Otherwise if the dipose method is called twice the material will
already be destroyed when texture_free_gl_resources is called so it
will issue a warning about an invalid handle.
When the quad log contains multiple textures (such as when a sliced
texture is drawn) it dispatches the log with multiple calls to
flush_quad_batch and walks a pointer along the list of vertices.
However this pointer was being incremented by only one vertex so the
next quad would be drawn with three of the vertices from the last
quad.
The 'no_slice' property means the texture should never be sliced. We
want cogl to create a texture with any amount of waste so we pass
max_waste as -1. However this got broken in commit 168d55 so that the
meaning got negated (no_slice enabled slicing).
The current code that handles the invariant that the new parent
of an actor needing a layout should also be queued for relayout
is hitting the short-circuiting we do in the queue_relayout()
method.
In order to fix this we can forcibly set the actor to need a
width/height request and an allocation; then we queue a relayout
on the parent.
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
The :alignment property is prone to generate confusion: developers
will set it thinking that the contents of a ClutterText will
automagically align themselves.
Instead of using the generic term :alignment, and following the
GTK+ convention, we should use a more specific term, conveying the
actual effect of the property: alignment of the lines with respect
to each other, and not to the overall allocated area.
See bug 1428:
http://bugzilla.openedhand.com/show_bug.cgi?id=1428
When setting the cogl texture, the ClutterTexture takes a reference to
the Cogl handle but the material takes an additional reference when it
is set as the layer. Nothing was unrefing the temporary reference so
the textures were being leaked.
The opacity of the source actor when painted from the clone should be
combined with the opacity of the clone as well as the clone's parents,
instead of just the parents.
The quad drawing code keeps track of the number of texture units that
have the tex coord array enabled so that in the next call it can
disabled any that are no longer enabled. However it was using 'i+1' as
the count but 'i' is already set to 'n_layers' from the previous for
loop.
Therefore it was disabling an extra texture unit. This doesn't
normally matter but it was causing GLES 2 to pointlessly realize an
extra unit.
- In cogl-material.h it directly sets the values of the
CoglMaterialLayerCombineFunc to some GL_* constants. However these
aren't defined in GLES 2 beacuse it has no fixed function texture
combining. Instead the CGL_* versions are now used. cogl-defines.h
now sets these to either the GL_* version if it is available,
otherwise it directly uses the number.
- Under GLES 2 cogl-material.c needs to access the CoglTexture struct
so it needs to include cogl-texture-private.h
- There are now #define's in cogl-gles2-wrapper.h to remap the GL
function names to the wrapper names. These are disabled in
cogl-gles2-wrapper.c by defining COGL_GLES2_WRAPPER_NO_REMAP.
- Added missing wrappers for glLoadMatrixf and glMaterialfv.
- Renamed the TexEnvf wrapper to TexEnvi because the latter is used
instead from the material API.
Cogl previously tried to cache the currently bound texture when
drawing through the material API to avoid excessive GL calls. However,
a few other places in Cogl and Clutter rebind the texture as well so
this can cause problems.
This was causing shaped windows to fail in Mutter because
ClutterGLXTexturePixmap was binding a different texture to update it
while the second texture unit was still active which meant the mask
texture would not be selected when the shaped window was drawn
subsequent times.
Ideally we would fix this by providing a wrapper around glBindTexture
which would affect the cached value. The cache would also have to be
cleared if a selected texture was deleted.
If the source of a ClutterClone does not have a parent actor the
clone will be unable to paint it because it's missing an allocation.
A simple way to fix it is to make the ClutterClone act like a
"foster parent": when it is allocated it will check if the source
actor has a parent and if not it will allocate the source with
its preferred size.
Final bit of integration between ClutterActor and Pango: a simple
method for creating a PangoLayout, pre-filled with text and ready
to be rendered using cogl_pango_render_layout().
This should make writing new Actors rendering custom text in their
paint() implementation easy and reliable.
ClutterText should merge the PangoAttributes set by using
clutter_text_set_attributes() with the attributes generated by
parsing Pango markup.
For this to work we must parse the markup and merge the attributes
we get out of pango_parse_markup() with the attributes set by
the user.
Setting the markup or the attributes on an editable text should
not work for the time being.
