clutter_actor_get_preferred_width/height currently caches only one size
requests, for a given height / width.
It's common for a layout manager to call get_preferred_width with 2
different heights during the same allocation cycle. Typically once in
the size request, once in the allocation. If
clutter_actor_get_preferred_width is called
alternatively with 2 different for_height, the cache is totally
inefficient, and we end up always querying the actor size even
when the actor does not need a re-allocation.
http://bugzilla.openedhand.com/show_bug.cgi?id=1876
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
Fix a copy-and-paste thinko where the cell size was computed using the
minimum size instead of the natural size. For actors with a minimum size
of zero, like Textures, this implied always a zero allocation.
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
This is an optimised version of CoglTexture2DSliced that always deals
with a single texture and always uses the GL_TEXTURE_2D
target. cogl_texture_new_from_bitmap now tries to use this backend
first. If it can't create a texture with that size then it falls back
the sliced backend.
cogl_texture_upload_data_prepare has been split into two functions
because the sliced backend needs to know the real internal format
before the conversion is performed. Otherwise the converted bitmap
will be wasted if the backend can't support the size.
This provides a way to upload the entire data for a texture without
having to first call glTexImage and then glTexSubImage. This should be
faster especially with indirect rendering where it would needlessy
send the data for the texture twice.
new_from_data and new_from_file can be implemented in terms of
new_from_bitmap so it makes sense to move these to cogl-texture rather
than having to implement them in every texture backend.
This adds a new texture backend which represents a sub texture of a
larger texture. The texture is created with a reference to the full
texture and a set of coordinates describing the region. The backend
simply defers to the full texture for all operations and maps the
coordinates to the other range. You can also use coordinates outside
the range [0,1] to create a repeated version of the full texture.
A new public API function called cogl_texture_new_from_sub_texture is
available to create the sub texture.
The CoglTextureSliceCallback function pointer now takes const pointers
for the texture coordinates. This makes it clearer that the callback
should not modify the array and therefore the backend can use the same
array for both sets of coords.
Given a region of texture coordinates this utility invokes a callback
enough times to cover the region with a subregion that spans the
texture at most once. Eg, if called with tx1 and tx2 as 0.5 and 3.0 it
it would invoke the callback with:
0.5,1.0 1.0,2.0 2.0,3.0
Manual repeating is needed by all texture backends regardless of
whether they can support hardware repeating because when Cogl calls
the foreach_sub_texture_in_region method then it sets the wrap mode to
GL_CLAMP_TO_EDGE and no hardware repeating is possible.
In _cogl_multitexture_quad_single_primitive we use a wrap mode of
GL_CLAMP_TO_EDGE if the texture coordinates are all in the range [0,1]
or GL_REPEAT otherwise. This is to avoid pulling in pixels from either
side when using GL_LINEAR filter mode and rendering the entire
texture. Previously it was checking using the unconverted texture
coordinates. This is ok unless the texture backend is radically
transforming the texture coordinates, such as in the sub texture
backend where the coordinates may map to something completely
different. We now check whether the coordinates are in range after
converting them.
Most of the fields that were previously in CoglTexture are specific to
the implementation of CoglTexture2DSliced so they should be placed
there instead. For example, the 'mipmaps_dirty' flag is an
implementation detail of the ensure_mipmaps function so it doesn't
make sense to force all texture backends to have this function.
Other fields such as width, height, gl_format and format may make
sense for all textures but I've added them as virtual functions
instead. This may make more sense for a sub-texture backend for
example where it can calculate these based on the full texture.
The CoglTexture struct previously contained some fields which are only
used to upload data such as the CoglBitmap and the source GL
format. These are now moved to a separate CoglTextureUploadData struct
which only exists for the duration of one of the cogl_texture_*_new
functions. In cogl-texture there are utility functions which operate
on this new struct rather than on CoglTexture directly.
Some of the fields that were previously stored in the CoglBitmap
struct are now copied to the CoglTexture such as the width, height,
format and internal GL format.
