Package org.gnome.gsk

Class Transform

java.lang.Object

io.github.jwharm.javagi.base.ProxyInstance

org.gnome.gsk.Transform

All Implemented Interfaces:

Proxy

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

GskTransform is an object to describe transform matrices.

Unlike graphene_matrix_t, GskTransform retains the steps in how a transform was constructed, and allows inspecting them. It is modeled after the way CSS describes transforms.

GskTransform objects are immutable and cannot be changed after creation. This means code can safely expose them as properties of objects without having to worry about others changing them.

Constructor Summary

Constructors

Constructor	Description
Transform()	Creates a new identity transform.
Transform(MemorySegment address)	Create a Transform proxy instance for the provided memory address.

Method Summary

Modifier and Type	Method	Description
boolean	equal(@Nullable Transform second)	Checks two transforms for equality.
TransformCategory	getCategory()	Returns the category this transform belongs to.
static Type	getType()	Get the GType of the Transform class
Transform	invert()	Inverts the given transform.
Transform	matrix(Matrix matrix)	Multiplies this Transform with the given matrix.
static boolean	parse(String string, Out<Transform> outTransform)	Parses the given string into a transform and puts it in outTransform.
Transform	perspective(float depth)	Applies a perspective projection transform.
void	print(GString string)	Converts this Transform into a human-readable string representation suitable for printing.
Transform	ref()	Acquires a reference on the given GskTransform.
Transform	rotate(float angle)	Rotates this Transform angle degrees in 2D - or in 3D-speak, around the Z axis.
Transform	rotate3d(float angle, Vec3 axis)	Rotates this Transform angle degrees around axis.
Transform	scale(float factorX, float factorY)	Scales this Transform in 2-dimensional space by the given factors.
Transform	scale3d(float factorX, float factorY, float factorZ)	Scales this Transform by the given factors.
Transform	skew(float skewX, float skewY)	Applies a skew transform.
void	to2d(Out<Float> outXx, Out<Float> outYx, Out<Float> outXy, Out<Float> outYy, Out<Float> outDx, Out<Float> outDy)	Converts a GskTransform to a 2D transformation matrix.
void	to2dComponents(Out<Float> outSkewX, Out<Float> outSkewY, Out<Float> outScaleX, Out<Float> outScaleY, Out<Float> outAngle, Out<Float> outDx, Out<Float> outDy)	Converts a GskTransform to 2D transformation factors.
void	toAffine(Out<Float> outScaleX, Out<Float> outScaleY, Out<Float> outDx, Out<Float> outDy)	Converts a GskTransform to 2D affine transformation factors.
void	toMatrix(Matrix outMatrix)	Computes the actual value of this Transform and stores it in outMatrix.
String	toString()	Converts a matrix into a string that is suitable for printing.
void	toTranslate(Out<Float> outDx, Out<Float> outDy)	Converts a GskTransform to a translation operation.
Transform	transform(@Nullable Transform other)	Applies all the operations from other to this Transform.
void	transformBounds(Rect rect, Rect outRect)	Transforms a graphene_rect_t using the given transform this Transform.
void	transformPoint(Point point, Point outPoint)	Transforms a graphene_point_t using the given transform this Transform.
Transform	translate(Point point)	Translates this Transform in 2-dimensional space by point.
Transform	translate3d(Point3D point)	Translates this Transform by point.
void	unref()	Releases a reference on the given GskTransform.

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, wait, wait, wait

Constructor Details

Transform

public Transform(MemorySegment address)

Create a Transform proxy instance for the provided memory address.

Parameters:

address - the memory address of the native object

Transform

public Transform()

Creates a new identity transform.

This function is meant to be used by language bindings. For C code, this is equivalent to using null.

Method Details

getType

public static Type getType()

Get the GType of the Transform class

Returns:

the GType

parse

public static boolean parse(String string,
 Out<Transform> outTransform)

Parses the given string into a transform and puts it in outTransform.

Strings printed via toString() can be read in again successfully using this function.

If string does not describe a valid transform, false is returned and null is put in outTransform.

Parameters:

string - the string to parse

outTransform - The location to put the transform in

Returns:

true if string described a valid transform.

equal

public boolean equal(@Nullable
 @Nullable Transform second)

Checks two transforms for equality.

