xform_2d.h

Go to the documentation of this file.

/*
 * xform_2d.h
 *
 * Copyright (C) 2007,2010  Thomas A. Vaughan
 * All rights reserved.
 *
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the <organization> nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THOMAS A. VAUGHAN ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THOMAS A. VAUGHAN BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *
 * 2D transformations (rotations, translations, scaling, skew, etc...)
 */

#ifndef WAVEPACKET_2D_XFORM_H__
#define WAVEPACKET_2D_XFORM_H__

// includes --------------------------------------------------------------------
#include "geometry_2d.h"

#include <math.h>


/// \ingroup geometry
/*@{*/

/// 2D transform object - basically a 2x2 rotation matrix + translation
struct xform_2d_t {
        typedef point2d_t<float> point_t;
        typedef rect2d_t<float> rect_t;

        // constructor + functions
        xform_2d_t(void) throw() { this->setIdentity(); }
        void clear(void) throw() { this->setIdentity(); }
        void setIdentity(void) throw() {
                        // set xform to identity matrix
                        t00 = t11 = 1.0;
                        t01 = t10 = 0.0;
                        dx = dy = 0.0;
                }
        void setZRotate(IN float phi) throw() {
                        // set xform to rotation by angle phi around z axis
                        // phi is in RADIANS, not degrees
                        t00 = t11 = cos(phi);
                        t01 = -sin(phi);
                        t10 = -t01;
                        dx = dy = 0.0;
                }
        void setTranslate(IN float x, IN float y) throw() {
                        // set xform to translation by dx,dy
                        t00 = t11 = 1.0;
                        t01 = t10 = 0.0;
                        dx = x;
                        dy = y;
                }

        void scale(IN float r) throw() {
                        // multiply xform by scalar r
                        scaleX(r);
                        scaleY(r);
                }

        void scaleX(IN float rx) throw() {
                        // scale up x-direction
                        t00 *= rx;
                        t01 *= rx;
                        dx *= rx;
                }

        void scaleY(IN float ry) throw() {
                        // scale up y-direction
                        t10 *= ry;
                        t11 *= ry;
                        dy *= ry;
                }

        void setToProductOf(IN const xform_2d_t& left,
                                IN const xform_2d_t& right) throw() {
                        // this xform = left * right
                        t00 = left.t00 * right.t00 + left.t01 * right.t10;
                        t01 = left.t00 * right.t01 + left.t01 * right.t11;
                        t10 = left.t10 * right.t00 + left.t11 * right.t10;
                        t11 = left.t10 * right.t01 + left.t11 * right.t11;
                        dx = left.t00 * right.dx + left.t01 * right.dy + left.dx;
                        dy = left.t10 * right.dx + left.t11 * right.dy + left.dy;
                }

        void transformPoint(IN const point_t& in,
                                OUT point_t& out) const throw() {
                        out.x = t00 * in.x + t01 * in.y + dx;
                        out.y = t10 * in.x + t11 * in.y + dy;
                }

        void transformRect(IN const rect_t& in,
                                OUT rect_t& out) const throw();

        void setToInverseOf(IN const xform_2d_t& T) throw();

        void dump(IN const char * title) const throw() {
                        DPRINTF("  %s (2d transform):", title);
                        DPRINTF("    [ %5.2f  %5.2f  %5.2f ]", t00, t01, dx);
                        DPRINTF("    [ %5.2f  %5.2f  %5.2f ]", t10, t11, dy);
                }

        // data fields
        float   t00;
        float   t01;
        float   t10;
        float   t11;
        float   dx;
        float   dy;
};



inline xform_2d_t::point_t operator *
(IN const xform_2d_t& T, IN const xform_2d_t::point_t& p)
throw()
{
        xform_2d_t::point_t q;
        T.transformPoint(p, q);
        return q;
}



#endif  // WAVEPACKET_2D_XFORM_H__