumulator */
   p_point *pset;               /* List of points in polygon */
   p_line  *lset;               /* List of lines in polygon */
   p_slice *tllist;             /* List of slices */
 
   ss_scanline templine;                /* scanline accumulator */
   p_point *pset;               /* List of points in polygon */
   p_line  *lset;               /* List of lines in polygon */
   p_slice *tllist;             /* List of slices */

+  size_t pcount, lcount;
+  dIMCTX;
+
+  im_log((aIMCTX, 1, "i_poly_poly_aa_low(im %p, count %d, polys %p, ctx %p, flusher %p)\n", im, count, polys, ctx, flusher));

 
 

-  mm_log((1, "i_poly_aa(im %p, l %d, x %p, y %p, ctx %p, flusher %p)\n", im, l, x, y, ctx, flusher));
+  i_clear_error();

 
 

-  for(i=0; i<l; i++) {
-    mm_log((2, "(%.2f, %.2f)\n", x[i], y[i]));
+  if (count < 1) {
+    i_push_error(0, "no polygons to draw");
+    return 0;
+  }
+
+  for (k = 0; k < count; ++k) {
+    if (polys[k].count < 3) {
+      i_push_error(0, "polygons must have at least 3 points");
+      return 0;
+    }
+  }
+
+  for (k = 0; k < count; ++k) {
+    const i_polygon_t *p = polys + k;
+    im_log((aIMCTX, 2, "poly %d\n", k));
+    for(i = 0; i < p->count; i++) {
+      im_log((aIMCTX, 2, " (%.2f, %.2f)\n", p->x[i], p->y[i]));
+    }

   }
 
 
   }
 
 


@@ -555,18 +488,17 @@ i_poly_aa_low(i_img *im, int l, const double *x, const double *y, void const *ct
           setbuf(stdout, NULL);
           );
 
           setbuf(stdout, NULL);
           );
 

-  tllist   = mymalloc(sizeof(p_slice)*l);
-  
-  ss_scanline_init(&templine, im->xsize, l);
+  pset     = point_set_new(polys, count, &pcount);
+  lset     = line_set_new(polys, count, &lcount);

 
 

-  pset     = point_set_new(x, y, l);
-  lset     = line_set_new(x, y, l);
+  ss_scanline_init(&templine, im->xsize, lcount);

 
 

-
-  qsort(pset, l, sizeof(p_point), (int(*)(const void *,const void *))p_compy);
+  tllist   = mymalloc(sizeof(p_slice) * lcount);
+  
+  qsort(pset, pcount, sizeof(p_point), (int(*)(const void *,const void *))p_compy);

   
   POLY_DEB(
   
   POLY_DEB(

-          for(i=0;i<l;i++) {
+          for(i=0;i<lcount;i++) {

             printf("%d [ %d ] (%d , %d) -> (%d , %d) yspan ( %d , %d )\n",
                    i, lset[i].n, lset[i].x1, lset[i].y1, lset[i].x2, lset[i].y2, lset[i].miny, lset[i].maxy);
           }
             printf("%d [ %d ] (%d , %d) -> (%d , %d) yspan ( %d , %d )\n",
                    i, lset[i].n, lset[i].x1, lset[i].y1, lset[i].x2, lset[i].y2, lset[i].miny, lset[i].maxy);
           }


@@ -575,45 +507,84 @@ i_poly_aa_low(i_img *im, int l, const double *x, const double *y, void const *ct
   
 
   /* loop on intervals */
   
 
   /* loop on intervals */

-  for(i=0; i<l-1; i++) {
-    int startscan = i_max( coarse(pset[i].y), 0);
-    int stopscan = i_min( coarse(pset[i+1].y+15), im->ysize);
+  for(i=0; i<pcount-1; i++) {
+    i_img_dim startscan = i_max( coarse(pset[i].y), 0);
+    i_img_dim stopscan = i_min( coarse(pset[i+1].y+15), im->ysize);
+    pcord miny, maxy;  /* y bounds in fine coordinates */

 
 

