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authorQt by Nokia <qt-info@nokia.com>2011-04-27 12:05:43 +0200
committeraxis <qt-info@nokia.com>2011-04-27 12:05:43 +0200
commit38be0d13830efd2d98281c645c3a60afe05ffece (patch)
tree6ea73f3ec77f7d153333779883e8120f82820abe /src/gui/painting/qmatrix.cpp
Initial import from the monolithic Qt.
This is the beginning of revision history for this module. If you want to look at revision history older than this, please refer to the Qt Git wiki for how to use Git history grafting. At the time of writing, this wiki is located here: http://qt.gitorious.org/qt/pages/GitIntroductionWithQt If you have already performed the grafting and you don't see any history beyond this commit, try running "git log" with the "--follow" argument. Branched from the monolithic repo, Qt master branch, at commit 896db169ea224deb96c59ce8af800d019de63f12
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+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qdatastream.h"
+#include "qdebug.h"
+#include "qmatrix.h"
+#include "qregion.h"
+#include "qpainterpath.h"
+#include "qvariant.h"
+#include <qmath.h>
+
+#include <limits.h>
+
+QT_BEGIN_NAMESPACE
+
+/*!
+ \class QMatrix
+ \brief The QMatrix class specifies 2D transformations of a
+ coordinate system.
+ \obsolete
+
+ \ingroup painting
+
+ A matrix specifies how to translate, scale, shear or rotate the
+ coordinate system, and is typically used when rendering graphics.
+ QMatrix, in contrast to QTransform, does not allow perspective
+ transformations. QTransform is the recommended transformation
+ class in Qt.
+
+ A QMatrix object can be built using the setMatrix(), scale(),
+ rotate(), translate() and shear() functions. Alternatively, it
+ can be built by applying \l {QMatrix#Basic Matrix
+ Operations}{basic matrix operations}. The matrix can also be
+ defined when constructed, and it can be reset to the identity
+ matrix (the default) using the reset() function.
+
+ The QMatrix class supports mapping of graphic primitives: A given
+ point, line, polygon, region, or painter path can be mapped to the
+ coordinate system defined by \e this matrix using the map()
+ function. In case of a rectangle, its coordinates can be
+ transformed using the mapRect() function. A rectangle can also be
+ transformed into a \e polygon (mapped to the coordinate system
+ defined by \e this matrix), using the mapToPolygon() function.
+
+ QMatrix provides the isIdentity() function which returns true if
+ the matrix is the identity matrix, and the isInvertible() function
+ which returns true if the matrix is non-singular (i.e. AB = BA =
+ I). The inverted() function returns an inverted copy of \e this
+ matrix if it is invertible (otherwise it returns the identity
+ matrix). In addition, QMatrix provides the determinant() function
+ returning the matrix's determinant.
+
+ Finally, the QMatrix class supports matrix multiplication, and
+ objects of the class can be streamed as well as compared.
+
+ \tableofcontents
+
+ \section1 Rendering Graphics
+
+ When rendering graphics, the matrix defines the transformations
+ but the actual transformation is performed by the drawing routines
+ in QPainter.
+
+ By default, QPainter operates on the associated device's own
+ coordinate system. The standard coordinate system of a
+ QPaintDevice has its origin located at the top-left position. The
+ \e x values increase to the right; \e y values increase
+ downward. For a complete description, see the \l {Coordinate
+ System}{coordinate system} documentation.
+
+ QPainter has functions to translate, scale, shear and rotate the
+ coordinate system without using a QMatrix. For example:
+
+ \table 100%
+ \row
+ \o \inlineimage qmatrix-simpletransformation.png
+ \o
+ \snippet doc/src/snippets/matrix/matrix.cpp 0
+ \endtable
+
+ Although these functions are very convenient, it can be more
+ efficient to build a QMatrix and call QPainter::setMatrix() if you
+ want to perform more than a single transform operation. For
+ example:
+
+ \table 100%
+ \row
+ \o \inlineimage qmatrix-combinedtransformation.png
+ \o
+ \snippet doc/src/snippets/matrix/matrix.cpp 1
+ \endtable
+
+ \section1 Basic Matrix Operations
+
+ \image qmatrix-representation.png
+
+ A QMatrix object contains a 3 x 3 matrix. The \c dx and \c dy
+ elements specify horizontal and vertical translation. The \c m11
+ and \c m22 elements specify horizontal and vertical scaling. And
+ finally, the \c m21 and \c m12 elements specify horizontal and
+ vertical \e shearing.
+
+ QMatrix transforms a point in the plane to another point using the
+ following formulas:
+
+ \snippet doc/src/snippets/code/src_gui_painting_qmatrix.cpp 0
+
+ The point \e (x, y) is the original point, and \e (x', y') is the
+ transformed point. \e (x', y') can be transformed back to \e (x,
+ y) by performing the same operation on the inverted() matrix.
