Modified i_line_aa to use a modified bresenham algorithm. This method

also does endpoint handling like i_line does.  This will hopefully make
line drawing more consistent.

diff --git a/Imager.pm b/Imager.pm
index 8e2502f7d1ba1deda741210d3400bb93f89e8bb9..34960712b8091edca414e61379f1ca4864e59d72 100644 (file)
--- a/Imager.pm
+++ b/Imager.pm
@@ -2039,7 +2039,7 @@ sub line {
   $opts{antialias} = $opts{aa} if defined $opts{aa};
   if ($opts{antialias}) {
     i_line_aa($self->{IMG},$opts{x1}, $opts{y1}, $opts{x2}, $opts{y2},
   $opts{antialias} = $opts{aa} if defined $opts{aa};
   if ($opts{antialias}) {
     i_line_aa($self->{IMG},$opts{x1}, $opts{y1}, $opts{x2}, $opts{y2},

-              $color);
+              $color, $opts{endp});

   } else {
     i_line($self->{IMG},$opts{x1}, $opts{y1}, $opts{x2}, $opts{y2},
            $color, $opts{endp});
   } else {
     i_line($self->{IMG},$opts{x1}, $opts{y1}, $opts{x2}, $opts{y2},
            $color, $opts{endp});


@@ -2074,7 +2074,7 @@ sub polyline {
   if ($opts{antialias}) {
     for $pt(@points) {
       if (defined($ls)) { 
   if ($opts{antialias}) {
     for $pt(@points) {
       if (defined($ls)) { 

-        i_line_aa($self->{IMG},$ls->[0],$ls->[1],$pt->[0],$pt->[1],$color);
+        i_line_aa($self->{IMG},$ls->[0],$ls->[1],$pt->[0],$pt->[1],$color, 1);

       }
       $ls=$pt;
     }
       }
       $ls=$pt;
     }

diff --git a/Imager.xs b/Imager.xs
index cae5ce156beb7e0786bbdeef879bd70769ddb303..c7f9dfb8a8eb0cabbe2986ef4a746ff1ea05c606 100644 (file)
--- a/Imager.xs
+++ b/Imager.xs
@@ -1260,13 +1260,14 @@ i_line(im,x1,y1,x2,y2,val,endp)
               int     endp
 
 void
               int     endp
 
 void

-i_line_aa(im,x1,y1,x2,y2,val)
+i_line_aa(im,x1,y1,x2,y2,val,endp)

     Imager::ImgRaw     im
               int     x1
               int     y1
               int     x2
               int     y2
      Imager::Color     val
     Imager::ImgRaw     im
               int     x1
               int     y1
               int     x2
               int     y2
      Imager::Color     val

+              int     endp

 
 void
 i_box(im,x1,y1,x2,y2,val)
 
 void
 i_box(im,x1,y1,x2,y2,val)

diff --git a/draw.c b/draw.c
index 9906f484d3afd961411447a86e20408026fe4fe7..6f98fe0c0ef2f1ab5aa5dbaeef2ba8ce909f1c8b 100644 (file)
--- a/draw.c
+++ b/draw.c
@@ -530,13 +530,51 @@ i_line(i_img *im, int x1, int y1, int x2, int y2, i_color *val, int endp) {
 
 
 void
 
 
 void

-i_line_aa(i_img *im,int x1,int y1,int x2,int y2,i_color *val) {
+i_line_dda(i_img *im, int x1, int y1, int x2, int y2, i_color *val) {
+
+  float dy;
+  int x;
+  
+  for(x=x1; x<=x2; x++) {
+    dy = y1+ (x-x1)/(float)(x2-x1)*(y2-y1);
+    i_ppix(im, x, rint(dy), val);
+  }
+}
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+void
+i_line_aa3(i_img *im,int x1,int y1,int x2,int y2,i_color *val) {

   i_color tval;
   float alpha;
   float dsec,dfrac;
   int temp,dx,dy,isec,ch;
 
   i_color tval;
   float alpha;
   float dsec,dfrac;
   int temp,dx,dy,isec,ch;
 