-    if (pset[i].y == pset[i+1].y) {
-      POLY_DEB( printf("current slice thickness = 0 => skipping\n") );
-      continue;
-    }
+    POLY_DEB( pcord cc = (pset[i].y + pset[i+1].y)/2 );

 
     POLY_DEB(
             printf("current slice is %d: %d to %d ( cpoint %d ) scanlines %d to %d\n", 
                    i, pset[i].y, pset[i+1].y, cc, startscan, stopscan)
             );
     
 
     POLY_DEB(
             printf("current slice is %d: %d to %d ( cpoint %d ) scanlines %d to %d\n", 
                    i, pset[i].y, pset[i+1].y, cc, startscan, stopscan)
             );
     

-    
-    clc = lines_in_interval(lset, l, tllist, pset[i].y, pset[i+1].y);
-    qsort(tllist, clc, sizeof(p_slice), (int(*)(const void *,const void *))p_compx);
-
-    mark_updown_slices(lset, tllist, clc);
+    if (pset[i].y == pset[i+1].y) {
+      POLY_DEB( printf("current slice thickness = 0 => skipping\n") );
+      continue;
+    }

 
 

-    POLY_DEB( printf("Interval contains %d lines\n", clc) );
+    clc = lines_in_interval(lset, lcount, tllist, pset[i].y, pset[i+1].y);
+    qsort(tllist, clc, sizeof(p_slice), (int(*)(const void *,const void *))p_compx);

 
 

-    for(k=0; k<clc; k++) {
-      POLY_DEB(
-              printf("%d:  line #%2d: (%2d, %2d)->(%2d, %2d) (%2d/%2d, %2d/%2d) -> (%2d/%2d, %2d/%2d) alignment=%s\n",
-                     k, lno, ln->x1, ln->y1, ln->x2, ln->y2, 
-                     coarse(ln->x1), fine(ln->x1), 
-                     coarse(ln->y1), fine(ln->y1), 
-                     coarse(ln->x2), fine(ln->x2), 
-                     coarse(ln->y2), fine(ln->y2),
-                     ln->updown == 0 ? "vert" : ln->updown == 1 ? "up" : "down")
-              );
+    mark_updown_slices(aIMCTX, lset, tllist, clc);
+
+    POLY_DEB
+      (
+       printf("Interval contains %d lines\n", clc);
+       for(k=0; k<clc; k++) {
+        int lno = tllist[k].n;
+        p_line *ln = lset+lno;
+        printf("%d:  line #%2d: (%2d, %2d)->(%2d, %2d) (%2d/%2d, %2d/%2d) -> (%2d/%2d, %2d/%2d) alignment=%s\n",
+               k, lno, ln->x1, ln->y1, ln->x2, ln->y2, 
+               coarse(ln->x1), fine(ln->x1), 
+               coarse(ln->y1), fine(ln->y1), 
+               coarse(ln->x2), fine(ln->x2), 
+               coarse(ln->y2), fine(ln->y2),
+               ln->updown == 0 ? "vert" : ln->updown == 1 ? "up" : "down");
+          
+       }
+       );
+    maxy = im->ysize * 16;
+    miny = 0;
+    for (k = 0; k < clc; ++k) {
+      p_line const * line = lset + tllist[k].n;
+      if (line->miny > miny)
+       miny = line->miny;
+      if (line->maxy < maxy)
+       maxy = line->maxy;
+      POLY_DEB( printf(" line miny %g maxy %g\n", line->miny/16.0, line->maxy/16.0) );

     }
     }

+    POLY_DEB( printf("miny %g maxy %g\n", miny/16.0, maxy/16.0) );
+

     for(cscl=startscan; cscl<stopscan; cscl++) {
     for(cscl=startscan; cscl<stopscan; cscl++) {

+      pcord scan_miny = i_max(miny, cscl * 16);
+      pcord scan_maxy = i_min(maxy, (cscl + 1 ) * 16);
+      

       tempy = i_min(cscl*16+16, pset[i+1].y);
       POLY_DEB( printf("evaluating scan line %d \n", cscl) );
       tempy = i_min(cscl*16+16, pset[i+1].y);
       POLY_DEB( printf("evaluating scan line %d \n", cscl) );