+
+ The various matrix elements can be set when constructing the
+ matrix, or by using the setMatrix() function later on. They can also
+ be manipulated using the translate(), rotate(), scale() and
+ shear() convenience functions, The currently set values can be
+ retrieved using the m11(), m12(), m21(), m22(), dx() and dy()
+ functions.
+
+ Translation is the simplest transformation. Setting \c dx and \c
+ dy will move the coordinate system \c dx units along the X axis
+ and \c dy units along the Y axis. Scaling can be done by setting
+ \c m11 and \c m22. For example, setting \c m11 to 2 and \c m22 to
+ 1.5 will double the height and increase the width by 50%. The
+ identity matrix has \c m11 and \c m22 set to 1 (all others are set
+ to 0) mapping a point to itself. Shearing is controlled by \c m12
+ and \c m21. Setting these elements to values different from zero
+ will twist the coordinate system. Rotation is achieved by
+ carefully setting both the shearing factors and the scaling
+ factors.
+
+ Here's the combined transformations example using basic matrix
+ operations:
+
+ \table 100%
+ \row
+ \o \inlineimage qmatrix-combinedtransformation.png
+ \o
+ \snippet doc/src/snippets/matrix/matrix.cpp 2
+ \endtable
+
+ \sa QPainter, QTransform, {Coordinate System},
+ {demos/affine}{Affine Transformations Demo}, {Transformations Example}
+*/
+
+
+// some defines to inline some code
+#define MAPDOUBLE(x, y, nx, ny) \
+{ \
+ qreal fx = x; \
+ qreal fy = y; \
+ nx = _m11*fx + _m21*fy + _dx; \
+ ny = _m12*fx + _m22*fy + _dy; \
+}
+
+#define MAPINT(x, y, nx, ny) \
+{ \
+ qreal fx = x; \
+ qreal fy = y; \
+ nx = qRound(_m11*fx + _m21*fy + _dx); \
+ ny = qRound(_m12*fx + _m22*fy + _dy); \
+}
+
+/*****************************************************************************
+ QMatrix member functions
+ *****************************************************************************/
+/*!
+ \fn QMatrix::QMatrix(Qt::Initialization)
+ \internal
+*/
+
+/*!
+ Constructs an identity matrix.
+
+ All elements are set to zero except \c m11 and \c m22 (specifying
+ the scale), which are set to 1.
+
+ \sa reset()
+*/
+
+QMatrix::QMatrix()
+ : _m11(1.)
+ , _m12(0.)
+ , _m21(0.)
+ , _m22(1.)
+ , _dx(0.)
+ , _dy(0.)
+{
+}
+
+/*!
+ Constructs a matrix with the elements, \a m11, \a m12, \a m21, \a
+ m22, \a dx and \a dy.
+
+ \sa setMatrix()
+*/
+
+QMatrix::QMatrix(qreal m11, qreal m12, qreal m21, qreal m22, qreal dx, qreal dy)
+ : _m11(m11)
+ , _m12(m12)
+ , _m21(m21)
+ , _m22(m22)
+ , _dx(dx)
+ , _dy(dy)
+{
+}
+
+
+/*!
+ Constructs a matrix that is a copy of the given \a matrix.
+ */
+QMatrix::QMatrix(const QMatrix &matrix)
+ : _m11(matrix._m11)
+ , _m12(matrix._m12)
+ , _m21(matrix._m21)
+ , _m22(matrix._m22)
+ , _dx(matrix._dx)
+ , _dy(matrix._dy)
+{
+}
+
+/*!
+ Sets the matrix elements to the specified values, \a m11, \a m12,
+ \a m21, \a m22, \a dx and \a dy.
+
+ Note that this function replaces the previous values. QMatrix
+ provide the translate(), rotate(), scale() and shear() convenience
+ functions to manipulate the various matrix elements based on the
+ currently defined coordinate system.
+
+ \sa QMatrix()
+*/
+
+void QMatrix::setMatrix(qreal m11, qreal m12, qreal m21, qreal m22, qreal dx, qreal dy)
+{
+ _m11 = m11;
+ _m12 = m12;
+ _m21 = m21;
+ _m22 = m22;
+ _dx = dx;
+ _dy = dy;
+}
+
+
+/*!
+ \fn qreal QMatrix::m11() const
+
+ Returns the horizontal scaling factor.
+
+ \sa scale(), {QMatrix#Basic Matrix Operations}{Basic Matrix
+ Operations}
+*/
+
+/*!
+ \fn qreal QMatrix::m12() const
+
+ Returns the vertical shearing factor.
+
+ \sa shear(), {QMatrix#Basic Matrix Operations}{Basic Matrix
+ Operations}
+*/
+
+/*!
+ \fn qreal QMatrix::m21() const
+
+ Returns the horizontal shearing factor.
+
+ \sa shear(), {QMatrix#Basic Matrix Operations}{Basic Matrix
+ Operations}
+*/
+
+/*!
+ \fn qreal QMatrix::m22() const
+
+ Returns the vertical scaling factor.