The rowstride was previously stored in CoglTexture and this was
publicly accessible with the cogl_texture_get_rowstride
function. However this doesn't seem to be a useful function because
there is no need to use the same rowstride again when uploading or
downloading new data. Instead cogl_texture_get_rowstride now just
calculates a suitable rowstride from the format and width of the
texture.
Commit 558b17ee1e added support for rectangle textures to the
framebuffer code. Under GLES there is no GL_TEXTURE_RECTANGLE_ARB
definition so this was breaking the build. The rest of Cogl uses
ifdef's around that constant so we should do the same here.
• The debug flags are pre-processor ones, so they should be listed
inside AM_CPPFLAGS.
• Clutter's publicly exported symbols match the following regular
expression:
^(clutter|cogl|json)_*
The old one also listed "pango" as a possible prefix, but the
Pango API is now under the Cogl namespace.
We need to add the row-spacing value when calculating the y position for lines
of actors in horizontal flowing layouts.
Similarly we need to add the col-spacing value when calculating the x posution
for actors in vertical flowing layouts.
When requesting the GLXFBConfig for creating the GLX context, we should
always request one that links to an ARGB visual instead of a plain RGB
one.
By using an ARGB visual we allow the ClutterStage:use-alpha property to
work as intended when running Clutter under a compositing manager.
The default behaviour of requesting an ARGB visual can be disabled by
using the:
CLUTTER_DISABLE_ARGB_VISUAL
Environment variable.
The ClutterStage:use-alpha property is used to let a stage know that it
should honour the alpha component of the ClutterStage:color property.
If :use-alpha is set to FALSE the stage always uses the full opacity
when clearing itself before a paint(); otherwise, the alpha value is
used.
The correct blend function for the alpha channel is:
GL_ONE, GL_ONE_MINUS_SRC_ALPHA
As per bug 1406. This fix was dropped when the switch to premultiplied
alpha was merged.
* text-direction:
docs: Add text-direction accessors
Set the default language on the Pango context
actor: Set text direction on parenting
tests: Display the index inside text-box-layout
box-layout: Honour :text-direction
text: Dirty layout cache on text direction changes
actor: Add :text-direction property
Use the newly added ClutterTextDirection enumeration
Add ClutterTextDirection enumeration
The ClutterLayoutMeta instances should be created on demand, whenever
the layout manager needs them - if the layout manager supports layout
properties.
This removes the requirement to call add_child_meta() and
remove_child_meta() on add and remove respectively; it also simplifies
the implementation of LayoutManager sub-classes since we can add
fallback code in the base abstract class.
Eventually, this will also lead to an easier to implement ClutterScript
parser for layout properties.
With the new scheme, the ClutterLayoutMeta instance is created whenever
the layout manager tries to access it; if there isn't an instance
already attached to the container's child, one is created -- assuming
that the LayoutManager sub-class has overridden the
get_child_meta_type() virtual function and it's returning a valid GType.
We can also provide a default implementation for create_child_meta(),
by getting the GType and instantiating a ClutterLayoutMeta with all the
fields already set. If the layout manager requires more work then it can
obviously override the default implementation (and even chain up to it).
The ClutterBox actor has been updated, as well as the ClutterBoxLayout
layout manager, to take advantage of the changes of LayoutManager.
The colour test for the stage in _clutter_do_pick checks for white to
determine whether the stage was picked but since 47db7af4d we were
setting the colur to black. This usually worked because the id of the
default stage ends up being 0 which equates to black. However if a
second stage is created then it will always end up picking the first
stage.
We currently enable blending if the material colour has
transparency. This patch makes it also enable blending if any of the
lighting colours have transparency. Arguably this isn't neccessary
because we don't expose any API to enable lighting so there is no
bug. However it is currently possible to enable lighting with a direct
call to glEnable and this otherwise works so it is a shame not to have
it.
http://bugzilla.openedhand.com/show_bug.cgi?id=1907
The stage's pick id can be written to the framebuffer when we call
cogl_clear so there's no need for the stage to also chain up in it's pick
function resulting in clutter-actor.c also emitting a rectangle for the
stage.
cogl_push_draw_buffer, cogl_set_draw_buffer and cogl_pop_draw_buffer are now
deprecated and new code should use the new cogl_framebuffer_* API instead.
