Gdk.Paintable¶

Implementations:: Gdk.Texture

Methods¶

class	`new_empty` (intrinsic_width, intrinsic_height)
	`compute_concrete_size` (specified_width, specified_height, default_width, default_height)
	`get_current_image` ()
	`get_flags` ()
	`get_intrinsic_aspect_ratio` ()
	`get_intrinsic_height` ()
	`get_intrinsic_width` ()
	`invalidate_contents` ()
	`invalidate_size` ()
	`snapshot` (snapshot, width, height)

Virtual Methods¶

	`do_get_current_image` ()
	`do_get_flags` ()
	`do_get_intrinsic_aspect_ratio` ()
	`do_get_intrinsic_height` ()
	`do_get_intrinsic_width` ()
	`do_snapshot` (snapshot, width, height)

Properties¶

None

Signals¶

Name	Short Description
`invalidate-contents`	Emitted when the contents of the paintable change.
`invalidate-size`	Emitted when the intrinsic size of the paintable changes.

Fields¶

None

Class Details¶

class Gdk.Paintable¶

Bases:: GObject.GInterface
Structure:: Gdk.PaintableInterface

GdkPaintable is a simple interface used by GTK to represent content that can be painted.

The content of a GdkPaintable can be painted anywhere at any size without requiring any sort of layout. The interface is inspired by similar concepts elsewhere, such as ClutterContent, HTML/CSS Paint Sources, or SVG Paint Servers.

A GdkPaintable can be snapshot at any time and size using [method`Gdk`.Paintable.snapshot]. How the paintable interprets that size and if it scales or centers itself into the given rectangle is implementation defined, though if you are implementing a GdkPaintable and don’t know what to do, it is suggested that you scale your paintable ignoring any potential aspect ratio.

The contents that a GdkPaintable produces may depend on the [class`Gdk`.Snapshot] passed to it. For example, paintables may decide to use more detailed images on higher resolution screens or when OpenGL is available. A GdkPaintable will however always produce the same output for the same snapshot.

A GdkPaintable may change its contents, meaning that it will now produce a different output with the same snapshot. Once that happens, it will call [method`Gdk`.Paintable.invalidate_contents] which will emit the [signal`Gdk`.Paintable::invalidate-contents] signal. If a paintable is known to never change its contents, it will set the Gdk.PaintableFlags.CONTENTS flag. If a consumer cannot deal with changing contents, it may call [method`Gdk`.Paintable.get_current_image] which will return a static paintable and use that.

A paintable can report an intrinsic (or preferred) size or aspect ratio it wishes to be rendered at, though it doesn’t have to. Consumers of the interface can use this information to layout thepaintable appropriately. Just like the contents, the size of a paintable can change. A paintable will indicate this by calling [method`Gdk`.Paintable.invalidate_size] which will emit the [signal`Gdk`.Paintable::invalidate-size] signal. And just like for contents, if a paintable is known to never change its size, it will set the Gdk.PaintableFlags.SIZE flag.

Besides API for applications, there are some functions that are only useful for implementing subclasses and should not be used by applications: [method`Gdk`.Paintable.invalidate_contents], [method`Gdk`.Paintable.invalidate_size], [func`Gdk`.Paintable.new_empty].

classmethod new_empty(intrinsic_width, intrinsic_height)[source]¶

Parameters:

intrinsic_width (int) – The intrinsic width to report. Can be 0 for no width.
intrinsic_height (int) – The intrinsic height to report. Can be 0 for no height.

Returns:

a GdkPaintable

Return type:

Gdk.Paintable

Returns a paintable that has the given intrinsic size and draws nothing.

This is often useful for implementing the [vfunc`Gdk`.Paintable.get_current_image] virtual function when the paintable is in an incomplete state (like a GtkMediaStream before receiving the first frame).

compute_concrete_size(specified_width, specified_height, default_width, default_height)[source]¶

Parameters:

specified_width (float) – the width self could be drawn into or 0.0 if unknown
specified_height (float) – the height self could be drawn into or 0.0 if unknown
default_width (float) – the width self would be drawn into if no other constraints were given
default_height (float) – the height self would be drawn into if no other constraints were given

Returns:

concrete_width:: will be set to the concrete width computed
concrete_height:: will be set to the concrete height computed

Return type:

(concrete_width: float, concrete_height: float)

Compute a concrete size for the GdkPaintable.

Applies the sizing algorithm outlined in the CSS Image spec to the given self. See that link for more details.

It is not necessary to call this function when both specified_width and specified_height are known, but it is useful to call this function in GtkWidget:measure implementations to compute the other dimension when only one dimension is given.

get_current_image()[source]¶

Returns:: An immutable paintable for the current contents of self
Return type:: Gdk.Paintable

Gets an immutable paintable for the current contents displayed by self.

This is useful when you want to retain the current state of an animation, for example to take a screenshot of a running animation.

If the self is already immutable, it will return itself.

get_flags()[source]¶

Returns:: The GdkPaintableFlags for this paintable
Return type:: Gdk.PaintableFlags

Get flags for the paintable.

This is oftentimes useful for optimizations.

See [flags`Gdk`.PaintableFlags] for the flags and what they mean.

get_intrinsic_aspect_ratio()[source]¶

Returns:: the intrinsic aspect ratio of self or 0 if none.
Return type:: float

Gets the preferred aspect ratio the self would like to be displayed at.

The aspect ratio is the width divided by the height, so a value of 0.5 means that the self prefers to be displayed twice as high as it is wide. Consumers of this interface can use this to preserve aspect ratio when displaying the paintable.

This is a purely informational value and does not in any way limit the values that may be passed to [method`Gdk`.Paintable.snapshot].

