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-rw-r--r--gfx/2d/Matrix.cpp134
1 files changed, 134 insertions, 0 deletions
diff --git a/gfx/2d/Matrix.cpp b/gfx/2d/Matrix.cpp
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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