+
+ \sa scale(), {QMatrix#Basic Matrix Operations}{Basic Matrix
+ Operations}
+*/
+
+/*!
+ \fn qreal QMatrix::dx() const
+
+ Returns the horizontal translation factor.
+
+ \sa translate(), {QMatrix#Basic Matrix Operations}{Basic Matrix
+ Operations}
+*/
+
+/*!
+ \fn qreal QMatrix::dy() const
+
+ Returns the vertical translation factor.
+
+ \sa translate(), {QMatrix#Basic Matrix Operations}{Basic Matrix
+ Operations}
+*/
+
+
+/*!
+ Maps the given coordinates \a x and \a y into the coordinate
+ system defined by this matrix. The resulting values are put in *\a
+ tx and *\a ty, respectively.
+
+ The coordinates are transformed using the following formulas:
+
+ \snippet doc/src/snippets/code/src_gui_painting_qmatrix.cpp 1
+
+ The point (x, y) is the original point, and (x', y') is the
+ transformed point.
+
+ \sa {QMatrix#Basic Matrix Operations}{Basic Matrix Operations}
+*/
+
+void QMatrix::map(qreal x, qreal y, qreal *tx, qreal *ty) const
+{
+ MAPDOUBLE(x, y, *tx, *ty);
+}
+
+
+
+/*!
+ \overload
+
+ Maps the given coordinates \a x and \a y into the coordinate
+ system defined by this matrix. The resulting values are put in *\a
+ tx and *\a ty, respectively. Note that the transformed coordinates
+ are rounded to the nearest integer.
+*/
+
+void QMatrix::map(int x, int y, int *tx, int *ty) const
+{
+ MAPINT(x, y, *tx, *ty);
+}
+
+QRect QMatrix::mapRect(const QRect &rect) const
+{
+ QRect result;
+ if (_m12 == 0.0F && _m21 == 0.0F) {
+ int x = qRound(_m11*rect.x() + _dx);
+ int y = qRound(_m22*rect.y() + _dy);
+ int w = qRound(_m11*rect.width());
+ int h = qRound(_m22*rect.height());
+ if (w < 0) {
+ w = -w;
+ x -= w;
+ }
+ if (h < 0) {
+ h = -h;
+ y -= h;
+ }
+ result = QRect(x, y, w, h);
+ } else {
+ // see mapToPolygon for explanations of the algorithm.
+ qreal x0, y0;
+ qreal x, y;
+ MAPDOUBLE(rect.left(), rect.top(), x0, y0);
+ qreal xmin = x0;
+ qreal ymin = y0;
+ qreal xmax = x0;
+ qreal ymax = y0;
+ MAPDOUBLE(rect.right() + 1, rect.top(), x, y);
+ xmin = qMin(xmin, x);
+ ymin = qMin(ymin, y);
+ xmax = qMax(xmax, x);
+ ymax = qMax(ymax, y);
+ MAPDOUBLE(rect.right() + 1, rect.bottom() + 1, x, y);
+ xmin = qMin(xmin, x);
+ ymin = qMin(ymin, y);
+ xmax = qMax(xmax, x);
+ ymax = qMax(ymax, y);
+ MAPDOUBLE(rect.left(), rect.bottom() + 1, x, y);
+ xmin = qMin(xmin, x);
+ ymin = qMin(ymin, y);
+ xmax = qMax(xmax, x);
+ ymax = qMax(ymax, y);
+ result = QRect(qRound(xmin), qRound(ymin), qRound(xmax)-qRound(xmin), qRound(ymax)-qRound(ymin));
+ }
+ return result;
+}
+
+/*!
+ \fn QRectF QMatrix::mapRect(const QRectF &rectangle) const
+
+ Creates and returns a QRectF object that is a copy of the given \a
+ rectangle, mapped into the coordinate system defined by this
+ matrix.
+
+ The rectangle's coordinates are transformed using the following
+ formulas:
+
+ \snippet doc/src/snippets/code/src_gui_painting_qmatrix.cpp 2
+
+ If rotation or shearing has been specified, this function returns
+ the \e bounding rectangle. To retrieve the exact region the given
+ \a rectangle maps to, use the mapToPolygon() function instead.