-  mm_log((1,"i_draw(im* 0x%x,x1 %d,y1 %d,x2 %d,y2 %d,val 0x%x)\n",im,x1,y1,x2,y2,val));
+  mm_log((1,"i_line_aa(im* 0x%x,x1 %d,y1 %d,x2 %d,y2 %d,val 0x%x)\n",im,x1,y1,x2,y2,val));

 
   dy=y2-y1;
   dx=x2-x1;
 
   dy=y2-y1;
   dx=x2-x1;


@@ -586,6 +624,138 @@ i_line_aa(i_img *im,int x1,int y1,int x2,int y2,i_color *val) {
   }
 }
 
   }
 }
 

+
+
+
+void
+i_line_aa(i_img *im, int x1, int y1, int x2, int y2, i_color *val, int endp) {
+  int x, y;
+  int dx, dy;
+  int p;
+  unsigned char *cp;
+
+  dx = x2 - x1;
+  dy = y2 - y1;
+
+  /* choose variable to iterate on */
+  if (abs(dx)>abs(dy)) {
+    int dx2, dy2, cpy;
+    
+    /* sort by x */
+    if (x1 > x2) {
+      int t;
+      t = x1; x1 = x2; x2 = t;
+      t = y1; y1 = y2; y2 = t;
+    }
+    
+    dx = abs(dx);
+    dx2 = dx*2;
+    dy = y2 - y1;
+
+    if (dy<0) {
+      dy = -dy;
+      cpy = -1;
+    } else {
+      cpy = 1;
+    }
+    dy2 = dy*2;
+    p = dy2 - dx2; /* this has to be like this for AA */
+    
+    y = y1;
+
+    for(x=x1; x<x2-1; x++) {
+      int ch;
+      i_color tval;
+      float t = (dy) ? -(float)(p)/(float)(dx2) : 1;
+      float t1, t2;
+
+      if (t<0) t = 0;
+      t1 = 1-t;
+      t2 = t;
+
+      i_gpix(im,x+1,y,&tval);
+      for(ch=0;ch<im->channels;ch++)
+       tval.channel[ch]=(unsigned char)(t1*(float)tval.channel[ch]+t2*(float)val->channel[ch]);
+      i_ppix(im,x+1,y,&tval);
+
+      i_gpix(im,x+1,y+cpy,&tval);
+      for(ch=0;ch<im->channels;ch++)
+       tval.channel[ch]=(unsigned char)(t2*(float)tval.channel[ch]+t1*(float)val->channel[ch]);
+      i_ppix(im,x+1,y+cpy,&tval);
+
+      if (p<0) {
+        p += dy2;
+      } else {
+        y += cpy;
+        p += dy2-dx2;
+      }
+    }
+  } else {
+    int dy2, dx2, cpx;
+
+    /* sort bx y */
+    if (y1 > y2) {
+      int t;
+      t = x1; x1 = x2; x2 = t;
+      t = y1; y1 = y2; y2 = t;
+    }
+    
+    dy = abs(dy);
+    dx = x2 - x1;
+    dy2 = dy*2;
+
+    if (dx<0) {
+      dx = -dx;
+      cpx = -1;
+    } else {
+      cpx = 1;
+    }
+    dx2 = dx*2;
+    p = dx2 - dy2; /* this has to be like this for AA */
+
+    x = x1;
+    
+    for(y=y1; y<y2-1; y++) {
+      int ch;
+      i_color tval;
+      float t = (dx) ? -(float)(p)/(float)(dy2) : 1;
+      float t1, t2;
+      
+      if (t<0) t = 0;
+      t1 = 1-t;
+      t2 = t;
+
+      i_gpix(im,x,y+1,&tval);
+      for(ch=0;ch<im->channels;ch++)
+       tval.channel[ch]=(unsigned char)(t1*(float)tval.channel[ch]+t2*(float)val->channel[ch]);
+      i_ppix(im,x,y+1,&tval);
+
+      i_gpix(im,x+cpx,y+1,&tval);
+      for(ch=0;ch<im->channels;ch++)
+       tval.channel[ch]=(unsigned char)(t2*(float)tval.channel[ch]+t1*(float)val->channel[ch]);
+      i_ppix(im,x+cpx,y+1,&tval);
+
+      if (p<0) {
+        p  += dx2;
+      } else {
+        x += cpx;
+        p += dx2-dy2;
+      }
+    }
+  }
+
+
+  if (endp) {
+    i_ppix(im, x1, y1, val);
+    i_ppix(im, x2, y2, val);
+  } else {
+    if (x1 != x2 || y1 != y2) 
+      i_ppix(im, x1, y1, val);
+  }
+}
+
+
+

 static double
 perm(int n,int k) {
   double r;
 static double
 perm(int n,int k) {
   double r;


