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gimp/libgimpmath/gimpmatrix.c

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/* LIBGIMP - The GIMP Library
* Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
*
* gimpmatrix.c
* Copyright (C) 1998 Jay Cox <jaycox@gimp.org>
*
* This library is free software: you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <glib-object.h>
#include "gimpmath.h"
/**
* SECTION: gimpmatrix
* @title: GimpMatrix
* @short_description: Utilities to set up and manipulate 3x3
* transformation matrices.
* @see_also: #GimpVector2, #GimpVector3, #GimpVector4
*
* When doing image manipulation you will often need 3x3
* transformation matrices that define translation, rotation, scaling,
* shearing and arbitrary perspective transformations using a 3x3
* matrix. Here you'll find a set of utility functions to set up those
* matrices and to perform basic matrix manipulations and tests.
*
* Each matrix class has a 2 dimensional gdouble coeff member. The
* element for row r and column c of the matrix is coeff[r][c].
**/
#define EPSILON 1e-6
static GimpMatrix2 * matrix2_copy (const GimpMatrix2 *matrix);
/**
* gimp_matrix2_get_type:
*
* Reveals the object type
*
* Returns: the #GType for Matrix2 objects
*
* Since: 2.4
**/
GType
gimp_matrix2_get_type (void)
{
static GType matrix_type = 0;
if (!matrix_type)
matrix_type = g_boxed_type_register_static ("GimpMatrix2",
(GBoxedCopyFunc) matrix2_copy,
(GBoxedFreeFunc) g_free);
return matrix_type;
}
/*
* GIMP_TYPE_PARAM_MATRIX2
*/
#define GIMP_PARAM_SPEC_MATRIX2(pspec) (G_TYPE_CHECK_INSTANCE_CAST ((pspec), GIMP_TYPE_PARAM_MATRIX2, GimpParamSpecMatrix2))
static void gimp_param_matrix2_class_init (GParamSpecClass *class);
static void gimp_param_matrix2_init (GParamSpec *pspec);
static void gimp_param_matrix2_set_default (GParamSpec *pspec,
GValue *value);
static gint gimp_param_matrix2_values_cmp (GParamSpec *pspec,
const GValue *value1,
const GValue *value2);
typedef struct _GimpParamSpecMatrix2 GimpParamSpecMatrix2;
struct _GimpParamSpecMatrix2
{
GParamSpecBoxed parent_instance;
GimpMatrix2 default_value;
};
/**
* gimp_param_matrix2_get_type:
*
* Reveals the object type
*
* Returns: the #GType for a GimpMatrix2 object
*
* Since: 2.4
**/
GType
gimp_param_matrix2_get_type (void)
{
static GType spec_type = 0;
if (!spec_type)
{
static const GTypeInfo type_info =
{
sizeof (GParamSpecClass),
NULL, NULL,
(GClassInitFunc) gimp_param_matrix2_class_init,
NULL, NULL,
sizeof (GimpParamSpecMatrix2),
0,
(GInstanceInitFunc) gimp_param_matrix2_init
};
spec_type = g_type_register_static (G_TYPE_PARAM_BOXED,
"GimpParamMatrix2",
&type_info, 0);
}
return spec_type;
}
static void
gimp_param_matrix2_class_init (GParamSpecClass *class)
{
class->value_type = GIMP_TYPE_MATRIX2;
class->value_set_default = gimp_param_matrix2_set_default;
class->values_cmp = gimp_param_matrix2_values_cmp;
}
static void
gimp_param_matrix2_init (GParamSpec *pspec)
{
GimpParamSpecMatrix2 *cspec = GIMP_PARAM_SPEC_MATRIX2 (pspec);
gimp_matrix2_identity (&cspec->default_value);
}
static void
gimp_param_matrix2_set_default (GParamSpec *pspec,
GValue *value)
{
GimpParamSpecMatrix2 *cspec = GIMP_PARAM_SPEC_MATRIX2 (pspec);
g_value_set_static_boxed (value, &cspec->default_value);
}
static gint
gimp_param_matrix2_values_cmp (GParamSpec *pspec,
const GValue *value1,
const GValue *value2)
{
GimpMatrix2 *matrix1;
GimpMatrix2 *matrix2;
gint i, j;
matrix1 = value1->data[0].v_pointer;
matrix2 = value2->data[0].v_pointer;
/* try to return at least *something*, it's useless anyway... */
if (! matrix1)
return matrix2 != NULL ? -1 : 0;
else if (! matrix2)
return matrix1 != NULL;
for (i = 0; i < 2; i++)
for (j = 0; j < 2; j++)
if (matrix1->coeff[i][j] != matrix2->coeff[i][j])
return 1;
return 0;
}
/**
* gimp_param_spec_matrix2:
* @name: Canonical name of the param
* @nick: Nickname of the param
* @blurb: Brief description of param.
