/*

 * Copyright © 2002 Keith Packard, member of The XFree86 Project, Inc.

 * 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.

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include <stdio.h>

#include <stdlib.h>

#include "pixman-private.h"

/*

 * Compute the smallest value greater than or equal to y which is on a

 * grid row.

 */

PIXMAN_EXPORT pixman_fixed_t

pixman_sample_ceil_y (pixman_fixed_t y, int n)

{

    pixman_fixed_t f = pixman_fixed_frac (y);

    pixman_fixed_t i = pixman_fixed_floor (y);

    f = DIV (f - Y_FRAC_FIRST (n) + (STEP_Y_SMALL (n) - pixman_fixed_e), STEP_Y_SMALL (n)) * STEP_Y_SMALL (n) +

	Y_FRAC_FIRST (n);

    if (f > Y_FRAC_LAST (n))

    {

	if (pixman_fixed_to_int (i) == 0x7fff)

	{

	    f = 0xffff; /* saturate */

	}

	else

	{

	    f = Y_FRAC_FIRST (n);

	    i += pixman_fixed_1;

	}

    }

    return (i | f);

}

/*

 * Compute the largest value strictly less than y which is on a

 * grid row.

 */

PIXMAN_EXPORT pixman_fixed_t

pixman_sample_floor_y (pixman_fixed_t y,

                       int            n)

{

    pixman_fixed_t f = pixman_fixed_frac (y);

    pixman_fixed_t i = pixman_fixed_floor (y);

    f = DIV (f - pixman_fixed_e - Y_FRAC_FIRST (n), STEP_Y_SMALL (n)) * STEP_Y_SMALL (n) +

	Y_FRAC_FIRST (n);

    if (f < Y_FRAC_FIRST (n))

    {

	if (pixman_fixed_to_int (i) == 0x8000)

	{

	    f = 0; /* saturate */

	}

	else

	{

	    f = Y_FRAC_LAST (n);

	    i -= pixman_fixed_1;

	}

    }

    return (i | f);

}

/*

 * Step an edge by any amount (including negative values)

 */

PIXMAN_EXPORT void

pixman_edge_step (pixman_edge_t *e,

                  int            n)

{

    pixman_fixed_48_16_t ne;

    e->x += n * e->stepx;

    ne = e->e + n * (pixman_fixed_48_16_t) e->dx;

    if (n >= 0)

    {

	if (ne > 0)

	{

	    int nx = (ne + e->dy - 1) / e->dy;

	    e->e = ne - nx * (pixman_fixed_48_16_t) e->dy;

	    e->x += nx * e->signdx;

	}

    }

    else

    {

	if (ne <= -e->dy)

	{

	    int nx = (-ne) / e->dy;

	    e->e = ne + nx * (pixman_fixed_48_16_t) e->dy;

	    e->x -= nx * e->signdx;

	}

    }

}

/*

 * A private routine to initialize the multi-step

 * elements of an edge structure

 */

static void

_pixman_edge_multi_init (pixman_edge_t * e,

                         int             n,

                         pixman_fixed_t *stepx_p,

                         pixman_fixed_t *dx_p)

{

    pixman_fixed_t stepx;

    pixman_fixed_48_16_t ne;

    ne = n * (pixman_fixed_48_16_t) e->dx;

    stepx = n * e->stepx;

    if (ne > 0)

    {

	int nx = ne / e->dy;

	ne -= nx * (pixman_fixed_48_16_t)e->dy;

	stepx += nx * e->signdx;

    }

    *dx_p = ne;

    *stepx_p = stepx;

}

/*

 * Initialize one edge structure given the line endpoints and a

 * starting y value

 */

PIXMAN_EXPORT void

pixman_edge_init (pixman_edge_t *e,

                  int            n,

                  pixman_fixed_t y_start,

                  pixman_fixed_t x_top,

                  pixman_fixed_t y_top,

                  pixman_fixed_t x_bot,

                  pixman_fixed_t y_bot)

