.. automodule:: libavg.avg
:no-members:
.. inheritance-diagram:: OffscreenCanvas
:parts: 1
.. inheritance-diagram:: Player
:parts: 1
This section describes the classes that provide a framework for rendering. The
:py:class:`Player` class is an interface to the avg renderer. The
:py:class:`Canvas` class and its descendant :py:class:`OffscreenCanvas` provide
areas to draw on.
.. autoclass:: Canvas
A Canvas is a tree of nodes. It is the place where a scenegraph is displayed. In
a libavg session, there is one main canvas that corresponds to the screen (which
is of class :py:class:`Canvas`) and zero or more canvases that are rendered
offscreen (which are of class :py:class:`OffscreenCanvas`).
.. py:method:: getElementByID(id) -> Node
Returns the element in the canvas's tree that has the :py:attr:`id`
given.
.. py:method:: screenshot() -> Bitmap
Returns the image the canvas has last rendered as :py:class:`Bitmap`. For
the main canvas, this is a real screenshot. For offscreen canvases, this
is the image rendered offscreen.
.. py:method:: getRootNode() -> CanvasNode
Returns the root of the scenegraph. For the main canvas, this is an
:py:class:`AVGNode`. For an offscreen canvas, this is a
:py:class:`CanvasNode`.
.. autoclass:: OffscreenCanvas
An OffscreenCanvas is a Canvas that is rendered to a texture. It can be
referenced in the href attribute of an image node. See
https://www.libavg.de/wiki/ProgrammersGuide/OffscreenRendering for an in-depth
explanation of using offscreen rendering. Offscreen canvases are created by
calling :py:meth:`Player.createCanvas`, :py:meth:`Player.loadCanvasFile` or
:py:meth:`Player.loadCanvasString`.
.. py:attribute:: autorender
Turns autorendering on or off. Default is :py:const:`True`.
.. py:attribute:: handleevents
:py:const:`True` if events that arrive at an image node that is displaying
this canvas are routed to the offscreen canvas. Read-only.
.. py:attribute:: mipmap
:py:const:`True` if mipmaps are generated and used for the canvas. This is
used instead of RasterNode.mipmap for images that render the canvas.
Read-only.
.. py:attribute:: multisamplesamples
Number of samples per pixel to use for multisampling. Setting this to
1 disables multisampling. Read-only.
.. py:attribute:: size
Size of the rendering area (and the :py:class:`CanvasNode`) in pixels.
Read-only.
.. py:method:: getID() -> string
Returns the id of the canvas. This is the same as
calling :samp:`canvas.getRootNode().getID()`.
.. py:method:: getNumDependentCanvases
Returns the number of canvases that reference this canvas. Used mainly
for unit tests.
.. py:method:: registerCameraNode
.. py:method:: render()
Forces an immediate redraw of the offscreen canvas. This makes sure that
following calls to screenshot() get a current version of the canvas and
is usually used in combination with :samp:`autorender=False`.
.. py:method:: unregisterCameraNode
.. py:classmethod:: isMultisampleSupported() -> bool
:py:const:`True` if the machine's OpenGL implementation supports offscreen
multisampling.
.. autoclass:: Player
The class used to load and play avg files and the main interface to the avg
renderer. Player is a singleton. There is only one instance, accessed by
:py:attr:`avg.player`.
**Messages:**
To get these messages, call :py:meth:`Publisher.subscribe`.
.. py:method:: KEY_DOWN(keyEvent)
Called whenever a key is pressed.
.. py:method:: KEY_UP(keyEvent)
Called whenever a key is released.
.. py:method:: ON_FRAME()
Called each frame.
.. py:attribute:: pluginPath
A list of directories where the player searches for plugins when
:py:meth:`loadPlugin()` is called. The separator between path entries is a
semicolon (';') under Windows and a colon (':') under Mac and Linux.
.. py:attribute:: volume
Total audio playback volume. 0 is silence, 1 passes media file
volume through unchanged. Values higher than 1 can be used to
amplify playback. A limiter prevents distortion when the volume
is set too high.
.. py:method:: addInputDevice(inputDevice)
Registers an :py:class:`InputDevice` with the system.
