/*
 * Copyright © 2007 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 the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS 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_DIX_CONFIG_H
#include <dix-config.h>
#endif

#include "misc.h"
#include "scrnintstr.h"
#include "os.h"
#include "regionstr.h"
#include "validate.h"
#include "windowstr.h"
#include "input.h"
#include "resource.h"
#include "colormapst.h"
#include "cursorstr.h"
#include "dixstruct.h"
#include "gcstruct.h"
#include "servermd.h"
#include "picturestr.h"

#define F(x)	IntToxFixed(x)

_X_EXPORT void
PictureTransformInitIdentity (PictTransformPtr matrix)
{
    int	i;
    memset (matrix, '\0', sizeof (PictTransform));
    for (i = 0; i < 3; i++)
	matrix->matrix[i][i] = F(1);
}

_X_EXPORT Bool
PictureTransformPoint3d (PictTransformPtr transform,
                         PictVectorPtr	vector)
{
    PictVector	    result;
    int		    i, j;
    xFixed_32_32    partial;
    xFixed_48_16    v;

    for (j = 0; j < 3; j++)
    {
	v = 0;
	for (i = 0; i < 3; i++)
	{
	    partial = ((xFixed_48_16) transform->matrix[j][i] *
		       (xFixed_48_16) vector->vector[i]);
	    v += partial >> 16;
	}
	if (v > MAX_FIXED_48_16 || v < MIN_FIXED_48_16)
	    return FALSE;
	result.vector[j] = (xFixed) v;
    }
    if (!result.vector[2])
	return FALSE;
    *vector = result;
    return TRUE;
}


_X_EXPORT Bool
PictureTransformPoint (PictTransformPtr transform,
		       PictVectorPtr	vector)
{
    PictVector	    result;
    int		    i, j;
    xFixed_32_32    partial;
    xFixed_48_16    v;

    for (j = 0; j < 3; j++)
    {
	v = 0;
	for (i = 0; i < 3; i++)
	{
	    partial = ((xFixed_48_16) transform->matrix[j][i] * 
		       (xFixed_48_16) vector->vector[i]);
	    v += partial >> 16;
	}
	if (v > MAX_FIXED_48_16 || v < MIN_FIXED_48_16)
	    return FALSE;
	result.vector[j] = (xFixed) v;
    }
    if (!result.vector[2])
	return FALSE;
    for (j = 0; j < 2; j++)
    {
	partial = (xFixed_48_16) result.vector[j] << 16;
	v = partial / result.vector[2];
	if (v > MAX_FIXED_48_16 || v < MIN_FIXED_48_16)
	    return FALSE;
	vector->vector[j] = (xFixed) v;
    }
    vector->vector[2] = xFixed1;
    return TRUE;
}

_X_EXPORT Bool
PictureTransformMultiply (PictTransformPtr dst, PictTransformPtr l, PictTransformPtr r)
{
    PictTransform   d;
    int		    dx, dy;
    int		    o;

    for (dy = 0; dy < 3; dy++)
	for (dx = 0; dx < 3; dx++)
	{
	    xFixed_48_16    v;
	    xFixed_32_32    partial;
	    v = 0;
	    for (o = 0; o < 3; o++)
	    {
		partial = (xFixed_32_32) l->matrix[dy][o] * (xFixed_32_32) r->matrix[o][dx];
		v += partial >> 16;
	    }
	    if (v > MAX_FIXED_48_16 || v < MIN_FIXED_48_16)
		return FALSE;
	    d.matrix[dy][dx] = (xFixed) v;
	}
    *dst = d;
    return TRUE;
}

_X_EXPORT void
PictureTransformInitScale (PictTransformPtr t, xFixed sx, xFixed sy)
{
    memset (t, '\0', sizeof (PictTransform));
    t->matrix[0][0] = sx;
    t->matrix[1][1] = sy;
    t->matrix[2][2] = F (1);
}

static xFixed
fixed_inverse (xFixed x)
{
    return (xFixed) ((((xFixed_48_16) F(1)) * F(1)) / x);
}

_X_EXPORT Bool
PictureTransformScale (PictTransformPtr forward,
		       PictTransformPtr reverse,
		       xFixed sx, xFixed sy)
{
    PictTransform   t;
    
    if (sx == 0 || sy == 0)
	return FALSE;

    PictureTransformInitScale (&t, sx, sy);
    if (!PictureTransformMultiply (forward, &t, forward))
	return FALSE;
    PictureTransformInitScale (&t, fixed_inverse (sx), fixed_inverse (sy));
    if (!PictureTransformMultiply (reverse, reverse, &t))
	return FALSE;
    return TRUE;
}

_X_EXPORT void
PictureTransformInitRotate (PictTransformPtr t, xFixed c, xFixed s)
{
    memset (t, '\0', sizeof (PictTransform));
    t->matrix[0][0] = c;
    t->matrix[0][1] = -s;
    t->matrix[1][0] = s;
    t->matrix[1][1] = c;
    t->matrix[2][2] = F (1);
}

_X_EXPORT Bool
PictureTransformRotate (PictTransformPtr forward,
			PictTransformPtr reverse,
			xFixed c, xFixed s)
{
    PictTransform   t;
    PictureTransformInitRotate (&t, c, s);
    if (!PictureTransformMultiply (forward, &t, forward))
	return FALSE;
    
    PictureTransformInitRotate (&t, c, -s);
    if (!PictureTransformMultiply (reverse, reverse, &t))
	return FALSE;
    return TRUE;
}