{

    pixman_fixed_t dx, dy;

    e->x = x_top;

    e->e = 0;

    dx = x_bot - x_top;

    dy = y_bot - y_top;

    e->dy = dy;

    e->dx = 0;

    if (dy)

    {

	if (dx >= 0)

	{

	    e->signdx = 1;

	    e->stepx = dx / dy;

	    e->dx = dx % dy;

	    e->e = -dy;

	}

	else

	{

	    e->signdx = -1;

	    e->stepx = -(-dx / dy);

	    e->dx = -dx % dy;

	    e->e = 0;

	}

	_pixman_edge_multi_init (e, STEP_Y_SMALL (n),

				 &e->stepx_small, &e->dx_small);

	_pixman_edge_multi_init (e, STEP_Y_BIG (n),

				 &e->stepx_big, &e->dx_big);

    }

    pixman_edge_step (e, y_start - y_top);

}

/*

 * Initialize one edge structure given a line, starting y value

 * and a pixel offset for the line

 */

PIXMAN_EXPORT void

pixman_line_fixed_edge_init (pixman_edge_t *            e,

                             int                        n,

                             pixman_fixed_t             y,

                             const pixman_line_fixed_t *line,

                             int                        x_off,

                             int                        y_off)

{

    pixman_fixed_t x_off_fixed = pixman_int_to_fixed (x_off);

    pixman_fixed_t y_off_fixed = pixman_int_to_fixed (y_off);

    const pixman_point_fixed_t *top, *bot;

    if (line->p1.y <= line->p2.y)

    {

	top = &line->p1;

	bot = &line->p2;

    }

    else

    {

	top = &line->p2;

	bot = &line->p1;

    }

    pixman_edge_init (e, n, y,

                      top->x + x_off_fixed,

                      top->y + y_off_fixed,

                      bot->x + x_off_fixed,

                      bot->y + y_off_fixed);

}

PIXMAN_EXPORT void

pixman_add_traps (pixman_image_t *     image,

                  int16_t              x_off,

                  int16_t              y_off,

                  int                  ntrap,

                  const pixman_trap_t *traps)

{

    int bpp;

    int height;

    pixman_fixed_t x_off_fixed;

    pixman_fixed_t y_off_fixed;

    pixman_edge_t l, r;

    pixman_fixed_t t, b;

    _pixman_image_validate (image);

    height = image->bits.height;

    bpp = PIXMAN_FORMAT_BPP (image->bits.format);

    x_off_fixed = pixman_int_to_fixed (x_off);

    y_off_fixed = pixman_int_to_fixed (y_off);

    while (ntrap--)

    {

	t = traps->top.y + y_off_fixed;

	if (t < 0)

	    t = 0;

	t = pixman_sample_ceil_y (t, bpp);

	b = traps->bot.y + y_off_fixed;

	if (pixman_fixed_to_int (b) >= height)

	    b = pixman_int_to_fixed (height) - 1;

	b = pixman_sample_floor_y (b, bpp);

	if (b >= t)

	{

	    /* initialize edge walkers */

	    pixman_edge_init (&l, bpp, t,

	                      traps->top.l + x_off_fixed,

	                      traps->top.y + y_off_fixed,

	                      traps->bot.l + x_off_fixed,

	                      traps->bot.y + y_off_fixed);

	    pixman_edge_init (&r, bpp, t,

	                      traps->top.r + x_off_fixed,

	                      traps->top.y + y_off_fixed,

	                      traps->bot.r + x_off_fixed,

	                      traps->bot.y + y_off_fixed);

	    pixman_rasterize_edges (image, &l, &r, t, b);

	}

	traps++;

    }

}

#if 0

static void

dump_image (pixman_image_t *image,

            const char *    title)