+
+ \sa mapToPolygon(), {QMatrix#Basic Matrix Operations}{Basic Matrix
+ Operations}
+*/
+QRectF QMatrix::mapRect(const QRectF &rect) const
+{
+ QRectF result;
+ if (_m12 == 0.0F && _m21 == 0.0F) {
+ qreal x = _m11*rect.x() + _dx;
+ qreal y = _m22*rect.y() + _dy;
+ qreal w = _m11*rect.width();
+ qreal h = _m22*rect.height();
+ if (w < 0) {
+ w = -w;
+ x -= w;
+ }
+ if (h < 0) {
+ h = -h;
+ y -= h;
+ }
+ result = QRectF(x, y, w, h);
+ } else {
+ qreal x0, y0;
+ qreal x, y;
+ MAPDOUBLE(rect.x(), rect.y(), x0, y0);
+ qreal xmin = x0;
+ qreal ymin = y0;
+ qreal xmax = x0;
+ qreal ymax = y0;
+ MAPDOUBLE(rect.x() + rect.width(), rect.y(), x, y);
+ xmin = qMin(xmin, x);
+ ymin = qMin(ymin, y);
+ xmax = qMax(xmax, x);
+ ymax = qMax(ymax, y);
+ MAPDOUBLE(rect.x() + rect.width(), rect.y() + rect.height(), x, y);
+ xmin = qMin(xmin, x);
+ ymin = qMin(ymin, y);
+ xmax = qMax(xmax, x);
+ ymax = qMax(ymax, y);
+ MAPDOUBLE(rect.x(), rect.y() + rect.height(), x, y);
+ xmin = qMin(xmin, x);
+ ymin = qMin(ymin, y);
+ xmax = qMax(xmax, x);
+ ymax = qMax(ymax, y);
+ result = QRectF(xmin, ymin, xmax-xmin, ymax - ymin);
+ }
+ return result;
+}
+
+/*!
+ \fn QRect QMatrix::mapRect(const QRect &rectangle) const
+ \overload
+
+ Creates and returns a QRect object that is a copy of the given \a
+ rectangle, mapped into the coordinate system defined by this
+ matrix. Note that the transformed coordinates are rounded to the
+ nearest integer.
+*/
+
+
+/*!
+ \fn QPoint operator*(const QPoint &point, const QMatrix &matrix)
+ \relates QMatrix
+
+ This is the same as \a{matrix}.map(\a{point}).
+
+ \sa QMatrix::map()
+*/
+
+QPoint QMatrix::map(const QPoint &p) const
+{
+ qreal fx = p.x();
+ qreal fy = p.y();
+ return QPoint(qRound(_m11*fx + _m21*fy + _dx),
+ qRound(_m12*fx + _m22*fy + _dy));
+}
+
+/*!
+ \fn QPointF operator*(const QPointF &point, const QMatrix &matrix)
+ \relates QMatrix
+
+ Same as \a{matrix}.map(\a{point}).
+
+ \sa QMatrix::map()
+*/
+
+/*!
+ \overload
+
+ Creates and returns a QPointF object that is a copy of the given
+ \a point, mapped into the coordinate system defined by this
+ matrix.
+*/
+QPointF QMatrix::map(const QPointF &point) const
+{
+ qreal fx = point.x();
+ qreal fy = point.y();
+ return QPointF(_m11*fx + _m21*fy + _dx, _m12*fx + _m22*fy + _dy);
+}
+
+/*!
+ \fn QPoint QMatrix::map(const QPoint &point) const
+ \overload
+
+ Creates and returns a QPoint object that is a copy of the given \a
+ point, mapped into the coordinate system defined by this
+ matrix. Note that the transformed coordinates are rounded to the
+ nearest integer.
+*/
+
+/*!
+ \fn QLineF operator*(const QLineF &line, const QMatrix &matrix)
+ \relates QMatrix
+
+ This is the same as \a{matrix}.map(\a{line}).
+
+ \sa QMatrix::map()
+*/
+
+/*!
+ \fn QLine operator*(const QLine &line, const QMatrix &matrix)
+ \relates QMatrix
+
+ This is the same as \a{matrix}.map(\a{line}).
+
+ \sa QMatrix::map()
+*/
+
+/*!
+ \overload
+
+ Creates and returns a QLineF object that is a copy of the given \a
+ line, mapped into the coordinate system defined by this matrix.
+*/
+QLineF QMatrix::map(const QLineF &line) const
+{
+ return QLineF(map(line.p1()), map(line.p2()));
+}
+
+/*!
+ \overload
+
+ Creates and returns a QLine object that is a copy of the given \a
+ line, mapped into the coordinate system defined by this matrix.
+ Note that the transformed coordinates are rounded to the nearest
+ integer.
+*/
+QLine QMatrix::map(const QLine &line) const
+{
+ return QLine(map(line.p1()), map(line.p2()));
+}
+
+/*!
+ \fn QPolygonF operator *(const QPolygonF &polygon, const QMatrix &matrix)
+ \relates QMatrix
+
+ This is the same as \a{matrix}.map(\a{polygon}).
+
+ \sa QMatrix::map()
+*/
+
+/*!
+ \fn QPolygon operator*(const QPolygon &polygon, const QMatrix &matrix)
+ \relates QMatrix
+
+ This is the same as \a{matrix}.map(\a{polygon}).
+
+ \sa QMatrix::map()
+*/
+
+QPolygon QMatrix::map(const QPolygon &a) const
+{
+ int size = a.size();
+ int i;
+ QPolygon p(size);
+ const QPoint *da = a.constData();
+ QPoint *dp = p.data();
+ for(i = 0; i < size; i++) {
+ MAPINT(da[i].x(), da[i].y(), dp[i].rx(), dp[i].ry());
+ }
+ return p;
+}
+
+/*!