@@ -633,7 +803,7 @@ i_bezier_multi(i_img *im,int l,double *x,double *y,i_color *val) {
     }
     /*    printf("%f -> (%d,%d)\n",t,(int)(0.5+cx),(int)(0.5+cy)); */
     if (i++) { 
     }
     /*    printf("%f -> (%d,%d)\n",t,(int)(0.5+cx),(int)(0.5+cy)); */
     if (i++) { 

-      i_line_aa(im,lx,ly,(int)(0.5+cx),(int)(0.5+cy),val);
+      i_line_aa(im,lx,ly,(int)(0.5+cx),(int)(0.5+cy),val, 1);

     }
       /*     i_ppix(im,(int)(0.5+cx),(int)(0.5+cy),val); */
     lx=(int)(0.5+cx);
     }
       /*     i_ppix(im,(int)(0.5+cx),(int)(0.5+cy),val); */
     lx=(int)(0.5+cx);

diff --git a/draw.h b/draw.h
index 5c1f894e0bc2c50ae68dc7c9da58cd8df8ab2328..ef0eeed4cdea5044ea9a6fe975d91ab453160c21 100644 (file)
--- a/draw.h
+++ b/draw.h
@@ -22,4 +22,5 @@ void i_mmarray_info(i_mmarray *ar);
 void i_arc(i_img *im,int x,int y,float rad,float d1,float d2,i_color *val);
 void i_box(i_img *im,int x0,int y0,int x1,int y1,i_color *val);
 void i_line(i_img *im,int x1,int y1,int x2,int y2,i_color *val, int endp);
 void i_arc(i_img *im,int x,int y,float rad,float d1,float d2,i_color *val);
 void i_box(i_img *im,int x0,int y0,int x1,int y1,i_color *val);
 void i_line(i_img *im,int x1,int y1,int x2,int y2,i_color *val, int endp);

+void i_line_aa(i_img *im,int x1,int y1,int x2,int y2,i_color *val, int endp);

 
 

diff --git a/image.h b/image.h
index 3d9143b6809af3bdeab8fb3bb71dd6093f066f4d..f18996b9986e6ebbe869a8ada76aad5a2dc25a25 100644 (file)
--- a/image.h
+++ b/image.h
@@ -204,7 +204,7 @@ void i_box         (i_img *im,int x1,int y1,int x2,int y2,i_color *val);
 void i_box_filled  (i_img *im,int x1,int y1,int x2,int y2,i_color *val);
 void i_box_cfill(i_img *im, int x1, int y1, int x2, int y2, i_fill_t *fill);
 void i_line        (i_img *im,int x1,int y1,int x2,int y2,i_color *val, int endp);
 void i_box_filled  (i_img *im,int x1,int y1,int x2,int y2,i_color *val);
 void i_box_cfill(i_img *im, int x1, int y1, int x2, int y2, i_fill_t *fill);
 void i_line        (i_img *im,int x1,int y1,int x2,int y2,i_color *val, int endp);

-void i_line_aa     (i_img *im,int x1,int y1,int x2,int y2,i_color *val);
+void i_line_aa     (i_img *im,int x1,int y1,int x2,int y2,i_color *val, int endp);

 void i_arc         (i_img *im,int x,int y,float rad,float d1,float d2,i_color *val);
 void i_arc_cfill(i_img *im,int x,int y,float rad,float d1,float d2,i_fill_t *fill);
 void i_circle_aa   (i_img *im,float x, float y,float rad,i_color *val);
 void i_arc         (i_img *im,int x,int y,float rad,float d1,float d2,i_color *val);
 void i_arc_cfill(i_img *im,int x,int y,float rad,float d1,float d2,i_fill_t *fill);
 void i_circle_aa   (i_img *im,float x, float y,float rad,i_color *val);