Function psl_vector

src/postscriptlight.c:2678–3004

#define FIN_HEIGHT_SCALE	0.5	/* 1/2 the width of the vector */

static int psl_vector (struct PSL_CTRL *PSL, double x, double y, double param[]) {
	/* Will make sure that arrow has a finite width in PS coordinates.
	 * param must hold up to 12 values:
	 * param[PSL_VEC_XTIP] = xtip;
    * param[PSL_VEC_YTIP] = ytip;
	 * param[PSL_VEC_TAIL_WIDTH] = tailwidth;
    * param[PSL_VEC_HEAD_LENGTH] = headlength;
    * param[PSL_VEC_HEAD_WIDTH] = headwidth;
	 * param[PSL_VEC_HEAD_SHAPE] = headshape;
    * param[PSL_VEC_STATUS] = status bit flags
	 * param[PSL_VEC_HEAD_TYPE_BEGIN] = begin head type;
    * param[PSL_VEC_HEAD_TYPE_END] = end head type
	 * param[PSL_VEC_TRIM_BEGIN] = begin trim value;
    * param[PSL_VEC_TRIM_END] = end trim value.
	 * param[PSL_VEC_HEAD_PENWIDTH] = head penwidth
	 */

	double angle, xtip, ytip, r, s, tailwidth, headlength, headwidth, headshape, length_inch;
	double xx[6], yy[6], xc[3], yc[3], off[2], yshift[2], trim[2], xp = 0.0, h_penwidth;
	int length, asymmetry[2], n, heads, outline, fill, status, head_check;
	unsigned int kind[2];
	char *line[2] = {"N", "P S"}, *dump[2] = {"", "fs"};

	xtip = param[PSL_VEC_XTIP];	ytip = param[PSL_VEC_YTIP];
	length_inch = hypot (x-xtip, y-ytip);					/* Vector length in inches */
	length = psl_iz (PSL, length_inch);					/* Vector length in PS units */
	if (length == 0) return (PSL_NO_ERROR);					/* NULL vector */
	angle = atan2 (ytip-y, xtip-x) * R2D;					/* Angle vector makes with horizontal, in degrees */
	status = lrint (param[PSL_VEC_STATUS]);
	h_penwidth = param[PSL_VEC_HEAD_PENWIDTH];
	/* Make any adjustments caused by trim */
	trim[PSL_BEGIN] = (status & PSL_VEC_OFF_BEGIN) ? param[PSL_VEC_TRIM_BEGIN] : 0.0;
	trim[PSL_END]   = (status & PSL_VEC_OFF_END)   ? param[PSL_VEC_TRIM_END]   : 0.0;
	if (fabs (angle) == 90.0) {	/* Vertical segment; only adjust y coordinates */
		y += copysign (trim[PSL_BEGIN], angle);	ytip -= copysign (trim[PSL_END], angle);
	}
	else {	/* General case, use trig */
		double s, c, a = angle * D2R;
		s = sin (a);		c = cos (a);
		x += c * trim[PSL_BEGIN];	y += s * trim[PSL_BEGIN];
		xtip -= c * trim[PSL_END];	ytip -= s * trim[PSL_END];
	}
	length_inch = hypot (x-xtip, y-ytip);					/* Recalculate vector length in inches */
	length = psl_iz (PSL, length_inch);					/* Vector length in PS units */
	if (length == 0) return (PSL_NO_ERROR);					/* NULL vector */
	tailwidth = param[PSL_VEC_TAIL_WIDTH];
	headlength = param[PSL_VEC_HEAD_LENGTH];	headwidth = 0.5 * param[PSL_VEC_HEAD_WIDTH];	headshape = param[PSL_VEC_HEAD_SHAPE];
	kind[PSL_BEGIN] = (unsigned int)lrint (param[PSL_VEC_HEAD_TYPE_BEGIN]);
	kind[PSL_END]   = (unsigned int)lrint (param[PSL_VEC_HEAD_TYPE_END]);
	off[PSL_BEGIN] = (kind[PSL_BEGIN] == PSL_VEC_ARROW) ? 0.5 * (2.0 - headshape) * headlength : 0.0;
	off[PSL_END]   = (kind[PSL_END] == PSL_VEC_ARROW)   ? 0.5 * (2.0 - headshape) * headlength : 0.0;
	if (kind[PSL_BEGIN] == PSL_VEC_ARROW_PLAIN) off[PSL_BEGIN] = 0.5 * tailwidth *  headlength / headwidth;
	else if (kind[PSL_BEGIN] == PSL_VEC_TAIL) off[PSL_BEGIN] = FIN_SLANT_COS * headwidth + FIN_LENGTH_SCALE * headlength - tailwidth;
	if (kind[PSL_END] == PSL_VEC_ARROW_PLAIN) off[PSL_END] = 0.5 * tailwidth *  headlength / headwidth;
	else if (kind[PSL_END] == PSL_VEC_TAIL) off[PSL_END] = FIN_SLANT_COS * headwidth + FIN_LENGTH_SCALE * headlength - tailwidth;
	heads = PSL_vec_head (status);		  /* 1 = at beginning, 2 = at end, 3 = both */
	head_check = PSL_vec_headcheck (status);		  /* nonzero if we should always place a head regardless of length */
	if (head_check) {	/* Must worry about head size relative to vector length */