Code that previously did:
cogl_push_draw_buffer ();
cogl_set_draw_buffer (COGL_OFFSCREEN_BUFFER, buffer);
/* draw */
cogl_pop_draw_buffer ();
should now be re-written as:
cogl_push_framebuffer (buffer);
/* draw */
cogl_pop_framebuffer ();
As can be seen from the example above the rename has been used as an
opportunity to remove the redundant target argument from
cogl_set_draw_buffer; it now only takes one call to redirect to an offscreen
buffer, and finally the term framebuffer may be a bit more familiar to
anyone coming from an OpenGL background.
Instead of storing an enum with the backend type for each texture and
then using a switch statement to decide which function to call, we
should store pointers to all of the functions in a struct and have
each texture point to that struct. This is potentially slightly faster
when there are more backends and it makes implementing new backends
easier because it's more obvious which functions have to be
implemented.
cogl_offscreen_new_to_texture previously bailed out if the given texture's
GL target was anything but GL_TEXTURE_2D, but it now also allows
foreign GL_TEXTURE_RECTANGLE_ARB textures.
Thanks to Owen for reporting this issue, ref:
https://bugzilla.gnome.org/show_bug.cgi?id=601032
cogl_material_copy can be used to create a new CoglHandle referencing a copy
of some given material.
From now on we will advise that developers always aim to use this function
instead of cogl_material_new() when creating a material that is in any way
derived from another.
By using cogl_material_copy, Cogl can maintain an ancestry for each material
and keep track of "similar" materials. The plan is that Cogl will use this
information to minimize the cost of GPU state transitions.
This function was #if 0'd before we released Clutter 1.0 so there's no
implementation of it. At some point we thought it might assist with
developers breaking out into raw OpenGL. Breaking out to raw GL is a
difficult problem though so we decided instead we will wait for a specific
use case to arrise before trying to support it.
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.
_cogl_material_get_layer expects a CoglMaterial* pointer but it was
being called with a CoglHandle. This doesn't matter because the
CoglHandle is actually just the CoglMaterial* pointer anyway but it
breaks the ability to change the _cogl_material_pointer_from_handle
macro.
• Use the same style for the Cogl API reference as the one used for
the Clutter API reference.
• Fix the introspection annotations for cogl_bitmap_get_size_from_file()
The imported Mesa matrix code has some documentation annotations
that make gtk-doc very angry. Since it's all private anyway we
can safely make gtk-doc ignore the offending stuff.
$(COGL_DRIVER)/cogl-defines.h is generated in the configure script so
it ends up in the build directory. Therefore the build rule for
cogl/cogl-defines.h should depend on the file in $(builddir) not
$(srcdir).
The deprecation notices in gtk-doc should also refer to the
release that added the deprecation, and if the deprecated
symbol has been replaced by something else then the new symbol
should be correctly referenced.
The main COGL header cogl.h is currently created at configure time
because it conditionally includes the driver-dependent defines. This
sometimes leads to a stale cogl.h with old definitions which can
break the build until you clean out the whole tree and start from
scratch.
We can generate a stable cogl-defines.h at build time from the
equivalent driver-dependent header and let cogl.h include that
file instead.
_cogl_feature_check expects the array of function names to be
terminated with a NULL pointer but I forgot to add this. This was
causing crashes depending on what happened to be in memory after the
array.
For VBOs, we don't need to check for the extension if the GL version
is greater than 1.5. Non-power-of-two textures are given in 2.0.
We could also assume shader support in GL 2.0 except that the function
names are different from those in the extension so it wouldn't work
well with the current mechanism.
Previously if you need to depend on a new GL feature you had to:
- Add typedefs for all of the functions in cogl-defines.h.in
- Add function pointers for each of the functions in
cogl-context-driver.h
- Add an initializer for the function pointers in
cogl-context-driver.c
- Add a check for the extension and all of the functions in
cogl_features_init. If the extension is available under multiple
names then you have to duplicate the checks.
