Module org.freedesktop.cairo

Package org.freedesktop.cairo

Class RasterSource

java.lang.Object

io.github.jwharm.cairobindings.Proxy

org.freedesktop.cairo.Pattern

org.freedesktop.cairo.RasterSource

public class RasterSource
extends Pattern

A user pattern providing raster data.

The raster source provides the ability to supply arbitrary pixel data whilst rendering. The pixels are queried at the time of rasterisation by means of user callback functions, allowing for the ultimate flexibility. For example, in handling compressed image sources, you may keep a MRU cache of decompressed images and decompress sources on the fly and discard old ones to conserve memory.

For the raster source to be effective, you must at least specify the acquire and release callbacks which are used to retrieve the pixel data for the region of interest and demark when it can be freed afterwards. Other callbacks are provided for when the pattern is copied temporarily during rasterisation, or more permanently as a snapshot in order to keep the pixel data available for printing.

Constructor Summary

Constructors

Constructor	Description
RasterSource(MemorySegment address)	Constructor used internally to instantiate a java RasterSource object for a native cairo_pattern_t instance

Method Summary

Modifier and Type	Method	Description
static RasterSource	create(Content content, int width, int height)	Creates a new user pattern for providing pixel data.
RasterSourceAcquireFunc	getAcquire()	Queries the current acquire callback
RasterSourceCopyFunc	getCopy()	Queries the current copy callback.
RasterSourceFinishFunc	getFinish()	Queries the current finish callback.
RasterSourceReleaseFunc	getRelease()	Queries the current release callback.
RasterSourceSnapshotFunc	getSnapshot()	Queries the current snapshot callback.
void	setAcquire(RasterSourceAcquireFunc acquire, RasterSourceReleaseFunc release)	Specifies the callbacks used to generate the image surface for a rendering operation (acquire) and the function used to cleanup that surface afterwards.
void	setCopy(RasterSourceCopyFunc copy)	Updates the copy callback which is used whenever a temporary copy of the pattern is taken.
void	setFinish(RasterSourceFinishFunc finish)	Updates the finish callback which is used whenever a pattern (or a copy thereof) will no longer be used.
void	setSnapshot(RasterSourceSnapshotFunc snapshot)	Sets the callback that will be used whenever a snapshot is taken of the pattern, that is whenever the current contents of the pattern should be preserved for later use.

Methods inherited from class org.freedesktop.cairo.Pattern

destroy, getDither, getExtend, getFilter, getMatrix, getPatternType, getType, getUserData, setDither, setExtend, setFilter, setMatrix, setUserData, status

Methods inherited from class io.github.jwharm.cairobindings.Proxy

equals, handle, hashCode

Methods inherited from class java.lang.Object

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

Constructor Details

RasterSource

public RasterSource(MemorySegment address)

Constructor used internally to instantiate a java RasterSource object for a native cairo_pattern_t instance

Parameters:

address - the memory address of the native cairo_pattern_t instance

Method Details

create

public static RasterSource create(Content content,
 int width,
 int height)

Creates a new user pattern for providing pixel data.

Use the setter functions to associate callbacks with the returned pattern. The only mandatory callback is acquire.

Parameters:

content - content type for the pixel data that will be returned. Knowing the content type ahead of time is used for analysing the operation and picking the appropriate rendering path.

width - maximum size of the sample area

height - maximum size of the sample area

Returns:

a newly created Pattern of type RasterSource

Since:

1.2

setAcquire

public void setAcquire(RasterSourceAcquireFunc acquire,
 RasterSourceReleaseFunc release)

Specifies the callbacks used to generate the image surface for a rendering operation (acquire) and the function used to cleanup that surface afterwards.

The acquire callback should create a surface (preferably an image surface created to match the target using Surface.createSimilarImage(Surface, Format, int, int)) that defines at least the region of interest specified by extents. The surface is allowed to be the entire sample area, but if it does contain a subsection of the sample area, the surface extents should be provided by setting the device offset (along with its width and height) using Surface.setDeviceOffset(double, double).

Parameters:

acquire - acquire callback

release - release callback

Since:

1.12

getAcquire

public RasterSourceAcquireFunc getAcquire()

Queries the current acquire callback

Returns:

the current acquire callback

Since:

1.2

getRelease

public RasterSourceReleaseFunc getRelease()

Queries the current release callback.

Returns:

the current release callback

Since:

1.2

setSnapshot

public void setSnapshot(RasterSourceSnapshotFunc snapshot)

Sets the callback that will be used whenever a snapshot is taken of the pattern, that is whenever the current contents of the pattern should be preserved for later use. This is typically invoked whilst printing.

Parameters:

snapshot - the pattern to update

Since:

1.12

getSnapshot

public RasterSourceSnapshotFunc getSnapshot()

Queries the current snapshot callback.

Returns:

the current snapshot callback

Since:

1.12

setCopy

public void setCopy(RasterSourceCopyFunc copy)

Updates the copy callback which is used whenever a temporary copy of the pattern is taken.

Parameters:

copy - the copy callback

Since:

1.12

getCopy

public RasterSourceCopyFunc getCopy()

Queries the current copy callback.

Returns:

the current copy callback

Since:

1.12

setFinish

public void setFinish(RasterSourceFinishFunc finish)

Updates the finish callback which is used whenever a pattern (or a copy thereof) will no longer be used.

Parameters:

finish - the finish callback

Since:

1.12

getFinish

public RasterSourceFinishFunc getFinish()

Queries the current finish callback.

Returns:

the current finish callback

Since:

1.12