{

    int i, j;

    if (!image->type == BITS)

	printf ("%s is not a regular image\n", title);

    if (!image->bits.format == PIXMAN_a8)

	printf ("%s is not an alpha mask\n", title);

    printf ("\n\n\n%s: \n", title);

    for (i = 0; i < image->bits.height; ++i)

    {

	uint8_t *line =

	    (uint8_t *)&(image->bits.bits[i * image->bits.rowstride]);

	for (j = 0; j < image->bits.width; ++j)

	    printf ("%c", line[j] ? '#' : ' ');

	printf ("\n");

    }

}

#endif

PIXMAN_EXPORT void

pixman_add_trapezoids (pixman_image_t *          image,

                       int16_t                   x_off,

                       int                       y_off,

                       int                       ntraps,

                       const pixman_trapezoid_t *traps)

{

    int i;

#if 0

    dump_image (image, "before");

#endif

    for (i = 0; i < ntraps; ++i)

    {

	const pixman_trapezoid_t *trap = &(traps[i]);

	if (!pixman_trapezoid_valid (trap))

	    continue;

	pixman_rasterize_trapezoid (image, trap, x_off, y_off);

    }

#if 0

    dump_image (image, "after");

#endif

}

PIXMAN_EXPORT void

pixman_rasterize_trapezoid (pixman_image_t *          image,

                            const pixman_trapezoid_t *trap,

                            int                       x_off,

                            int                       y_off)

{

    int bpp;

    int height;

    pixman_fixed_t y_off_fixed;

    pixman_edge_t l, r;

    pixman_fixed_t t, b;

    return_if_fail (image->type == BITS);

    _pixman_image_validate (image);

    if (!pixman_trapezoid_valid (trap))

	return;

    height = image->bits.height;

    bpp = PIXMAN_FORMAT_BPP (image->bits.format);

    y_off_fixed = pixman_int_to_fixed (y_off);

    t = trap->top + y_off_fixed;

    if (t < 0)

	t = 0;

    t = pixman_sample_ceil_y (t, bpp);

    b = trap->bottom + y_off_fixed;

    if (pixman_fixed_to_int (b) >= height)

	b = pixman_int_to_fixed (height) - 1;

    b = pixman_sample_floor_y (b, bpp);

    if (b >= t)

    {

	/* initialize edge walkers */

	pixman_line_fixed_edge_init (&l, bpp, t, &trap->left, x_off, y_off);

	pixman_line_fixed_edge_init (&r, bpp, t, &trap->right, x_off, y_off);

	pixman_rasterize_edges (image, &l, &r, t, b);

    }

}

static const pixman_bool_t zero_src_has_no_effect[PIXMAN_N_OPERATORS] =

{

    FALSE,	/* Clear		0			0    */

    FALSE,	/* Src			1			0    */

    TRUE,	/* Dst			0			1    */

    TRUE,	/* Over			1			1-Aa */

    TRUE,	/* OverReverse		1-Ab			1    */

    FALSE,	/* In			Ab			0    */

    FALSE,	/* InReverse		0			Aa   */

    FALSE,	/* Out			1-Ab			0    */

    TRUE,	/* OutReverse		0			1-Aa */

    TRUE,	/* Atop			Ab			1-Aa */

    FALSE,	/* AtopReverse		1-Ab			Aa   */

    TRUE,	/* Xor			1-Ab			1-Aa */

    TRUE,	/* Add			1			1    */

};

static pixman_bool_t

get_trap_extents (pixman_op_t op, pixman_image_t *dest,

		  const pixman_trapezoid_t *traps, int n_traps,

		  pixman_box32_t *box)

{

    int i;

    /* When the operator is such that a zero source has an

     * effect on the underlying image, we have to

     * composite across the entire destination

     */

    if (!zero_src_has_no_effect [op])

    {

	box->x1 = 0;

	box->y1 = 0;

	box->x2 = dest->bits.width;

	box->y2 = dest->bits.height;

	return TRUE;