Usually when a self returns nonzero values from [method`Gdk`.Paintable.get_intrinsic_width] and [method`Gdk`.Paintable.get_intrinsic_height] the aspect ratio should conform to those values, though that is not required.

If the self does not have a preferred aspect ratio, it returns 0. Negative values are never returned.

get_intrinsic_height()[source]¶

Returns:: the intrinsic height of self or 0 if none.
Return type:: int

Gets the preferred height the self would like to be displayed at.

Consumers of this interface can use this to reserve enough space to draw the paintable.

This is a purely informational value and does not in any way limit the values that may be passed to [method`Gdk`.Paintable.snapshot].

If the self does not have a preferred height, it returns 0. Negative values are never returned.

get_intrinsic_width()[source]¶

Returns:: the intrinsic width of self or 0 if none.
Return type:: int

Gets the preferred width the self would like to be displayed at.

Consumers of this interface can use this to reserve enough space to draw the paintable.

This is a purely informational value and does not in any way limit the values that may be passed to [method`Gdk`.Paintable.snapshot].

If the self does not have a preferred width, it returns 0. Negative values are never returned.

invalidate_contents()[source]¶

Called by implementations of GdkPaintable to invalidate their contents.

Unless the contents are invalidated, implementations must guarantee that multiple calls of [method`Gdk`.Paintable.snapshot] produce the same output.

This function will emit the [signal`Gdk`.Paintable::invalidate-contents] signal.

If a self reports the Gdk.PaintableFlags.CONTENTS flag, it must not call this function.

invalidate_size()[source]¶

Called by implementations of GdkPaintable to invalidate their size.

As long as the size is not invalidated, self must return the same values for its intrinsic width, height and aspect ratio.

This function will emit the [signal`Gdk`.Paintable::invalidate-size] signal.

If a self reports the Gdk.PaintableFlags.SIZE flag, it must not call this function.

snapshot(snapshot, width, height)[source]¶

Parameters:

snapshot (Gdk.Snapshot) – a GdkSnapshot to snapshot to
width (float) – width to snapshot in
height (float) – height to snapshot in

Snapshots the given paintable with the given width and height.

The paintable is drawn at the current (0,0) offset of the snapshot. If width and height are not larger than zero, this function will do nothing.

do_get_current_image() virtual¶

Returns:: An immutable paintable for the current contents of paintable
Return type:: Gdk.Paintable

Gets an immutable paintable for the current contents displayed by paintable.

This is useful when you want to retain the current state of an animation, for example to take a screenshot of a running animation.

If the paintable is already immutable, it will return itself.

do_get_flags() virtual¶

Returns:: The GdkPaintableFlags for this paintable
Return type:: Gdk.PaintableFlags

Get flags for the paintable.

This is oftentimes useful for optimizations.

See [flags`Gdk`.PaintableFlags] for the flags and what they mean.

do_get_intrinsic_aspect_ratio() virtual¶

Returns:: the intrinsic aspect ratio of paintable or 0 if none.
Return type:: float

Gets the preferred aspect ratio the paintable would like to be displayed at.

The aspect ratio is the width divided by the height, so a value of 0.5 means that the paintable prefers to be displayed twice as high as it is wide. Consumers of this interface can use this to preserve aspect ratio when displaying the paintable.

This is a purely informational value and does not in any way limit the values that may be passed to [method`Gdk`.Paintable.snapshot].

Usually when a paintable returns nonzero values from [method`Gdk`.Paintable.get_intrinsic_width] and [method`Gdk`.Paintable.get_intrinsic_height] the aspect ratio should conform to those values, though that is not required.

If the paintable does not have a preferred aspect ratio, it returns 0. Negative values are never returned.

do_get_intrinsic_height() virtual¶

Returns:: the intrinsic height of paintable or 0 if none.
Return type:: int

Gets the preferred height the paintable would like to be displayed at.

Consumers of this interface can use this to reserve enough space to draw the paintable.

This is a purely informational value and does not in any way limit the values that may be passed to [method`Gdk`.Paintable.snapshot].

If the paintable does not have a preferred height, it returns 0. Negative values are never returned.

do_get_intrinsic_width() virtual¶

Returns:: the intrinsic width of paintable or 0 if none.
Return type:: int

Gets the preferred width the paintable would like to be displayed at.

Consumers of this interface can use this to reserve enough space to draw the paintable.

This is a purely informational value and does not in any way limit the values that may be passed to [method`Gdk`.Paintable.snapshot].

If the paintable does not have a preferred width, it returns 0. Negative values are never returned.

do_snapshot(snapshot, width, height) virtual¶

Parameters:

snapshot (Gdk.Snapshot) – a GdkSnapshot to snapshot to
width (float) – width to snapshot in
height (float) – height to snapshot in

Snapshots the given paintable with the given width and height.

The paintable is drawn at the current (0,0) offset of the snapshot. If width and height are not larger than zero, this function will do nothing.

Signal Details¶

Gdk.Paintable.signals.invalidate_contents(paintable)¶

Signal Name:: invalidate-contents
Flags:: RUN_LAST
Parameters:: paintable (Gdk.Paintable) – The object which received the signal

Emitted when the contents of the paintable change.

Examples for such an event would be videos changing to the next frame or the icon theme for an icon changing.

Gdk.Paintable.signals.invalidate_size(paintable)¶

Signal Name:: invalidate-size
Flags:: RUN_LAST
Parameters:: paintable (Gdk.Paintable) – The object which received the signal

Emitted when the intrinsic size of the paintable changes.

This means the values reported by at least one of [method`Gdk`.Paintable.get_intrinsic_width], [method`Gdk`.Paintable.get_intrinsic_height] or [method`Gdk`.Paintable.get_intrinsic_aspect_ratio] has changed.

Examples for such an event would be a paintable displaying the contents of a toplevel surface being resized.