/*  Part of XPCE --- The SWI-Prolog GUI toolkit

    Author:        Jan Wielemaker and Anjo Anjewierden
    E-mail:        jan@swi.psy.uva.nl
    WWW:           http://www.swi.psy.uva.nl/projects/xpce/
    Copyright (c)  2000-2011, University of Amsterdam
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:

    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in
       the documentation and/or other materials provided with the
       distribution.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    POSSIBILITY OF SUCH DAMAGE.
*/

#include <h/kernel.h>
#include <h/graphics.h>
#include <math.h>

#define MAXPTS 100

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Implementation of Quadratic Bezier Curves.  Using algorithm description
from:

http://graphics.cs.ucdavis.edu/CAGDNotes/Divide-and-Conquer-Bezier-Curve/Divide-and-Conquer-Bezier-Curve.html

Cubic (using 4 control-points) are described in:

http://muldoon.cipic.ucdavis.edu/CAGDNotes/Cubic-Bezier-Curves/Cubic-Bezier-Curves.html
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

static status
initialiseBezier(Bezier b, Point start, Point end,
		 Point c1, Point c2)
{ initialiseGraphical(b, ZERO, ZERO, ZERO, ZERO);

  if ( isDefault(c2) )
    c2 = NIL;

  assign(b, start,    start);
  assign(b, end,      end);
  assign(b, control1, c1);
  assign(b, control2, c2);

  return requestComputeGraphical(b, DEFAULT);
}


		 /*******************************
		 *	      ARROWS		*
		 *******************************/

status
adjustFirstArrowBezier(Bezier b)
{ if ( notNil(b->first_arrow) )
  { Any av[4];

    av[0] = b->start->x;
    av[1] = b->start->y;
    av[2] = b->control1->x;
    av[3] = b->control1->y;

    if ( qadSendv(b->first_arrow, NAME_points, 4, av) )
    { assign(b->first_arrow, displayed, ON);

      return ComputeGraphical(b->first_arrow);
    }
  }

  fail;
}


status
adjustSecondArrowBezier(Bezier b)
{ if ( notNil(b->second_arrow) )
  { Any av[4];

    av[0] = b->end->x;
    av[1] = b->end->y;
    if ( notNil(b->control2) )
    { av[2] = b->control2->x;
      av[3] = b->control2->y;
    } else
    { av[2] = b->control1->x;
      av[3] = b->control1->y;
    }

    if ( qadSendv(b->second_arrow, NAME_points, 4, av) )
    { assign(b->second_arrow, displayed, ON);
      return ComputeGraphical(b->second_arrow);
    }
  }

  fail;
}




		 /*******************************
		 *	     COMPUTING		*
		 *******************************/

static void
shiftpts(FPoint pts, int to, int shift)
{
  DEBUG(NAME_bezier, Cprintf("Shift to %d\n", to));
  to--;
  for(; to>=shift; to--)
    pts[to] = pts[to-shift];
}


#define mkmid(p, p1, p2) \
	{ p.x = (p1.x + p2.x + 1)/2; \
	  p.y = (p1.y + p2.y + 1)/2; \
	}

static int
splitQuadratic(FPoint pts, int i, int *n)
{ fpoint m;
  int md = 1;

  pts += i;
  mkmid(m, pts[0], pts[2]);

  if ( fabs(m.x-pts[1].x) > md || fabs(m.y-pts[1].y) > md )
  { fpoint p1;

    p1 = pts[1];

    *n = *n + 2;
    shiftpts(pts, *n-i, 2);

    mkmid(pts[1], pts[0], p1);
    mkmid(pts[3], p1,     pts[4]);
    mkmid(pts[2], pts[1], pts[3]);

    return TRUE;
  }

  return FALSE;
}


static int
splitCubic(FPoint pts, int i, int *n)
{ pts += i;

  if ( distanceLineToPoint(pts[0].x, pts[0].y, pts[3].x, pts[3].y,
			   pts[1].x, pts[1].y, TRUE) > 1 ||
       distanceLineToPoint(pts[0].x, pts[0].y, pts[3].x, pts[3].y,
			   pts[2].x, pts[2].y, TRUE) > 1 )
  { fpoint p1, p2, p12;

    p1 = pts[1];
    p2 = pts[2];

