diff options
Diffstat (limited to 'src/gui/painting')
| -rw-r--r-- | src/gui/painting/qtransform.cpp | 36 |
1 files changed, 21 insertions, 15 deletions
diff --git a/src/gui/painting/qtransform.cpp b/src/gui/painting/qtransform.cpp index 45939c1..a322fe4 100644 --- a/src/gui/painting/qtransform.cpp +++ b/src/gui/painting/qtransform.cpp @@ -101,7 +101,7 @@ QT_BEGIN_NAMESPACE allowing perspective transformations. QTransform's toAffine() method allows casting QTransform to QMatrix. If a perspective transformation has been specified on the matrix, then the - conversion to an affine QMatrix will cause loss of data. + conversion will cause loss of data. QTransform is the recommended transformation class in Qt. @@ -125,11 +125,13 @@ QT_BEGIN_NAMESPACE 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, QTransform provides the det() function - returning the matrix's determinant. + matrix), and adjoint() returns the matrix's classical adjoint. + In addition, QTransform provides the determinant() function which + returns the matrix's determinant. - Finally, the QTransform class supports matrix multiplication, and - objects of the class can be streamed as well as compared. + Finally, the QTransform class supports matrix multiplication, addition + and subtraction, and objects of the class can be streamed as well + as compared. \tableofcontents @@ -191,7 +193,7 @@ QT_BEGIN_NAMESPACE 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 + shear() convenience functions. The currently set values can be retrieved using the m11(), m12(), m13(), m21(), m22(), m23(), m31(), m32(), m33(), dx() and dy() functions. @@ -204,9 +206,9 @@ QT_BEGIN_NAMESPACE 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. Perspective transformation is achieved by carefully setting - both the projection factors and the scaling factors. + setting both the shearing factors and the scaling factors. Perspective + transformation is achieved by setting both the projection factors and + the scaling factors. Here's the combined transformations example using basic matrix operations: @@ -958,8 +960,8 @@ QTransform & QTransform::operator=(const QTransform &matrix) /*! 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. + to zero, except \c m11 and \c m22 (specifying the scale) and \c m33 + which are set to 1. \sa QTransform(), isIdentity(), {QTransform#Basic Matrix Operations}{Basic Matrix Operations} @@ -1773,7 +1775,7 @@ bool QTransform::quadToQuad(const QPolygonF &one, Sets the matrix elements to the specified values, \a m11, \a m12, \a m13 \a m21, \a m22, \a m23 \a m31, \a m32 and \a m33. Note that this function replaces the previous values. - QMatrix provides the translate(), rotate(), scale() and shear() + QTransform provides the translate(), rotate(), scale() and shear() convenience functions to manipulate the various matrix elements based on the currently defined coordinate system. @@ -1951,8 +1953,11 @@ void QTransform::map(int x, int y, int *tx, int *ty) const } /*! - Returns the QTransform cast to a QMatrix. - */ + Returns the QTransform as an affine matrix. + + \warning If a perspective transformation has been specified, + then the conversion will cause loss of data. +*/ const QMatrix &QTransform::toAffine() const { return affine; @@ -2030,8 +2035,9 @@ QTransform::operator QVariant() const /*! \fn qreal QTransform::det() const + \obsolete - Returns the matrix's determinant. + Returns the matrix's determinant. Use determinant() instead. */ |