* @default_value: Value to use if none is assigned.
* @flags: a combination of #GParamFlags
*
* Creates a param spec to hold a #GimpMatrix2 value.
* See g_param_spec_internal() for more information.
*
* Returns: a newly allocated #GParamSpec instance
*
* Since: 2.4
**/
GParamSpec *
gimp_param_spec_matrix2 (const gchar *name,
const gchar *nick,
const gchar *blurb,
const GimpMatrix2 *default_value,
GParamFlags flags)
{
GimpParamSpecMatrix2 *cspec;
g_return_val_if_fail (default_value != NULL, NULL);
cspec = g_param_spec_internal (GIMP_TYPE_PARAM_MATRIX2,
name, nick, blurb, flags);
cspec->default_value = *default_value;
return G_PARAM_SPEC (cspec);
}
static GimpMatrix2 *
matrix2_copy (const GimpMatrix2 *matrix)
{
return (GimpMatrix2 *) g_memdup (matrix, sizeof (GimpMatrix2));
}
/**
* gimp_matrix2_identity:
* @matrix: A matrix.
*
* Sets the matrix to the identity matrix.
*/
void
gimp_matrix2_identity (GimpMatrix2 *matrix)
{
static const GimpMatrix2 identity = { { { 1.0, 0.0 },
{ 0.0, 1.0 } } };
*matrix = identity;
}
/**
* gimp_matrix2_mult:
* @matrix1: The first input matrix.
* @matrix2: The second input matrix which will be overwritten by the result.
*
* Multiplies two matrices and puts the result into the second one.
*/
void
gimp_matrix2_mult (const GimpMatrix2 *matrix1,
GimpMatrix2 *matrix2)
{
GimpMatrix2 tmp;
tmp.coeff[0][0] = (matrix1->coeff[0][0] * matrix2->coeff[0][0] +
matrix1->coeff[0][1] * matrix2->coeff[1][0]);
tmp.coeff[0][1] = (matrix1->coeff[0][0] * matrix2->coeff[0][1] +
matrix1->coeff[0][1] * matrix2->coeff[1][1]);
tmp.coeff[1][0] = (matrix1->coeff[1][0] * matrix2->coeff[0][0] +
matrix1->coeff[1][1] * matrix2->coeff[1][0]);
tmp.coeff[1][1] = (matrix1->coeff[1][0] * matrix2->coeff[0][1] +
matrix1->coeff[1][1] * matrix2->coeff[1][1]);
*matrix2 = tmp;
}
/**
* gimp_matrix2_determinant:
* @matrix: The input matrix.
*
* Calculates the determinant of the given matrix.
*
* Returns: The determinant.
*
* Since: 2.10.16
*/
gdouble
gimp_matrix2_determinant (const GimpMatrix2 *matrix)
{
return matrix->coeff[0][0] * matrix->coeff[1][1] -
matrix->coeff[0][1] * matrix->coeff[1][0];
}
/**
* gimp_matrix2_invert:
* @matrix: The matrix that is to be inverted.
*
* Inverts the given matrix.
*
* Since: 2.10.16
*/
void
gimp_matrix2_invert (GimpMatrix2 *matrix)
{
gdouble det = gimp_matrix2_determinant (matrix);
gdouble temp;
if (fabs (det) <= EPSILON)
return;
temp = matrix->coeff[0][0];
matrix->coeff[0][0] = matrix->coeff[1][1] / det;
matrix->coeff[0][1] /= -det;
matrix->coeff[1][0] /= -det;
matrix->coeff[1][1] = temp / det;
}
/**
* gimp_matrix2_transform_point:
* @matrix: The transformation matrix.
* @x: The source X coordinate.
* @y: The source Y coordinate.
