Callbacks

	ArgumentClassMapFn (object_class, pspec, argument_class, a, b)
	ArgumentMapFn (object, pspec, argument_class, argument_instance, a, b)
	CallbackFn (a, b)
	ClassMapFn (cls, a)
	GenerateFn (out, seq, a, b, stop)
	ImageMapFn (image, name, value, a)
	InterpolateMethod (interpolate, out, in_, x, y)
	ObjectSetArguments (object, a, b)
	OperationBuildFn (object)
	RegionWrite (region, area, a)
	SListFold2Fn (item, a, b, c)
	SListMap2Fn (item, a, b)
	SListMap4Fn (item, a, b, c, d)
	SinkNotify (im, rect, a)
	StartFn (out, a, b)
	StopFn (seq, a, b)
	ThreadpoolAllocateFn (state, a, stop)
	ThreadpoolProgressFn (a)
	ThreadpoolWorkFn (state, a)
	TypeMap2Fn (type, a, b)
	TypeMapFn (type, a)

Details

Vips.ArgumentClassMapFn(object_class, pspec, argument_class, a, b)

Parameters:

• object_class (Vips.ObjectClass) –

• pspec (GObject.ParamSpec) –

• argument_class (Vips.ArgumentClass) –

• a (object or None) –

• b (object or None) –

Return type:

object or None

Vips.ArgumentMapFn(object, pspec, argument_class, argument_instance, a, b)

Parameters:

• object (Vips.Object) –

• pspec (GObject.ParamSpec) –

• argument_class (Vips.ArgumentClass) –

• argument_instance (Vips.ArgumentInstance) –

• a (object or None) –

• b (object or None) –

Return type:

object or None

Vips.CallbackFn(a, b)

Parameters:

• a (object or None) –

• b (object or None) –

Return type:

int

Vips.ClassMapFn(cls, a)

Parameters:

• cls (Vips.ObjectClass) –

• a (object or None) –

Return type:

object or None

Vips.GenerateFn(out, seq, a, b, stop)

Parameters:

• out (Vips.Region) – [class`Region`] to fill

• seq (object or None) – sequence value

• a (object or None) – user data

• b (object or None) – user data

• stop (bool) – set this to stop processing

Returns:

0 on success, -1 on error.

Return type:

int

Fill out->valid with pixels. seq contains per-thread state, such as the input regions. Set stop to TRUE to stop processing.

::: seealso [method`Image`.generate], [func`stop_many`].

Vips.ImageMapFn(image, name, value, a)

Parameters:

• image (Vips.Image) –

• name (str) –

• value (GObject.Value) –

• a (object or None) –

Return type:

object or None

Vips.InterpolateMethod(interpolate, out, in_, x, y)

Parameters:

• interpolate (Vips.Interpolate) – the interpolator

• out (object or None) – write the interpolated pixel here

• in (Vips.Region) – read source pixels from here

• x (float) – interpolate value at this position

• y (float) – interpolate value at this position

An interpolation function. It should read source pixels from in with [funcREGION_ADDR], it can look left and up from (x, y) by window_offset pixels and it can access pixels in a window of size window_size.

The interpolated value should be written to the pixel pointed to by out.

::: seealso [struct`InterpolateClass`].

Vips.ObjectSetArguments(object, a, b)

Parameters:

• object (Vips.Object) –

• a (object or None) –

• b (object or None) –

Return type:

object or None

Vips.OperationBuildFn(object)

Parameters:

object (Vips.Object) –

Return type:

bool

Vips.RegionWrite(region, area, a)

Parameters:

• region (Vips.Region) – get pixels from here

• area (Vips.Rect) – area to write

• a (object or None) – client data

Returns:

0 on success, -1 on error.

Return type:

int

The function should write the pixels in area from region. a is the value passed into [method`Image`.sink_disc].

::: seealso [method`Image`.sink_disc].

Vips.SListFold2Fn(item, a, b, c)

Parameters:

• item (object or None) –

• a (object or None) –

• b (object or None) –

• c (object or None) –

Return type:

object or None

Vips.SListMap2Fn(item, a, b)

Parameters:

• item (object or None) –

• a (object or None) –

• b (object or None) –

Return type:

object or None

Vips.SListMap4Fn(item, a, b, c, d)

Parameters:

• item (object or None) –

• a (object or None) –

• b (object or None) –

• c (object or None) –

• d (object or None) –

Return type:

object or None

Vips.SinkNotify(im, rect, a)

Parameters:

• im (Vips.Image) –

• rect (Vips.Rect) –

• a (object or None) –

Vips.StartFn(out, a, b)

Parameters:

• out (Vips.Image) – image being calculated

• a (object or None) – user data

• b (object or None) – user data

Returns:

a new sequence value

Return type:

object or None

Start a new processing sequence for this generate function. This allocates per-thread state, such as an input region.

::: seealso [func`start_one`], [func`start_many`].

Vips.StopFn(seq, a, b)

Parameters:

• seq (object or None) – sequence value

• a (object or None) – user data

• b (object or None) – user data

Returns:

0 on success, -1 on error.

Return type:

int

Stop a processing sequence. This frees per-thread state, such as an input region.

::: seealso [func`stop_one`], [func`stop_many`].

Vips.ThreadpoolAllocateFn(state, a, stop)

Parameters:

• state (Vips.ThreadState) – per-thread state

• a (object or None) – client data

• stop (bool) – set this to signal end of computation

Returns:

0 on success, or -1 on error

Return type:

int

This function is called to allocate a new work unit for the thread. It is always single-threaded, so it can modify per-pool state (such as a counter).

It should set stop to TRUE to indicate that no work could be allocated because the job is done.

::: seealso [func`threadpool_run`].

Vips.ThreadpoolProgressFn(a)

Parameters:

a (object or None) – client data

Returns:

0 on success, or -1 on error

Return type:

int

This function is called by the main thread once for every work unit processed. It can be used to give the user progress feedback.

::: seealso [func`threadpool_run`].

Vips.ThreadpoolWorkFn(state, a)

Parameters:

• state (Vips.ThreadState) – per-thread state

• a (object or None) – client data

Returns:

0 on success, or -1 on error

Return type:

int

This function is called to process a work unit. Many copies of this can run at once, so it should not write to the per-pool state. It can write to per-thread state.

::: seealso [func`threadpool_run`].

Vips.TypeMap2Fn(type, a, b)

Parameters:

• type (GObject.GType) –

• a (object or None) –

• b (object or None) –

Return type:

object or None

Vips.TypeMapFn(type, a)

Parameters:

• type (GObject.GType) –

• a (object or None) –

Return type:

object or None