sswf::Matrix Class Reference

The position matrix. More...

#include <libsswf.h>

List of all members.

Public Member Functions
bool	IsNull (void) const
	Check whether the matrix has an effect.
	Matrix (void)
	Initialize a matrix to a "no effect" matrix.
bool	operator!= (const Matrix &matrix) const
	Compare two matrices for inequality.
bool	operator== (const Matrix &matrix) const
	Compare two matrices for equality.
void	Reset (void)
	Reset a matrix to a "no effect" matrix.
void	Save (Data &data)
	Save a matrix to a data buffer.
void	SetRotate (double rotate)
	Change the rotation.Set the rotation in radian.
void	SetScale (double scale)
	Define the scale of the object.
void	SetScale (double x, double y)
	Define the horizontal and vertical scaling factors.
void	SetSkew (double skew0, double skew1)
	Set a skew (sliding off).
void	SetTranslate (long x, long y)
	Define the matrix translation.
Private Member Functions
void	ComputeMatrix (signed_matrix_t &m) const
	Internal function used to compute the matrix.
Private Attributes
double	f_rotate
double	f_scale_x
double	f_scale_y
double	f_skew_0
double	f_skew_1
long	f_translate_x
long	f_translate_y
Classes
struct	signed_matrix_t
	Matrix of longs; used to compute the matrix to be saved in the movie. More...

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Detailed Description

This class is used to position shapes. The matrix supports rotations, skews, offsets and scaling.

The matrix is a 2D matrix and thus is only a 3x3.

The default is the identity matrix:

  | 1 0 0 |
  | 0 1 0 |
  | 0 0 1 |

However, the matrix is not managed as a matrix. Instead, you define the scaling, skewing, rotation and translation parameters. The library takes care of generating the matrix when it is saved in the SWF movie.

Notice that the translation is defined in twips and not floating point values.

See also:

SWF Alexis' Reference—swf_matrix

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Constructor & Destructor Documentation

Matrix::Matrix

(

void

)

The constructor creates and initializes a matrix with no effect. (i.e. the identity matrix.)

See also:

sswf::Matrix::Reset(void)

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Member Function Documentation

void Matrix::ComputeMatrix

(

signed_matrix_t &

m

)

const [private]

This function computes the matrix of signed values. The matrix is saved as 4x 16.16 fixed point values. This function computes the 4 fixed point values using the current definition of the matrix (i.e. rotation, skew and scaling.) The translation is not added in this matrix since this matrix is a 2x2 matrix.

Parameters:

[out]

m

When the computed matrix is saved

See also:

sswf::Matrix::IsNull(void) const

Matrix::Save(Data& data)

Matrix::operator == (const Matrix& matrix) const

Matrix::operator != (const Matrix& matrix) const

bool Matrix::IsNull

(

void

)

const

This function checks whether the different parameters define a null matrix. If so, then the function returns true.

The test is performed with the floating point values transformed in 16.16 fixed points as when they are saved in the final matrix. To ensures that the normal rounding is applied and thus it catches more matrices as null matrices.

Returns:

true if the matrix is the identity matrix.

See also:

sswf::TagBase::Double2Signed(double value)

bool Matrix::operator!=

(

const Matrix &

matrix

)

const

This operator compares two matrices to know whether they are inequal.

Note that the doubles are first transformed into 16.16 fixed point values and these are compared for inequality. This means less matrices may look inequal than what their exact definitions with doubles would imply.

See also:

sswf::Matrix::operator != (const Matrix& matrix) const

bool Matrix::operator==

(

const Matrix &

matrix

)

const

This operator compares two matrices to know whether they are equal or not.

Note that the doubles are first transformed into 16.16 fixed point values and these are compared for equality. This means more matrices may look equal than what their exact definitions with doubles would imply.

See also:

sswf::Matrix::operator != (const Matrix& matrix) const

void Matrix::Reset

(

void

)

The Reset() function sets all the parameters to no effect. (i.e. the identity matrix.)

void Matrix::Save

(

Data &

data

)

The Save() function computes the matrix and then saves it in the specified data buffer.