* @newx: The transformed X coordinate.
* @newy: The transformed Y coordinate.
*
* Transforms a point in 2D as specified by the transformation matrix.
*
* Since: 2.10.16
*/
void
gimp_matrix2_transform_point (const GimpMatrix2 *matrix,
gdouble x,
gdouble y,
gdouble *newx,
gdouble *newy)
{
*newx = matrix->coeff[0][0] * x + matrix->coeff[0][1] * y;
*newy = matrix->coeff[1][0] * x + matrix->coeff[1][1] * y;
}
static GimpMatrix3 * matrix3_copy (const GimpMatrix3 *matrix);
/**
* gimp_matrix3_get_type:
*
* Reveals the object type
*
* Returns: the #GType for Matrix3 objects
*
* Since: 2.8
**/
GType
gimp_matrix3_get_type (void)
{
static GType matrix_type = 0;
if (!matrix_type)
matrix_type = g_boxed_type_register_static ("GimpMatrix3",
(GBoxedCopyFunc) matrix3_copy,
(GBoxedFreeFunc) g_free);
return matrix_type;
}
/*
* GIMP_TYPE_PARAM_MATRIX3
*/
#define GIMP_PARAM_SPEC_MATRIX3(pspec) (G_TYPE_CHECK_INSTANCE_CAST ((pspec), GIMP_TYPE_PARAM_MATRIX3, GimpParamSpecMatrix3))
static void gimp_param_matrix3_class_init (GParamSpecClass *class);
static void gimp_param_matrix3_init (GParamSpec *pspec);
static void gimp_param_matrix3_set_default (GParamSpec *pspec,
GValue *value);
static gint gimp_param_matrix3_values_cmp (GParamSpec *pspec,
const GValue *value1,
const GValue *value2);
typedef struct _GimpParamSpecMatrix3 GimpParamSpecMatrix3;
struct _GimpParamSpecMatrix3
{
GParamSpecBoxed parent_instance;
GimpMatrix3 default_value;
};
/**
* gimp_param_matrix3_get_type:
*
* Reveals the object type
*
* Returns: the #GType for a GimpMatrix3 object
*
* Since: 2.8
**/
GType
gimp_param_matrix3_get_type (void)
{
static GType spec_type = 0;
if (!spec_type)
{
static const GTypeInfo type_info =
{
sizeof (GParamSpecClass),
NULL, NULL,
(GClassInitFunc) gimp_param_matrix3_class_init,
NULL, NULL,
sizeof (GimpParamSpecMatrix3),
0,
(GInstanceInitFunc) gimp_param_matrix3_init
};
spec_type = g_type_register_static (G_TYPE_PARAM_BOXED,
"GimpParamMatrix3",
&type_info, 0);
}
return spec_type;
}
static void
gimp_param_matrix3_class_init (GParamSpecClass *class)
{
class->value_type = GIMP_TYPE_MATRIX3;
class->value_set_default = gimp_param_matrix3_set_default;
class->values_cmp = gimp_param_matrix3_values_cmp;
}
static void
gimp_param_matrix3_init (GParamSpec *pspec)
{
GimpParamSpecMatrix3 *cspec = GIMP_PARAM_SPEC_MATRIX3 (pspec);
gimp_matrix3_identity (&cspec->default_value);
}
static void
gimp_param_matrix3_set_default (GParamSpec *pspec,
GValue *value)
{
GimpParamSpecMatrix3 *cspec = GIMP_PARAM_SPEC_MATRIX3 (pspec);
g_value_set_static_boxed (value, &cspec->default_value);
}
static gint
gimp_param_matrix3_values_cmp (GParamSpec *pspec,
const GValue *value1,
const GValue *value2)
{
GimpMatrix3 *matrix1;
GimpMatrix3 *matrix2;
gint i, j;
matrix1 = value1->data[0].v_pointer;
matrix2 = value2->data[0].v_pointer;
/* try to return at least *something*, it's useless anyway... */
if (! matrix1)
return matrix2 != NULL ? -1 : 0;
else if (! matrix2)
return matrix1 != NULL;
for (i = 0; i < 3; i++)
for (j = 0; j < 3; j++)
if (matrix1->coeff[i][j] != matrix2->coeff[i][j])
return 1;
return 0;
}
/**
* gimp_param_spec_matrix3:
* @name: Canonical name of the param
* @nick: Nickname of the param
* @blurb: Brief description of param.