    }

    box->x1 = INT32_MAX;

    box->y1 = INT32_MAX;

    box->x2 = INT32_MIN;

    box->y2 = INT32_MIN;

    for (i = 0; i < n_traps; ++i)

    {

	const pixman_trapezoid_t *trap = &(traps[i]);

	int y1, y2;

	if (!pixman_trapezoid_valid (trap))

	    continue;

	y1 = pixman_fixed_to_int (trap->top);

	if (y1 < box->y1)

	    box->y1 = y1;

	y2 = pixman_fixed_to_int (pixman_fixed_ceil (trap->bottom));

	if (y2 > box->y2)

	    box->y2 = y2;

#define EXTEND_MIN(x)							\

	if (pixman_fixed_to_int ((x)) < box->x1)			\

	    box->x1 = pixman_fixed_to_int ((x));

#define EXTEND_MAX(x)							\

	if (pixman_fixed_to_int (pixman_fixed_ceil ((x))) > box->x2)	\

	    box->x2 = pixman_fixed_to_int (pixman_fixed_ceil ((x)));

#define EXTEND(x)							\

	EXTEND_MIN(x);							\

	EXTEND_MAX(x);

	EXTEND(trap->left.p1.x);

	EXTEND(trap->left.p2.x);

	EXTEND(trap->right.p1.x);

	EXTEND(trap->right.p2.x);

    }

    if (box->x1 >= box->x2 || box->y1 >= box->y2)

	return FALSE;

    return TRUE;

}

/*

 * pixman_composite_trapezoids()

 *

 * All the trapezoids are conceptually rendered to an infinitely big image.

 * The (0, 0) coordinates of this image are then aligned with the (x, y)

 * coordinates of the source image, and then both images are aligned with

 * the (x, y) coordinates of the destination. Then these three images are

 * composited across the entire destination.

 */

PIXMAN_EXPORT void

pixman_composite_trapezoids (pixman_op_t		op,

			     pixman_image_t *		src,

			     pixman_image_t *		dst,

			     pixman_format_code_t	mask_format,

			     int			x_src,

			     int			y_src,

			     int			x_dst,

			     int			y_dst,

			     int			n_traps,

			     const pixman_trapezoid_t *	traps)

{

    int i;

    return_if_fail (PIXMAN_FORMAT_TYPE (mask_format) == PIXMAN_TYPE_A);

    if (n_traps <= 0)

	return;

    _pixman_image_validate (src);

    _pixman_image_validate (dst);

    if (op == PIXMAN_OP_ADD &&

	(src->common.flags & FAST_PATH_IS_OPAQUE)		&&

	(mask_format == dst->common.extended_format_code)	&&

	!(dst->common.have_clip_region))

    {

	for (i = 0; i < n_traps; ++i)

	{

	    const pixman_trapezoid_t *trap = &(traps[i]);

	    if (!pixman_trapezoid_valid (trap))

		continue;

	    pixman_rasterize_trapezoid (dst, trap, x_dst, y_dst);

	}

    }

    else

    {

	pixman_image_t *tmp;

	pixman_box32_t box;

	int i;

	if (!get_trap_extents (op, dst, traps, n_traps, &box))

	    return;

	if (!(tmp = pixman_image_create_bits (

		  mask_format, box.x2 - box.x1, box.y2 - box.y1, NULL, -1)))

	    return;

	for (i = 0; i < n_traps; ++i)

	{

	    const pixman_trapezoid_t *trap = &(traps[i]);

	    if (!pixman_trapezoid_valid (trap))

		continue;

	    pixman_rasterize_trapezoid (tmp, trap, - box.x1, - box.y1);

	}

	pixman_image_composite (op, src, tmp, dst,

				x_src + box.x1, y_src + box.y1,

				0, 0,

				x_dst + box.x1, y_dst + box.y1,

				box.x2 - box.x1, box.y2 - box.y1);

	pixman_image_unref (tmp);

    }

}

static int

greater_y (const pixman_point_fixed_t *a, const pixman_point_fixed_t *b)

{

    if (a->y == b->y)

	return a->x > b->x;

    return a->y > b->y;

}

/*

 * Note that the definition of this function is a bit odd because

 * of the X coordinate space (y increasing downwards).