When processing a motion event, we need to spin the event loop two extra
times to ensure that any enter/leave events that might have been synthesized
are pumped through (otherwise they end up being pushed down the queue and
never processed).
This tries to make a number of files more comparable with the intention of
moving some code into cogl/common/
Files normalized:
cogl.c
cogl-context.c
cogl-context.h
cogl-texture.c
Someone not sure which cogl_color_set_from_* version is "best" may use
set_from_4d because taking doubles implies higher precision. Currently
it doesn't have any advantage.
This makes it consistent with cogl_rectangle_with_{multi,}texture_coords.
Notably the reason cogl_rectangle_with_{multi,}texture_coords wasn't changed
instead is that the former approach lets you describe back facing rectangles.
(though technically you could pass negative width/height values to achieve
this; it doesn't seem as neat.)
The code is #if 0 guarded, but when uncommented it outlines all drawn
rectangles with an un-blended red, green or blue border. This may e.g. help
with debugging texture slicing issues or blending issues, plus it looks quite
cool.
Bug 1349 - Using the anchor point to set the scale center is messy
The branch adds an extra center point for scaling which can be used
for example to set a scale about the center without affecting the
position of the actor.
The scale center can be specified as a unit offset from the origin or
as a gravity. If specified as a gravity it will be stored as a
fraction of the actor's size so that the position will track when the
actor changes size.
The anchor point and rotation centers have been modified so they can
be set with a gravity in the same way. However, only the Z rotation
exposes a property to set using a gravity because the other two
require a Z coordinate which doesn't make sense to interpret as a
fraction of the actor's width or height.
Conflicts:
clutter/clutter-actor.c
When drawing a texture with waste in _cogl_multitexture_unsliced_quad
it scales the texture coordinates so that the waste is not
included. However the formula was the wrong way around so it was
calculating as if the texture coordinates are ordered x1,x2,y1,y2 but
it is actually x1,y1,x2,y2.
When the texture is sliced it drops back to a fallback function and
passes it the texture coordinates from the rectangle. However if no
tex coords are given it would crash. Now it passes the default
0.0->1.0 tex coords instead.
If no texture coordinates are given then texture_unsliced_quad tries
to generate its own coordinates. However it also tries to read the
texture coordinates to check if they are in [0.0,1.0] range so it will
crash before it reaches that.
Instead of having a separate set of font options that override the
backend options when clutter_set_font_flags is called, it now just
directly sets the backend font options. So now the font flags are just
a convenience wrapper around the backend font options.
This also makes the ClutterText labels automatically update when the
font flags are changed because they will respond to the 'font-changed'
signal from the backend.
Whenever a ClutterText is created it now connects to the font-changed
signal. When it is emitted the layout cache is dirtied and a relayout
is queued. That way changes to the font options or resolution will
cause an immediate update to the labels in the scene.
* generic-actor-clone:
Remove CloneTexture from the API
[tests] Clean up the Clone interactive test
Rename ActorClone to Clone/2
Rename ActorClone to Clone/1
Improves the unit test to verify more awkward scaling and some corresponding fixes
Implements a generic ClutterActorClone that doesn't need fbos.
Conflicts:
clutter/cogl/gl/cogl-texture.c
clutter/cogl/gles/cogl-primitives.c
* cogl-material:
clutter-{clone-,}texture weren't updating their material opacity.
Updates GLES1 support for CoglMaterial
Normalizes gl vs gles code in preperation for synching material changes
Removes cogl_blend_func and cogl_alpha_func
Fully integrates CoglMaterial throughout the rest of Cogl
[cogl-material] Restore the GL_TEXTURE_ENV_MODE after material_rectangle
[cogl-material] Make the user_tex_coords parameter of _rectangle const
[test-cogl-material] Remove return value from material_rectangle_paint
Add cogl-material.h and cogl-matrix.h to libclutterinclude_HEADERS
[cogl-material] improvements for cogl_material_rectangle
[cogl-material] Adds a cogl_material_set_color function
[cogl-material] Some improvements for how we sync CoglMaterial state with OpenGL
[cogl-material] Converts clutter-texture/clutter-clone-texture to the material API
[doc] Hooks up cogl-material reference documentation
Updates previous GLES multi-texturing code to use CoglMaterial
Adds a CoglMaterial abstraction, which includes support for multi-texturing
[doc] Hooks up cogl-matrix reference documentation
Adds CoglMatrix utility code
[tests] Adds an interactive unit test for multi-texturing
[multi-texturing] This adds a new cogl_multi_texture API for GL,GLES1 + GLES2
ClutterClone supercedes ClutterCloneTexture, since it can clone
every kind of actor -- including composite ones.
