Normally this leak goes unnoticed because basic fundamental types
are typically used with clutter_actor_animate(), the leak shows up
if boxed or object types are passed (such as ClutterVertex in the
case I stumbled upon).
We can use ClutterTimeline and its progress mode inside
ClutterAnimation; obviously, we have to maintain the invariants because
of the ClutterAnimation:alpha property, but if all you set is the :mode
property using one of the Clutter animation modes then we can skip the
ClutterAlpha entirely.
A bunch of private functions we use when parsing got exposed accidentaly
to the list of public symbols by virtue of not having the leading '_'
that we use to filter them out of the shared object — all the while the
header that declares them is a private, non installed one.
Let's rectify this situation with a bit of minor surgery on the code.
The easing test is a nice example of what ClutterAnimation and
clutter_actor_animate() can do. The "tween ball to the pointer
event coordinates" is a bit of a staple in animation libraries
and their documentation.
ClutterAnimation uses the weak ref machinery of GObject when associated
to ClutterActor by clutter_actor_animate() and friends - all the while
taking a reference on the actor itself. In order to trigger the weak ref
callback, external code would need to unref the Actor at least twice,
which has slim chance of happening. Plus, the way to destroy an Actor is
to call destroy(), not call unref().
The destruction sequence of ClutterActor emits the ::destroy signal, which
should be used by classes to release external references the might be
holding. My oh my, this sounds *exactly* the case!
So, let's switch to using the ::destroy signal for clutter_actor_animate()
and friends, since we know that the object bound to the Animation is
an Actor, and has a ::destroy signal.
This change has the added benefit of allowing destroying an actor as the
result of the Animation::completed signal without getting a segfault or
other bad things to happen.
Obviously, the change does not affect other GObject classes, or Animation
instances created using clutter_animation_new(); for those, the current
"let's take a reference on the object to avoid it going away in-flight"
mechanism should still suffice.
Side note: it would be interesting if GObject had an interface for
"destructible" objects, so that we could do a safe type check. I guess
it's a Rainy Day Project(tm)...
While we do check for compatibility and transformability of a GValue
with the GParamSpec value type, we are actually failing really badly
at it.
First of all, we bail out on the wrong conditions.
Then we use the type of the value passed instead of using the type
of the property itself.
This makes it impossible to actually use transformation functions for
GValue types - even those that have been registered by GLib itself -
when using the Animation API directly, instead of going through the
clutter_actor_animate() wrappers.
When animating an actor through clutter_actor_animate() and friends we
might want forcibly detach the animation instance from the actor in
order to start a new one - for instance, in response to user
interaction.
Currently, there is no way to do that except in a very convoluted way,
by emitting the ::completed signal and adding a special case in the
signal handlers; this is due to the fact that clutter_actor_animate()
adds more logic than the one added by clutter_animation_set_object(),
so calling set_object(NULL) or unreferencing the animation instance
itself won't be enough.
The right way to approach this is to add a new method to Clutter.Actor
that detaches any eventual Animation currently referencing it.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2051
This adds a wrapper macro to clutter-private that will use
g_object_notify_by_pspec if it's compiled against a version of GLib
that is sufficiently new. Otherwise it will notify by the property
name as before by extracting the name from the pspec. The objects can
then store a static array of GParamSpecs and notify using those as
suggested in the documentation for g_object_notify_by_pspec.
Note that the name of the variable used for storing the array of
GParamSpecs is obj_props instead of properties as used in the
documentation because some places in Clutter uses 'properties' as the
name of a local variable.
Mose of the classes in Clutter have been converted using the script in
the bug report. Some classes have not been modified even though the
script picked them up as described here:
json-generator:
We probably don't want to modify the internal copy of JSON
behaviour-depth:
rectangle:
score:
stage-manager:
These aren't using the separate GParamSpec* variable style.
blur-effect:
win32/device-manager:
Don't actually define any properties even though it has the enum.
box-layout:
flow-layout:
Have some per-child properties that don't work automatically with
the script.
clutter-model:
The script gets confused with ClutterModelIter
stage:
Script gets confused because PROP_USER_RESIZE doesn't match
"user-resizable"
test-layout:
Don't really want to modify the tests
http://bugzilla.clutter-project.org/show_bug.cgi?id=2150
The Animatable interface was created specifically for the Animation
class. It turns out that it might be fairly useful to others - such as
ClutterAnimator and ClutterState.
The newly-added API in this cycle for querying and accessing custom
properties should not require that we pass a ClutterAnimation to the
implementations: the Animatable itself should be enough.
This is necessary to allow language bindings to wrap
clutter_actor_animate() correctly and do type validation and
demarshalling between native values and GValues; an Animation instance
is not available until the animate() call returns, and validation must
be performed before that happens.
There is nothing we can do about the animate_property() virtual
function - but in that case we might want to be able to access the
animation from an Animatable implementation to get the Interval for
the property, just like ClutterActor does in order to animate
ClutterActorMeta objects.