-      for(k=0; k<clc-1; k+=2) {
-       POLY_DEB( printf("evaluating slice %d\n", k) );
-       render_slice_scanline(&templine, cscl, lset+tllist[k].n, lset+tllist[k+1].n);
+      if (mode == i_pfm_evenodd) {
+       for(k=0; k<clc-1; k+=2) {
+         POLY_DEB( printf("evaluating slice %d\n", k) );
+         render_slice_scanline(&templine, cscl, lset+tllist[k].n, lset+tllist[k+1].n, scan_miny, scan_maxy);
+       }
+      }
+      else {
+       k = 0;
+       while (k < clc) {
+         p_line *left = lset + tllist[k++].n;
+         p_line *current = NULL;
+         int acc = left->dir;
+
+         while (k < clc && acc) {
+           current = lset + tllist[k++].n;
+           acc += current->dir;
+         }
+         if (acc == 0) {
+           render_slice_scanline(&templine, cscl, left, current,
+                                 scan_miny, scan_maxy);
+         }
+       }

       }
       if (16*coarse(tempy) == tempy) {
        POLY_DEB( printf("flushing scan line %d\n", cscl) );
       }
       if (16*coarse(tempy) == tempy) {
        POLY_DEB( printf("flushing scan line %d\n", cscl) );


@@ -636,139 +607,63 @@ i_poly_aa_low(i_img *im, int l, const double *x, const double *y, void const *ct
   myfree(pset);
   myfree(lset);
   myfree(tllist);
   myfree(pset);
   myfree(lset);
   myfree(tllist);

-  
-} /* Function */

 
 

-void
-i_poly_aa(i_img *im, int l, const double *x, const double *y, const i_color *val) {
-  i_poly_aa_low(im, l, x, y, val, scanline_flush);
+  return 1;

 }
 
 }
 

-#if 0
-struct poly_cfill_state {
-  i_color *fillbuf;
-  i_color *linebuf;
-  int *cover;
-  i_fill_t *fill;
-};
+/*
+=item i_poly_poly_aa(im, count, polys, mode, color)
+=synopsis i_poly_poly_aa(im, 1, &poly, mode, color);
+=category Drawing

 
 

-static void
-scanline_flush_cfill(i_img *im, ss_scanline *ss, int y, const void *ctx) {
-  int x, ch, tv;
-  int pos;
-  int left, right;
-  struct poly_cfill_state const *state = (struct poly_cfill_state const *)ctx;
-  i_color *fillbuf = state->fillbuf;
-  i_color *line = state->linebuf;
+Fill the C<count> polygons defined by C<polys> the color specified by
+C<color>.

 
 

-  left = 0;
-  while (left < im->xsize && ss->line[left] <= 0)
-    ++left;
-  if (left < im->xsize) {
-    right = im->xsize;
-    /* since going from the left found something, moving from the 
-       right should */
-    while (/* right > left && */ ss->line[right-1] <= 0) 
-      --right;
-    
-    (state->fill->fill_with_color)(state->fill, left, y, right-left, 
-                                   im->channels, fillbuf);
-    i_glin(im, left, right, y, line);
-    pos = 0;
-    if (state->fill->combine) {
-      for (x = left; x < right; ++x) {
-        tv = saturate(ss->line[x]);
-        fillbuf[pos].channel[3] = 
-          fillbuf[pos].channel[3] * tv / 255;
-       pos++;
-      }
-      (state->fill->combine)(line, fillbuf, im->channels, right-left);
-    }
-    else {
-      for (x = left; x < right; ++x) {
-        tv = saturate(ss->line[x]);
-        if (tv) { 
-          if (tv == 255) {
-            line[pos] = fillbuf[pos];
-          }
-          else {
-            i_color *to = line + pos;
-            i_color *from = fillbuf + pos;
-            for (ch = 0; ch < im->channels; ++ch) {
-              to->channel[ch] = (tv * from->channel[ch] + 
-                                 (255 - tv) * to->channel[ch]) / 255;
-            }
-          }
-        }
-        pos++;
-      }
-    }
-    i_plin(im, left, right, y, line);
-  }
+At least one polygon must be supplied.
+
+All polygons must have at least 3 points.
+
+=cut
+*/
+
+int
+i_poly_poly_aa(i_img *im, int count, const i_polygon_t *polys,
+              i_poly_fill_mode_t mode, const i_color *val) {
+  i_color c = *val;
+  return i_poly_poly_aa_low(im, count, polys, mode, &c, scanline_flush);

