Subversion Repositories Kolibri OS

/*

 * Copyright © 2004 Keith Packard

 *

 * Permission to use, copy, modify, distribute, and sell this software and its

 * documentation for any purpose is hereby granted without fee, provided that

 * the above copyright notice appear in all copies and that both that

 * copyright notice and this permission notice appear in supporting

 * documentation, and that the name of Keith Packard not be used in

 * advertising or publicity pertaining to distribution of the software without

 * specific, written prior permission.  Keith Packard makes no

 * representations about the suitability of this software for any purpose.  It

 * is provided "as is" without express or implied warranty.

 *

 * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,

 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO

 * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR

 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,

 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER

 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR

 * PERFORMANCE OF THIS SOFTWARE.

 */

#ifndef rasterize_span

#endif

static void

RASTERIZE_EDGES (pixman_image_t  *image,

		pixman_edge_t	*l,

		pixman_edge_t	*r,

		pixman_fixed_t		t,

		pixman_fixed_t		b)

{

    pixman_fixed_t  y = t;

    uint32_t  *line;

    uint32_t *buf = (image)->bits.bits;

    int stride = (image)->bits.rowstride;

    int width = (image)->bits.width;

    line = buf + pixman_fixed_to_int (y) * stride;

    for (;;)

    {

	pixman_fixed_t	lx;

	pixman_fixed_t      rx;

	int	lxi;

	int rxi;

	lx = l->x;

	rx = r->x;

#if N_BITS == 1

	/* For the non-antialiased case, round the coordinates up, in effect

	 * sampling just slightly to the left of the pixel. This is so that

	 * when the sample point lies exactly on the line, we round towards

	 * north-west.

	 *

	 * (The AA case does a similar  adjustment in RENDER_SAMPLES_X)

	 */

	lx += X_FRAC_FIRST(1) - pixman_fixed_e;

	rx += X_FRAC_FIRST(1) - pixman_fixed_e;

#endif

	/* clip X */

	if (lx < 0)

	    lx = 0;

	if (pixman_fixed_to_int (rx) >= width)

#if N_BITS == 1

	    rx = pixman_int_to_fixed (width);

#else

	    /* Use the last pixel of the scanline, covered 100%.

	     * We can't use the first pixel following the scanline,

	     * because accessing it could result in a buffer overrun.

	     */

	    rx = pixman_int_to_fixed (width) - 1;

#endif

	/* Skip empty (or backwards) sections */

	if (rx > lx)

	{

	    /* Find pixel bounds for span */

	    lxi = pixman_fixed_to_int (lx);

	    rxi = pixman_fixed_to_int (rx);

#if N_BITS == 1

	    {

#define LEFT_MASK(x)							\

		(((x) & 0x1f) ?						\

		 SCREEN_SHIFT_RIGHT (0xffffffff, (x) & 0x1f) : 0)

#define RIGHT_MASK(x)							\

		(((32 - (x)) & 0x1f) ?					\

		 SCREEN_SHIFT_LEFT (0xffffffff, (32 - (x)) & 0x1f) : 0)

#define MASK_BITS(x,w,l,n,r) {						\

		    n = (w);						\

		    r = RIGHT_MASK ((x) + n);				\

		    l = LEFT_MASK (x);					\

		    if (l) {						\

			n -= 32 - ((x) & 0x1f);				\

			if (n < 0) {					\

			    n = 0;					\

			    l &= r;					\

			    r = 0;					\

			}						\

		    }							\

		    n >>= 5;						\

		}

		uint32_t  *a = line;

		uint32_t  startmask;

		uint32_t  endmask;

		int	    nmiddle;

		int	    width = rxi - lxi;

		int	    x = lxi;

		a += x >> 5;

		x &= 0x1f;

		MASK_BITS (x, width, startmask, nmiddle, endmask);

		if (startmask) {

		    WRITE(image, a, READ(image, a) | startmask);

		    a++;

		}

		while (nmiddle--)

		    WRITE(image, a++, 0xffffffff);

		if (endmask)

		    WRITE(image, a, READ(image, a) | endmask);

	    }

#else

	    {

		DEFINE_ALPHA(line,lxi);

		int	    lxs;

		int     rxs;

		/* Sample coverage for edge pixels */

		lxs = RENDER_SAMPLES_X (lx, N_BITS);

		rxs = RENDER_SAMPLES_X (rx, N_BITS);

		/* Add coverage across row */

		if (lxi == rxi)

		{

		    ADD_ALPHA (rxs - lxs);

		}

		else

		{

		    int	xi;

		    ADD_ALPHA (N_X_FRAC(N_BITS) - lxs);

		    STEP_ALPHA;

		    for (xi = lxi + 1; xi < rxi; xi++)

		    {

			ADD_ALPHA (N_X_FRAC(N_BITS));

			STEP_ALPHA;

		    }

		    ADD_ALPHA (rxs);

		}

	    }

#endif

	}

	if (y == b)

	    break;

#if N_BITS > 1

	if (pixman_fixed_frac (y) != Y_FRAC_LAST(N_BITS))

	{

	    RENDER_EDGE_STEP_SMALL (l);

	    RENDER_EDGE_STEP_SMALL (r);

	    y += STEP_Y_SMALL(N_BITS);

	}

	else

#endif

	{

	    RENDER_EDGE_STEP_BIG (l);

	    RENDER_EDGE_STEP_BIG (r);

	    y += STEP_Y_BIG(N_BITS);

	    line += stride;

	}

    }

}

#undef rasterize_span