This is another "brain surgery with a shotgun" kind of commit: it
removes CloneTexture and updates every test case using CloneTexture
to ClutterClone. The API fallout is minimal, luckily for us.
The hope is that this function makes it easier to extend the font
settings with more flags without having to add a function for every
setting.
A new flag for enabling hinting has been added. If set, this changes
the font options on the global PangoContext and any newly created
PangoContexts. The options are only set if the flag is changed from
the default so it won't override any detailed setting chosen by the
backend.
cogl_set_source_color4ub was previously used to set a transparent
white source color according to the actors opacity, but since
cogl_set_source_color now always implies you want a solid fill we
we use cogl_material_set_color4ub to achieve the same result.
This updates cogl/gles in line with the integration of CoglMaterial throughout
Cogl that has been done for cogl/gl.
Note: This is still buggy, but at least it builds again and test-actors works.
Some GLES2 specific changes were made, but these haven't been tested yet.
This changes all GLES code to use the OpenGL function names instead of
the cogl_wrap_* names. For GLES2 we now define the OpenGL name to point
to the wrapper, as opposed to defining the wrapper to point to the
OpenGL name for GLES1.
I've also done a quick pass through gl/cogl.c and gles/cogl.c to make
them more easily comparable. (most of the code is now identical)
The GL blend function and alpha function are now controlled by the material
code, and even internally Cogl should now be using the material API when
it needs control of these.
This glues CoglMaterial in as the fundamental way that Cogl describes how to
fill in geometry.
It adds cogl_set_source (), which is used to set the material which will be
used by all subsequent drawing functions
It adds cogl_set_source_texture as a convenience for setting up a default
material with a single texture layer, and cogl_set_source_color is now also
a convenience for setting up a material with a solid fill.
"drawing functions" include, cogl_rectangle, cogl_texture_rectangle,
cogl_texture_multiple_rectangles, cogl_texture_polygon (though the
cogl_texture_* funcs have been renamed; see below for details),
cogl_path_fill/stroke and cogl_vertex_buffer_draw*.
cogl_texture_rectangle, cogl_texture_multiple_rectangles and
cogl_texture_polygon no longer take a texture handle; instead the current
source material is referenced. The functions have also been renamed to:
cogl_rectangle_with_texture_coords, cogl_rectangles_with_texture_coords
and cogl_polygon respectivly.
Most code that previously did:
cogl_texture_rectangle (tex_handle, x, y,...);
needs to be changed to now do:
cogl_set_source_texture (tex_handle);
cogl_rectangle_with_texture_coords (x, y,....);
In the less likely case where you were blending your source texture with a color
like:
cogl_set_source_color4ub (r,g,b,a); /* where r,g,b,a isn't just white */
cogl_texture_rectangle (tex_handle, x, y,...);
you will need your own material to do that:
mat = cogl_material_new ();
cogl_material_set_color4ub (r,g,b,a);
cogl_material_set_layer (mat, 0, tex_handle));
cogl_set_source_material (mat);
Code that uses the texture coordinates, 0, 0, 1, 1 don't need to use
cog_rectangle_with_texure_coords since these are the coordinates that
cogl_rectangle will use.
For cogl_texture_polygon; as well as dropping the texture handle, the
n_vertices and vertices arguments were transposed for consistency. So
code previously written as:
cogl_texture_polygon (tex_handle, 3, verts, TRUE);
need to be written as:
cogl_set_source_texture (tex_handle);
cogl_polygon (verts, 3, TRUE);
All of the unit tests have been updated to now use the material API and
test-cogl-material has been renamed to test-cogl-multitexture since any
textured quad is now technically a test of CoglMaterial but this test
specifically creates a material with multiple texture layers.
Note: The GLES backend has not been updated yet; that will be done in a
following commit.
Step two: rename the object and its methods.
While we're at it, adhere more strictly to the coding style
practises; rename :clone-source to :source; add a setter method
for the :source property; take a reference on the source actor
to avoid it disappearing while we're still accessing it.