This is quite tedious and error prone. This patch moves all of the
features and their functions into a list of macro invocations in
cogl-feature-functions.h. The macros can be redefined to implement all
of the above tasks from the same header.
The features are described in a struct with a pointer to a table of
functions. A new function takes the feature description from this
struct and checks for its availability. The feature can take a list of
extension names with a list of alternate namespaces (such as "EXT" or
"ARB"). It can also detect the feature from a particular version of
GL.
The typedefs are now gone and instead the function pointer in the Cogl
context just directly contains the type.
Some of the functions in the context were previously declared with the
'ARB' extension. This has been removed so that now all the functions
have no suffix. This makes more sense when the extension could
potentially be merged into GL core as well.
There is a new internal Cogl function called _cogl_check_driver_valid
which looks at the value of the GL_VERSION string to determine whether
the driver is supported. Clutter now calls this after the stage is
realized. If it fails then the stage is marked as unrealized and a
warning is shown.
_cogl_features_init now also checks the version number before getting
the function pointers for glBlendFuncSeparate and
glBlendEquationSeparate. It is not safe to just check for the presence
of the functions because some drivers may define the function without
fully implementing the spec.
The GLES version of _cogl_check_driver_valid just always returns TRUE
because there are no version requirements yet.
Eventually the function could also check for mandatory extensions if
there were any.
http://bugzilla.openedhand.com/show_bug.cgi?id=1875
We can not process events for a stage that has been destroyed so we
should make sure that the events for the stage are removed from the
global event queue during dispose.
http://bugzilla.openedhand.com/show_bug.cgi?id=1882
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.
When _cogl_add_path_to_stencil_buffer is used to draw a path we don't
need to clear the entire stencil buffer. Instead it can clear just the
bounding box of the path. This adds an extra parameter called
'need_clear' which is only set if the stencil buffer is being used for
clipping.
http://bugzilla.openedhand.com/show_bug.cgi?id=1829
When the text direction changes we should evict the cached layouts
to avoid stale entries in case the direction change produces a layout
with the same size.
Every actor should have a property for retrieving (and setting) the
text direction.
The text direction is used to provide a consisten behaviour in both
left-to-right and right-to-left languages. For instance, ClutterText
should perform key navigation following text direction. Layout
managers should also take into account text direction to derive the
right packing order for their children.
Instead of using PangoDirection directly we should use the
ClutterTextDirection enumeration.
We also need a pair of accessor functions for setting and
getting the default text direction.
This fixes a warning about an uninitialised value. It could also
potentially fix some crashes for example if the enable_flags value
happened to include a bit for enabling a vertex array if no vertex
buffer pointer was set.
While loading a JPEG from disk (with clutter_texture_new_from_file),
I got the following:
<Error>: CGBitmapContextCreate: unsupported parameter combination: 8
integer bits/component; 24 bits/pixel; 3-component colorspace;
kCGImageAlphaNone; 3072 bytes/row.
<Error>: CGContextDrawImage: invalid context
Looking around, I found that CGBitmapContextCreate can't make 24bpp
offscreen pixmaps without an alpha channel...
This fixes the bug, and seems to not break other things...
http://bugzilla.openedhand.com/show_bug.cgi?id=1159
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
Apple where nice and changed API between releases. This patch checks the
version of the compilation environment and tries to use the right parameter
type.
http://bugzilla.openedhand.com/show_bug.cgi?id=1866
In the new Clutter world backend stage implementations should be lightweight
objects implementing the ClutterStageWindow interface and not ClutterActor
subclasses.
This patch performs various cut-n-pastes to acheive that for the OSX backend
http://bugzilla.openedhand.com/show_bug.cgi?id=1864
ClutterBehaviour should implement the Scriptable interface
and parse ClutterAlpha when implicitly defined, instead of
having this ad hoc code inside ClutterScriptParser itself.
After all, only ClutterBehaviour supports Alpha defined
implicitly.
