#include <libbase/libbase.h>
#include <stdbool.h>

Include dependency graph for dblbuf.h:

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Typedefs
typedef struct _wlmcl_dblbuf_t	wlmcl_dblbuf_t

typedef bool(*	wlmcl_dblbuf_ready_callback_t) (bs_gfxbuf_t gfxbuf_ptr, void ud_ptr)

Functions
wlmcl_dblbuf_t *	wlmcl_dblbuf_create (const char app_id_ptr, struct wl_surface wl_surface_ptr, struct wl_shm *wl_shm_ptr, unsigned width, unsigned height)

void	wlmcl_dblbuf_destroy (wlmcl_dblbuf_t *dblbuf_ptr)

void	wlmcl_dblbuf_register_ready_callback (wlmcl_dblbuf_t dblbuf_ptr, wlmcl_dblbuf_ready_callback_t callback, void callback_ud_ptr)

Detailed Description

Functions for working with a double buffer on a wayland surface.

Copyright: Copyright (c) 2026 Philipp Kaeser (kaese.nosp@m.r@gu.nosp@m.bbe.c.nosp@m.h) Copyright 2025 Google LLC

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Typedef Documentation

◆ wlmcl_dblbuf_ready_callback_t

typedef bool(* wlmcl_dblbuf_ready_callback_t) (bs_gfxbuf_t *gfxbuf_ptr, void *ud_ptr)

Callback that indicates the buffer is ready to draw into.

◆ wlmcl_dblbuf_t

typedef struct _wlmcl_dblbuf_t wlmcl_dblbuf_t

Forward declaration: Double buffer state.

Function Documentation

◆ wlmcl_dblbuf_create()

wlmcl_dblbuf_t * wlmcl_dblbuf_create	(	const char *	app_id_ptr,
		struct wl_surface *	wl_surface_ptr,
		struct wl_shm *	wl_shm_ptr,
		unsigned	width,
		unsigned	height
	)

Creates a double buffer for the surface with provided dimensions.

Parameters

app_id_ptr	Application ID, used to prefix the name of the shared memory object. Can be NULL.
wl_surface_ptr
wl_shm_ptr
width
height

Returns: Pointer to state of the double buffer, or NULL on error. Call wlmcl_dblbuf_destroy for freeing up the associated resources.

◆ wlmcl_dblbuf_destroy()

void wlmcl_dblbuf_destroy ( wlmcl_dblbuf_t * dblbuf_ptr )

Destroys the double buffer.

◆ wlmcl_dblbuf_register_ready_callback()

void wlmcl_dblbuf_register_ready_callback	(	wlmcl_dblbuf_t *	dblbuf_ptr,
		wlmcl_dblbuf_ready_callback_t	callback,
		void *	callback_ud_ptr
	)

Registers a callback for when a frame can be drawn into the buffer.

The frame can be drawn if (1) it is due, and (2) there is a back buffer available ("released") for drawing into. If these conditions hold true, callback will be called right away. Otherwise, it will be called once these conditions are fulfilled.

The callback will be called only once. If the client wishes further notifications, they must call wlmcl_dblbuf_register_ready_callback again.

The callback must be registered only after the surface is ready. Eg. for an XDG toplevel, after it has received & acknowledged configure.