Like clutter_timeline_advance(), calling advance_to_marker() will
not emit ::new-frame for the frame where the marker is set on; it
will also not emit ::marker-reached for the marker we are advancing
the timeline to.
When calling clutter_timeline_advance(), a timeline will not emit
the ::new-frame signal for the frame we are advancing to, as this
would break the invariants of the timeline behaviour.
The documentation should make this clear.
The clutter_timeline_new() constructor is not checking the full
range of the passed :fps property. The ParamSpec of the property
and the setter method perform this check, so the ctor should as
well.
The "is-timeline-complete" condition is pretty long, spanning
four lines and four logical sub-conditions. It is possible to
neatly move it into an is_complete() function and make the
code more readable.
The long description of the ClutterTimeline class is very C
developer-oriented. Since many language bindings will refer to
the C API reference we should probably be more verbose and
language agnostic -- at least in the class description.
The methods documentation also requires a little pass to increase
the consistency of the terminology, the grammar and the syntax.
Finally, comments never killed anyone.
Since not every timeline will have markers it's unfair to make
all of them crete two empty hash tables (with a preallocated
fixed size).
This commit moves the responsibility of creating the hash tables
to the marker API itself, and adds the relative checks.
Since we are using milliseconds granularity to integrate timelines
with the GLib main loop, we cannot allow values of the :fps
property bigger than 1000. This means validating the fps value both
in the GParamSpec and the clutter_timeline_set_speed() accessor
function.
This should also fix floating point exceptions when trying to
perform "n_frames = milliseconds / (1000 / fps)".
See bug 1354:
http://bugzilla.openedhand.com/show_bug.cgi?id=1354
If a ClutterTexture does not sync size, it should be possible to
change the texture size without causing a relayout.
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
There is some GL work and a repaint anytime the clip is set
or unset, so avoid that if it isn't really changed.
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
The stage will usually be painted before the first ConfigureNotify
arrives so we need to set the SYNC_MATRICES flag to ensure that the
viewport will be correct for that paint. Unfortunately this means that
the viewport will be set again once the ConfigureNotify is received
but compared to rendering an initial invalid scene I think it is the
lesser of two evils.
When calling clutter_behaviour_apply() the new actor is prepended
to the list of actors to which a behaviour is applied; this breaks
the rest of methods working on the actors list, e.g.:
# adding actors
apply(actor_0);
apply(actor_1);
apply(actor_2);
# expected: [ actor_0, actor_1, actor_2 ]
[ actor_2, actor_1, actor_0 ] = get_actors();
# expected: actor_2
actor_0 = get_nth_actor(2);
This commit fixes the inconsistency in the returned values.
The Cogl primitives broke for GLES 1.1 and 2 after the cogl-float
branch merge.
CoglPathNode was still being declared as GLfixed for the GLES backend
but it was being filled with float values so they were all ending up
as numbers < 1.
glDrawArrays was being called with GL_FIXED so this has been changed
to GL_FLOAT.
The scanline rasterizer had a leftover hardcoded ClutterFixed constant
to add a small amount to the height of each line.
struct _CoglFloatVec2 has been removed because it is no longer used
anywhere.
The special check to invert the progress when the timeline direction
is backwards is not necessary because the actual frame number will be
decreasing in that case. Inverting just makes it progress forwards
again.
This is more apparent since the float-alpha-value branch merge because
the clutter_linear function directly returns the value from
get_progress. For example in test-depth, the animations loop instead
of oscillating back and forth.
The documentation has been updated to reflect the fact that the anchor
point will move when the actor changes size if it was specified using
a gravity value. The new functions for setting the scale center and z
rotation gravity are also documented.
Currently only the Z axis rotation center can be set using a gravity
but the other rotations also store their center as an AnchorCoord for
consistency. Specifying the center as a gravity makes less sense for
the other axes because the actors have no size along the Z axis.
The rotation angles are now stored as gdoubles and the fixed point *x
entry points have been removed.
The Z rotation can now be set with a gravity center using the
following new function:
void clutter_actor_set_z_rotation_from_gravity (ClutterActor *self,
gdouble angle,
ClutterGravity gravity);
This sets the center point from which the scaling will occur. This can
be used insetad of the anchor point to avoid moving the actor. Like
the anchor point, it can be specified as either a coordinate in units
or a gravity enum.
