mirror of https://github.com/GNOME/gimp.git
241 lines
6.8 KiB
C
241 lines
6.8 KiB
C
/* The GIMP -- an image manipulation program
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* Copyright (C) 1995-2001 Spencer Kimball, Peter Mattis, and others
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include "config.h"
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#include <glib-object.h>
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#include "libgimpmath/gimpmath.h"
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#include "core-types.h"
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#include "gimp-transform-utils.h"
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void
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gimp_transform_matrix_flip (GimpOrientationType flip_type,
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gdouble axis,
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GimpMatrix3 *result)
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{
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gimp_matrix3_identity (result);
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switch (flip_type)
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{
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case GIMP_ORIENTATION_HORIZONTAL:
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gimp_matrix3_translate (result, - axis, 0.0);
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gimp_matrix3_scale (result, -1.0, 1.0);
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gimp_matrix3_translate (result, axis, 0.0);
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break;
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case GIMP_ORIENTATION_VERTICAL:
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gimp_matrix3_translate (result, 0.0, - axis);
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gimp_matrix3_scale (result, 1.0, -1.0);
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gimp_matrix3_translate (result, 0.0, axis);
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break;
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case GIMP_ORIENTATION_UNKNOWN:
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break;
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}
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}
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void
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gimp_transform_matrix_rotate (gint x1,
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gint y1,
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gint x2,
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gint y2,
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gdouble angle,
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GimpMatrix3 *result)
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{
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gdouble cx;
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gdouble cy;
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cx = (gdouble) (x1 + x2) / 2.0;
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cy = (gdouble) (y1 + y2) / 2.0;
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gimp_matrix3_identity (result);
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gimp_matrix3_translate (result, -cx, -cy);
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gimp_matrix3_rotate (result, angle);
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gimp_matrix3_translate (result, +cx, +cy);
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}
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void
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gimp_transform_matrix_rotate_center (gdouble cx,
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gdouble cy,
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gdouble angle,
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GimpMatrix3 *result)
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{
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gimp_matrix3_identity (result);
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gimp_matrix3_translate (result, -cx, -cy);
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gimp_matrix3_rotate (result, angle);
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gimp_matrix3_translate (result, +cx, +cy);
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}
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void
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gimp_transform_matrix_scale (gint x1,
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gint y1,
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gint x2,
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gint y2,
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gdouble tx1,
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gdouble ty1,
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gdouble tx2,
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gdouble ty2,
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GimpMatrix3 *result)
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{
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gdouble scalex;
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gdouble scaley;
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scalex = scaley = 1.0;
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if ((x2 - x1) > 0)
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scalex = (tx2 - tx1) / (gdouble) (x2 - x1);
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if ((y2 - y1) > 0)
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scaley = (ty2 - ty1) / (gdouble) (y2 - y1);
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gimp_matrix3_identity (result);
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gimp_matrix3_translate (result, -x1, -y1);
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gimp_matrix3_scale (result, scalex, scaley);
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gimp_matrix3_translate (result, tx1, ty1);
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}
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void
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gimp_transform_matrix_shear (gint x1,
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gint y1,
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gint x2,
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gint y2,
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GimpOrientationType orientation,
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gdouble amount,
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GimpMatrix3 *result)
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{
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gint width;
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gint height;
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gdouble cx;
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gdouble cy;
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width = x2 - x1;
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height = y2 - y1;
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if (width == 0)
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width = 1;
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if (height == 0)
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height = 1;
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cx = (gdouble) (x1 + x2) / 2.0;
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cy = (gdouble) (y1 + y2) / 2.0;
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gimp_matrix3_identity (result);
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gimp_matrix3_translate (result, -cx, -cy);
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if (orientation == GIMP_ORIENTATION_HORIZONTAL)
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gimp_matrix3_xshear (result, amount / height);
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else
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gimp_matrix3_yshear (result, amount / width);
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gimp_matrix3_translate (result, +cx, +cy);
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}
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void
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gimp_transform_matrix_perspective (gint x1,
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gint y1,
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gint x2,
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gint y2,
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gdouble tx1,
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gdouble ty1,
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gdouble tx2,
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gdouble ty2,
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gdouble tx3,
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gdouble ty3,
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gdouble tx4,
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gdouble ty4,
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GimpMatrix3 *result)
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{
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GimpMatrix3 matrix;
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gdouble scalex;
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gdouble scaley;
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scalex = scaley = 1.0;
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if ((x2 - x1) > 0)
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scalex = 1.0 / (gdouble) (x2 - x1);
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if ((y2 - y1) > 0)
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scaley = 1.0 / (gdouble) (y2 - y1);
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/* Determine the perspective transform that maps from
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* the unit cube to the transformed coordinates
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*/
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{
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gdouble dx1, dx2, dx3, dy1, dy2, dy3;
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dx1 = tx2 - tx4;
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dx2 = tx3 - tx4;
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dx3 = tx1 - tx2 + tx4 - tx3;
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dy1 = ty2 - ty4;
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dy2 = ty3 - ty4;
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dy3 = ty1 - ty2 + ty4 - ty3;
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/* Is the mapping affine? */
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if ((dx3 == 0.0) && (dy3 == 0.0))
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{
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matrix.coeff[0][0] = tx2 - tx1;
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matrix.coeff[0][1] = tx4 - tx2;
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matrix.coeff[0][2] = tx1;
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matrix.coeff[1][0] = ty2 - ty1;
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matrix.coeff[1][1] = ty4 - ty2;
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matrix.coeff[1][2] = ty1;
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matrix.coeff[2][0] = 0.0;
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matrix.coeff[2][1] = 0.0;
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}
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else
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{
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gdouble det1, det2;
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det1 = dx3 * dy2 - dy3 * dx2;
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det2 = dx1 * dy2 - dy1 * dx2;
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if (det1 == 0.0 && det2 == 0.0)
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matrix.coeff[2][0] = 1.0;
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else
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matrix.coeff[2][0] = det1 / det2;
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det1 = dx1 * dy3 - dy1 * dx3;
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if (det1 == 0.0 && det2 == 0.0)
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matrix.coeff[2][1] = 1.0;
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else
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matrix.coeff[2][1] = det1 / det2;
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matrix.coeff[0][0] = tx2 - tx1 + matrix.coeff[2][0] * tx2;
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matrix.coeff[0][1] = tx3 - tx1 + matrix.coeff[2][1] * tx3;
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matrix.coeff[0][2] = tx1;
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matrix.coeff[1][0] = ty2 - ty1 + matrix.coeff[2][0] * ty2;
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matrix.coeff[1][1] = ty3 - ty1 + matrix.coeff[2][1] * ty3;
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matrix.coeff[1][2] = ty1;
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}
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matrix.coeff[2][2] = 1.0;
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}
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gimp_matrix3_identity (result);
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gimp_matrix3_translate (result, -x1, -y1);
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gimp_matrix3_scale (result, scalex, scaley);
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gimp_matrix3_mult (&matrix, result);
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}
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