+ \fn QPolygonF QMatrix::map(const QPolygonF &polygon) const
+ \overload
+
+ Creates and returns a QPolygonF object that is a copy of the given
+ \a polygon, mapped into the coordinate system defined by this
+ matrix.
+*/
+QPolygonF QMatrix::map(const QPolygonF &a) const
+{
+ int size = a.size();
+ int i;
+ QPolygonF p(size);
+ const QPointF *da = a.constData();
+ QPointF *dp = p.data();
+ for(i = 0; i < size; i++) {
+ MAPDOUBLE(da[i].xp, da[i].yp, dp[i].xp, dp[i].yp);
+ }
+ return p;
+}
+
+/*!
+ \fn QPolygon QMatrix::map(const QPolygon &polygon) const
+ \overload
+
+ Creates and returns a QPolygon object that is a copy of the given
+ \a polygon, mapped into the coordinate system defined by this
+ matrix. Note that the transformed coordinates are rounded to the
+ nearest integer.
+*/
+
+/*!
+ \fn QRegion operator*(const QRegion &region, const QMatrix &matrix)
+ \relates QMatrix
+
+ This is the same as \a{matrix}.map(\a{region}).
+
+ \sa QMatrix::map()
+*/
+
+extern QPainterPath qt_regionToPath(const QRegion &region);
+
+/*!
+ \fn QRegion QMatrix::map(const QRegion &region) const
+ \overload
+
+ Creates and returns a QRegion object that is a copy of the given
+ \a region, mapped into the coordinate system defined by this matrix.
+
+ Calling this method can be rather expensive if rotations or
+ shearing are used.
+*/
+QRegion QMatrix::map(const QRegion &r) const
+{
+ if (_m11 == 1.0 && _m22 == 1.0 && _m12 == 0.0 && _m21 == 0.0) { // translate or identity
+ if (_dx == 0.0 && _dy == 0.0) // Identity
+ return r;
+ QRegion copy(r);
+ copy.translate(qRound(_dx), qRound(_dy));
+ return copy;
+ }
+
+ QPainterPath p = map(qt_regionToPath(r));
+ return p.toFillPolygon().toPolygon();
+}
+
+/*!
+ \fn QPainterPath operator *(const QPainterPath &path, const QMatrix &matrix)
+ \relates QMatrix
+
+ This is the same as \a{matrix}.map(\a{path}).
+
+ \sa QMatrix::map()
+*/
+
+/*!
+ \overload
+
+ Creates and returns a QPainterPath object that is a copy of the
+ given \a path, mapped into the coordinate system defined by this
+ matrix.
+*/
+QPainterPath QMatrix::map(const QPainterPath &path) const
+{
+ if (path.isEmpty())
+ return QPainterPath();
+
+ QPainterPath copy = path;
+
+ // Translate or identity
+ if (_m11 == 1.0 && _m22 == 1.0 && _m12 == 0.0 && _m21 == 0.0) {
+
+ // Translate
+ if (_dx != 0.0 || _dy != 0.0) {
+ copy.detach();
+ for (int i=0; i<path.elementCount(); ++i) {
+ QPainterPath::Element &e = copy.d_ptr->elements[i];
+ e.x += _dx;
+ e.y += _dy;
+ }
+ }
+
+ // Full xform
+ } else {
+ copy.detach();
+ for (int i=0; i<path.elementCount(); ++i) {
+ QPainterPath::Element &e = copy.d_ptr->elements[i];
+ qreal fx = e.x, fy = e.y;
+ e.x = _m11*fx + _m21*fy + _dx;
+ e.y = _m12*fx + _m22*fy + _dy;
+ }
+ }
+
+ return copy;
+}
+
+/*!
+ \fn QRegion QMatrix::mapToRegion(const QRect &rectangle) const
+
+ Returns the transformed rectangle \a rectangle as a QRegion
+ object. A rectangle which has been rotated or sheared may result
+ in a non-rectangular region being returned.
+
+ Use the mapToPolygon() or map() function instead.
+*/
+#ifdef QT3_SUPPORT
+QRegion QMatrix::mapToRegion(const QRect &rect) const
+{
+ QRegion result;
+ if (isIdentity()) {
+ result = rect;
+ } else if (m12() == 0.0F && m21() == 0.0F) {
+ int x = qRound(m11()*rect.x() + dx());
+ int y = qRound(m22()*rect.y() + dy());
+ int w = qRound(m11()*rect.width());
+ int h = qRound(m22()*rect.height());
+ if (w < 0) {
+ w = -w;
+ x -= w - 1;
+ }
+ if (h < 0) {
+ h = -h;
+ y -= h - 1;
+ }
+ result = QRect(x, y, w, h);
+ } else {
+ result = QRegion(mapToPolygon(rect));
+ }
+ return result;
+
+}
+#endif
+/*!
