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// -*- c-basic-offset: 4 -*-
/*
Rosegarden
A sequencer and musical notation editor.
This program is Copyright 2000-2008
Guillaume Laurent <glaurent@telegraph-road.org>,
Chris Cannam <cannam@all-day-breakfast.com>,
Richard Bown <bownie@bownie.com>
The moral right of the authors to claim authorship of this work
has been asserted.
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. See the file
COPYING included with this distribution for more information.
*/
#include "Equation.h"
namespace Rosegarden {
void Equation::solve(Unknown u, double &y, double &m, double &x, double &c)
{
switch(u) {
case Y: y = m*x + c; break;
case M: m = (y - c) / x; break;
case X: x = (y - c) / m; break;
case C: c = y - m*x; break;
}
}
void Equation::solve(Unknown u, int &y, double &m, int &x, int &c)
{
switch(u) {
case Y: y = static_cast<int>(m*x) + c; break;
case M: m = static_cast<double>(y - c) / static_cast<double>(x); break;
case X: x = static_cast<int>(static_cast<float>(y - c) / m); break;
case C: c = y - static_cast<int>(m*x); break;
}
}
void Equation::solveForYByEndPoints(Point a, Point b, double x, double &y)
{
double m, c, y1, x1;
m = static_cast<double>(b.y - a.y) / static_cast<double>(b.x - a.x);
x1 = a.x; y1 = a.y;
solve(C, y1, m, x1, c);
solve(Y, y, m, x, c);
}
void Equation::solveForYByEndPoints(Point a, Point b, int x, int &y)
{
double m;
int c;
m = static_cast<double>(b.y - a.y) / static_cast<double>(b.x - a.x);
solve(C, a.y, m, a.x, c);
solve(Y, y, m, x, c);
}
}
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