Package org.gnome.pango

Class Matrix

java.lang.Object

io.github.jwharm.javagi.base.ProxyInstance

org.gnome.pango.Matrix

All Implemented Interfaces:

Proxy

@Generated("io.github.jwharm.JavaGI")
public class Matrix
extends ProxyInstance

A PangoMatrix specifies a transformation between user-space and device coordinates.

The transformation is given by

 x_device = x_user * matrix->xx + y_user * matrix->xy + matrix->x0;
 y_device = x_user * matrix->yx + y_user * matrix->yy + matrix->y0;
 

Constructor Summary

Constructors

Constructor	Description
Matrix()	Allocate a new Matrix.
Matrix(double xx, double xy, double yx, double yy, double x0, double y0)	Allocate a new Matrix with the fields set to the provided values.
Matrix(double xx, double xy, double yx, double yy, double x0, double y0, Arena arena)	Allocate a new Matrix with the fields set to the provided values.
Matrix(Arena arena)	Allocate a new Matrix.
Matrix(MemorySegment address)	Create a Matrix proxy instance for the provided memory address.

Method Summary

Modifier and Type	Method	Description
void	concat(Matrix newMatrix)	Changes the transformation represented by this Matrix to be the transformation given by first applying transformation given by newMatrix then applying the original transformation.
Matrix	copy()	Copies a PangoMatrix.
void	free()	Free a PangoMatrix.
double	getFontScaleFactor()	Returns the scale factor of a matrix on the height of the font.
void	getFontScaleFactors(@Nullable Out<Double> xscale, @Nullable Out<Double> yscale)	Calculates the scale factor of a matrix on the width and height of the font.
static MemoryLayout	getMemoryLayout()	The memory layout of the native struct.
double	getSlantRatio()	Gets the slant ratio of a matrix.
static Type	getType()	Get the GType of the Matrix class
double	readX0()	Read the value of the field x0.
double	readXx()	Read the value of the field xx.
double	readXy()	Read the value of the field xy.
double	readY0()	Read the value of the field y0.
double	readYx()	Read the value of the field yx.
double	readYy()	Read the value of the field yy.
void	rotate(double degrees)	Changes the transformation represented by this Matrix to be the transformation given by first rotating by degrees degrees counter-clockwise then applying the original transformation.
void	scale(double scaleX, double scaleY)	Changes the transformation represented by this Matrix to be the transformation given by first scaling by sx in the X direction and sy in the Y direction then applying the original transformation.
void	transformDistance(Out<Double> dx, Out<Double> dy)	Transforms the distance vector (dx,dy) by this Matrix.
void	transformPixelRectangle(@Nullable Rectangle rect)	First transforms the rect using this Matrix, then calculates the bounding box of the transformed rectangle.
void	transformPoint(Out<Double> x, Out<Double> y)	Transforms the point (x, y) by this Matrix.
void	transformRectangle(@Nullable Rectangle rect)	First transforms rect using this Matrix, then calculates the bounding box of the transformed rectangle.
void	translate(double tx, double ty)	Changes the transformation represented by this Matrix to be the transformation given by first translating by (tx, ty) then applying the original transformation.
void	writeX0(double x0)	Write a value in the field x0.
void	writeXx(double xx)	Write a value in the field xx.
void	writeXy(double xy)	Write a value in the field xy.
void	writeY0(double y0)	Write a value in the field y0.
void	writeYx(double yx)	Write a value in the field yx.
void	writeYy(double yy)	Write a value in the field yy.

Methods inherited from class io.github.jwharm.javagi.base.ProxyInstance

equals, handle, hashCode

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Matrix

public Matrix(MemorySegment address)

Create a Matrix proxy instance for the provided memory address.

Parameters:

address - the memory address of the native object

Matrix

public Matrix(Arena arena)

Allocate a new Matrix.

Parameters:

arena - to control the memory allocation scope

Matrix

public Matrix()

Allocate a new Matrix. The memory is allocated with Arena.ofAuto().

Matrix

public Matrix(double xx,
 double xy,
 double yx,
 double yy,
 double x0,
 double y0,
 Arena arena)

Allocate a new Matrix with the fields set to the provided values.

Parameters:

xx - value for the field xx

xy - value for the field xy

yx - value for the field yx

yy - value for the field yy

x0 - value for the field x0

y0 - value for the field y0

arena - to control the memory allocation scope

Matrix

public Matrix(double xx,
 double xy,
 double yx,
 double yy,
 double x0,
 double y0)

Allocate a new Matrix with the fields set to the provided values. The memory is allocated with Arena.ofAuto().

Parameters:

xx - value for the field xx

xy - value for the field xy

yx - value for the field yx

yy - value for the field yy

x0 - value for the field x0

y0 - value for the field y0

Method Details

getType

public static Type getType()

Get the GType of the Matrix class

Returns:

the GType

getMemoryLayout

public static MemoryLayout getMemoryLayout()

The memory layout of the native struct.

Returns:

the memory layout

readXx

public double readXx()

Read the value of the field xx.

Returns:

The value of the field xx

writeXx

public void writeXx(double xx)

Write a value in the field xx.

Parameters:

xx - The new value for the field xx

readXy

public double readXy()

Read the value of the field xy.

Returns:

The value of the field xy

writeXy

public void writeXy(double xy)

Write a value in the field xy.

Parameters:

xy - The new value for the field xy

readYx

public double readYx()

Read the value of the field yx.

Returns:

The value of the field yx

writeYx

public void writeYx(double yx)

Write a value in the field yx.