It is valid to save an identity matrix.

Parameters:

[in]

data

The buffer where the matrix is to be saved

See also:

sswf::Matrix::IsNull(void) const

void Matrix::SetRotate

(

double

rotate

)

The SetRotate() function takes a radian angle and saves it as the current rotation angle. This function is not cumulative. Instead the new angle overwrites any other angle previously defined with SetRotate().

Parameters:

[in]

rotate

The rotation angle

See also:

sswf::Matrix::SetScale(double x, double y)

sswf::Matrix::SetScale(double scale)

sswf::Matrix::SetSkew(double skew0, double skew1)

sswf::Matrix::SetTranslate(long x, long y)

sswf::Matrix::SetScale

(

double

scale

)

[inline]

This function changes the matrix scaling. This function can be used to change the scaling uniformly in both directions. This is often used when you need to enlarge or reduce an object without losing its aspect ratio.

A call to this function is not cumulative. Each call sets the new scale to the specified value by overwriting the previous value.

It is equivalent to call SetScale() with the same value in x and y:

  // both calls are equivalent
  SetScale(scale);
  SetScale(scale, scale);

Parameters:

[in]

scale

Defines the new horizontal and vertical scaling

See also:

sswf::Matrix::SetScale(double x, double y)

sswf::Matrix::SetRotate(double rotate)

sswf::Matrix::SetSkew(double skew0, double skew1)

sswf::Matrix::SetTranslate(long x, long y)

sswf::Matrix::SetScale	(	double	x,
		double	y
	)			[inline]

This function changes the matrix scaling. This function can be used to change the horizontal and vertical scaling with different values. This let's you scale objects exactly the way you want.

A call to this function is not cumulative. Each call sets the new scaling values to the specified (x, y) scaling by overwriting the previous values.

Parameters:

[in]	x	Defines the new horizontal scaling
[in]	y	Defines the new vertical scaling

See also:

sswf::Matrix::SetScale(double scale)

sswf::Matrix::SetRotate(double rotate)

sswf::Matrix::SetSkew(double skew0, double skew1)

sswf::Matrix::SetTranslate(long x, long y)

sswf::Matrix::SetSkew	(	double	skew0,
		double	skew1
	)			[inline]

This function is used to change the skew parameters. The skew makes the top and bottom (or left and right) edges move horizontally (vertically) away from each others.

The skew defined by this function is not cumulative. Instead it replaces the current value with the new values.

The unit of the skew is the twips times the scaling factors.

Parameters:

[in]	skew0	The horizontal skew
[in]	skew1	The vertical skew

See also:

sswf::Matrix::SetScale(double x, double y)

sswf::Matrix::SetScale(double scale)

sswf::Matrix::SetRotate(double rotate)

sswf::Matrix::SetTranslate(long x, long y)

sswf::Matrix::SetTranslate	(	long	x,
		long	y
	)			[inline]

Set the translation to (x, y). Previous translations are replaced by each new call to this function.

The translation is defined in twips and taken as long values. (i.e. 20 represents 1 pixel on the screen.)

Parameters:

[in]	x	The horizontal translation
[in]	y	The vertical translation

See also:

sswf::Matrix::SetScale(double x, double y)

sswf::Matrix::SetScale(double scale)

sswf::Matrix::SetRotate(double rotate)

sswf::Matrix::SetSkew(double skew0, double skew1)

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Member Data Documentation

double sswf::Matrix::f_rotate [private]

double sswf::Matrix::f_scale_x [private]

double sswf::Matrix::f_scale_y [private]

double sswf::Matrix::f_skew_0 [private]

double sswf::Matrix::f_skew_1 [private]

long sswf::Matrix::f_translate_x [private]

long sswf::Matrix::f_translate_y [private]

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The documentation for this class was generated from the following files:

• libsswf.h
• libsswf_tags.c++

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