_X_EXPORT void
PictureTransformInitTranslate (PictTransformPtr t, xFixed tx, xFixed ty)
{
    memset (t, '\0', sizeof (PictTransform));
    t->matrix[0][0] = F (1);
    t->matrix[0][2] = tx;
    t->matrix[1][1] = F (1);
    t->matrix[1][2] = ty;
    t->matrix[2][2] = F (1);
}

_X_EXPORT Bool
PictureTransformTranslate (PictTransformPtr forward,
			   PictTransformPtr reverse,
			   xFixed tx, xFixed ty)
{
    PictTransform   t;
    PictureTransformInitTranslate (&t, tx, ty);
    if (!PictureTransformMultiply (forward, &t, forward))
	return FALSE;
    
    PictureTransformInitTranslate (&t, -tx, -ty);
    if (!PictureTransformMultiply (reverse, reverse, &t))
	return FALSE;
    return TRUE;
}

_X_EXPORT void
PictureTransformBounds (BoxPtr b, PictTransformPtr matrix)
{
    PictVector	v[4];
    int		i;
    int		x1, y1, x2, y2;

    v[0].vector[0] = F (b->x1);    v[0].vector[1] = F (b->y1);	v[0].vector[2] = F(1);
    v[1].vector[0] = F (b->x2);    v[1].vector[1] = F (b->y1);	v[1].vector[2] = F(1);
    v[2].vector[0] = F (b->x2);    v[2].vector[1] = F (b->y2);	v[2].vector[2] = F(1);
    v[3].vector[0] = F (b->x1);    v[3].vector[1] = F (b->y2);	v[3].vector[2] = F(1);
    for (i = 0; i < 4; i++)
    {
	PictureTransformPoint (matrix, &v[i]);
	x1 = xFixedToInt (v[i].vector[0]);
	y1 = xFixedToInt (v[i].vector[1]);
	x2 = xFixedToInt (xFixedCeil (v[i].vector[0]));
	y2 = xFixedToInt (xFixedCeil (v[i].vector[1]));
	if (i == 0)
	{
	    b->x1 = x1; b->y1 = y1;
	    b->x2 = x2; b->y2 = y2;
	}
	else
	{
	    if (x1 < b->x1) b->x1 = x1;
	    if (y1 < b->y1) b->y1 = y1;
	    if (x2 > b->x2) b->x2 = x2;
	    if (y2 > b->y2) b->y2 = y2;
	}
    }
}

static Bool
within_epsilon (xFixed a, xFixed b, xFixed epsilon)
{
    xFixed  t = a - b;
    if (t < 0) t = -t;
    return t <= epsilon;
}

#define epsilon	(xFixed) (2)

#define IsSame(a,b) (within_epsilon (a, b, epsilon))
#define IsZero(a)   (within_epsilon (a, 0, epsilon))
#define IsOne(a)    (within_epsilon (a, F(1), epsilon))
#define IsUnit(a)   (within_epsilon (a, F( 1), epsilon) || \
		     within_epsilon (a, F(-1), epsilon) || \
		     IsZero (a))
#define IsInt(a)    (IsZero (xFixedFrac(a)))
		     
_X_EXPORT Bool
PictureTransformIsIdentity(PictTransform *t)
{
    return (IsUnit (t->matrix[0][0]) &&
	    IsUnit (t->matrix[0][1]) &&
            IsInt  (t->matrix[0][2]) &&
	    IsUnit (t->matrix[1][0]) &&
	    IsUnit (t->matrix[1][1]) &&
            IsInt  (t->matrix[1][2]) &&
            IsZero (t->matrix[2][0]) &&
            IsZero (t->matrix[2][1]) &&
	    IsOne  (t->matrix[2][2]));
}

_X_EXPORT Bool
PictureTransformIsUnit(PictTransform *t)
{
    return (IsSame (t->matrix[0][0],t->matrix[1][1]) &&
	    IsSame (t->matrix[0][0], t->matrix[2][2]) &&
            !IsZero (t->matrix[0][0]) &&
	    IsZero (t->matrix[0][1]) &&
            IsZero (t->matrix[0][2]) &&
            IsZero (t->matrix[1][0]) &&
            IsZero (t->matrix[1][2]) &&
            IsZero (t->matrix[2][0]) &&
            IsZero (t->matrix[2][1]));
}

_X_EXPORT Bool
PictureTransformIsScale(PictTransform *t)
{
    return (!IsZero (t->matrix[0][0]) &&
	     IsZero (t->matrix[0][1]) &&
	     IsZero (t->matrix[0][2]) &&
	    
	     IsZero (t->matrix[1][0]) &&
	    !IsZero (t->matrix[1][1]) &&
	     IsZero (t->matrix[1][2]) &&
	    
	     IsZero (t->matrix[2][0]) &&
	     IsZero (t->matrix[2][1]) &&
	     IsOne (t->matrix[2][2]));
}

_X_EXPORT Bool
PictureTransformIsTranslate(PictTransform *t)
{
    return ( IsOne  (t->matrix[0][0]) &&
	     IsZero (t->matrix[0][1]) &&
	     IsInt  (t->matrix[0][2]) &&
	    
	     IsZero (t->matrix[1][0]) &&
	     IsOne  (t->matrix[1][1]) &&
	     IsInt  (t->matrix[1][2]) &&
	    
	     IsZero (t->matrix[2][0]) &&
	     IsZero (t->matrix[2][1]) &&
	     IsOne  (t->matrix[2][2]));
}

_X_EXPORT Bool
PictureTransformIsInverse (PictTransform *a, PictTransform *b)
{
    PictTransform   t;

    PictureTransformMultiply (&t, a, b);
    return PictureTransformIsIdentity (&t);
}