* @default_value: Value to use if none is assigned.
* @flags: a combination of #GParamFlags
*
* Creates a param spec to hold a #GimpMatrix3 value.
* See g_param_spec_internal() for more information.
*
* Returns: a newly allocated #GParamSpec instance
*
* Since: 2.8
**/
GParamSpec *
gimp_param_spec_matrix3 (const gchar *name,
const gchar *nick,
const gchar *blurb,
const GimpMatrix3 *default_value,
GParamFlags flags)
{
GimpParamSpecMatrix3 *cspec;
cspec = g_param_spec_internal (GIMP_TYPE_PARAM_MATRIX3,
name, nick, blurb, flags);
if (default_value)
cspec->default_value = *default_value;
return G_PARAM_SPEC (cspec);
}
static GimpMatrix3 *
matrix3_copy (const GimpMatrix3 *matrix)
{
return (GimpMatrix3 *) g_memdup (matrix, sizeof (GimpMatrix3));
}
/**
* gimp_matrix3_identity:
* @matrix: A matrix.
*
* Sets the matrix to the identity matrix.
*/
void
gimp_matrix3_identity (GimpMatrix3 *matrix)
{
static const GimpMatrix3 identity = { { { 1.0, 0.0, 0.0 },
{ 0.0, 1.0, 0.0 },
{ 0.0, 0.0, 1.0 } } };
*matrix = identity;
}
/**
* gimp_matrix3_transform_point:
* @matrix: The transformation matrix.
* @x: The source X coordinate.
* @y: The source Y coordinate.
* @newx: The transformed X coordinate.
* @newy: The transformed Y coordinate.
*
* Transforms a point in 2D as specified by the transformation matrix.
*/
void
gimp_matrix3_transform_point (const GimpMatrix3 *matrix,
gdouble x,
gdouble y,
gdouble *newx,
gdouble *newy)
{
gdouble w;
w = matrix->coeff[2][0] * x + matrix->coeff[2][1] * y + matrix->coeff[2][2];
if (w == 0.0)
w = 1.0;
else
w = 1.0/w;
*newx = (matrix->coeff[0][0] * x +
matrix->coeff[0][1] * y +
matrix->coeff[0][2]) * w;
*newy = (matrix->coeff[1][0] * x +
matrix->coeff[1][1] * y +
matrix->coeff[1][2]) * w;
}
/**
* gimp_matrix3_mult:
* @matrix1: The first input matrix.
* @matrix2: The second input matrix which will be overwritten by the result.
*
* Multiplies two matrices and puts the result into the second one.
*/
void
gimp_matrix3_mult (const GimpMatrix3 *matrix1,
GimpMatrix3 *matrix2)
{
gint i, j;
GimpMatrix3 tmp;
gdouble t1, t2, t3;
for (i = 0; i < 3; i++)
{
t1 = matrix1->coeff[i][0];
t2 = matrix1->coeff[i][1];
t3 = matrix1->coeff[i][2];
for (j = 0; j < 3; j++)
{
tmp.coeff[i][j] = t1 * matrix2->coeff[0][j];
tmp.coeff[i][j] += t2 * matrix2->coeff[1][j];
tmp.coeff[i][j] += t3 * matrix2->coeff[2][j];
}
}
*matrix2 = tmp;
}
/**
* gimp_matrix3_translate:
* @matrix: The matrix that is to be translated.
* @x: Translation in X direction.
* @y: Translation in Y direction.
*
* Translates the matrix by x and y.
*/
void
gimp_matrix3_translate (GimpMatrix3 *matrix,
gdouble x,
gdouble y)
{
gdouble g, h, i;
g = matrix->coeff[2][0];
h = matrix->coeff[2][1];
i = matrix->coeff[2][2];
matrix->coeff[0][0] += x * g;
matrix->coeff[0][1] += x * h;
matrix->coeff[0][2] += x * i;
matrix->coeff[1][0] += y * g;
matrix->coeff[1][1] += y * h;
matrix->coeff[1][2] += y * i;
}
/**
* gimp_matrix3_scale:
* @matrix: The matrix that is to be scaled.
* @x: X scale factor.