The ClutterScriptParser should do most of the heavy-lifting for
parsing a JSON object member defining another JSON object into
a GObject property defined using a GParamSpecObject.
cogl_clip_push, and cogl_clip_push_window_rect which are now deprecated were
used in various places internally so this just switches to using the
replacement functions.
cogl_clip_push() which accepts a rectangle in model space shouldn't have
been defined to take x,y,width,height arguments because this isn't consistant
with other Cogl API dealing with model space rectangles. If you are using a
coordinate system with the origin at the center and the y+ extending up,
then x,y,width,height isn't as natural as (x0,y0)(x1,y1). This API has
now been replace with cogl_clip_push_rectangle()
(As a general note: the Cogl API should only use the x,y,width,height style
when the appropriate coordinate space is defined by Cogl to have a top left
origin. E.g. window coordinates, or potentially texture coordinates)
cogl_clip_push_window_rect() shouldn't have been defined to take float
arguments since we only clip with integral pixel precision. We also
shouldn't have abbreviated "rectangle". This API has been replaced with
cogl_clip_push_window_rectangle()
cogl_clip_ensure() wasn't documented at all in Clutter 1.0 and probably
no one even knew it existed. This API isn't useful, and so it's now
deprecated. If no one complains we may remove the API altogether for
Clutter 1.2.
cogl_clip_stack_save() and cogl_clip_stack_restore() were originally added
to allow us to save/restore the clip when switching to/from offscreen
rendering. Now that offscreen draw buffers are defined to own their clip
state and the state will be automatically saved and restored this API is now
redundant and so deprecated.
For a long time now the GLES driver for Cogl has supported a fallback
scanline rasterizer for filling paths when no stencil buffer is available,
but now that we build the same cogl-primitives code for GL and GLES I
thought it may sometimes be useful for debugging to force Cogl to use the
scanline rasterizer instead of the current stencil buffer approach.
In order to know if a layout property exists and retrieve its
description in form of a GParamSpec, we need a wrapper API inside
ClutterLayoutManager. This allows introspecting a LayoutManager
sub-class and eventually serialize and deserialize it.
The ClutterScript parser needs to be extended to parse child properties
and apply them after an actor has been added to a container. In order to
distinguish child properties from regular GObject properties we can use
the "child::" prefix, e.g.:
{
"type" : "ClutterRectangle",
"id" : "child-01",
"child::has-focus" : true,
...
}
Parsing child properties can be deferred to the ClutterScriptable
interface, just like regular properties.
These files were practically identical, except the gles code had additional
support for filling paths without a stencil buffer. All the driver code has
now been moved into cogl/cogl-primitives.c
All the ClutterColor parsing rules should be coalesced inside
clutter_script_parse_color(): object, array and string notations
are the canonical ways of defining a ClutterColor inside a
ClutterScript definition. Having a single function in charge of
the parsing cleans up the code.
Currently, ClutterScriptParser will construct the object (using the
construct-only and construct parameters), apply the properties from
the ClutterScript definition, and eventuall will add children and
behaviours.
The construction phase should be more compartimentalized: the objects
should be constructed first and eventual children and behaviours
added. Then, once an object is requested or when the parsing process
has terminated, all the properties should be applied.
This change allows us to set up the actors before setting their
non-construct properties.
ClutterScript is currently a mix of parser-related code and
the ClutterScript object. All the parser-related code should
be moved inside a private class, ClutterScriptParser, inheriting
from JsonParser.
Instead of counting on a JsonNode pointer to survive we should take
a copy. This allows keeping unresolved properties across different
ClutterScript passes.
It's useful when initialzing offscreen draw buffers to be able to ask
Cogl to create a texture of a given size and with the default internal
pixel format.
When rendering to an fbo for supporting clutter_texture_new_from_actor we
render to an fbo with the same size as the source actor, but with a viewport
the same size as the stage. We offset the viewport so when we render the
source actor in its normal transformed stage position it lands on the fbo.
