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264 lines
8.0 KiB
C++
264 lines
8.0 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Oracle Corporation code.
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*
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* The Initial Developer of the Original Code is Oracle Corporation.
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* Portions created by the Initial Developer are Copyright (C) 2005
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Stuart Parmenter <pavlov@pavlov.net>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef GFX_MATRIX_H
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#define GFX_MATRIX_H
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#include "gfxPoint.h"
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#include "gfxTypes.h"
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#include "gfxRect.h"
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#include "gfxUtils.h"
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#include "nsMathUtils.h"
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// XX - I don't think this class should use gfxFloat at all,
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// but should use 'double' and be called gfxDoubleMatrix;
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// we can then typedef that to gfxMatrix where we typedef
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// double to be gfxFloat.
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/**
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* A matrix that represents an affine transformation. Projective
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* transformations are not supported. This matrix looks like:
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*
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* / a b 0 \
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* | c d 0 |
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* \ tx ty 1 /
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*
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* So, transforming a point (x, y) results in:
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*
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* / a b 0 \ / a * x + c * y + tx \ T
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* (x y 1) * | c d 0 | = | b * x + d * y + ty |
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* \ tx ty 1 / \ 1 /
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*
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*/
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struct THEBES_API gfxMatrix {
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double xx; double yx;
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double xy; double yy;
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double x0; double y0;
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public:
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/**
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* Initializes this matrix as the identity matrix.
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*/
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gfxMatrix() { Reset(); }
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/**
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* Initializes the matrix from individual components. See the class
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* description for the layout of the matrix.
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*/
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gfxMatrix(gfxFloat a, gfxFloat b, gfxFloat c, gfxFloat d, gfxFloat tx, gfxFloat ty) :
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xx(a), yx(b),
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xy(c), yy(d),
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x0(tx), y0(ty) { }
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/**
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* Post-multiplies m onto the matrix.
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*/
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const gfxMatrix& operator *= (const gfxMatrix& m) {
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return Multiply(m);
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}
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/**
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* Multiplies *this with m and returns the result.
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*/
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gfxMatrix operator * (const gfxMatrix& m) const {
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return gfxMatrix(*this).Multiply(m);
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}
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// matrix operations
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/**
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* Resets this matrix to the identity matrix.
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*/
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const gfxMatrix& Reset();
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/**
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* Inverts this matrix, if possible. Otherwise, the matrix is left
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* unchanged.
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*
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* XXX should this do something with the return value of
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* cairo_matrix_invert?
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*/
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const gfxMatrix& Invert();
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/**
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* Check if matrix is singular (no inverse exists).
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*/
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PRBool IsSingular() const {
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// if the determinant (ad - bc) is zero it's singular
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return (xx * yy) == (yx * xy);
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}
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/**
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* Scales this matrix. The scale is pre-multiplied onto this matrix,
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* i.e. the scaling takes place before the other transformations.
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*/
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const gfxMatrix& Scale(gfxFloat x, gfxFloat y);
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/**
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* Translates this matrix. The translation is pre-multiplied onto this matrix,
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* i.e. the translation takes place before the other transformations.
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*/
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const gfxMatrix& Translate(const gfxPoint& pt);
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/**
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* Rotates this matrix. The rotation is pre-multiplied onto this matrix,
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* i.e. the translation takes place after the other transformations.
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*
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* @param radians Angle in radians.
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*/
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const gfxMatrix& Rotate(gfxFloat radians);
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/**
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* Multiplies the current matrix with m.
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* This is a post-multiplication, i.e. the transformations of m are
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* applied _after_ the existing transformations.
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*
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* XXX is that difference (compared to Rotate etc) a good thing?
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*/
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const gfxMatrix& Multiply(const gfxMatrix& m);
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/**
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* Multiplies the current matrix with m.
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* This is a pre-multiplication, i.e. the transformations of m are
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* applied _before_ the existing transformations.
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*/
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const gfxMatrix& PreMultiply(const gfxMatrix& m);
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/**
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* Transforms a point according to this matrix.
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*/
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gfxPoint Transform(const gfxPoint& point) const;
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/**
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* Transform a distance according to this matrix. This does not apply
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* any translation components.
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*/
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gfxSize Transform(const gfxSize& size) const;
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/**
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* Transforms both the point and distance according to this matrix.
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*/
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gfxRect Transform(const gfxRect& rect) const;
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gfxRect TransformBounds(const gfxRect& rect) const;
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/**
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* Returns the translation component of this matrix.
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*/
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gfxPoint GetTranslation() const {
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return gfxPoint(x0, y0);
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}
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/**
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* Returns true if the matrix is anything other than a straight
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* translation by integers.
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*/
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PRBool HasNonIntegerTranslation() const {
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return HasNonTranslation() ||
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!gfxUtils::FuzzyEqual(x0, NS_floor(x0 + 0.5)) ||
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!gfxUtils::FuzzyEqual(y0, NS_floor(y0 + 0.5));
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}
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/**
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* Returns true if the matrix has any transform other
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* than a straight translation
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*/
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PRBool HasNonTranslation() const {
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return !gfxUtils::FuzzyEqual(xx, 1.0) || !gfxUtils::FuzzyEqual(yy, 1.0) ||
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!gfxUtils::FuzzyEqual(xy, 0.0) || !gfxUtils::FuzzyEqual(yx, 0.0);
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}
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/**
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* Returns true if the matrix has any transform other
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* than a translation or a -1 y scale (y axis flip)
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*/
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PRBool HasNonTranslationOrFlip() const {
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return !gfxUtils::FuzzyEqual(xx, 1.0) ||
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(!gfxUtils::FuzzyEqual(yy, 1.0) && !gfxUtils::FuzzyEqual(yy, -1.0)) ||
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!gfxUtils::FuzzyEqual(xy, 0.0) || !gfxUtils::FuzzyEqual(yx, 0.0);
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}
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/**
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* Returns true if the matrix has any transform other
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* than a translation or scale; this is, if there is
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* no rotation.
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*/
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PRBool HasNonAxisAlignedTransform() const {
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return !gfxUtils::FuzzyEqual(xy, 0.0) || !gfxUtils::FuzzyEqual(yx, 0.0);
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}
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/**
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* Computes the determinant of this matrix.
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*/
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double Determinant() const {
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return xx*yy - yx*xy;
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}
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/* Computes the scale factors of this matrix; that is,
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* the amounts each basis vector is scaled by.
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* The xMajor parameter indicates if the larger scale is
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* to be assumed to be in the X direction or not.
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*/
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gfxSize ScaleFactors(PRBool xMajor) const {
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double det = Determinant();
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if (det == 0.0)
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return gfxSize(0.0, 0.0);
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gfxSize sz((xMajor != 0 ? 1.0 : 0.0),
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(xMajor != 0 ? 0.0 : 1.0));
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sz = Transform(sz);
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double major = sqrt(sz.width * sz.width + sz.height * sz.height);
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double minor = 0.0;
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// ignore mirroring
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if (det < 0.0)
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det = - det;
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if (major)
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minor = det / major;
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if (xMajor)
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return gfxSize(major, minor);
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return gfxSize(minor, major);
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}
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};
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#endif /* GFX_MATRIX_H */
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