Parameters:

second - the second transform

Returns:

true if the two transforms perform the same operation

getCategory

public TransformCategory getCategory()

Returns the category this transform belongs to.

Returns:

The category of the transform

invert

public Transform invert()

Inverts the given transform.

If this Transform is not invertible, null is returned. Note that inverting null also returns null, which is the correct inverse of null. If you need to differentiate between those cases, you should check this Transform is not null before calling this function.

This function consumes this Transform. Use ref() first if you want to keep it around.

Returns:

The inverted transform

matrix

public Transform matrix(Matrix matrix)

Multiplies this Transform with the given matrix.

This function consumes this Transform. Use ref() first if you want to keep it around.

Parameters:

matrix - the matrix to multiply this Transform with

Returns:

The new transform

perspective

public Transform perspective(float depth)

Applies a perspective projection transform.

This transform scales points in X and Y based on their Z value, scaling points with positive Z values away from the origin, and those with negative Z values towards the origin. Points on the z=0 plane are unchanged.

This function consumes this Transform. Use ref() first if you want to keep it around.

Parameters:

depth - distance of the z=0 plane. Lower values give a more flattened pyramid and therefore a more pronounced perspective effect.

Returns:

The new transform

print

public void print(GString string)

Converts this Transform into a human-readable string representation suitable for printing.

The result of this function can later be parsed with parse(java.lang.String, io.github.jwharm.javagi.base.Out<org.gnome.gsk.Transform>).

Parameters:

string - The string to print into

ref

public Transform ref()

Acquires a reference on the given GskTransform.

Returns:

the GskTransform with an additional reference

rotate

public Transform rotate(float angle)

Rotates this Transform angle degrees in 2D - or in 3D-speak, around the Z axis. The rotation happens around the origin point of (0, 0).

This function consumes this Transform. Use ref() first if you want to keep it around.

Parameters:

angle - the rotation angle, in degrees (clockwise)

Returns:

The new transform

rotate3d

public Transform rotate3d(float angle,
 Vec3 axis)

Rotates this Transform angle degrees around axis.

For a rotation in 2D space, use rotate(float)

This function consumes this Transform. Use ref() first if you want to keep it around.

Parameters:

angle - the rotation angle, in degrees (clockwise)

axis - The rotation axis

Returns:

The new transform

scale

public Transform scale(float factorX,
 float factorY)

Scales this Transform in 2-dimensional space by the given factors.

Use scale3d(float, float, float) to scale in all 3 dimensions.

This function consumes this Transform. Use ref() first if you want to keep it around.

Parameters:

factorX - scaling factor on the X axis

factorY - scaling factor on the Y axis

Returns:

The new transform

scale3d

public Transform scale3d(float factorX,
 float factorY,
 float factorZ)

Scales this Transform by the given factors.

This function consumes this Transform. Use ref() first if you want to keep it around.

Parameters:

factorX - scaling factor on the X axis

factorY - scaling factor on the Y axis

factorZ - scaling factor on the Z axis

Returns:

The new transform

skew

public Transform skew(float skewX,
 float skewY)

Applies a skew transform.

This function consumes this Transform. Use ref() first if you want to keep it around.

Parameters:

skewX - skew factor, in degrees, on the X axis

skewY - skew factor, in degrees, on the Y axis

Returns:

The new transform

to2d

public void to2d(Out<Float> outXx,
 Out<Float> outYx,
 Out<Float> outXy,
 Out<Float> outYy,
 Out<Float> outDx,
 Out<Float> outDy)

Converts a GskTransform to a 2D transformation matrix.

this Transform must be a 2D transformation. If you are not sure, use gsk_transform_get_category() >= TransformCategory._2D to check.

The returned values have the following layout:

   | xx yx |   |  a  b  0 |
   | xy yy | = |  c  d  0 |
   | dx dy |   | tx ty  1 |
 

This function can be used to convert between a GskTransform and a matrix type from other 2D drawing libraries, in particular Cairo.

