Interpolating between two transformations expressed using a 3D matrix
can be achieved by decomposing the matrices into their transformations
and do a simple numeric interpolation between the initial and final
states, like we do for other data types.
Luckily for us, the CSS Transforms specification from the W3C provides
the decomposition algorithm, using the "unmatrix" code taken from the
book "Graphics Gems II, edited by Jim Arvo".
Once the matrices have been decomposed, we can simply interpolate the
transformations, and re-apply them onto the result matrix, using the
facilities that Clutter provides for interpolating between two known
GTypes.
The Geometry type is an *awful* representation of a integer rectangle,
as it uses unsigned integers for its size, leading to overflow issues
when unioning and intersecting. We have better rectangle types in
Cairo and Clutter, these days.
The TransitionGroup class is a logical container for running multiple
transitions.
TransitionGroup is not a Score: it is a Transition that advances each
Transition it contains using the delta between frames, and ensures that
all transitions are in a consistent state; these transitions are not
advanced by the master clock.
Instead of a single new() constructor that both allocates and
initializes, split the allocation and initialization into two separate
functions for types that are typically used on the stack, and rarely
allocated on the heap, like ClutterPoint and friends.
This is also applied retroactively to ClutterActorBox and ClutterVertex,
given that the same considerations on usage apply to them as well; we
can add a return value to clutter_actor_box_init() and
clutter_vertex_init() in an ABI-compatible way, so that
clutter_actor_box_new() and clutter_vertex_new() can be effectively
reimplemented as "init (alloc ())".
ClutterContent is an interface for creating delegate objects that handle
what an actor is going to paint.
Since they are a newly added type, they only hook into the new PaintNode
based API.
The position and size of the content is controlled in part by the
content's own preferred size, and by the ClutterContentGravity
enumeration.
Now that we have a proper scene graph API, we should split out the
rendering part from the logical and event handling part.
ClutterPaintNode is a lightweight fundamental type that encodes only the
paint operations: pipeline state and geometry. At its most simple, is a
way to structure setting up the programmable pipeline using a
CoglPipeline, and submitting Cogl primitives. The important take away
from this API is that you are not allowed to call Cogl API like
cogl_set_source() or cogl_primitive_draw() directly.
The interesting approach to this is that, in the future, we should be
able to move to a purely retained mode: we will decide which actors need
to be painted, they will update their own branch of the render graph,
and we'll take the render graph and build all the rendering commands
from that.
For the 1.x API, we will have to maintain invariants and the existing
behaviour, but as soon as we can break API, the old paint signal will
just go away, and Actors will only be allowed to manipulate the render
tree.
As a convenience for the C API.
Language bindings should already be using the GValue variants.
This commit also moves the custom progress functions out of the
clutter-interval.c, as they are meant to be generic interpolation
functions and not ClutterInterval-specific.
Creating PaintVolume instances is not possible, and it's not recommended
anyway. It is, though, necessary to union paint volumes, especially with
2D boxes, in some cases.
Clutter should provide a simple convenience function that allows
unioning volumes to boxes in a moderately efficient way.
https://bugzilla.gnome.org/show_bug.cgi?id=670021
This should avoid trying to fix the origin of a paint volume set from
the allocation's origin, and thus breaking everything.
A PaintVolume for an actor is defined to be relative to the actor's
modelview unless specifically modified by internal functions; the origin
of an actor's allocation is, on the other hand, parent-relative.
Iterating over children and ancestors of an actor is a relatively common
operation. Currently, you only have one option: start a for() loop, get
the first child of the actor, and advance to the next sibling for the
list of children; or start a for() loop and advance to the parent of the
actor.
These operations can be easily done through the ClutterActor API, but
they all require going through the public API, and performing multiple
type checks on the arguments.
Along with the DOM API, it would be nice to have an ancillary, utility
API that uses an iterator structure to hold the state, and can be
advanced in a loop.
https://bugzilla.gnome.org/show_bug.cgi?id=668669
We need to queue a relayout when removing a visible child from a visible
parent.
We also need to insert the child at the right position (depending on the
depth) so that newly added actors will be painted on top.
The actor class should be able to hold the margin offsets like it does
for expand and alignment flags.
Instead of filling the private data structure with data, we should be
able to use an ancillary data structure, given that all this data is
optional and might never be set in the first place.
Now that ClutterActor implements the Container contract we can actually
defer the size negotiation to a ClutterLayoutManager directly from the
default implementation of the Actor's virtual functions.
Add a public version of the clipped queue redraw, using a 2D clip. This
allows implementing actors with trackable 2D clipped regions, like the
ClutterX11TexturePixmap, outside of Clutter itself.
https://bugzilla.gnome.org/show_bug.cgi?id=660997
Just like GLIB_DEPRECATED and GLIB_DEPRECATED_FOR, Clutter should have
its own wrappers for G_DEPRECATED and G_DEPRECATED_FOR, to allow opting
out of deprecation warnings.
Deprecation warnings are enabled by default, now, even when building
Clutter.
This moves a couple of definitions to the common types header, and makes
sure that ClutterBehaviour subclasses include clutter-behaviour.h first,
so that their types can be fully expanded without necessarily have the
ClutterBehaviour header header included by their public headers. This is
the necessary prelude to have clutter-behaviour.[ch] moved to the
deprecated section.
We already have two mechanisms for controlling the font rendering
quality on a per-application basis:
• ClutterSettings properties
• clutter_backend_set_font_options()
The font flags were always a stop-gap solution, and one that tried to
simplify a fairly complex issue beyond the point of actually being
useful.
https://bugzilla.gnome.org/show_bug.cgi?id=660786