+ \fn QPolygon QMatrix::mapToPolygon(const QRect &rectangle) const
+
+ Creates and returns a QPolygon representation of the given \a
+ rectangle, mapped into the coordinate system defined by this
+ matrix.
+
+ The rectangle's coordinates are transformed using the following
+ formulas:
+
+ \snippet doc/src/snippets/code/src_gui_painting_qmatrix.cpp 3
+
+ Polygons and rectangles behave slightly differently when
+ transformed (due to integer rounding), so
+ \c{matrix.map(QPolygon(rectangle))} is not always the same as
+ \c{matrix.mapToPolygon(rectangle)}.
+
+ \sa mapRect(), {QMatrix#Basic Matrix Operations}{Basic Matrix
+ Operations}
+*/
+QPolygon QMatrix::mapToPolygon(const QRect &rect) const
+{
+ QPolygon a(4);
+ qreal x[4], y[4];
+ if (_m12 == 0.0F && _m21 == 0.0F) {
+ x[0] = _m11*rect.x() + _dx;
+ y[0] = _m22*rect.y() + _dy;
+ qreal w = _m11*rect.width();
+ qreal h = _m22*rect.height();
+ if (w < 0) {
+ w = -w;
+ x[0] -= w;
+ }
+ if (h < 0) {
+ h = -h;
+ y[0] -= h;
+ }
+ x[1] = x[0]+w;
+ x[2] = x[1];
+ x[3] = x[0];
+ y[1] = y[0];
+ y[2] = y[0]+h;
+ y[3] = y[2];
+ } else {
+ qreal right = rect.x() + rect.width();
+ qreal bottom = rect.y() + rect.height();
+ MAPDOUBLE(rect.x(), rect.y(), x[0], y[0]);
+ MAPDOUBLE(right, rect.y(), x[1], y[1]);
+ MAPDOUBLE(right, bottom, x[2], y[2]);
+ MAPDOUBLE(rect.x(), bottom, x[3], y[3]);
+ }
+#if 0
+ int i;
+ for(i = 0; i< 4; i++)
+ qDebug("coords(%d) = (%f/%f) (%d/%d)", i, x[i], y[i], qRound(x[i]), qRound(y[i]));
+ qDebug("width=%f, height=%f", qSqrt((x[1]-x[0])*(x[1]-x[0]) + (y[1]-y[0])*(y[1]-y[0])),
+ qSqrt((x[0]-x[3])*(x[0]-x[3]) + (y[0]-y[3])*(y[0]-y[3])));
+#endif
+ // all coordinates are correctly, tranform to a pointarray
+ // (rounding to the next integer)
+ a.setPoints(4, qRound(x[0]), qRound(y[0]),
+ qRound(x[1]), qRound(y[1]),
+ qRound(x[2]), qRound(y[2]),
+ qRound(x[3]), qRound(y[3]));
+ return a;
+}
+
+/*!
+ Resets the matrix to an identity matrix, i.e. all elements are set
+ to zero, except \c m11 and \c m22 (specifying the scale) which are
+ set to 1.
+
+ \sa QMatrix(), isIdentity(), {QMatrix#Basic Matrix
+ Operations}{Basic Matrix Operations}
+*/
+
+void QMatrix::reset()
+{
+ _m11 = _m22 = 1.0;
+ _m12 = _m21 = _dx = _dy = 0.0;
+}
+
+/*!
+ \fn bool QMatrix::isIdentity() const
+
+ Returns true if the matrix is the identity matrix, otherwise
+ returns false.
+
+ \sa reset()
+*/
+
+/*!
+ Moves the coordinate system \a dx along the x axis and \a dy along
+ the y axis, and returns a reference to the matrix.
+
+ \sa setMatrix()
+*/
+
+QMatrix &QMatrix::translate(qreal dx, qreal dy)
+{
+ _dx += dx*_m11 + dy*_m21;
+ _dy += dy*_m22 + dx*_m12;
+ return *this;
+}
+
+/*!
+ \fn QMatrix &QMatrix::scale(qreal sx, qreal sy)
+
+ Scales the coordinate system by \a sx horizontally and \a sy
+ vertically, and returns a reference to the matrix.
+
+ \sa setMatrix()
+*/
+
+QMatrix &QMatrix::scale(qreal sx, qreal sy)
+{
+ _m11 *= sx;
+ _m12 *= sx;
+ _m21 *= sy;
+ _m22 *= sy;
+ return *this;
+}
+
+/*!
+ Shears the coordinate system by \a sh horizontally and \a sv
+ vertically, and returns a reference to the matrix.
+
+ \sa setMatrix()
+*/
+
+QMatrix &QMatrix::shear(qreal sh, qreal sv)
+{
+ qreal tm11 = sv*_m21;
+ qreal tm12 = sv*_m22;
+ qreal tm21 = sh*_m11;
+ qreal tm22 = sh*_m12;
+ _m11 += tm11;
+ _m12 += tm12;
+ _m21 += tm21;
+ _m22 += tm22;
+ return *this;
+}
+
+const qreal deg2rad = qreal(0.017453292519943295769); // pi/180
+
+/*!
