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