.. py:method:: areFullShadersSupported() -> bool
Returns :py:const:`True` if the current OpenGL configuration has full shader
support. Platforms without full shader support (this includes OpenGL ES) disable
several :py:class:`FXNode` types. Calling this when playback is not running is
an error.
.. py:method:: assumePixelsPerMM(ppmm)
Tells the system to assume a resolution for the physical screen, overriding
operating system information. The parameter is the number of pixels per
millimeter as a :samp:`float`. This function affects the values returned by
:py:meth:`getPhysicalScreenDimensions` and :py:meth:`getPixelsPerMM`. It is
useful for situations in which the OS cannot know the resolution (e.g.
projectors) and when the automatic functions return wrong values (which
happens, unfortunately, because of operating system deficiencies).
.. py:method:: callFromThread(pyfunc)
Executes :py:attr:`pyfunc` in the main thread of execution, in the next event
handling phase. This method is the only libavg method that is thread-safe and
can be called from secondary threads of execution. :py:attr:`pyfunc` can be
any python callable, including any libavg methods.
.. py:method:: clearInterval(id) -> bool
Stops a timeout, an interval or an onFrameHandler from being called.
Returns :py:const:`True` if there was an interval with the given
:py:attr:`id`, :py:const:`False` if not.
:param int id:
An id returned by :py:meth:`setInterval`, :py:meth:`setTimeout`
or :py:meth:`setOnFrameHandler`.
.. py:method:: createCanvas(*params) -> OffscreenCanvas
Creates an empty offscreen canvas. Parameters are given under
:py:class:`OffscreenCanvas`.
.. py:method:: createMainCanvas(*params) -> Canvas
Creates an empty canvas with a render window and an AVGNode as root node.
Parameters are given under :py:class:`AVGNode`.
.. py:method:: createNode(xml) -> Node
Creates a new Node. This node can be used as parameter to
:py:meth:`DivNode.appendChild()` and :py:meth:`DivNode.insertChild()`.
This method will create any type of node, including :samp:`<div>` nodes
with children.
:param xml:
xml string conforming to the avg dtd that specifies the node to create.
.. py:method:: createNode(type, args) -> Node
Creates a new Node. This node can be used as parameter to
:py:meth:`DivNode.appendChild()` and :py:meth:`DivNode.insertChild()`.
This method will only create one node at a time.
:param string type:
Type string of the node to create (For example, :samp:`image` and
:samp:`words` are valid type strings).
:param dict args: a dictionary specifying attributes of the node.
.. py:method:: deleteCanvas(id)
Removes the canvas given by id from the player's internal list of
canvases. It is an error to delete a canvas that is still referenced by
an image node.
.. py:method:: enableGLErrorChecks(enable)
Enables or disables checking for errors after each OpenGL call. By default,
this is :py:const:`False`, since it hurts performance in some setups. It is
enabled by the tests. You do not need this method unless you are looking for
errors inside libavg.
.. py:method:: enableMouse(enable)
Enables or disable mouse event handling.
.. py:method:: enableMultitouch()
Enables multitouch event handling. Several drivers are available that
generate multitouch events. To choose a driver, set the environment
variable :envvar:`AVG_MULTITOUCH_DRIVER` to the appropriate value:
:samp:`TUIO`:
Listens for TUIO events from a tracker that conforms to the TUIO
protocol (http://www.tuio.org), a de-facto standard for multitouch
events. By default, it listens to events on the default TUIO UDP port
3333, but this can be configured using the environment variable
:envvar:`AVG_TUIO_PORT`.
:samp:`APPLETRACKPAD`:
Uses the trackpad built into Mac Book Pros to generate events.
:samp:`LINUXMTDEV`:
Uses the linux mtdev library to interface to multitouch devices.
The environment variable :envvar:`AVG_LINUX_MULTITOUCH_DEVICE` is used
to determine which device file to open. Default is
:samp:`/dev/input/event3`.
:samp:`TRACKER`:
Enables the internal camera-based tracker. Configuring this tracker is
described under https://www.libavg.de/wiki/ProgrammersGuide/Tracker.
:samp:`WIN7TOUCH`:
Enables handling of Windows 7 touch events. This works with all devices
which have Windows 7 drivers.
:samp:`XINPUT`:
Uses X11-based multitouch detection. This needs X11 with XInput >= 2.1
support. For backwards compatibility reasons, XINPUT21 is supported as
value as well.