    *n = *n + 3;
    shiftpts(pts, *n-i, 3);

    mkmid(p12,    p1,     p2);
    mkmid(pts[1], pts[0], p1);
    mkmid(pts[5], p2,     pts[6]);
    mkmid(pts[2], pts[1], p12);
    mkmid(pts[4], pts[5], p12);
    mkmid(pts[3], pts[2], pts[4]);

    return TRUE;
  }

  return FALSE;
}


/*
static void
printPts(IPoint pts, int n)
{ int i;

  for(i=0; i<n; i++)
    Cprintf(" %d,%d", pts[i].x, pts[i].y);

  Cprintf("\n");
}
*/

static void
compute_points_bezier(Bezier b, FPoint pts, int *mx)
{ int mxpts = *mx;
  int npts;
  int i;
  FPoint p = pts;

  p->x = valNum(b->start->x);
  p->y = valNum(b->start->y);
  p++;
  p->x = valNum(b->control1->x);
  p->y = valNum(b->control1->y);
  p++;
  if ( notNil(b->control2) )
  { p->x = valNum(b->control2->x);
    p->y = valNum(b->control2->y);
    p++;
  }
  p->x = valNum(b->end->x);
  p->y = valNum(b->end->y);
  p++;

  npts = p-pts;
  if ( notNil(b->control2) )
  { for(i=0; i <= npts-3; i += 3)
    { if ( npts >= mxpts-3 )
	break;
      while(splitCubic(pts, i, &npts))
	;
    }
  } else
  { for(i=0; i <= npts-3; i += 2)
    { if ( npts >= mxpts-2 )
	break;
      while(splitQuadratic(pts, i, &npts))
	;
    }
  }

  *mx = npts;
}


typedef struct reg
{ int minx, miny, maxx, maxy;
} reg;


static void
include_in_reg(reg *r, Point pt)
{ int px = valInt(pt->x);
  int py = valInt(pt->y);

  r->minx = min(r->minx, px);
  r->maxx = max(r->maxx, px);
  r->miny = min(r->miny, py);
  r->maxy = max(r->maxy, py);
}


static status
computeBoundingBoxBezier(Bezier b)
{ reg r;

  r.minx = 1000000;
  r.miny = 1000000;
  r.maxx = -1000000;
  r.maxy = -10000000;

  if ( b->selected == ON )
  { int mw=5, mh=5;

    include_in_reg(&r, b->start);
    include_in_reg(&r, b->end);
    include_in_reg(&r, b->control1);
    if ( notNil(b->control2) )
      include_in_reg(&r, b->control2);

    r.minx -= (mw+1)/2;
    r.maxx += (mw+1)/2;
    r.miny -= (mh+1)/2;
    r.maxy += (mh+1)/2;
  } else
  { fpoint ptsbuf[MAXPTS];
    FPoint pts = ptsbuf;
    int npts = MAXPTS;
    int i;

    compute_points_bezier(b, pts, &npts);

    for(i=0; i<npts; i++,pts++)
    { if ( pts[0].x < r.minx ) r.minx = pts[0].x;
      if ( pts[0].x > r.maxx ) r.maxx = pts[0].x;
      if ( pts[0].y < r.miny ) r.miny = pts[0].y;
      if ( pts[0].y > r.maxy ) r.maxy = pts[0].y;
    }
  }

  if ( r.maxx >= r.minx && r.maxy >= r.miny )
  { int pens = valInt(b->pen) / 2;
    int pena = (valInt(b->pen) % 2 == 0 ? pens : pens + 1);

    r.minx -= pens; r.maxx += pena;
    r.miny -= pens; r.maxy += pena;

    assign(b->area, x, toInt(r.minx));
    assign(b->area, y, toInt(r.miny));
    assign(b->area, w, toInt(r.maxx - r.minx));
    assign(b->area, h, toInt(r.maxy - r.miny));
  } else
    clearArea(b->area);

  if ( adjustFirstArrowBezier(b) )
    unionNormalisedArea(b->area, b->first_arrow->area);
  if ( adjustSecondArrowBezier(b) )
    unionNormalisedArea(b->area, b->second_arrow->area);

  succeed;
}


static status
computeBezier(Bezier b)
{ if ( notNil(b->request_compute) )
  { CHANGING_GRAPHICAL(b,
		       { computeBoundingBoxBezier(b);
			 changedEntireImageGraphical(b);
		       });