* @y: Y scale factor.
*
* Scales the matrix by x and y
*/
void
gimp_matrix3_scale (GimpMatrix3 *matrix,
gdouble x,
gdouble y)
{
matrix->coeff[0][0] *= x;
matrix->coeff[0][1] *= x;
matrix->coeff[0][2] *= x;
matrix->coeff[1][0] *= y;
matrix->coeff[1][1] *= y;
matrix->coeff[1][2] *= y;
}
/**
* gimp_matrix3_rotate:
* @matrix: The matrix that is to be rotated.
* @theta: The angle of rotation (in radians).
*
* Rotates the matrix by theta degrees.
*/
void
gimp_matrix3_rotate (GimpMatrix3 *matrix,
gdouble theta)
{
gdouble t1, t2;
gdouble cost, sint;
cost = cos (theta);
sint = sin (theta);
t1 = matrix->coeff[0][0];
t2 = matrix->coeff[1][0];
matrix->coeff[0][0] = cost * t1 - sint * t2;
matrix->coeff[1][0] = sint * t1 + cost * t2;
t1 = matrix->coeff[0][1];
t2 = matrix->coeff[1][1];
matrix->coeff[0][1] = cost * t1 - sint * t2;
matrix->coeff[1][1] = sint * t1 + cost * t2;
t1 = matrix->coeff[0][2];
t2 = matrix->coeff[1][2];
matrix->coeff[0][2] = cost * t1 - sint * t2;
matrix->coeff[1][2] = sint * t1 + cost * t2;
}
/**
* gimp_matrix3_xshear:
* @matrix: The matrix that is to be sheared.
* @amount: X shear amount.
*
* Shears the matrix in the X direction.
*/
void
gimp_matrix3_xshear (GimpMatrix3 *matrix,
gdouble amount)
{
matrix->coeff[0][0] += amount * matrix->coeff[1][0];
matrix->coeff[0][1] += amount * matrix->coeff[1][1];
matrix->coeff[0][2] += amount * matrix->coeff[1][2];
}
/**
* gimp_matrix3_yshear:
* @matrix: The matrix that is to be sheared.
* @amount: Y shear amount.
*
* Shears the matrix in the Y direction.
*/
void
gimp_matrix3_yshear (GimpMatrix3 *matrix,
gdouble amount)
{
matrix->coeff[1][0] += amount * matrix->coeff[0][0];
matrix->coeff[1][1] += amount * matrix->coeff[0][1];
matrix->coeff[1][2] += amount * matrix->coeff[0][2];
}
/**
* gimp_matrix3_affine:
* @matrix: The input matrix.
* @a: the 'a' coefficient
* @b: the 'b' coefficient
* @c: the 'c' coefficient
* @d: the 'd' coefficient
* @e: the 'e' coefficient
* @f: the 'f' coefficient
*
* Applies the affine transformation given by six values to @matrix.
* The six values form define an affine transformation matrix as
* illustrated below:
*
* ( a c e )
* ( b d f )
* ( 0 0 1 )
**/
void
gimp_matrix3_affine (GimpMatrix3 *matrix,
gdouble a,
gdouble b,
gdouble c,
gdouble d,
gdouble e,
gdouble f)
{
GimpMatrix3 affine;
affine.coeff[0][0] = a;
affine.coeff[1][0] = b;
affine.coeff[2][0] = 0.0;
affine.coeff[0][1] = c;
affine.coeff[1][1] = d;
affine.coeff[2][1] = 0.0;
affine.coeff[0][2] = e;
affine.coeff[1][2] = f;
affine.coeff[2][2] = 1.0;
gimp_matrix3_mult (&affine, matrix);
}
/**
* gimp_matrix3_determinant:
* @matrix: The input matrix.
*
* Calculates the determinant of the given matrix.
*
* Returns: The determinant.
*/
gdouble
gimp_matrix3_determinant (const GimpMatrix3 *matrix)
{
gdouble determinant;
determinant = (matrix->coeff[0][0] *
(matrix->coeff[1][1] * matrix->coeff[2][2] -
matrix->coeff[1][2] * matrix->coeff[2][1]));
determinant -= (matrix->coeff[1][0] *
(matrix->coeff[0][1] * matrix->coeff[2][2] -
matrix->coeff[0][2] * matrix->coeff[2][1]));
determinant += (matrix->coeff[2][0] *
(matrix->coeff[0][1] * matrix->coeff[1][2] -
matrix->coeff[0][2] * matrix->coeff[1][1]));
return determinant;
}
/**
* gimp_matrix3_invert:
* @matrix: The matrix that is to be inverted.