If :envvar:`AVG_MULTITOUCH_DRIVER` is not set, the driver defaults to
a plattform-specific one. Under Linux, the default is :samp:`XINPUT` if
XInput multitouch is supported on the system, otherwise :samp:`LINUXMTDEV`.
Under Windows, the default is :samp:`WIN7TOUCH`.
:py:meth:`enableMultitouch` throws an exception if the chosen driver is not
available or no multitouch device could be found. (Exception: Since there is
no way to determine if a TUIO device is available, :py:meth:`enableMultitouch`
always appears to succeed in this case.)
.. py:method:: getCanvas(id) -> OffscreenCanvas
Returns the offscreen canvas with the :py:attr:`id` given.
.. py:method:: getCurrentEvent() -> Event
Must be called inside an event handler and returns the event that's being
processed. Throws an exception if called outside an event handler.
.. py:method:: getEffectiveFramerate() -> float
Returns the framerate that the player is actually achieving. The
value returned is not averaged and reflects only the current frame.
.. py:method:: getElementByID(id) -> Node
Returns an element in the main avg tree.
:param id: id attribute of the node to return.
.. py:method:: getEventHook() -> pyfunc
Returns the last event hook set using :py:meth:`setEventHook`.
.. py:method:: getFrameDuration() -> float
Returns the number of milliseconds that have elapsed since the last
frame (i.e. the last display update).
.. py:method:: getFramerate() -> float
Returns the current target framerate in frames per second. To get the
actual framerate that the player is currently achieving, call
:py:meth:`getEffectiveFramerate`.
.. py:method:: getFrameTime() -> int
Returns the number of milliseconds that have elapsed since playback
has started. Honors FakeFPS. The time returned stays constant for an
entire frame; it is the time of the last display update.
.. py:method:: getKeyModifierState() -> KeyModifier
Returns the current modifier keys pressed, or'ed together. For a list of
possible values, see :py:attr:`KeyEvent.modifiers`.
.. py:method:: getMainCanvas() -> Canvas
Returns the main canvas. This is the canvas loaded using :py:meth:`loadFile`
or :py:meth:`loadString` and displayed on screen.
.. py:method:: getMouseState() -> MouseEvent
Returns the last mouse event generated.
.. py:method:: getPhysicalScreenDimensions() -> Point2D
Returns the size of the primary screen in millimeters.
.. py:method:: getPixelsPerMM() -> float
Returns the number of dots per millimeter of the primary display. Assumes
square pixels.
.. py:method:: getRootNode() -> Node
Returns the outermost element in the main avg tree.
.. py:method:: getScreenResolution() -> Point2D
Returns the size in pixels of the current screen.
.. py:method:: getTestHelper
.. py:method:: getTracker() -> Tracker
Returns a tracker previously created using :py:meth:`enableMultitouch` with
the internal tracker configured.
.. py:method:: getVideoMemInstalled() -> int
Returns the amount of dedicated video memory installed in the system in
bytes (which might be zero in case of shared-memory graphics cards).
Only available when using NVidia drivers.
.. py:method:: getVideoMemUsed() -> int
Returns the amount of dedicated video memory used in bytes. This
is the total amount used by all programs. Only available when using NVidia
drivers.
.. py:method:: getMemoryUsage() -> int
Returns the amount of memory used by the application in bytes. More
precisely, this function returns the resident set size of the process
in bytes. This does not include shared libraries or memory paged out to
disk.
.. py:method:: getVideoRefreshRate() -> float
Returns the current hardware video refresh rate in number of
refreshes per second.
.. py:method:: isCursorShown()
Returns :py:const:`True` if the mouse cursor is visible.
.. py:method:: isFullscreen()
Returns :py:const:`True` if the player is running in fullscreen mode.
.. py:method:: isMultitouchAvailable() -> bool
Returns :py:const:`True` if a multitouch device has been configured and is
active, :py:const:`False` if not. Must be called after :py:meth:`play()`.
.. py:method:: isPlaying() -> bool
Returns :py:const:`True` if :py:meth:`play()` is currently executing,
:py:const:`False` if not.