Previously we were rounding the transformed position given as a float by
truncating the fraction (just using a C cast) but that resulted in an
incorrect pixel offset when rendering offscreen depending on the source
position.
We now simply + 0.5 before casting (or -0.5 for negative numbers)
For supporting clutter_texture_new_from_actor(): when updating a
ClutterTexture's fbo we previously set up an offset frustum in the
perspective matrix before rendering source actors to an offscreen draw
buffer so as to give a perspective as if it were being drawn at its
original stage location.
Now that Cogl supports offset viewports there is a simpler way...
When we come to render the source actor to our offscreen draw buffer we
now copy the projection matrix from the stage; we create a viewport
that's also the same size as the stage (though larger than the offscreen
draw buffer) and as before we apply the modelview transformations of
the source actors ancestry before painting it.
The only trick we need now is to offset the viewport according to the
transformed (to screen space) allocation of the source actor (something we
required previously too). We negatively offset the stage sized viewport
such that the smaller offscreen draw buffer is positioned to sit underneath
the source actor in stage coordinates.
To help keep clutter_texture_paint maintainable this splits out a big
chunk of standalone code that's responsible for updating the fbo when
clutter_texture_new_from_actor has been used.
When updating the FBO for a source actor (to support
clutter_texture_new_from_actor()) we used to simply set an offscreen draw
buffer to be current, paint the source actor and then explicitly set the
window to be current again. This precluded chaining texture_new_from_actor
though because updating another FBO associated with a source actor would end
up restoring the window as the current buffer instead of the previous
offscreen buffer. Now that we use Cogl's draw buffer stack; chaining
clutter_texture_new_from_actor() should be possible.
Before we call glViewport we need to convert Cogl viewport coordinates
(where the origin is defined to be top left) to OpenGL coordinates
(where the origin is defined to be bottom left)
We weren't considering that offscreen rendering is always upside down
and in this case Cogl coordinates == OpenGL coordinates.
Firstly this now uses the draw buffer height not the viewport height
when we need to perform a y = height - y conversion, since (as the
name suggests) we are dealing with window coordinates not viewport
coordinates.
Secondly this skips any conversion when the current draw buffer is an
offscreen draw buffer since offscreen rendering is always forced to be
upside down and in this case Cogl window coordinates == GL window
coordinates.
This new API takes advantage of the recently imported Mesa code to support
inverse matrix calculation. The matrix code keeps track (via internal
flags) of the transformations a matrix represents so that it can select an
optimized inversion function.
Note: although other aspects of the Cogl matrix API have followed a similar
style to Cairo's matrix API we haven't added a cogl_matrix_invert API
because the inverse of a CoglMatrix is actually cached as part of the
CoglMatrix structure meaning a destructive API like cogl_matrix_invert
doesn't let users take advantage of this caching design.
This adds a COGL_DEBUG=matrices debug option that can be used to trace all
matrix manipulation done using the Cogl API. This can be handy when you
break something in such a way that a trace is still comparable with a
previous working version since you can simply diff a log of the broken
version vs the working version to home in on the bug.
This pulls in code from Mesa to improve our matrix manipulation support. It
includes support for calculating the inverse of matrices based on top of a
matrix categorizing system that allows optimizing certain matrix types.
(the main thing we were after) but also adds some optimisations for
rotations.
Changes compared to the original code from Mesa:
- Coding style is consistent with the rest of Cogl
- Instead of allocating matrix->m and matrix->inv using malloc, our public
CoglMatrix typedef is large enough to directly contain the matrix, its
inverse, a type and a set of flags.
- Instead of having a _math_matrix_analyse which updates the type, flags and
inverse, we have _math_matrix_update_inverse which essentially does the
same thing (internally making use of _math_matrix_update_type_and_flags())
but with additional guards in place to bail out when the inverse matrix is
still valid.
