gimp/app/core/gimp-transform-utils.c

272 lines
8.0 KiB
C

/* The GIMP -- an image manipulation program
* Copyright (C) 1995-2001 Spencer Kimball, Peter Mattis, and others
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include <glib-object.h>
#include "libgimpmath/gimpmath.h"
#include "core-types.h"
#include "gimp-transform-utils.h"
void
gimp_transform_matrix_flip (GimpOrientationType flip_type,
gdouble axis,
GimpMatrix3 *result)
{
g_return_if_fail (result != NULL);
gimp_matrix3_identity (result);
switch (flip_type)
{
case GIMP_ORIENTATION_HORIZONTAL:
gimp_matrix3_translate (result, - axis, 0.0);
gimp_matrix3_scale (result, -1.0, 1.0);
gimp_matrix3_translate (result, axis, 0.0);
break;
case GIMP_ORIENTATION_VERTICAL:
gimp_matrix3_translate (result, 0.0, - axis);
gimp_matrix3_scale (result, 1.0, -1.0);
gimp_matrix3_translate (result, 0.0, axis);
break;
case GIMP_ORIENTATION_UNKNOWN:
break;
}
}
void
gimp_transform_matrix_flip_free (gint x,
gint y,
gint width,
gint height,
gdouble x1,
gdouble y1,
gdouble x2,
gdouble y2,
GimpMatrix3 *result)
{
gdouble angle;
g_return_if_fail (result != NULL);
angle = atan2 (y2 - y1, x2 - x1);
gimp_matrix3_identity (result);
gimp_matrix3_translate (result, -x1, -y1);
gimp_matrix3_rotate (result, -angle);
gimp_matrix3_scale (result, 1.0, -1.0);
gimp_matrix3_rotate (result, angle);
gimp_matrix3_translate (result, x1, y1);
}
void
gimp_transform_matrix_rotate (gint x,
gint y,
gint width,
gint height,
gdouble angle,
GimpMatrix3 *result)
{
gdouble center_x;
gdouble center_y;
g_return_if_fail (result != NULL);
center_x = (gdouble) x + (gdouble) width / 2.0;
center_y = (gdouble) y + (gdouble) height / 2.0;
gimp_matrix3_identity (result);
gimp_matrix3_translate (result, -center_x, -center_y);
gimp_matrix3_rotate (result, angle);
gimp_matrix3_translate (result, +center_x, +center_y);
}
void
gimp_transform_matrix_rotate_center (gdouble center_x,
gdouble center_y,
gdouble angle,
GimpMatrix3 *result)
{
g_return_if_fail (result != NULL);
gimp_matrix3_identity (result);
gimp_matrix3_translate (result, -center_x, -center_y);
gimp_matrix3_rotate (result, angle);
gimp_matrix3_translate (result, +center_x, +center_y);
}
void
gimp_transform_matrix_scale (gint x,
gint y,
gint width,
gint height,
gdouble t_x,
gdouble t_y,
gdouble t_width,
gdouble t_height,
GimpMatrix3 *result)
{
gdouble scale_x = 1.0;
gdouble scale_y = 1.0;
g_return_if_fail (result != NULL);
if (width > 0)
scale_x = t_width / (gdouble) width;
if (height > 0)
scale_y = t_height / (gdouble) height;
gimp_matrix3_identity (result);
gimp_matrix3_translate (result, -x, -y);
gimp_matrix3_scale (result, scale_x, scale_y);
gimp_matrix3_translate (result, t_x, t_y);
}
void
gimp_transform_matrix_shear (gint x,
gint y,
gint width,
gint height,
GimpOrientationType orientation,
gdouble amount,
GimpMatrix3 *result)
{
gdouble center_x;
gdouble center_y;
g_return_if_fail (result != NULL);
if (width == 0)
width = 1;
if (height == 0)
height = 1;
center_x = (gdouble) x + (gdouble) width / 2.0;
center_y = (gdouble) y + (gdouble) height / 2.0;
gimp_matrix3_identity (result);
gimp_matrix3_translate (result, -center_x, -center_y);
if (orientation == GIMP_ORIENTATION_HORIZONTAL)
gimp_matrix3_xshear (result, amount / height);
else
gimp_matrix3_yshear (result, amount / width);
gimp_matrix3_translate (result, +center_x, +center_y);
}
void
gimp_transform_matrix_perspective (gint x,
gint y,
gint width,
gint height,
gdouble t_x1,
gdouble t_y1,
gdouble t_x2,
gdouble t_y2,
gdouble t_x3,
gdouble t_y3,
gdouble t_x4,
gdouble t_y4,
GimpMatrix3 *result)
{
GimpMatrix3 matrix;
gdouble scalex;
gdouble scaley;
g_return_if_fail (result != NULL);
scalex = scaley = 1.0;
if (width > 0)
scalex = 1.0 / (gdouble) width;
if (height > 0)
scaley = 1.0 / (gdouble) height;
/* Determine the perspective transform that maps from
* the unit cube to the transformed coordinates
*/
{
gdouble dx1, dx2, dx3, dy1, dy2, dy3;
dx1 = t_x2 - t_x4;
dx2 = t_x3 - t_x4;
dx3 = t_x1 - t_x2 + t_x4 - t_x3;
dy1 = t_y2 - t_y4;
dy2 = t_y3 - t_y4;
dy3 = t_y1 - t_y2 + t_y4 - t_y3;
/* Is the mapping affine? */
if ((dx3 == 0.0) && (dy3 == 0.0))
{
matrix.coeff[0][0] = t_x2 - t_x1;
matrix.coeff[0][1] = t_x4 - t_x2;
matrix.coeff[0][2] = t_x1;
matrix.coeff[1][0] = t_y2 - t_y1;
matrix.coeff[1][1] = t_y4 - t_y2;
matrix.coeff[1][2] = t_y1;
matrix.coeff[2][0] = 0.0;
matrix.coeff[2][1] = 0.0;
}
else
{
gdouble det1, det2;
det1 = dx3 * dy2 - dy3 * dx2;
det2 = dx1 * dy2 - dy1 * dx2;
if (det1 == 0.0 && det2 == 0.0)
matrix.coeff[2][0] = 1.0;
else
matrix.coeff[2][0] = det1 / det2;
det1 = dx1 * dy3 - dy1 * dx3;
if (det1 == 0.0 && det2 == 0.0)
matrix.coeff[2][1] = 1.0;
else
matrix.coeff[2][1] = det1 / det2;
matrix.coeff[0][0] = t_x2 - t_x1 + matrix.coeff[2][0] * t_x2;
matrix.coeff[0][1] = t_x3 - t_x1 + matrix.coeff[2][1] * t_x3;
matrix.coeff[0][2] = t_x1;
matrix.coeff[1][0] = t_y2 - t_y1 + matrix.coeff[2][0] * t_y2;
matrix.coeff[1][1] = t_y3 - t_y1 + matrix.coeff[2][1] * t_y3;
matrix.coeff[1][2] = t_y1;
}
matrix.coeff[2][2] = 1.0;
}
gimp_matrix3_identity (result);
gimp_matrix3_translate (result, -x, -y);
gimp_matrix3_scale (result, scalex, scaley);
gimp_matrix3_mult (&matrix, result);
}