Parameters:

yx - The new value for the field yx

readYy

public double readYy()

Read the value of the field yy.

Returns:

The value of the field yy

writeYy

public void writeYy(double yy)

Write a value in the field yy.

Parameters:

yy - The new value for the field yy

readX0

public double readX0()

Read the value of the field x0.

Returns:

The value of the field x0

writeX0

public void writeX0(double x0)

Write a value in the field x0.

Parameters:

x0 - The new value for the field x0

readY0

public double readY0()

Read the value of the field y0.

Returns:

The value of the field y0

writeY0

public void writeY0(double y0)

Write a value in the field y0.

Parameters:

y0 - The new value for the field y0

concat

public void concat(Matrix newMatrix)

Changes the transformation represented by this Matrix to be the transformation given by first applying transformation given by newMatrix then applying the original transformation.

Parameters:

newMatrix - a PangoMatrix

copy

public Matrix copy()

Copies a PangoMatrix.

Returns:

the newly allocated PangoMatrix

free

public void free()

Free a PangoMatrix.

getFontScaleFactor

public double getFontScaleFactor()

Returns the scale factor of a matrix on the height of the font.

That is, the scale factor in the direction perpendicular to the vector that the X coordinate is mapped to. If the scale in the X coordinate is needed as well, use getFontScaleFactors(io.github.jwharm.javagi.base.Out<java.lang.Double>, io.github.jwharm.javagi.base.Out<java.lang.Double>).

Returns:

the scale factor of this Matrix on the height of the font, or 1.0 if this Matrix is null.

getFontScaleFactors

public void getFontScaleFactors(@Nullable
 @Nullable Out<Double> xscale,
 @Nullable
 @Nullable Out<Double> yscale)

Calculates the scale factor of a matrix on the width and height of the font.

That is, xscale is the scale factor in the direction of the X coordinate, and yscale is the scale factor in the direction perpendicular to the vector that the X coordinate is mapped to.

Note that output numbers will always be non-negative.

Parameters:

xscale - output scale factor in the x direction

yscale - output scale factor perpendicular to the x direction

getSlantRatio

public double getSlantRatio()

Gets the slant ratio of a matrix.

For a simple shear matrix in the form:

1 λ 0 1

this is simply λ.

Returns:

the slant ratio of this Matrix

rotate

public void rotate(double degrees)

Changes the transformation represented by this Matrix to be the transformation given by first rotating by degrees degrees counter-clockwise then applying the original transformation.

Parameters:

degrees - degrees to rotate counter-clockwise

scale

public void scale(double scaleX,
 double scaleY)

Changes the transformation represented by this Matrix to be the transformation given by first scaling by sx in the X direction and sy in the Y direction then applying the original transformation.

Parameters:

scaleX - amount to scale by in X direction

scaleY - amount to scale by in Y direction

transformDistance

public void transformDistance(Out<Double> dx,
 Out<Double> dy)

Transforms the distance vector (dx,dy) by this Matrix.

This is similar to transformPoint(io.github.jwharm.javagi.base.Out<java.lang.Double>, io.github.jwharm.javagi.base.Out<java.lang.Double>), except that the translation components of the transformation are ignored. The calculation of the returned vector is as follows:

 dx2 = dx1 * xx + dy1 * xy;
 dy2 = dx1 * yx + dy1 * yy;
 

Affine transformations are position invariant, so the same vector always transforms to the same vector. If (x1,y1) transforms to (x2,y2) then (x1+dx1,y1+dy1) will transform to (x1+dx2,y1+dy2) for all values of x1 and x2.

Parameters:

dx - in/out X component of a distance vector

dy - in/out Y component of a distance vector

transformPixelRectangle

public void transformPixelRectangle(@Nullable
 @Nullable Rectangle rect)

First transforms the rect using this Matrix, then calculates the bounding box of the transformed rectangle.

This function is useful for example when you want to draw a rotated PangoLayout to an image buffer, and want to know how large the image should be and how much you should shift the layout when rendering.

For better accuracy, you should use transformRectangle(org.gnome.pango.Rectangle) on original rectangle in Pango units and convert to pixels afterward using Pango.extentsToPixels(org.gnome.pango.Rectangle, org.gnome.pango.Rectangle)'s first argument.

Parameters:

rect - in/out bounding box in device units

transformPoint

public void transformPoint(Out<Double> x,
 Out<Double> y)

Transforms the point (x, y) by this Matrix.

Parameters:

x - in/out X position

y - in/out Y position

transformRectangle

public void transformRectangle(@Nullable
 @Nullable Rectangle rect)

First transforms rect using this Matrix, then calculates the bounding box of the transformed rectangle.

This function is useful for example when you want to draw a rotated PangoLayout to an image buffer, and want to know how large the image should be and how much you should shift the layout when rendering.

If you have a rectangle in device units (pixels), use transformPixelRectangle(org.gnome.pango.Rectangle).

If you have the rectangle in Pango units and want to convert to transformed pixel bounding box, it is more accurate to transform it first (using this function) and pass the result to pango_extents_to_pixels(), first argument, for an inclusive rounded rectangle. However, there are valid reasons that you may want to convert to pixels first and then transform, for example when the transformed coordinates may overflow in Pango units (large matrix translation for example).

Parameters:

rect - in/out bounding box in Pango units

translate

public void translate(double tx,
 double ty)

Changes the transformation represented by this Matrix to be the transformation given by first translating by (tx, ty) then applying the original transformation.

Parameters:

tx - amount to translate in the X direction

ty - amount to translate in the Y direction