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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "Matrix.h"
#include "Quaternion.h"
#include "Tools.h"
#include <algorithm>
#include <ostream>
#include <math.h>
#include <float.h> // for FLT_EPSILON
#include "mozilla/FloatingPoint.h" // for UnspecifiedNaN
using namespace std;
namespace mozilla {
namespace gfx {
/* Force small values to zero. We do this to avoid having sin(360deg)
* evaluate to a tiny but nonzero value.
*/
double
FlushToZero(double aVal)
{
// XXX Is double precision really necessary here
if (-FLT_EPSILON < aVal && aVal < FLT_EPSILON) {
return 0.0f;
} else {
return aVal;
}
}
/* Computes tan(aTheta). For values of aTheta such that tan(aTheta) is
* undefined or very large, SafeTangent returns a manageably large value
* of the correct sign.
*/
double
SafeTangent(double aTheta)
{
// XXX Is double precision really necessary here
const double kEpsilon = 0.0001;
/* tan(theta) = sin(theta)/cos(theta); problems arise when
* cos(theta) is too close to zero. Limit cos(theta) to the
* range [-1, -epsilon] U [epsilon, 1].
*/
double sinTheta = sin(aTheta);
double cosTheta = cos(aTheta);
if (cosTheta >= 0 && cosTheta < kEpsilon) {
cosTheta = kEpsilon;
} else if (cosTheta < 0 && cosTheta >= -kEpsilon) {
cosTheta = -kEpsilon;
}
return FlushToZero(sinTheta / cosTheta);
}
std::ostream&
operator<<(std::ostream& aStream, const Matrix& aMatrix)
{
return aStream << "[ " << aMatrix._11
<< " " << aMatrix._12
<< "; " << aMatrix._21
<< " " << aMatrix._22
<< "; " << aMatrix._31
<< " " << aMatrix._32
<< "; ]";
}
Matrix
Matrix::Rotation(Float aAngle)
{
Matrix newMatrix;
Float s = sinf(aAngle);
Float c = cosf(aAngle);
newMatrix._11 = c;
newMatrix._12 = s;
newMatrix._21 = -s;
newMatrix._22 = c;
return newMatrix;
}
Rect
Matrix::TransformBounds(const Rect &aRect) const
{
int i;
Point quad[4];
Float min_x, max_x;
Float min_y, max_y;
quad[0] = TransformPoint(aRect.TopLeft());
quad[1] = TransformPoint(aRect.TopRight());
quad[2] = TransformPoint(aRect.BottomLeft());
quad[3] = TransformPoint(aRect.BottomRight());
min_x = max_x = quad[0].x;
min_y = max_y = quad[0].y;
for (i = 1; i < 4; i++) {
if (quad[i].x < min_x)
min_x = quad[i].x;
if (quad[i].x > max_x)
max_x = quad[i].x;
if (quad[i].y < min_y)
min_y = quad[i].y;
if (quad[i].y > max_y)
max_y = quad[i].y;
}
return Rect(min_x, min_y, max_x - min_x, max_y - min_y);
}
Matrix&
Matrix::NudgeToIntegers()
{
NudgeToInteger(&_11);
NudgeToInteger(&_12);
NudgeToInteger(&_21);
NudgeToInteger(&_22);
NudgeToInteger(&_31);
NudgeToInteger(&_32);
return *this;
}
} // namespace gfx
} // namespace mozilla
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