 */

static int

clockwise (const pixman_point_fixed_t *ref,

	   const pixman_point_fixed_t *a,

	   const pixman_point_fixed_t *b)

{

    pixman_point_fixed_t	ad, bd;

    ad.x = a->x - ref->x;

    ad.y = a->y - ref->y;

    bd.x = b->x - ref->x;

    bd.y = b->y - ref->y;

    return ((pixman_fixed_32_32_t) bd.y * ad.x -

	    (pixman_fixed_32_32_t) ad.y * bd.x) < 0;

}

static void

triangle_to_trapezoids (const pixman_triangle_t *tri, pixman_trapezoid_t *traps)

{

    const pixman_point_fixed_t *top, *left, *right, *tmp;

    top = &tri->p1;

    left = &tri->p2;

    right = &tri->p3;

    if (greater_y (top, left))

    {

	tmp = left;

	left = top;

	top = tmp;

    }

    if (greater_y (top, right))

    {

	tmp = right;

	right = top;

	top = tmp;

    }

    if (clockwise (top, right, left))

    {

	tmp = right;

	right = left;

	left = tmp;

    }

    /*

     * Two cases:

     *

     *		+		+

     *	       / \             / \

     *	      /   \           /	  \

     *	     /     +         +	   \

     *      /    --           --    \

     *     /   --               --   \

     *    / ---                   --- \

     *	 +--                         --+

     */

    traps->top = top->y;

    traps->left.p1 = *top;

    traps->left.p2 = *left;

    traps->right.p1 = *top;

    traps->right.p2 = *right;

    if (right->y < left->y)

	traps->bottom = right->y;

    else

	traps->bottom = left->y;

    traps++;

    *traps = *(traps - 1);

    if (right->y < left->y)

    {

	traps->top = right->y;

	traps->bottom = left->y;

	traps->right.p1 = *right;

	traps->right.p2 = *left;

    }

    else

    {

	traps->top = left->y;

	traps->bottom = right->y;

	traps->left.p1 = *left;

	traps->left.p2 = *right;

    }

}

static pixman_trapezoid_t *

convert_triangles (int n_tris, const pixman_triangle_t *tris)

{

    pixman_trapezoid_t *traps;

    int i;

    if (n_tris <= 0)

	return NULL;

    traps = pixman_malloc_ab (n_tris, 2 * sizeof (pixman_trapezoid_t));

    if (!traps)

	return NULL;

    for (i = 0; i < n_tris; ++i)

	triangle_to_trapezoids (&(tris[i]), traps + 2 * i);

    return traps;

}

PIXMAN_EXPORT void

pixman_composite_triangles (pixman_op_t			op,

			    pixman_image_t *		src,

			    pixman_image_t *		dst,

			    pixman_format_code_t	mask_format,

			    int				x_src,

			    int				y_src,

			    int				x_dst,

			    int				y_dst,

			    int				n_tris,

			    const pixman_triangle_t *	tris)

{

    pixman_trapezoid_t *traps;

    if ((traps = convert_triangles (n_tris, tris)))

    {

	pixman_composite_trapezoids (op, src, dst, mask_format,

				     x_src, y_src, x_dst, y_dst,

				     n_tris * 2, traps);

	free (traps);

    }

}

PIXMAN_EXPORT void

pixman_add_triangles (pixman_image_t          *image,

		      int32_t	               x_off,

		      int32_t	               y_off,

		      int	               n_tris,

		      const pixman_triangle_t *tris)

{

    pixman_trapezoid_t *traps;

    if ((traps = convert_triangles (n_tris, tris)))

    {

	pixman_add_trapezoids (image, x_off, y_off,

			       n_tris * 2, traps);

	free (traps);

    }

}