To set the center you can use two new variants of set_scale:
clutter_actor_set_scale_full (ClutterActor *self,
gdouble scale_x,
gdouble scale_y,
int center_x,
int center_y);
or
clutter_actor_set_scale_with_gravity (ClutterActor *self,
gdouble scale_x,
gdouble scale_y,
ClutterGravity gravity);
The ClutterFixed variants of the set_scale functions have been removed
and the scale value is now always stored as a double.
This makes it so when the anchor point is set using a gravity enum
then the anchor point moves when the actor changes size. A new
property is added for the anchor point gravity. If the anchor point is
set from gravity then the position in units can also be retreived with
the regular API.
A new union type is used to store the anchor point with helper
accessor functions. The hope is these can be reused for the scale and
rotation center points.
The clutter_stage_get_resolution() and fixed-point API are just
shorthands for:
clutter_backend_get_resolution (default_backend);
And as such do not fit at all in the ClutterStage class. The only
reason for their existence was the ClutterUnit conversion macros,
which have now been fixed to use the default backend through a
function call instead.
Thus, we can safely remove the stage entry points.
The maintainer compiler flags we use trigger warnings and errors
in the autogenerated code that gtk-doc creates to scan the header
and source files. Since we cannot control that, and we must run
a distcheck with both --enable-gtk-doc and --enable-maintainer-flags
turned on, we need to use less-strict compiler flags when inside
the doc/reference subdirectories.
The way to do this is to split the maintainer compiler flags into
their own Makefile variable, called MAINTAINER_CFLAGS. The we
can use $(MAINTAINER_CFLAGS) in the INCLUDES or _CFLAGS sections
of each part of the source directories we wish to check with the
anal retentiveness suited for maintainers.
* float-alpha-value:
[script] Parse easing modes by name
[docs] Update the easing modes documentation
[animation] Implement new easing functions
[animation] Move the alpha value to floating point
Since we allow overriding the paint() implementation through the
::paint signal to change the way an actor is being painted, we
should also allow overriding the pick() implementation using a
::pick signal.
The script converted calls to COGL_FIXED_MUL(x,y) to (x*y). However
this fails for cases like this:
COGL_FIXED_MUL(a + b, c)
which become
(a + b * c)
The meaning of this is of course different because multiplication has
a higher precedence than addition.
This was causing breakages in cogl_texture_quad_sw when the vertex
coordinates are not in increasing order. This was the case in
test-backface-culling when NPOTs are not available.
Improve clutter_sinx() by replacing the low precision CFX_SIN_STEP
with a multiply/divide pair. This reduces the maximum error from
1.8e-04 to 2.4e-05.
http://bugzilla.openedhand.com/show_bug.cgi?id=1314
Based on a patch by Owen W. Taylor <otaylor@fishsoup.net>
Since a pick is really a paint operation, we can safely get
the allocation box, instead of using get_width() and get_height().
This should help cutting down the function calls. If we were
feeling adventurous, we could even use the allocation directly
from the private data structure.
Based on a patch by Gwenole Beauchesne <gbeauchesne@splitted-desktop.org>
Compute the value of the camera distance as exactly half the xx
component of the projection matrix. The heuristically derived
value for 60 degrees was off by about 0.016%, causing noticeable
blurring, and other field of view angles which didn't have the
heuristic adjustment off by much more.
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
If an actor is not set as visible, or if it is in a section of
the scenegraph that it's set as not visible (e.g. one of the
parents is not visible) then we should not queue a redraw for
it.
Patch based on code from Michael Boccara <michael@graphtech.co.il>
The intention behind ::queue-redraw is to be able to block the
default handler by attaching a callback and calling one of the
g_signal_stop_emission variants.
However this doesn't work, because ::queue-redraw has the
G_SIGNAL_RUN_FIRST flag instead of G_SIGNAL_RUN_LAST.
The GValue and GParamSpec integration of ClutterUnit was still
using the old, fixed-point based logic.
Storing ClutterUnits in a GValue should use floating point values,
and ClutterParamSpecUnit should follow suit.
Instead of recomputing the number of units needed to fit in
an em each time clutter_units_em() is called, we can store this
value into the default Backend along with the resolution and
font name. The value should also be updated each time the
resolution and font are changed, to keep it up to date.
