Canvases - Part One (libobs)

docs/sphinx/reference-canvases.rst

@@ -0,0 +1,287 @@
+Canvas API Reference (obs_canvas_t)
+===================================
+
+Canvases are reference-counted objects that contain scenes and define how those are rendered.
+They provide a video object which can be used with encoders or raw outputs.
+
+libobs maintains a main canvas that exists at all times and is used for the default video outputs.
+
+.. type:: obs_canvas_t
+
+   A reference-counted canvas.
+
+.. type:: obs_weak_canvas_t
+
+   A weak reference to a canvas.
+
+.. code:: cpp
+
+   #include <obs.h>
+
+.. _canvas_signal_handler_reference:
+
+Canvas Signals
+--------------
+
+The following signals are defined for canvases:
+
+**remove** (ptr canvas)
+
+   Called when the :c:func:`obs_canvas_remove()` function is called on the canvas.
+
+**destroy** (ptr canvas)
+
+   Called when a canvas is about to be destroyed.
+
+**video_reset** (ptr canvas)
+
+   Called when the canvas's video mix has been reset after a call to
+   :c:func:`obs_reset_video()` or :c:func:`obs_canvas_reset_video()`.
+
+**source_add** (ptr canvas, ptr source)
+
+   Called when a source has been added to the canvas.
+
+**source_remove** (ptr canvas, ptr source)
+
+   Called when a source has been removed from the canvas.
+
+**rename** (ptr canvas, string new_name, string prev_name)
+
+   Called when the canvas has been renamed.
+
+**channel_change** (ptr canvas, int channel, in out ptr source, ptr prev_source)
+
+   Called when a channel source has been changed.
+
+Canvas Flags
+------------
+
+Canvases can have different behaviours, these can be controlled via the **flags** paramter when creating a canvas.
+
+Flags may be 0 or a bitwise OR combination of the following values:
+
+- **MAIN** - Main canvas, cannot be renamed or reset, cannot be set by user
+- **ACTIVATE** - Canvas's sources will become active when they are visible
+- **MIX_AUDIO** - Audio from channels in this canvas will be mixed into the audio output
+- **SCENE_REF** - Canvas will hold references for scene sources
+- **EPHEMERAL** - Indicates this canvas is not supposed to be saved
+
+Additionally, the following preset combinations of flags are defined:
+
+- **PROGRAM** which equals `ACTIVATE | MIX_AUDIO | SCENE_REF`
+- **PREVIEW** which equals `EPHEMERAL`
+- **DEVICE** which equals `ACTIVATE | EPHEMERAL`
+
+General Canvas Functions
+------------------------
+
+.. function:: obs_canvas_t *obs_get_main_canvas()
+
+   Get a strong reference to the main OBS canvas
+
+---------------------
+
+.. function:: obs_canvas_t *obs_canvas_create(const char *name, struct obs_video_info *ovi, uint32_t flags)
+
+   Creates a new canvas.
+
+   :param name: Name, will be deduplicated if necessary
+   :param ovi: Video configuration to use for this canvas's video output
+   :param flags: Canvas flags
+   :return: Canvas object
+
+---------------------
+
+.. function:: obs_canvas_t *obs_canvas_create_private(const char *name, struct obs_video_info *ovi, uint32_t flags)
+
+   Creates a new private canvas
+
+   :param name: Name, will **not** be deduplicated
+   :param ovi: Video configuration to use for this canvas's video output
+   :param flags: Canvas flags
+   :return: Canvas object
+
+---------------------
+
+.. function:: void obs_canvas_remove(obs_canvas_t *canvas)
+
+   Signal that references to canvas should be released and mark the canvas as removed.
+
+---------------------
+
+.. function:: bool obs_canvas_removed(obs_canvas_t *canvas)
+
+   Returns if a canvas is marked as removed (i.e. should no longer be used)
+
+---------------------
+
+.. function:: void obs_canvas_set_name(obs_canvas_t *canvas, const char *name)
+
+   Set canvas name
+
+---------------------
+
+.. function:: const char *obs_canvas_get_name(const obs_canvas_t *canvas)
+
+   Get canvas name
+
+---------------------
+
+.. function:: const char *obs_canvas_get_uuid(const obs_canvas_t *canvas)
