/* Copyright (C) 2002 artofcode LLC. All rights reserved.
  
  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License version 2
  as published by the Free Software Foundation.


  This software is provided AS-IS with no warranty, either express or
  implied. That is, this program is distributed in the hope that it will 
  be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details

  You should have received a copy of the GNU General Public License along
  with this program; if not, write to the Free Software Foundation, Inc.,
  59 Temple Place, Suite 330, Boston, MA, 02111-1307.
  
  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: vdtrace.c,v 1.6 2002/09/16 23:45:02 giles Exp $ */
/* Visual tracer service */

#include "math_.h"
#include "gxfixed.h"
#include "vdtrace.h"

/* Global data for all instances : */
vd_trace_interface * vd_trace0 = NULL, * vd_trace1 = NULL;
char vd_flags[128] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0""\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"
                     "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0""\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"
                     "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0""\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"
                     "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0""\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";

private double px, py;

#define NullRET if(vd_trace1 == NULL) return

private inline double scale_x(vd_trace_interface *I, double x)
{ return (x - I->orig_x) * I->scale_x + I->shift_x;
}

private inline double scale_y(vd_trace_interface *I, double y)
{ return (y - I->orig_y) * I->scale_y + I->shift_y;
}

#define SX(x) scale_x(vd_trace1, x)
#define SY(y) scale_y(vd_trace1, y)

private inline double bezier_point(double p0, double p1, double p2, double p3, double t)
{   double s = 1-t;
    return p0*s*s*s + 3*p1*s*s*t + 3*p2*s*t*t + p3*t*t*t;
}

private void vd_flatten(double p0x, double p0y, double p1x, double p1y, double p2x, double p2y, double p3x, double p3y)
{   double flat = 0.5;
    double d2x0 = (p0x - 2 * p1x + p2x), d2y0 = (p0y - 2 * p1y + p2y);
    double d2x1 = (p1x - 2 * p2x + p3x), d2y1 = (p1y - 2 * p2y + p3y);
    double d2norm0 = hypot(d2x0, d2y0);
    double d2norm1 = hypot(d2x1, d2y1);
    double D = max(d2norm0, d2norm1); /* This is half of maximum norm of 2nd derivative of the curve by parameter t. */
    int NN = (int)ceil(sqrt(D * 3 / 4 / flat)); /* Number of output segments. */
    int i;
    int N = max(NN, 1); /* safety (if the curve degenerates to line) */
    double e = 0.5 / N;
    for (i = 0; i < N; i++) {
	double t = (double)i / N + e;
	double px = bezier_point(p0x, p1x, p2x, p3x, t);
	double py = bezier_point(p0y, p1y, p2y, p3y, t);
	vd_lineto(px, py);
    }
    vd_lineto(p3x, p3y);
}

void vd_impl_moveto(double x, double y)
{   NullRET;
    px = SX(x), py = SY(y);
    vd_trace1->moveto(vd_trace1, px, py);
}

void vd_impl_lineto(double x, double y)
{   NullRET;
    px = SX(x), py = SY(y);
    vd_trace1->lineto(vd_trace1, px, py);
}

void vd_impl_lineto_multi(struct gs_fixed_point_s *p, int n)
{   int i;
    NullRET;
    for (i = 0; i < n; i++) {
        px = SX(p[i].x), py = SY(p[i].y);
        vd_trace1->lineto(vd_trace1, px, py);
    }
}

void vd_impl_curveto(double x1, double y1, double x2, double y2, double x3, double y3)
{   double p1x, p1y, p2x, p2y, p3x, p3y;
    NullRET;
    p1x = SX(x1), p1y = SY(y1);
    p2x = SX(x2), p2y = SY(y2);
    p3x = SX(x3), p3y = SY(y3);
    if (vd_trace1->curveto != NULL)
        vd_trace1->curveto(vd_trace1, p1x, p1y, p2x, p2y, p3x, p3y);
    else
        vd_flatten(px, py, p1x, p1y, p2x, p2y, p3x, p3y);
    px = p3x, py = p3y;
}

void vd_impl_bar(double x0, double y0, double x1, double y1, int w, unsigned long c)
{   NullRET;
    vd_trace1->setcolor(vd_trace1, c);
    vd_trace1->setlinewidth(vd_trace1, w);
    vd_trace1->beg_path(vd_trace1);
    vd_trace1->moveto(vd_trace1, SX(x0), SY(y0));
    vd_trace1->lineto(vd_trace1, SX(x1), SY(y1));
    vd_trace1->end_path(vd_trace1);
    vd_trace1->stroke(vd_trace1);
}

void vd_impl_square(double x, double y, int w, unsigned int c)
{   NullRET;
    vd_trace1->setcolor(vd_trace1, c);
    vd_trace1->setlinewidth(vd_trace1, 1);
    vd_trace1->beg_path(vd_trace1);
    vd_trace1->moveto(vd_trace1, SX(x) - w, SY(y) - w);
    vd_trace1->lineto(vd_trace1, SX(x) + w, SY(y) - w);
    vd_trace1->lineto(vd_trace1, SX(x) + w, SY(y) + w);
    vd_trace1->lineto(vd_trace1, SX(x) - w, SY(y) + w);
    vd_trace1->lineto(vd_trace1, SX(x) - w, SY(y) - w);
    vd_trace1->end_path(vd_trace1);
    vd_trace1->stroke(vd_trace1);
}

void vd_impl_curve(double x0, double y0, double x1, double y1, double x2, double y2, double x3, double y3, int w, unsigned long c)
{   NullRET;
    vd_trace1->setcolor(vd_trace1, c);
    vd_trace1->setlinewidth(vd_trace1, w);
    vd_trace1->beg_path(vd_trace1);
    vd_trace1->beg_path(vd_trace1);
    vd_trace1->moveto(vd_trace1, SX(x0), SY(y0));
    vd_impl_curveto(x1, y1, x2, y2, x3, y3);
    vd_trace1->end_path(vd_trace1);
    vd_trace1->stroke(vd_trace1);
}

void vd_impl_circle(double x, double y, int r, unsigned long c)
{   NullRET;
    vd_trace1->setcolor(vd_trace1, c);
    vd_trace1->setlinewidth(vd_trace1, 1);
    vd_trace1->circle(vd_trace1, SX(x), SY(y), r);
}

void vd_impl_round(double x, double y, int r, unsigned long c)
{   NullRET;
    vd_trace1->setcolor(vd_trace1, c);
    vd_trace1->setlinewidth(vd_trace1, 1);
    vd_trace1->round(vd_trace1, SX(x), SY(y), r);
}

void vd_impl_text(double x, double y, char *s, unsigned long c)
{   NullRET;
    vd_trace1->setcolor(vd_trace1, c);
    vd_trace1->text(vd_trace1, SX(x), SY(y), s);
}

void vd_setflag(char f, char v)
{   vd_flags[f & 127] = v;
}