The coordinates of each ButtonEvent are relative to the stage that
received the event, so we should document this in the structure
annotation.
It should also be mentioned that the coordinates can be transformed
into actor-relative coordinates by using transform_stage_point().
An em is a unit of measurement in typography, equal to the point
size of the current font.
It should be possible to convert a value expressed in em to
ClutterUnits by using the current font and the current DPI as
stored by the default backend.
The stage-with/height-percentage converters had been broken by
the multiple-stages support of Clutter 0.8. They are also made
useless by the fact that Units are now floating point values.
The millimeters and typographic points converters also depended
on the default stage, but they can be reworked to use the default
DPI coming from the default Backend instead.
Boolean arguments for functions are pretty evil and usually
lead to combinatorial explosion of parameters in case multiple
settings are added.
In the case of the COGL texture constructors we have a boolean
argument for enabling the auto-mipmapping; it is conceivable that
we might want to add more settings for a COGL texture without
breaking API or ABI compatibility, so the boolean argument should
become a bitmask.
The internals have not been changed: instead of checking for
a non-zero value, we check for a bitmask being set.
ClutterMedia was a rough cut at a simple media API; it needs some
re-evaluation before 1.0 in order to keep it simple to use, and
simple to implement.
- ClutterMedia:position
The position property accessors collide with the corresponding
ClutterActor methods, which make it impossible to bind them in
high-level languages:
video_texture.set_position()
video_texture.get_position()
In order to resolve the collision, we have to go through the
GObject properties API:
video_texture.set('position', value)
value = video_texture.get('position')
A :position in seconds is also a GStreamer-ism, and should rather
be converted to a :progress property, with a normalized value
between 0 and 1. the current position in seconds would then simply
be progress*duration. For non-seekable streams, 0.0 would always
be returned. This makes it easier to use the progress inside
animations, Timelines or ClutterPath instances.
- ClutterMedia:volume should be renamed to :audio-volume and normalized
as well, instead of being a floating point value between 0 and 100.
- ClutterMedia:buffer-percent should just be :buffer-fill and normalized
between 0.0 and 1.0
This better reflects the fact that the api manages sets of vertex attributes,
and the attributes really have no implied form. It is only when you use the
attributes to draw that they become mesh like; when you specify how they should
be interpreted, e.g. as triangle lists or fans etc. This rename frees up the
term "mesh", which can later be applied to a concept slightly more fitting.
E.g. at some point it would be nice to have a higher level abstraction that
sits on top of cogl vertex buffers that adds the concept of faces. (Somthing
like Blender's mesh objects.) There have also been some discussions over
particle engines, and these can be defined in terms of emitter faces; so some
other kind of mesh abstraction might be usefull here.
Okey; to summarise the changes...
We have converted Clutter and Cogl over to using floating point internally
instead of 16.16 fixed, but we have maintained the cogl-fixed API as a
utility to applications in case they want to implement their own optimizations.
The Clutter API has not changed (though ClutterFixed and ClutterUnit are now
internally floats) but all Cogl entry points have been changed to accept floats
now instead of CoglFixed.
To summarise the rationale...
There have been a number of issues with using fixed point though out Clutter
and Cogl including: lack of precision, lack of range, excessive format
conversion (GPUs tend to work nativly with IEEE floats) and maintainability.
One of the main arguments for fixed point - performance - hasn't shown
itself to be serious in practice so far since we seem to be more limited
by GPU performance and making improvements regarding how we submit data to
OpenGL[ES]/the GPU has had a more significant impact.
Ref: The recent multiple rectangle queuing changes + the
cogl-texture-agressive-batching branch which show significant performance
gains, and that recent tests on the ipodtouch (ARM + MBX) also showed no
loss of performance running with floats.
So finally; please forgive the inevitable fallout, this is a far reaching
change. There are still a few known issues with the fixed to float
conversion but enough works for all our conformance tests to pass, and the
remaining issues hopefully wont be too tricky to solve. For reference two
tags will be available either side of this change: "cogl-fixed-end" and
"cogl-float-start"
The easing modes for a ClutterAlpha can either be parsed by using
the enumeration "nickname" (the shorthand form of the enumeration
value) or by using the common naming policy used in other
animation frameworks, like:
easeInCubic
easeOutElastic
easeInOutBounce