The marshallers we use for the signals are declared in a private header,
and it stands to reason that they should also be hidden in the shared
object by using the common '_' prefix. We are also using some direct
g_cclosure_marshal_* symbol from GLib, instead of consistently use the
clutter_marshal_* symbol.
The Animation class should use the Animatable API for custom properties
to override finding a property definition, getting the initial state and
setting the final state of an object.
GLib 2.24 (but starting from the 2.23.2 unstable release) added a new
macro for collecting GValues from a va_list.
The newly added G_VALUE_COLLECT_INIT() macro should be used in place
of initializing the GValue and calling G_VALUE_COLLECT(), and improves
the collection performances by avoiding multiple checks, free and
initialization calls.
The signal-swapped-after:: modifier for signal connection inside the
clutter_actor_animate* variadic arguments functions is not mentioned in
the documentation.
• Remove one unused variable.
• We ignore the result of get_timeline_internal() so we need to tell
the compiler that - though a better solution would be to split the
timeline implicit creation into its own function.
Instead of taking a string and duplicating the "is it a string or an
integer" check in both Alpha and Animation, the function in
ClutterScript that resolves the animation mode values should take a
JsonNode and do all the checks it needs.
Be more drastic if the internal state is broken, and assert() if the
expected Alpha and Timeline instances we need are not valid. This
usually implies a library bug or a massive heap corruption.
The Animation code does transformation of values between type A and A'
after checking for compatibility using g_value_type_compatible(). This
is incorrect: compatibility means that the two types can be copied. The
correct conversion should follow:
if (compatible (type (A), type (A')))
copy (A, A');
else
if (transformable (type (A), type (A')))
transform (A, A');
else
error("Unable to trasform type A in A'");
The transformation might still fail, so we need to check for errors
there as well as a fall-through case.
We should not just check for compatibility, but also for the ability to
transform a GValue of type A into another of type A'.
Usually compatibility is enough, especially if types can be
introspected beforehand; some times, though, we also need to check for
transformability as a type can provide the transformation functions
necessary for the operation.
Actors, unlike objects, can effectively go away whilst being
animated - usually because of an explicit destoy().
The Animation created by clutter_actor_animate() and friends
should keep a weak reference on the actor and eventually
get rid of the animation itself in case the actor goes away
whilst being animated.
Both ClutterAlpha:mode and ClutterAnimation:mode can be defined using:
• an integer id
• the "nick" field of the AnimationMode GEnumValue
• a custom, tweener-like string
All these methods should be documented.
Like in ClutterAlpha, ClutterAnimation:mode must be overridden when
parsing a Script definition, as we accept both a numeric id and the
string id for easing modes.
The old code checked whether the property began with 'signal-' and
then checked for 'signal-swapped' and 'signal-after'. This prevented
you from animating a property called for example 'signal-strength'.
The check for the prefix is now in a separate function which also adds
a 'signal-swapped-after' prefix for completeness.
Fixes bug:
http://bugzilla.openedhand.com/show_bug.cgi?id=1798
Currently, to update a property inside an animation you have to
get the interval for that property and then call the set_final_value()
method.
We can provide a simpler, bind()-like method for the convenience of
the developers that just validates everything and then calls the
Interval.set_final_value().
If the timeline is running backwards, the completed signal handler should
set the final state from the interval's initial value.
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
In case we are skipping too many frames, we should force the animation
instance to apply the final state of the animated interval inside the
::completed signal handler.
In order to chain up animations using clutter_actor_animate() and
friends you have to use an idle handler that guarantees that the
main loop spins at least once after the animation pointer has been
detached from the actor.
This has several drawbacks, first and foremost the fact that the
slice of the main loop for the idle handler might be starved by
other operations, like redrawing. This inevitably leads to tricks
with priorities and the like, contributing to the overall complexity.
Instead, we should guarantee that the animation instance created by
clutter_actor_animate() is valid for the ::completed signal until
it reaches its default handler; after that, the animation is detached
from the actor and destroyed. This means that it's possible to
create a new animation after the first is complete by simply using
g_signal_connect_after().
This unfortunately makes it impossible to keep a reference to the
animation pointer attached to the actor by using g_object_ref(); a
way to "fix" this would be to have a clutter_animation_attach()
and a clutter_animation_detach() pair of methods that allow attaching
any animation to an actor. This might overcomplicate what it is
the simple animation API, though, so it's currently not implemented
and left for future versions.
The test-easing interactive demo has been modified to show how
the animation queuing works by adding a command line switch that
recenters the animated actor once the first animation has ended.
Continuing in the tradition on making clutter_actor_animate() the
next g_object_connect(), here's the addition of the signal-after::
and signal-swapped:: modifiers for the automagic signal connection
arguments.
Fixes bug:
http://bugzilla.openedhand.com/show_bug.cgi?id=1646
