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/***
Olive - Non-Linear Video Editor
Copyright (C) 2019 Olive Team
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 3 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, see <http://www.gnu.org/licenses/>.
***/
#include "bezier.h"
#include <QtMath>
OLIVE_NAMESPACE_ENTER
double Bezier::QuadraticXtoT(double x, double a, double b, double c)
{
return (a - b + qSqrt(a*x + c*x - 2*b*x + qPow(b, 2) - a*c))/(a - 2*b + c);
}
double Bezier::QuadraticTtoY(double a, double b, double c, double t)
{
return qPow(1.0 - t, 2)*a + 2*(1.0 - t)*t*b + qPow(t, 2)*c;
}
double Bezier::CubicXtoT(double x_target, double a, double b, double c, double d)
{
double tolerance = 0.0001;
double lower = 0.0;
double upper = 1.0;
double percent = 0.5;
double x = CubicTtoY(a, b, c, d, percent);
while (qAbs(x_target - x) > tolerance) {
if (x_target > x) {
lower = percent;
} else {
upper = percent;
}
percent = (upper + lower) / 2.0;
x = CubicTtoY(a, b, c, d, percent);
}
return percent;
}
double Bezier::CubicTtoY(double a, double b, double c, double d, double t)
{
return qPow(1.0 - t, 3)*a + 3*qPow(1.0 - t, 2)*t*b + 3*(1.0 - t)*qPow(t, 2)*c + qPow(t, 3)*d;
}
OLIVE_NAMESPACE_EXIT
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