DrawContext

class DrawContext(**properties: Any)

Superclasses: Object

Subclasses: CairoContext, GLContext, VulkanContext

Base class for objects implementing different rendering methods.

GdkDrawContext is the base object used by contexts implementing different rendering methods, such as CairoContext or GLContext. It provides shared functionality between those contexts.

You will always interact with one of those subclasses.

A GdkDrawContext is always associated with a single toplevel surface.

Methods

class DrawContext

begin_frame(region: Region) → None

Indicates that you are beginning the process of redrawing region on the context’s surface.

Calling this function begins a drawing operation using context on the surface that context was created from. The actual requirements and guarantees for the drawing operation vary for different implementations of drawing, so a CairoContext and a GLContext need to be treated differently.

A call to this function is a requirement for drawing and must be followed by a call to end_frame, which will complete the drawing operation and ensure the contents become visible on screen.

Note that the region passed to this function is the minimum region that needs to be drawn and depending on implementation, windowing system and hardware in use, it might be necessary to draw a larger region. Drawing implementation must use get_frame_region to query the region that must be drawn.

When using GTK, the widget system automatically places calls to begin_frame() and end_frame() via the use of `GskRenderer <../gsk4/class.Renderer.html>`_s, so application code does not need to call these functions explicitly.

Parameters:: region – minimum region that should be drawn

end_frame() → None

Ends a drawing operation started with begin_frame().

This makes the drawing available on screen. See begin_frame for more details about drawing.

When using a GLContext, this function may call glFlush() implicitly before returning; it is not recommended to call glFlush() explicitly before calling this function.

get_display() → Display | None: Retrieves the GdkDisplay the context is created for

get_frame_region() → Region | None

Retrieves the region that is currently being repainted.

After a call to begin_frame this function will return a union of the region passed to that function and the area of the surface that the context determined needs to be repainted.

If context is not in between calls to begin_frame and end_frame, None will be returned.

get_surface() → Surface | None: Retrieves the surface that context is bound to.

is_in_frame() → bool

Returns True if context is in the process of drawing to its surface.

This is the case between calls to begin_frame and end_frame. In this situation, drawing commands may be effecting the contents of the context’s surface.

Properties

class DrawContext

props.display: Display: The GdkDisplay used to create the GdkDrawContext.

props.surface: Surface: The GdkSurface the context is bound to.