+
+   Get canvas UUID
+
+---------------------
+
+.. function:: uint32_t obs_canvas_get_flags(const obs_canvas_t *canvas)
+
+   Gets flags set on a canvas
+
+---------------------
+
+Saving/Loading Functions
+------------------------
+
+.. function:: obs_data_t *obs_save_canvas(obs_canvas_t *source)
+
+   Saves a canvas to settings data
+
+---------------------
+
+.. function:: obs_canvas_t *obs_load_canvas(obs_data_t *data)
+
+   Loads a canvas from settings data
+
+---------------------
+
+Reference Counting Functions
+----------------------------
+
+.. function:: obs_canvas_t *obs_canvas_get_ref(obs_canvas_t *canvas)
+
+   Add strong reference to a canvas
+
+---------------------
+
+.. function:: void obs_canvas_release(obs_canvas_t *canvas)
+
+   Release strong reference
+
+---------------------
+
+.. function:: void obs_weak_canvas_addref(obs_weak_canvas_t *weak)
+
+   Add weak reference
+
+---------------------
+
+.. function:: void obs_weak_canvas_release(obs_weak_canvas_t *weak)
+
+   Release weak reference
+
+---------------------
+
+.. function:: obs_weak_canvas_t *obs_canvas_get_weak_canvas(obs_canvas_t *canvas)
+
+   Get weak reference from strong reference
+
+---------------------
+
+.. function:: obs_canvas_t *obs_weak_canvas_get_canvas(obs_weak_canvas_t *weak)
+
+   Get strong reference from weak reference
+
+---------------------
+
+Canvas Channel Functions
+------------------------
+
+.. function:: void obs_canvas_set_channel(obs_canvas_t *canvas, uint32_t channel, obs_source_t *source)
+
+   Sets the source to be used for a canvas channel.
+
+---------------------
+
+.. function:: obs_source_t *obs_canvas_get_channel(obs_canvas_t *canvas, uint32_t channel)
+
+   Gets the source currently in use for a canvas channel.
+
+---------------------
+
+Canvas Source List Functions
+----------------------------
+
+.. function:: obs_scene_t *obs_canvas_scene_create(obs_canvas_t *canvas, const char *name)
+
+   Create scene attached to a canvas.
+
+---------------------
+
+.. function:: void obs_canvas_scene_remove(obs_scene_t *scene)
+
+   Remove a scene from a canvas.
+
+---------------------
+
+.. function:: void obs_canvas_move_scene(obs_scene_t *scene, obs_canvas_t *dst)
+
+   Move scene to another canvas, detaching it from the previous one and deduplicating the name if needed.
+
+---------------------
+
+.. function:: void obs_canvas_enum_scenes(obs_canvas_t *canvas, bool (*enum_proc)(void *, obs_source_t *), void *param)
+
+   Enumerates scenes belonging to a canvas.
+
+   Callback function returns true to continue enumeration, or false to end
+   enumeration.
+
+---------------------
+
+.. function:: obs_source_t *obs_canvas_get_source_by_name(const char *name)
+
+   Gets a canvas source by its name.
+
+   Increments the source reference counter, use
+   :c:func:`obs_source_release()` to release it when complete.
+
+---------------------
+
+.. function:: obs_scene_t *obs_canvas_get_scene_by_name(const char *name)
+
+   Gets a canvas scene by its name.
+
+   Increments the source reference counter, use
+   :c:func:`obs_scene_release()` to release it when complete.
+
+---------------------
+
+Canvas Video Functions
+----------------------
+
+.. function:: bool obs_canvas_reset_video(obs_canvas_t *canvas, struct obs_video_info *ovi)
+
+   Reset a canvas's video configuration.
+
+   Note that the frame rate property is ignored and the global rendering frame rate is used instead.
+
+---------------------
+
+.. function:: bool obs_canvas_has_video(obs_canvas_t *canvas)
+
+   Returns true if the canvas video is configured.
+
+---------------------
+
+.. function:: video_t *obs_canvas_get_video(const obs_canvas_t *canvas)
+
+   Get canvas video output
+
+---------------------
+
+.. function:: bool obs_canvas_get_video_info(const obs_canvas_t *, struct obs_video_info *ovi)
+
+   Get canvas video info (if any)
+
+---------------------