+ \fn QMatrix &QMatrix::rotate(qreal degrees)
+
+ Rotates the coordinate system the given \a degrees
+ counterclockwise.
+
+ Note that if you apply a QMatrix to a point defined in widget
+ coordinates, the direction of the rotation will be clockwise
+ because the y-axis points downwards.
+
+ Returns a reference to the matrix.
+
+ \sa setMatrix()
+*/
+
+QMatrix &QMatrix::rotate(qreal a)
+{
+ qreal sina = 0;
+ qreal cosa = 0;
+ if (a == 90. || a == -270.)
+ sina = 1.;
+ else if (a == 270. || a == -90.)
+ sina = -1.;
+ else if (a == 180.)
+ cosa = -1.;
+ else{
+ qreal b = deg2rad*a; // convert to radians
+ sina = qSin(b); // fast and convenient
+ cosa = qCos(b);
+ }
+ qreal tm11 = cosa*_m11 + sina*_m21;
+ qreal tm12 = cosa*_m12 + sina*_m22;
+ qreal tm21 = -sina*_m11 + cosa*_m21;
+ qreal tm22 = -sina*_m12 + cosa*_m22;
+ _m11 = tm11; _m12 = tm12;
+ _m21 = tm21; _m22 = tm22;
+ return *this;
+}
+
+/*!
+ \fn bool QMatrix::isInvertible() const
+
+ Returns true if the matrix is invertible, otherwise returns false.
+
+ \sa inverted()
+*/
+
+/*!
+ \obsolete
+ \fn qreal QMatrix::det() const
+
+ Returns the matrix's determinant.
+
+ \sa determinant()
+*/
+
+/*!
+ \since 4.6
+ \fn qreal QMatrix::determinant() const
+
+ Returns the matrix's determinant.
+*/
+
+/*!
+ \fn QMatrix QMatrix::invert(bool *invertible) const
+
+ Returns an inverted copy of this matrix.
+
+ Use the inverted() function instead.
+*/
+
+/*!
+ Returns an inverted copy of this matrix.
+
+ If the matrix is singular (not invertible), the returned matrix is
+ the identity matrix. If \a invertible is valid (i.e. not 0), its
+ value is set to true if the matrix is invertible, otherwise it is
+ set to false.
+
+ \sa isInvertible()
+*/
+
+QMatrix QMatrix::inverted(bool *invertible) const
+{
+ qreal dtr = determinant();
+ if (dtr == 0.0) {
+ if (invertible)
+ *invertible = false; // singular matrix
+ return QMatrix(true);
+ }
+ else { // invertible matrix
+ if (invertible)
+ *invertible = true;
+ qreal dinv = 1.0/dtr;
+ return QMatrix((_m22*dinv), (-_m12*dinv),
+ (-_m21*dinv), (_m11*dinv),
+ ((_m21*_dy - _m22*_dx)*dinv),
+ ((_m12*_dx - _m11*_dy)*dinv),
+ true);
+ }
+}
+
+
+/*!
+ \fn bool QMatrix::operator==(const QMatrix &matrix) const
+
+ Returns true if this matrix is equal to the given \a matrix,
+ otherwise returns false.
+*/
+
+bool QMatrix::operator==(const QMatrix &m) const
+{
+ return _m11 == m._m11 &&
+ _m12 == m._m12 &&
+ _m21 == m._m21 &&
+ _m22 == m._m22 &&
+ _dx == m._dx &&
+ _dy == m._dy;
+}
+
+/*!
+ \fn bool QMatrix::operator!=(const QMatrix &matrix) const
+
+ Returns true if this matrix is not equal to the given \a matrix,
+ otherwise returns false.
+*/
+
+bool QMatrix::operator!=(const QMatrix &m) const
+{
+ return _m11 != m._m11 ||
+ _m12 != m._m12 ||
+ _m21 != m._m21 ||
+ _m22 != m._m22 ||
+ _dx != m._dx ||
+ _dy != m._dy;
+}
+
+/*!
+ \fn QMatrix &QMatrix::operator *=(const QMatrix &matrix)
+ \overload
+
+ Returns the result of multiplying this matrix by the given \a
+ matrix.
+*/
+
+QMatrix &QMatrix::operator *=(const QMatrix &m)
+{
+ qreal tm11 = _m11*m._m11 + _m12*m._m21;
+ qreal tm12 = _m11*m._m12 + _m12*m._m22;
+ qreal tm21 = _m21*m._m11 + _m22*m._m21;
+ qreal tm22 = _m21*m._m12 + _m22*m._m22;
+
+ qreal tdx = _dx*m._m11 + _dy*m._m21 + m._dx;
+ qreal tdy = _dx*m._m12 + _dy*m._m22 + m._dy;
+
+ _m11 = tm11; _m12 = tm12;
+ _m21 = tm21; _m22 = tm22;
+ _dx = tdx; _dy = tdy;
+ return *this;
+}
+
+/*!