.. py:method:: keepWindowOpen()
Tells the player to keep the playback window open after :py:meth:`play()`
has returned. This makes it possible to reuse the window with another scene
and :py:meth:`play()` call. It is used by the tests to keep flickering to a
minimum and increase speed.
.. py:method:: loadCanvasFile(filename) -> OffscreenCanvas
Loads the canvas file specified in filename and adds it to the
registered offscreen canvases.
.. py:method:: loadCanvasString(avgString) -> OffscreenCanvas
Parses avgString, loads the nodes it contains and adds the hierarchy
to the registered offscreen canvases.
:param string avgString: An xml string containing an avg node hierarchy.
.. py:method:: loadFile(filename) -> Canvas
Loads the avg file specified in filename. Returns the canvas loaded.
The canvas is the main canvas displayed onscreen.
.. py:method:: loadPlugin(name)
Load a Plugin.
:param string name: filename of the plugin without directory and
file extension.
.. py:method:: loadString(avgString) -> Canvas
Parses avgString and loads the nodes it contains. Returns the canvas
loaded. The canvas is the main canvas displayed onscreen.
:param string avgString: An xml string containing an avg node hierarchy.
.. py:method:: play()
Opens a playback window or screen and starts playback. play returns
when playback has ended.
.. py:method:: screenshot() -> Bitmap
Returns the contents of the current screen as a bitmap.
.. py:method:: setCursor(bitmap, hotspot)
Sets the mouse cursor to the bitmap given. The bitmap must have a size
divisible by 8 and an RGBA pixel format. The cursor generated is
binary black and white with a binary transparency channel. hotspot is
the relative position of the actual pointing coordinate in the
bitmap.
.. py:method:: setEventHook(pyfunc)
Set a callable which will receive all events before the standard event
handlers receive them. If this callable returns :py:const:`True`,
the event is not propagated to the standard event handlers.
Generally, :py:meth:`setEventHook` should be used as a last resort. In most
cases, standard event handlers are a lot cleaner. Also, setting several event
hooks is not supported by libavg. To get around this limitation, you can
use :py:meth:`getEventHook` to chain event hook functions.
Note that :py:attr:`event.node` is not set in the callback, since the
system hasn't determined the node to send the event to at that
point.
.. py:method:: setFakeFPS(fps)
Sets a fixed number of virtual frames per second that are used as
clock source for video playback, animations and other time-based
actions. If a value of :samp:`-1` is given as parameter, the real clock is
used. :py:meth:`setFakeFPS` can be used to get reproducible results for
recordings or automated tests. Setting FakeFPS has the side-effect of
disabling audio.
.. py:method:: setFramerate(framerate)
Sets the desired framerate for playback. Turns off syncronization
to the vertical blanking interval.
.. py:method:: setGamma(red, green, blue)
Sets display gamma. This is a control for overall brightness and
contrast that leaves black and white unchanged but adjusts greyscale
values. :samp:`1.0` is identity, higher values give a brighter image, lower
values a darker one.
.. py:method:: setInterval(time, pyfunc) -> int
Sets a python callable object that should be executed regularly.
:py:meth:`setInterval` returns an id that can be used to
call :py:meth:`clearInterval()` to stop the function from being called. The
callback is called at most once per frame.
:param int time: Number of milliseconds between two calls.
:param pyfunc: Python callable to execute.
.. py:method:: setMousePos(pos)
Sets the position of the mouse cursor. Generates a mouse motion event.
.. py:method:: setMultiSampleSamples(multiSampleSamples)
Sets the number of samples per pixel to compute.
This costs performance and smoothes the edges of polygons. A value of
:samp:`1` turns multisampling (also knowna as FSAA - Full-Screen
Antialiasing) off. Good values are dependent on the graphics driver and
the performance of the graphics card.
.. py:method:: setOGLOptions(usePOW2Textures, usePixelBuffers, multiSampleSamples, shaderUsage=AUTO, useDebugContext=False)
Determines which OpenGL extensions to check for and use if possible.
This method is mainly used for debugging purposes while developing libavg,
but can also be used to work around buggy drivers. The values set here
override those in the :file:`avgrc` file. Note that with the exception of
multiSampleSamples, fallbacks are always used - if a feature is
specified that the system doesn't support, a less demanding one will
be used.
Must be called before :py:meth:`play`.