*
* Inverts the given matrix.
*/
void
gimp_matrix3_invert (GimpMatrix3 *matrix)
{
GimpMatrix3 inv;
gdouble det;
det = gimp_matrix3_determinant (matrix);
if (det == 0.0)
return;
det = 1.0 / det;
inv.coeff[0][0] = (matrix->coeff[1][1] * matrix->coeff[2][2] -
matrix->coeff[1][2] * matrix->coeff[2][1]) * det;
inv.coeff[1][0] = - (matrix->coeff[1][0] * matrix->coeff[2][2] -
matrix->coeff[1][2] * matrix->coeff[2][0]) * det;
inv.coeff[2][0] = (matrix->coeff[1][0] * matrix->coeff[2][1] -
matrix->coeff[1][1] * matrix->coeff[2][0]) * det;
inv.coeff[0][1] = - (matrix->coeff[0][1] * matrix->coeff[2][2] -
matrix->coeff[0][2] * matrix->coeff[2][1]) * det;
inv.coeff[1][1] = (matrix->coeff[0][0] * matrix->coeff[2][2] -
matrix->coeff[0][2] * matrix->coeff[2][0]) * det;
inv.coeff[2][1] = - (matrix->coeff[0][0] * matrix->coeff[2][1] -
matrix->coeff[0][1] * matrix->coeff[2][0]) * det;
inv.coeff[0][2] = (matrix->coeff[0][1] * matrix->coeff[1][2] -
matrix->coeff[0][2] * matrix->coeff[1][1]) * det;
inv.coeff[1][2] = - (matrix->coeff[0][0] * matrix->coeff[1][2] -
matrix->coeff[0][2] * matrix->coeff[1][0]) * det;
inv.coeff[2][2] = (matrix->coeff[0][0] * matrix->coeff[1][1] -
matrix->coeff[0][1] * matrix->coeff[1][0]) * det;
*matrix = inv;
}
/* functions to test for matrix properties */
/**
* gimp_matrix3_is_identity:
* @matrix: The matrix that is to be tested.
*
* Checks if the given matrix is the identity matrix.
*
* Returns: %TRUE if the matrix is the identity matrix, %FALSE otherwise
*/
gboolean
gimp_matrix3_is_identity (const GimpMatrix3 *matrix)
{
gint i, j;
for (i = 0; i < 3; i++)
{
for (j = 0; j < 3; j++)
{
if (i == j)
{
if (fabs (matrix->coeff[i][j] - 1.0) > EPSILON)
return FALSE;
}
else
{
if (fabs (matrix->coeff[i][j]) > EPSILON)
return FALSE;
}
}
}
return TRUE;
}
/**
* gimp_matrix3_is_diagonal:
* @matrix: The matrix that is to be tested.
*
* Checks if the given matrix is diagonal.
*
* Returns: %TRUE if the matrix is diagonal, %FALSE otherwise
*/
gboolean
gimp_matrix3_is_diagonal (const GimpMatrix3 *matrix)
{
gint i, j;
for (i = 0; i < 3; i++)
{
for (j = 0; j < 3; j++)
{
if (i != j && fabs (matrix->coeff[i][j]) > EPSILON)
return FALSE;
}
}
return TRUE;
}
/**
* gimp_matrix3_is_affine:
* @matrix: The matrix that is to be tested.
*
* Checks if the given matrix defines an affine transformation.
*
* Returns: %TRUE if the matrix defines an affine transformation,
* %FALSE otherwise
*
* Since: 2.4
*/
gboolean
gimp_matrix3_is_affine (const GimpMatrix3 *matrix)
{
return (fabs (matrix->coeff[2][0]) < EPSILON &&
fabs (matrix->coeff[2][1]) < EPSILON &&
fabs (matrix->coeff[2][2] - 1.0) < EPSILON);
}
/**
* gimp_matrix3_is_simple:
* @matrix: The matrix that is to be tested.
*
* Checks if we'll need to interpolate when applying this matrix as
* a transformation.