    assign(b, request_compute, NIL);
  }

  succeed;
}


		 /*******************************
		 *	      REDRAW		*
		 *******************************/

static status
RedrawAreaBezier(Bezier b, Area a)
{ int x, y, w, h;
  fpoint start = {valNum(b->start->x), valNum(b->start->y)};
  fpoint end = {valNum(b->end->x), valNum(b->end->y)};
  fpoint control1 = {valNum(b->control1->x), valNum(b->control1->y)};
  fpoint control2;

  if ( notNil(b->control2) )
  { control2 = (fpoint){valNum(b->control2->x), valNum(b->control2->y)};
  } else
  { control2 = (fpoint){(2*control1.x + end.x) / 3.0,
			(2*control1.y + end.y) / 3.0};
    control1 = (fpoint){(start.x + 2*control1.x) / 3.0,
			(start.y + 2*control1.y) / 3.0};
  }

  initialiseDeviceGraphical(b, &x, &y, &w, &h);

  r_thickness(valNum(b->pen));
  r_dash(b->texture);

  r_bezier(start, control1, control2, end);

  if ( adjustFirstArrowBezier(b) )
    RedrawArea(b->first_arrow, a);
  if ( adjustSecondArrowBezier(b) )
    RedrawArea(b->second_arrow, a);

  return RedrawAreaGraphical(b, a);
}


static void
drawControlPt(Point pt)
{ int bx = valInt(pt->x);
  int by = valInt(pt->y);

  r_fill(bx-2, by-2, 5, 5, NAME_foreground);
}


static void
pt_line(Point p1, Point p2)
{ r_line(valInt(p1->x), valInt(p1->y),
	 valInt(p2->x), valInt(p2->y));
}


static status
paintSelectedBezier(Bezier b)
{ PceWindow sw = getWindowGraphical((Graphical) b);

  if ( sw && sw->selection_feedback == (Any) NAME_handles )
  { int x, y, w, h;

    initialiseDeviceGraphical(b, &x, &y, &w, &h);
    drawControlPt(b->start);
    drawControlPt(b->control1);
    if ( notNil(b->control2) )
      drawControlPt(b->control2);
    drawControlPt(b->end);

    if ( 1 )				/* draw lines */
    { r_dash(NAME_dotted);
      r_thickness(1);
      pt_line(b->start, b->control1);
      if ( notNil(b->control2) )
      { pt_line(b->control1, b->control2);
	pt_line(b->control2, b->end);
      } else
	pt_line(b->control1, b->end);
    }

    succeed;
  } else
    return paintSelectedGraphical((Graphical)b);
}



		 /*******************************
		 *	    PROPERTIES		*
		 *******************************/

static status
startBezier(Bezier b, Point pt)
{ return assignGraphical(b, NAME_start, pt);
}


static status
control1Bezier(Bezier b, Point pt)
{ return assignGraphical(b, NAME_control1, pt);
}


static status
control2Bezier(Bezier b, Point pt)
{ return assignGraphical(b, NAME_control2, pt);
}


static status
endBezier(Bezier b, Point pt)
{ return assignGraphical(b, NAME_end, pt);
}


static status
pointsBezier(Bezier b, Int sx, Int sy, Int ex, Int ey)
{ assign(b->start, x, sx);
  assign(b->start, y, sy);
  assign(b->end, x, ex);
  assign(b->end, y, ey);

  requestComputeGraphical(b, DEFAULT);

  CHANGING_GRAPHICAL(b,
		     { ComputeGraphical(b);
		       changedEntireImageGraphical(b);
		     });

  succeed;
}


static status
selectedBezier(Bezier b, BoolObj val)
{ return assignGraphical(b, NAME_selected, val);
}


		 /*******************************
		 *	PATH INTEGRATION	*
		 *******************************/

static status
setPointBezier(Bezier b, Point pt, Int x, Int y)
{ setPoint(pt, x, y);

  return requestComputeGraphical(b, DEFAULT);
}


static void
closerPoint(Point pt, Point pos, int *best, Point *r)
{ int d = valInt(getDistancePoint(pt, pos));

  if ( d < *best )
  { *best = d;
    *r = pt;
  }
}


static Point
getPointBezier(Bezier b, Point pos, Int dist)
{ Point rval = NIL;
  int bestd = 0;			/* make gcc happy */

  if ( instanceOfObject(pos, ClassEvent) && notNil(b->device) )
    pos = getPositionEvent((EventObj) pos, (Graphical) b->device);

