#define SP_PRECISION 0.5

int spStarted = FALSE;

double spStartX = 0, spStartY = 0;

double spPenX = 0, spPenY = 0;

void spSkipSpace(const char **pos)

  { while(**pos && isspace(**pos)) ++*pos; }

double spReadNum(const char **pos) {

  spSkipSpace(pos);

  char *end = "";

  double x = strtod(*pos, &end);

  *pos = end;

  return x;

}

double spMax(double a, double b)

  { return a > b ? a : b; }

void spMoveTo(double x, double y) {

  if (spStarted) strokePath();

  spStarted = TRUE;

  moveTo(x, y);

  spStartX = spPenX = x;

  spStartY = spPenY = y;

}

void spLineTo(double x, double y) {

  if (!spStarted) spMoveTo(spPenX, spPenY);

  lineTo(x, y);

  spPenX = x;

  spPenY = y;

}

void spClose() {

  if (spStarted) { lineTo(spStartX, spStartY); closePath(); }

  spMoveTo(spStartX, spStartY);

}

void spQuadraticTo(double x1, double y1, double x2, double y2) {

  double dx = spMax(x1 - spPenX, x2 - spPenX);

  double dy = spMax(y1 - spPenY, y2 - spPenY);

  if (dx*dx + dy*dy <= SP_PRECISION*SP_PRECISION) {

    spLineTo(x2, y2);

    return;

  }

  double xx0 = 0.5*(spPenX + x1);

  double yy0 = 0.5*(spPenY + y1);

  double xx1 = 0.5*(x1 + x2);

  double yy1 = 0.5*(y1 + y2);

  double xxx0 = 0.5*(xx0 + xx1);

  double yyy0 = 0.5*(yy0 + yy1);

  spQuadraticTo(xx0, yy0, xxx0, yyy0);

  spQuadraticTo(xx1, yy1, x2, y2);

}

void spCurveTo(double x1, double y1, double x2, double y2, double x3, double y3) {

  double dx = spMax(spMax(x1 - spPenX, x2 - spPenX), x3 - spPenX);

  double dy = spMax(spMax(y1 - spPenY, y2 - spPenY), y3 - spPenY);

  if (dx*dx + dy*dy <= SP_PRECISION*SP_PRECISION) {

    spLineTo(x2, y2);

    return;

  }

  double xx0 = 0.5*(spPenX + x1);

  double yy0 = 0.5*(spPenY + y1);

  double xx1 = 0.5*(x1 + x2);

  double yy1 = 0.5*(y1 + y2);

  double xx2 = 0.5*(x2 + x3);

  double yy2 = 0.5*(y2 + y3);

  double xxx0 = 0.5*(xx0 + xx1);

  double yyy0 = 0.5*(yy0 + yy1);

  double xxx1 = 0.5*(xx1 + xx2);

  double yyy1 = 0.5*(yy1 + yy2);

  double xxxx0 = 0.5*(xxx0 + xxx1);

  double yyyy0 = 0.5*(yyy0 + yyy1);

  spCurveTo(xx0, yy0, xxx0, yyy0, xxxx0, yyyy0);

  spCurveTo(xxx1, yyy1, xx2, yy2, x3, y3);

}

void spParse(const char *path) {

  double x1, x2, x3;

  double y1, y2, y3;

  const char *c = path;

  spSkipSpace(&c);

  while(*c) {

    switch(*c++) {

    case 'M':

      x1 = spReadNum(&c);

      y1 = spReadNum(&c);

      spMoveTo(x1, y1);

      break;

    case 'm':

      x1 = spPenX + spReadNum(&c);

      y1 = spPenY + spReadNum(&c);

      spMoveTo(x1, y1);

      break;

    case 'L':

      x1 = spReadNum(&c);

      y1 = spReadNum(&c);

      spLineTo(x1, y1);

      break;

    case 'l':

      x1 = spPenX + spReadNum(&c);

      y1 = spPenY + spReadNum(&c);

      spLineTo(x1, y1);

      break;

    case 'Q':

      x1 = spReadNum(&c);

      y1 = spReadNum(&c);

      x2 = spReadNum(&c);

      y2 = spReadNum(&c);

      spQuadraticTo(x1, y1, x2, y2);

      break;

    case 'q':

      x1 = spPenX + spReadNum(&c);

      y1 = spPenY + spReadNum(&c);

      x2 = spPenX + spReadNum(&c);

      y2 = spPenY + spReadNum(&c);

      spQuadraticTo(x1, y1, x2, y2);

      break;

    case 'C':

      x1 = spReadNum(&c);

      y1 = spReadNum(&c);

      x2 = spReadNum(&c);

      y2 = spReadNum(&c);

      x3 = spReadNum(&c);

      y3 = spReadNum(&c);

      spCurveTo(x1, y1, x2, y2, x3, y3);

      break;

    case 'c':

      x1 = spPenX + spReadNum(&c);

      y1 = spPenY + spReadNum(&c);

      x2 = spPenX + spReadNum(&c);

      y2 = spPenY + spReadNum(&c);

      x3 = spPenX + spReadNum(&c);

      y3 = spPenY + spReadNum(&c);

      spCurveTo(x1, y1, x2, y2, x3, y3);

      break;

    case 'Z':

    case 'z':

      spClose();

      break;

    default:

      printf("unknown path command \'%c\'\n", *(c - 1));

    }

    spSkipSpace(&c);

  }

}

void spTrack(const char *path, double *x, double *y) {

  double sx = *x, sy = *y;

  const char *c = path;

  spSkipSpace(&c);

  while(*c) {

    switch(*c++) {

    case 'M':

      sx = (*x = spReadNum(&c));

      sy = (*y = spReadNum(&c));

      break;

    case 'm':

      sx = (*x += spReadNum(&c));

      sy = (*y += spReadNum(&c));

      break;

    case 'C':

      spReadNum(&c);

      spReadNum(&c);

    case 'Q':

      spReadNum(&c);

      spReadNum(&c);

    case 'L':

      *x = spReadNum(&c);

      *y = spReadNum(&c);

      break;

    case 'c':

      spReadNum(&c);

      spReadNum(&c);

    case 'q':

      spReadNum(&c);

      spReadNum(&c);

    case 'l':

      *x += spReadNum(&c);

      *y += spReadNum(&c);

      break;

    case 'Z':

    case 'z':

      *x = sx;

      *y = sy;

      break;

    default:

      printf("unknown path command \'%c\'\n", *(c - 1));

    }

    spSkipSpace(&c);

  }

}