docs/sphinx/reference-core.rst

@@ -324,6 +324,19 @@ Libobs Objects
 
 ---------------------
 
+.. function:: void obs_enum_canvases(bool (*enum_proc)(void*, obs_canvas_t*), void *param)
+
+   Enumerates canvases.
+
+   Callback function returns true to continue enumeration, or false to end
+   enumeration.
+
+   Use :c:func:`obs_canvas_get_ref()` or
+   :c:func:`obs_canvas_get_weak_encoder()` if you want to retain a
+   reference after obs_enum_canvases finishes.
+
+---------------------
+
 .. function:: obs_source_t *obs_get_source_by_name(const char *name)
 
    Gets a source by its name.
@@ -400,6 +413,24 @@ Libobs Objects
 
 ---------------------
 
+.. function:: obs_canvas_t *obs_get_canvas_by_name(const char *name)
+
+   Get a canvas by its name.
+
+   Increments the canvas reference counter, use
+   :c:func:`obs_canvas_release()` to release it when complete.
+
+---------------------
+
+.. function:: obs_canvas_t *obs_get_canvas_by_uuid(const char *uuid)
+
+   Get a canvas by its UUID.
+
+   Increments the canvas reference counter, use
+   :c:func:`obs_canvas_release()` to release it when complete.
+
+---------------------
+
 .. function:: obs_data_t *obs_save_source(obs_source_t *source)
 
    :return: A new reference to a source's saved data. Use
@@ -718,6 +749,31 @@ Core OBS Signals
 
    Called when a hotkey's bindings has changed.
 
+**canvas_create** (ptr canvas)
+
+   Called when a new public canvas has been created.
+
+**canvas_remove** (ptr canvas)
+
+   Called when the :c:func:`obs_canvas_remove()` function is called on a public canvas.
+
+**canvas_destroy** (ptr canvas)
+
+   Called when a public canvas is about to be destroyed.
+
+**canvas_video_reset** (ptr canvas)
+
+   Called when a public canvas's video mix has been reset after a call to
+   :c:func:`obs_reset_video()` or :c:func:`obs_canvas_reset_video()`.
+
+**canvas_rename** (ptr canvas, string new_name, string prev_name)
+
+   Called when a public canvas has been renamed.
+
+**video_reset** ()
+
+   Called when a the main OBS video has been reset.
+
 ---------------------
 
 

docs/sphinx/reference-sources.rst

@@ -176,6 +176,9 @@ Source Definition Structure (obs_source_info)
      to have its properties shown on creation (prefers to rely on
      defaults first)
 
+   - **OBS_SOURCE_CANVAS_LOCKED** - Source type is tied to a canvas,
+     and can only be moved between canvases, but not added to more than one.
+
 .. member:: const char *(*obs_source_info.get_name)(void *type_data)
 
    Get the translated name of the source type.
@@ -1500,6 +1503,11 @@ General Source Functions
 
 ---------------------
 
+.. function:: obs_canvas_t *obs_source_get_canvas(const obs_source_t *source)
+
+   Get canvas this source belongs to (reference incremented)
+
+---------------------
 
 Functions used by sources
 -------------------------

libobs/CMakeLists.txt

@@ -38,6 +38,7 @@ target_sources(
     obs-av1.h
     obs-avc.c
     obs-avc.h
+    obs-canvas.c
     obs-config.h
     obs-data.c
     obs-data.h