  if ( isDefault(dist) )
    dist = toInt(10);			/* TBD */

  bestd = valInt(getDistancePoint(b->start, pos));
  rval  = b->start;
  closerPoint(b->end, pos, &bestd, &rval);
  closerPoint(b->control1, pos, &bestd, &rval);
  if ( notNil(b->control2) )
    closerPoint(b->control2, pos, &bestd, &rval);

  if ( notNil(rval) && bestd < valInt(dist) )
    answer(rval);

  fail;
}


		 /*******************************
		 *	      MOVING		*
		 *******************************/

static status
geometryBezier(Bezier b, Int x, Int y, Int w, Int h)
{ if ( notDefault(x) || notDefault(y) )
  { Int dx, dy;

    ComputeGraphical(b);
    if ( notDefault(x) )
      dx = sub(x, b->area->x);
    else
      dx = ZERO;

    if ( notDefault(y) )
      dy = sub(y, b->area->y);
    else
      dy = ZERO;

    if ( dx != ZERO || dy != ZERO )
    { offsetPoint(b->start, dx, dy);
      offsetPoint(b->end, dx, dy);
      offsetPoint(b->control1, dx, dy);
      if ( notNil(b->control2) )
	offsetPoint(b->control2, dx, dy);

      CHANGING_GRAPHICAL(b,
			 { assign(b->area, x, add(b->area->x, dx));
			   assign(b->area, y, add(b->area->y, dy));
			 });
    }
  }

  succeed;
}


		 /*******************************
		 *	 CLASS DECLARATION	*
		 *******************************/

/* Type declarations */

static char *T_initialise[] =
        { "start=point", "end=point",
	  "control1=point", "control2=[point]*"
	};
static char *T_points[] =
        { "start_x=int", "start_y=int", "end_x=int", "end_y=int" };
static char *T_geometry[] =
        { "x=[int]", "y=[int]", "width=[int]", "height=[int]" };
static char *T_setPoint[] =
        { "point=point", "x=[int]", "y=[int]" };
static char *T_point[] =
        { "near=point|event", "max_distance=[int]" };


/* Instance Variables */

static vardecl var_bezier[] =
{ SV(NAME_start, "point", IV_GET|IV_STORE, startBezier,
     NAME_tip, "Start point of Bezier curve"),
  SV(NAME_end, "point", IV_GET|IV_STORE, endBezier,
     NAME_tip, "End point of Bezier curve"),
  SV(NAME_control1, "point", IV_GET|IV_STORE, control1Bezier,
     NAME_appearance, "1st Control-point of the Bezier curve"),
  SV(NAME_control2, "point*", IV_GET|IV_STORE, control2Bezier,
     NAME_appearance, "2nd Control-point of the Bezier curve")
};

/* Send Methods */

static senddecl send_bezier[] =
{ SM(NAME_initialise, 4, T_initialise, initialiseBezier,
     DEFAULT, "Create bezier from start, control and end"),
  SM(NAME_compute, 0, NULL, computeBezier,
     DEFAULT, "Recompute area"),
  SM(NAME_geometry, 4, T_geometry, geometryBezier,
     DEFAULT, "Move the Bezier curve"),
  SM(NAME_paintSelected, 0, NULL, paintSelectedBezier,
     NAME_appearance, "Paint inverted drops on control-points"),
  SM(NAME_points, 4, T_points, pointsBezier,
     NAME_tip, "Set start- and end-point"),
  SM(NAME_setPoint, 3, T_setPoint, setPointBezier,
     NAME_points, "Move (member) point to (X, Y)"),
  SM(NAME_selected, 1, "bool", selectedBezier,
     NAME_selection, "If @on, I'm selected")
};


/* Get Methods */

static getdecl get_bezier[] =
{ GM(NAME_point, 2, "point", T_point, getPointBezier,
     NAME_event, "Find closest point"),
};


/* Resources */

#define rc_bezier NULL
/*
static classvardecl rc_bezier[] =
{
};
*/

/* Class Declaration */

static Name bezier_termnames[] = { NAME_width, NAME_height };

ClassDecl(bezier_decls,
          var_bezier, send_bezier, get_bezier, rc_bezier,
          2, bezier_termnames,
          "$Rev$");


status
makeClassBezier(Class class)
{ declareClass(class, &bezier_decls);

  setRedrawFunctionClass(class, RedrawAreaBezier);

  succeed;
}