 }
 
 }
 

-struct poly_cfill_state_f {
-  i_fcolor *fillbuf;
-  i_fcolor *linebuf;
-  int *cover;
-  i_fill_t *fill;
-};
+/*
+=item i_poly_aa_m(im, count, x, y, mode, color)
+=synopsis i_poly_aa_m(im, count, x, y, mode, color);
+=category Drawing

 
 

-static void
-scanline_flush_cfill_f(i_img *im, ss_scanline *ss, int y, const void *ctx) {
-  int x, ch, tv;
-  int pos;
-  int left, right;
-  struct poly_cfill_state_f const *state = (struct poly_cfill_state_f const *)ctx;
-  i_fcolor *fillbuf = state->fillbuf;
-  i_fcolor *line = state->linebuf;
+Fill a polygon defined by the points specified by the x and y arrays with
+the color specified by C<color>.

 
 

-  left = 0;
-  while (left < im->xsize && ss->line[left] <= 0)
-    ++left;
-  if (left < im->xsize) {
-    right = im->xsize;
-    /* since going from the left found something, moving from the 
-       right should */
-    while (/* right > left && */ ss->line[right-1] <= 0) 
-      --right;
-    
-    (state->fill->fill_with_fcolor)(state->fill, left, y, right-left, 
-                                    im->channels, fillbuf);
-    i_glinf(im, left, right, y, line);
-    pos = 0;
-    if (state->fill->combinef) {
-      for (x = left; x < right; ++x) {
-        tv = saturate(ss->line[x]);
-        fillbuf[pos].channel[3] = 
-          fillbuf[pos].channel[3] * tv / 255;
-       pos++;
-      }
-      (state->fill->combinef)(line, fillbuf, im->channels, right-left);
-    }
-    else {
-      for (x = left; x < right; ++x) {
-        tv = saturate(ss->line[x]);
-        if (tv) { 
-          if (tv == 255) {
-            line[pos] = fillbuf[pos];
-          }
-          else {
-            i_fcolor *to = line + pos;
-            i_fcolor *from = fillbuf + pos;
-            for (ch = 0; ch < im->channels; ++ch) {
-              to->channel[ch] = (tv * from->channel[ch] + 
-                                 (255 - tv) * to->channel[ch]) / 255;
-            }
-          }
-        }
-        pos++;
-      }
-    }
-    i_plinf(im, left, right, y, line);
-  }
+=cut
+*/
+
+int
+i_poly_aa_m(i_img *im, int l, const double *x, const double *y,
+           i_poly_fill_mode_t mode, const i_color *val) {
+  i_polygon_t poly;
+
+  poly.count = l;
+  poly.x = x;
+  poly.y = y;
+  return i_poly_poly_aa(im, 1, &poly, mode, val);
+}
+
+int
+i_poly_aa(i_img *im, int l, const double *x, const double *y, const i_color *val) {
+  i_polygon_t poly;
+
+  poly.count = l;
+  poly.x = x;
+  poly.y = y;
+  return i_poly_poly_aa(im, 1, &poly, i_pfm_evenodd, val);

 }
 }

-#endif

 
 struct poly_render_state {
   i_render render;
 
 struct poly_render_state {
   i_render render;


@@ -777,11 +672,10 @@ struct poly_render_state {
 };
 
 static void
 };
 
 static void

-scanline_flush_render(i_img *im, ss_scanline *ss, int y, const void *ctx) {
-  int x, ch, tv;
-  int pos;
-  int left, right;
-  struct poly_render_state const *state = (struct poly_render_state const *)ctx;
+scanline_flush_render(i_img *im, ss_scanline *ss, int y, void *ctx) {
+  i_img_dim x;
+  i_img_dim left, right;
+  struct poly_render_state *state = (struct poly_render_state *)ctx;

 
   left = 0;
   while (left < im->xsize && ss->line[left] <= 0)
 
   left = 0;
   while (left < im->xsize && ss->line[left] <= 0)


