Esempio n. 1
0
/*
 * Handle the case of a large value or a value with a fraction part.
 * See gxmatrix.h for more details.
 */
fixed
fixed_coeff_mult(fixed value, long coeff, const fixed_coeff *pfc, int maxb)
{
    int shift = pfc->shift;

    /*
     * Test if the value is too large for simple long math.
     */
    if ((value + (fixed_1 << (maxb - 1))) & (-fixed_1 << maxb)) {
        /* The second argument of fixed_mult_quo must be non-negative. */
        return
            (coeff < 0 ?
             -fixed_mult_quo(value, -coeff, fixed_1 << shift) :
             fixed_mult_quo(value, coeff, fixed_1 << shift));
    } else {
        /*
         * The construction above guarantees that the multiplications
         * won't overflow the capacity of an int.
         */
        return (fixed)
            arith_rshift(fixed2int_var(value) * coeff
                         + fixed2int(fixed_fraction(value) * coeff)
                         + pfc->round, shift);
    }
}
Esempio n. 2
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static fixed
edge_x_at_y(const gs_fixed_edge * edge, fixed y)
{
    return fixed_mult_quo(edge->end.x - edge->start.x,
			  y - edge->start.y,
			  edge->end.y - edge->start.y) + edge->start.x;
}
Esempio n. 3
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/* Compute ldi, ldf, and xf similarly. */
static inline void
compute_ldx(trap_line *tl, fixed ys)
{
    int di = tl->di;
    fixed df = tl->df;
    fixed h = tl->h;

    if ( df < YMULT_LIMIT ) {
	 if ( df == 0 )		/* vertical edge, worth checking for */
	     tl->ldi = int2fixed(di), tl->ldf = 0, tl->xf = -h;
	 else {
	     tl->ldi = int2fixed(di) + int2fixed(df) / h;
	     tl->ldf = int2fixed(df) % h;
	     tl->xf =
		 (ys < fixed_1 ? ys * df % h : fixed_mult_rem(ys, df, h)) - h;
	 }
    }
    else {
	tl->ldi = int2fixed(di) + fixed_mult_quo(fixed_1, df, h);
	tl->ldf = fixed_mult_rem(fixed_1, df, h);
	tl->xf = fixed_mult_rem(ys, df, h) - h;
    }
}
Esempio n. 4
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static inline fixed Y_AT_X(active_line *alp, fixed xp)
{   return alp->start.y + fixed_mult_quo(xp - alp->start.x,  alp->diff.y, alp->diff.x);
}
Esempio n. 5
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/* We should swap axes to get best accuracy, but we don't. */
int
gx_default_fill_triangle(gx_device * dev,
		 fixed px, fixed py, fixed ax, fixed ay, fixed bx, fixed by,
		  const gx_device_color * pdevc, gs_logical_operation_t lop)
{
    fixed t;
    fixed ym;

    dev_proc_fill_trapezoid((*fill_trapezoid)) =
	dev_proc(dev, fill_trapezoid);
    gs_fixed_edge left, right;
    int code;

    /* Ensure ay >= 0, by >= 0. */
    if (ay < 0)
	px += ax, py += ay, bx -= ax, by -= ay, ax = -ax, ay = -ay;
    if (by < 0)
	px += bx, py += by, ax -= bx, ay -= by, bx = -bx, by = -by;
    /* Ensure ay <= by. */
    if (ay > by)
	SWAP(ax, bx, t), SWAP(ay, by, t);
    /*
     * Make a special check for a flat bottom or top,
     * which we can handle with a single call on fill_trapezoid.
     */
    left.start.x = right.start.x = px;
    left.start.y = right.start.y = py;
    if (ay == 0) {
	/* Flat top */
	if (ax < 0)
	    left.start.x = px + ax;
	else
	    right.start.x = px + ax;
	left.end.x = right.end.x = px + bx;
	left.end.y = right.end.y = py + by;
	ym = py;
    } else if (ay == by) {
	/* Flat bottom */
	if (ax < bx)
	    left.end.x = px + ax, right.end.x = px + bx;
	else
	    left.end.x = px + bx, right.end.x = px + ax;
	left.end.y = right.end.y = py + by;
	ym = py;
    } else {
	ym = py + ay;
	if (fixed_mult_quo(bx, ay, by) < ax) {
	    /* The 'b' line is to the left of the 'a' line. */
	    left.end.x = px + bx, left.end.y = py + by;
	    right.end.x = px + ax, right.end.y = py + ay;
	    code = (*fill_trapezoid) (dev, &left, &right, py, ym,
				      false, pdevc, lop);
	    right.start = right.end;
	    right.end = left.end;
	} else {
	    /* The 'a' line is to the left of the 'b' line. */
	    left.end.x = px + ax, left.end.y = py + ay;
	    right.end.x = px + bx, right.end.y = py + by;
	    code = (*fill_trapezoid) (dev, &left, &right, py, ym,
				      false, pdevc, lop);
	    left.start = left.end;
	    left.end = right.end;
	}
	if (code < 0)
	    return code;
    }
    return (*fill_trapezoid) (dev, &left, &right, ym, right.end.y,
			      false, pdevc, lop);
}
Esempio n. 6
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/* Define the 'remainder' analogue of fixed_mult_quo. */
static fixed
fixed_mult_rem(fixed a, fixed b, fixed c)
{
    /* All kinds of truncation may happen here, but it's OK. */
    return a * b - fixed_mult_quo(a, b, c) * c;
}