*
* Returns: %TRUE if all entries of the upper left 2x2 matrix are
* either 0 or 1, %FALSE otherwise
*/
gboolean
gimp_matrix3_is_simple (const GimpMatrix3 *matrix)
{
gdouble absm;
gint i, j;
for (i = 0; i < 2; i++)
{
for (j = 0; j < 2; j++)
{
absm = fabs (matrix->coeff[i][j]);
if (absm > EPSILON && fabs (absm - 1.0) > EPSILON)
return FALSE;
}
}
return TRUE;
}
/**
* gimp_matrix3_equal:
* @matrix1: The first matrix
* @matrix2: The second matrix
*
* Checks if two matrices are equal.
*
* Returns: %TRUE the matrices are equal, %FALSE otherwise
*
* Since: 2.10.16
*/
gboolean
gimp_matrix3_equal (const GimpMatrix3 *matrix1,
const GimpMatrix3 *matrix2)
{
gint i, j;
for (i = 0; i < 3; i++)
{
for (j = 0; j < 3; j++)
{
if (fabs (matrix1->coeff[i][j] - matrix2->coeff[i][j]) > EPSILON)
return FALSE;
}
}
return TRUE;
}
/**
* gimp_matrix4_identity:
* @matrix: A matrix.
*
* Sets the matrix to the identity matrix.
*
* Since: 2.10.16
*/
void
gimp_matrix4_identity (GimpMatrix4 *matrix)
{
gint i, j;
for (i = 0; i < 4; i++)
{
for (j = 0; j < 4; j++)
matrix->coeff[i][j] = i == j;
}
}
/**
* gimp_matrix4_mult:
* @matrix1: The first input matrix.
* @matrix2: The second input matrix which will be overwritten by the result.
*
* Multiplies two matrices and puts the result into the second one.
*
* Since: 2.10.16
*/
void
gimp_matrix4_mult (const GimpMatrix4 *matrix1,
GimpMatrix4 *matrix2)
{
GimpMatrix4 result = {};
gint i, j, k;
for (i = 0; i < 4; i++)
{
for (j = 0; j < 4; j++)
{
for (k = 0; k < 4; k++)
result.coeff[i][j] += matrix1->coeff[i][k] * matrix2->coeff[k][j];
}
}
*matrix2 = result;
}
/**
* gimp_matrix4_to_deg:
* @matrix:
* @a:
* @b:
* @c:
*
*
**/
void
gimp_matrix4_to_deg (const GimpMatrix4 *matrix,
gdouble *a,
gdouble *b,
gdouble *c)
{
*a = 180 * (asin (matrix->coeff[1][0]) / G_PI_2);
*b = 180 * (asin (matrix->coeff[2][0]) / G_PI_2);
*c = 180 * (asin (matrix->coeff[2][1]) / G_PI_2);
}
/**
* gimp_matrix4_transform_point:
* @matrix: The transformation matrix.
* @x: The source X coordinate.
* @y: The source Y coordinate.
* @z: The source Z coordinate.
* @newx: The transformed X coordinate.
* @newy: The transformed Y coordinate.
* @newz: The transformed Z coordinate.
*
* Transforms a point in 3D as specified by the transformation matrix.
*
* Returns: The transformed W coordinate.
*
* Since: 2.10.16
*/
gdouble
gimp_matrix4_transform_point (const GimpMatrix4 *matrix,
gdouble x,
gdouble y,
gdouble z,
gdouble *newx,
gdouble *newy,
gdouble *newz)
{
gdouble neww;
*newx = matrix->coeff[0][0] * x +
matrix->coeff[0][1] * y +
matrix->coeff[0][2] * z +
matrix->coeff[0][3];
*newy = matrix->coeff[1][0] * x +
matrix->coeff[1][1] * y +
matrix->coeff[1][2] * z +
matrix->coeff[1][3];
*newz = matrix->coeff[2][0] * x +
matrix->coeff[2][1] * y +
matrix->coeff[2][2] * z +
matrix->coeff[2][3];
neww = matrix->coeff[3][0] * x +
matrix->coeff[3][1] * y +
matrix->coeff[3][2] * z +
matrix->coeff[3][3];
*newx /= neww;
*newy /= neww;
*newz /= neww;
return neww;
}
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