Renderer

class Renderer(**properties: Any)

Superclasses: Object

Subclasses: BroadwayRenderer, CairoRenderer, GLRenderer, NglRenderer, VulkanRenderer

GskRenderer is a class that renders a scene graph defined via a tree of RenderNode instances.

Typically you will use a GskRenderer instance to repeatedly call render to update the contents of its associated Surface.

It is necessary to realize a GskRenderer instance using realize before calling render, in order to create the appropriate windowing system resources needed to render the scene.

Constructors

class Renderer

classmethod new_for_surface(surface: Surface) → Renderer | None

Creates an appropriate GskRenderer instance for the given surface.

If the GSK_RENDERER environment variable is set, GSK will try that renderer first, before trying the backend-specific default. The ultimate fallback is the cairo renderer.

The renderer will be realized before it is returned.

Parameters:

surface – a GdkSurface

Methods

class Renderer

get_surface() → Surface | None

Retrieves the GdkSurface set using gsk_enderer_realize().

If the renderer has not been realized yet, None will be returned.

is_realized() → bool

Checks whether the renderer is realized or not.

realize(surface: Surface | None = None) → bool

Creates the resources needed by the renderer to render the scene graph.

Since GTK 4.6, the surface may be NULL, which allows using renderers without having to create a surface. Since GTK 4.14, it is recommended to use realize_for_display instead.

Note that it is mandatory to call unrealize before destroying the renderer.

Parameters:

surface – the GdkSurface renderer will be used on

realize_for_display(display: Display) → bool

Creates the resources needed by the renderer to render the scene graph.

Note that it is mandatory to call unrealize before destroying the renderer.

Added in version 4.14.

Parameters:

display – the GdkDisplay renderer will be used on

render(root: RenderNode, region: Region | None = None) → None

Renders the scene graph, described by a tree of GskRenderNode instances to the renderer’s surface, ensuring that the given region gets redrawn.

If the renderer has no associated surface, this function does nothing.

Renderers must ensure that changes of the contents given by the root node as well as the area given by region are redrawn. They are however free to not redraw any pixel outside of region if they can guarantee that it didn’t change.

The renderer will acquire a reference on the GskRenderNode tree while the rendering is in progress.

Parameters:

• root – a GskRenderNode

• region – the cairo_region_t that must be redrawn or None for the whole window

render_texture(root: RenderNode, viewport: Rect | None = None) → Texture

Renders the scene graph, described by a tree of GskRenderNode instances, to a GdkTexture.

The renderer will acquire a reference on the GskRenderNode tree while the rendering is in progress.

If you want to apply any transformations to root, you should put it into a transform node and pass that node instead.

Parameters:

• root – a GskRenderNode

• viewport – the section to draw or None to use root’s bounds

unrealize() → None

Releases all the resources created by realize().

Properties

class Renderer

props.realized: bool

Whether the renderer has been associated with a surface or draw context.

props.surface: Surface

The surface associated with renderer.