Parameters:

outXx - return location for the xx member

outYx - return location for the yx member

outXy - return location for the xy member

outYy - return location for the yy member

outDx - return location for the x0 member

outDy - return location for the y0 member

to2dComponents

public void to2dComponents(Out<Float> outSkewX,
 Out<Float> outSkewY,
 Out<Float> outScaleX,
 Out<Float> outScaleY,
 Out<Float> outAngle,
 Out<Float> outDx,
 Out<Float> outDy)

Converts a GskTransform to 2D transformation factors.

To recreate an equivalent transform from the factors returned by this function, use

gsk_transform_skew ( gsk_transform_scale ( gsk_transform_rotate ( gsk_transform_translate (NULL, &GRAPHENE_POINT_T (dx, dy)), angle), scale_x, scale_y), skew_x, skew_y)

this Transform must be a 2D transformation. If you are not sure, use

gsk_transform_get_category() >= TransformCategory._2D

to check.

Parameters:

outSkewX - return location for the skew factor in the x direction

outSkewY - return location for the skew factor in the y direction

outScaleX - return location for the scale factor in the x direction

outScaleY - return location for the scale factor in the y direction

outAngle - return location for the rotation angle

outDx - return location for the translation in the x direction

outDy - return location for the translation in the y direction

toAffine

public void toAffine(Out<Float> outScaleX,
 Out<Float> outScaleY,
 Out<Float> outDx,
 Out<Float> outDy)

Converts a GskTransform to 2D affine transformation factors.

To recreate an equivalent transform from the factors returned by this function, use

gsk_transform_scale (gsk_transform_translate (NULL, &GRAPHENE_POINT_T (dx, dy)), sx, sy)

this Transform must be a 2D affine transformation. If you are not sure, use

gsk_transform_get_category() >= TransformCategory._2D_AFFINE

to check.

Parameters:

outScaleX - return location for the scale factor in the x direction

outScaleY - return location for the scale factor in the y direction

outDx - return location for the translation in the x direction

outDy - return location for the translation in the y direction

toMatrix

public void toMatrix(Matrix outMatrix)

Computes the actual value of this Transform and stores it in outMatrix.

The previous value of outMatrix will be ignored.

Parameters:

outMatrix - The matrix to set

toString

public String toString()

Converts a matrix into a string that is suitable for printing.

The resulting string can be parsed with parse(java.lang.String, io.github.jwharm.javagi.base.Out<org.gnome.gsk.Transform>).

This is a wrapper around print(org.gnome.glib.GString).

Overrides:

toString in class Object

Returns:

A new string for this Transform

toTranslate

public void toTranslate(Out<Float> outDx,
 Out<Float> outDy)

Converts a GskTransform to a translation operation.

this Transform must be a 2D transformation. If you are not sure, use

gsk_transform_get_category() >= TransformCategory._2D_TRANSLATE

to check.

Parameters:

outDx - return location for the translation in the x direction

outDy - return location for the translation in the y direction

transform

public Transform transform(@Nullable
 @Nullable Transform other)

Applies all the operations from other to this Transform.

This function consumes this Transform. Use ref() first if you want to keep it around.

Parameters:

other - Transform to apply

Returns:

The new transform

transformBounds

public void transformBounds(Rect rect,
 Rect outRect)

Transforms a graphene_rect_t using the given transform this Transform.

The result is the bounding box containing the coplanar quad.

Parameters:

rect - a graphene_rect_t

outRect - return location for the bounds of the transformed rectangle

transformPoint

public void transformPoint(Point point,
 Point outPoint)

Transforms a graphene_point_t using the given transform this Transform.

Parameters:

point - a graphene_point_t

outPoint - return location for the transformed point

translate

public Transform translate(Point point)

Translates this Transform in 2-dimensional space by point.

This function consumes this Transform. Use ref() first if you want to keep it around.

Parameters:

point - the point to translate the transform by

Returns:

The new transform

translate3d

public Transform translate3d(Point3D point)

Translates this Transform by point.

This function consumes this Transform. Use ref() first if you want to keep it around.

Parameters:

point - the point to translate the transform by

Returns:

The new transform

unref

public void unref()

Releases a reference on the given GskTransform.

If the reference was the last, the resources associated to the this Transform are freed.