:param bool usePOW2Textures:
If :py:const:`True`, restricts textures to power-of-two dimensions.
:param bool usePixelBuffers:
If :py:const:`False`, disables the use of OpenGL pixel buffer objects.
:param int multiSampleSamples:
The number of samples per pixel to compute.
This costs performance and smoothes the edges of polygons. A value of
:samp:`1` turns multisampling (also known as FSAA - Full-Screen
Antialiasing) off. Good values are dependent on the graphics driver and
the performance of the graphics card.
:param shaderUsage:
Either :py:const:`avg.SHADERUSAGE_FULL`,
:py:const:`avg.SHADERUSAGE_MINIMAL` or :py:const:`avg.SHADERUSAGE_AUTO`.
:py:const:`SHADERUSAGE_MINIMAL` restricts shader usage to a subset that
doesn't use much GPU power.
:param useDebugContext:
Uses an OpenGL Debug Context for rendering if the graphics driver supports
it. This causes more verbose error messages and warnings in the case of
OpenGL errors.
.. py:method:: setOnFrameHandler(pyfunc) -> int
Sets a python callable object that should be executed once per frame.
This is the same as :samp:`setInterval(0, pyfunc)`. Returns an id that can
be used to call :py:meth:`clearInterval()` to stop the function from being
called.
:param pyfunc: Python callable to execute.
.. py:method:: setResolution(fullscreen, width, height, bpp)
Sets display engine parameters. Must be called before :py:meth:`loadFile` or
:py:meth:`loadString`.
:param bool fullscreen:
:py:const:`True` if the avg file should be rendered fullscreen.
:param int width, height:
The window size (if fullscreen is :py:const:`False`)
or screen resolution (if fullscreen is :py:const:`True`).
:param int bpp:
Number of bits per pixel to use. Valid values are :py:const:`16` or
:py:const:`24`.
.. py:method:: setTimeout(time, pyfunc) -> int
Sets a python callable object that should be executed after a set
amount of time. :py:meth:`setTimeout` returns an id that can be used to
call :py:meth:`clearInterval()` to stop the function from being called.
:param int time: Number of milliseconds before the call.
:param pyfunc: Python callable to execute.
.. py:method:: setVBlankFramerate(rate)
Sets the desired number of monitor refreshes before the next
frame is displayed. The resulting framerate is determined by the
monitor refresh rate divided by the rate parameter.
:param int rate:
Number of vertical blanking intervals to wait. On Mac OS X, only :samp:`1`
is supported as rate.
.. py:method:: setWindowConfig(configFileName)
Sets the window configuration for multi-window setups. Multi-window setups are
supported on X11 and can span more than one X11 display (and thus, multiple
GPUs). A sample config file can be found under
:file:`src/test/avg_windowconfig.xml`. Using this file, window positions and
sizes can be set. Each window can show a separate portion of the main scene
(a 'viewport').
.. py:method:: setWindowFrame(hasWindowFrame)
:py:attr:`hasWindowFrame` should be set to :py:const:`True` if a
non-fullscreen player should have a window frame. If set to
:py:const:`False`, the player runs with no title bar or window frame. Must
be called before :py:meth:`play` is called.
.. py:method:: setWindowPos(x, y)
Sets the location of the player window. Must be called before loadFile
or loadString.
.. py:method:: setWindowTitle(title)
Sets the string displayed in the title bar of the libavg window. Default is
'libavg'.
.. py:method:: showCursor(show)
Shows or hides the mouse cursor.
:param bool show: :py:const:`True` if the mouse cursor should be visible.
.. py:method:: stop()
Stops playback and resets the video mode if necessary.
.. py:method:: stopOnEscape(stop)
Toggles player stop upon escape keystroke. If stop is :py:const:`True`
(the default), if player will halt playback when :kbd:`Esc` is pressed.
.. py:method:: useGLES(gles)
Chooses whether to use OpenGL ES or desktop OpenGL for rendering.
Must be called before :py:meth:`play`.
:param bool gles: :py:const:`True` if OpenGL ES should be used.
.. py:classmethod:: get() -> Player
.. deprecated:: 1.8
Use :attr:`avg.player` instead.
This method gives access to the player instance. If no player has been
created yet, a player is created.