+ \fn QMatrix QMatrix::operator *(const QMatrix &matrix) const
+
+ Returns the result of multiplying this matrix by the given \a
+ matrix.
+
+ Note that matrix multiplication is not commutative, i.e. a*b !=
+ b*a.
+*/
+
+QMatrix QMatrix::operator *(const QMatrix &m) const
+{
+ qreal tm11 = _m11*m._m11 + _m12*m._m21;
+ qreal tm12 = _m11*m._m12 + _m12*m._m22;
+ qreal tm21 = _m21*m._m11 + _m22*m._m21;
+ qreal tm22 = _m21*m._m12 + _m22*m._m22;
+
+ qreal tdx = _dx*m._m11 + _dy*m._m21 + m._dx;
+ qreal tdy = _dx*m._m12 + _dy*m._m22 + m._dy;
+ return QMatrix(tm11, tm12, tm21, tm22, tdx, tdy, true);
+}
+
+/*!
+ Assigns the given \a matrix's values to this matrix.
+*/
+QMatrix &QMatrix::operator=(const QMatrix &matrix)
+{
+ _m11 = matrix._m11;
+ _m12 = matrix._m12;
+ _m21 = matrix._m21;
+ _m22 = matrix._m22;
+ _dx = matrix._dx;
+ _dy = matrix._dy;
+ return *this;
+}
+
+/*!
+ \since 4.2
+
+ Returns the matrix as a QVariant.
+*/
+QMatrix::operator QVariant() const
+{
+ return QVariant(QVariant::Matrix, this);
+}
+
+Q_GUI_EXPORT QPainterPath operator *(const QPainterPath &p, const QMatrix &m)
+{
+ return m.map(p);
+}
+
+
+/*****************************************************************************
+ QMatrix stream functions
+ *****************************************************************************/
+#ifndef QT_NO_DATASTREAM
+/*!
+ \fn QDataStream &operator<<(QDataStream &stream, const QMatrix &matrix)
+ \relates QMatrix
+
+ Writes the given \a matrix to the given \a stream and returns a
+ reference to the stream.
+
+ \sa {Serializing Qt Data Types}
+*/
+
+QDataStream &operator<<(QDataStream &s, const QMatrix &m)
+{
+ if (s.version() == 1) {
+ s << (float)m.m11() << (float)m.m12() << (float)m.m21()
+ << (float)m.m22() << (float)m.dx() << (float)m.dy();
+ } else {
+ s << double(m.m11())
+ << double(m.m12())
+ << double(m.m21())
+ << double(m.m22())
+ << double(m.dx())
+ << double(m.dy());
+ }
+ return s;
+}
+
+/*!
+ \fn QDataStream &operator>>(QDataStream &stream, QMatrix &matrix)
+ \relates QMatrix
+
+ Reads the given \a matrix from the given \a stream and returns a
+ reference to the stream.
+
+ \sa {Serializing Qt Data Types}
+*/
+
+QDataStream &operator>>(QDataStream &s, QMatrix &m)
+{
+ if (s.version() == 1) {
+ float m11, m12, m21, m22, dx, dy;
+ s >> m11; s >> m12; s >> m21; s >> m22;
+ s >> dx; s >> dy;
+ m.setMatrix(m11, m12, m21, m22, dx, dy);
+ }
+ else {
+ double m11, m12, m21, m22, dx, dy;
+ s >> m11;
+ s >> m12;
+ s >> m21;
+ s >> m22;
+ s >> dx;
+ s >> dy;
+ m.setMatrix(m11, m12, m21, m22, dx, dy);
+ }
+ return s;
+}
+#endif // QT_NO_DATASTREAM
+
+#ifndef QT_NO_DEBUG_STREAM
+QDebug operator<<(QDebug dbg, const QMatrix &m)
+{
+ dbg.nospace() << "QMatrix("
+ << "11=" << m.m11()
+ << " 12=" << m.m12()
+ << " 21=" << m.m21()
+ << " 22=" << m.m22()
+ << " dx=" << m.dx()
+ << " dy=" << m.dy()
+ << ')';
+ return dbg.space();
+}
+#endif
+
+/*!
+ \fn QRect QMatrix::map(const QRect &rect) const
+ \compat
+
+ Creates and returns a QRect object that is a copy of the given
+ rectangle, mapped into the coordinate system defined by this
+ matrix.
+
+ Use the mapRect() function instead.
+*/
+
+
+/*!
+ \fn bool qFuzzyCompare(const QMatrix& m1, const QMatrix& m2)
+
+ \relates QMatrix
+ \since 4.6
+
+ \brief The qFuzzyCompare function is for comparing two matrices
+ using a fuzziness factor.
+
+ Returns true if \a m1 and \a m2 are equal, allowing for a small
+ fuzziness factor for floating-point comparisons; false otherwise.
+*/
+
+QT_END_NAMESPACE