@@ -802,37 +696,71 @@ scanline_flush_render(i_img *im, ss_scanline *ss, int y, const void *ctx) {
   }
 }
 
   }
 }
 

-void
-i_poly_aa_cfill(i_img *im, int l, const double *x, const double *y, 
-               i_fill_t *fill) {
+/*
+=item i_poly_poly_aa_cfill(im, count, polys, mode, fill)
+=synopsis i_poly_poly_aa_cfill(im, 1, &poly, mode, fill);
+=category Drawing
+
+Fill the C<count> polygons defined by C<polys> the fill specified by
+C<fill>.
+
+At least one polygon must be supplied.
+
+All polygons must have at least 3 points.
+
+=cut
+*/
+
+int
+i_poly_poly_aa_cfill(i_img *im, int count, const i_polygon_t *polys,
+                    i_poly_fill_mode_t mode, i_fill_t *fill) {

   struct poly_render_state ctx;
   struct poly_render_state ctx;

+  int result;

 
   i_render_init(&ctx.render, im, im->xsize);
   ctx.fill = fill;
   ctx.cover = mymalloc(im->xsize);
 
   i_render_init(&ctx.render, im, im->xsize);
   ctx.fill = fill;
   ctx.cover = mymalloc(im->xsize);

-  i_poly_aa_low(im, l, x, y, &ctx, scanline_flush_render);
+
+  result = i_poly_poly_aa_low(im, count, polys, mode, &ctx,
+                             scanline_flush_render);
+

   myfree(ctx.cover);
   i_render_done(&ctx.render);
   myfree(ctx.cover);
   i_render_done(&ctx.render);

-#if 0
-  if (im->bits == i_8_bits && fill->fill_with_color) {
-    struct poly_cfill_state ctx;
-    ctx.fillbuf = mymalloc(sizeof(i_color) * im->xsize * 2);
-    ctx.linebuf = ctx.fillbuf + im->xsize;
-    ctx.cover = mymalloc(sizeof(int) * im->xsize);
-    ctx.fill = fill;
-    i_poly_aa_low(im, l, x, y, &ctx, scanline_flush_cfill);
-    myfree(ctx.fillbuf);
-    myfree(ctx.cover);
-  }
-  else {
-    struct poly_cfill_state_f ctx;
-    ctx.fillbuf = mymalloc(sizeof(i_fcolor) * im->xsize * 2);
-    ctx.linebuf = ctx.fillbuf + im->xsize;
-    ctx.cover = mymalloc(sizeof(int) * im->xsize);
-    ctx.fill = fill;
-    i_poly_aa_low(im, l, x, y, &ctx, scanline_flush_cfill_f);
-    myfree(ctx.fillbuf);
-    myfree(ctx.cover);
-  }
-#endif
+
+  return result;
+}
+
+/*
+=item i_poly_aa_cfill_m(im, count, x, y, mode, fill)
+=synopsis i_poly_aa_cfill(im, count, x, y, mode, fill);
+=category Drawing
+
+Fill a polygon defined by the points specified by the x and y arrays with
+the fill specified by C<fill>.
+
+=cut
+*/
+
+int
+i_poly_aa_cfill_m(i_img *im, int l, const double *x, const double *y, 
+               i_poly_fill_mode_t mode, i_fill_t *fill) {
+  i_polygon_t poly;
+
+  poly.count = l;
+  poly.x = x;
+  poly.y = y;
+
+  return i_poly_poly_aa_cfill(im, 1, &poly, mode, fill);
+}
+
+int
+i_poly_aa_cfill(i_img *im, int l, const double *x, const double *y, 
+               i_fill_t *fill) {
+  i_polygon_t poly;
+
+  poly.count = l;
+  poly.x = x;
+  poly.y = y;
+
+  return i_poly_poly_aa_cfill(im, 1, &poly, i_pfm_evenodd, fill);

 }
 }