- When initializing a matrix with the identity matrix we don't immediately
initialize the inverse matrix; rather we just set the dirty flag for the
inverse (since it's likely the user won't request the inverse of the
identity matrix)
Because Cogl defines the origin for texture as top left and offscreen draw
buffers can be used to render to textures, we (internally) force all
offscreen rendering to be upside down. (because OpenGL defines the origin
to be bottom left)
By forcing the users scene to be rendered upside down though we also reverse
the winding order of all the drawn triangles which may interfere with the
users use of backface culling. This patch ensures that we reverse the
winding order for a front face (if culling is in use) while rendering
offscreen so we don't conflict with the users back face culling.
The debugging function read_pixels_to_file() and _clutter_do_pick were both
directly calling glReadPixels, but we don't wan't Clutter making direct
OpenGL calls and Cogl provides a suitable alternative. It also means
read_pixels_to_file() doesn't need to manually flip the data read due to
differences in Clutter/Cogl coordinate systems.
Technically this change shouldn't make a difference since we are
calling glReadPixels with GL_RGBA GL_UNSIGNED_BYTE which is a 4
byte format and it should always result in the same value according
to how OpenGL calculates the location of sequential rows.
i.e. k = a/s * ceil(snl/a) where:
a = alignment
s = component size (1)
n = number of components per pixel (4)
l = number of pixels in a row
gives:
k = 4/1 * ceil(4l/4) and k = 1/1 * ceil(4l/1) which are equivalent
I'm changing it because I've seen i915 driver code that bails out of
hardware accelerated paths if the alignment isn't 1, and because
conceptually we have no alignment constraints here so even if the current
value has no effect, when we start reading back other formats it may upset
things.
We were previously calling cogl_flush() after setting up the glPixelStore
state for calling glReadPixels, but flushing the journal could itself
change the glPixelStore state.
Since offscreen rendering is forced to be upside down we don't need to do
any conversion of the users coordinates to go from Cogl window coordinates
to OpenGL window coordinates.
Since we do all offscreen rendering upside down (so that we can have the
origin for texture coordinates be the top left of textures for the cases
where offscreen draw buffers are bound to textures) we don't need to flip
data read back from an offscreen framebuffer before we we return it to the
user.
I was originally expecting the code not to handle offset viewports or
viewports with a different size to the framebuffer, but it turns out the
code worked fine. In the process though I think I made the code slightly
more readable.
cogl_viewport only accepted a viewport width and height, but there are times
when it's also desireable to have a viewport offset so that a scene can be
translated after projection but before hitting the framebuffer.
Because Cogl defines the origin of viewport and window coordinates to be
top-left it always needs to know the size of the current window so that Cogl
window/viewport coordinates can be transformed into OpenGL coordinates.
This also fixes cogl_read_pixels to use the current draw buffer height
instead of the viewport height to determine the OpenGL y coordinate to use
for glReadPixels.
First a few notes about Cogl coordinate systems:
- Cogl defines the window origin, viewport origin and texture coordinates
origin to be top left unlike OpenGL which defines them as bottom left.
- Cogl defines the modelview and projection identity matrices in exactly the
same way as OpenGL.
- I.e. we believe that for 2D centric constructs: windows/framebuffers,
viewports and textures developers are more used to dealing with a top left
origin, but when modeling objects in 3D; an origin at the center with y
going up is quite natural.
The way Cogl handles textures is by uploading data upside down in OpenGL
terms so that bottom left becomes top left. (Note: This also has the
benefit that we don't need to flip the data we get from image decoding
libraries since they typically also consider top left to be the image
origin.)
The viewport and window coords are mostly handled with various y =
height - y tweaks before we pass y coordinates to OpenGL.
Generally speaking though the handling of coordinate spaces in Cogl is a bit
fragile. I guess partly because none of it was design to be, it just
evolved from how Clutter defines its coordinates without much consideration
or testing. I hope to improve this over a number of commits; starting here.
This commit deals with the fact that offscreen draw buffers may be bound to
textures but we don't "upload" the texture data upside down, and so if you
texture from an offscreen draw buffer you need to manually flip the texture
coordinates to get it the right way around. We now force offscreen
rendering to be flipped upside down by tweaking the projection matrix right
before we submit it to OpenGL to scale y by -1. The tweak is entirely
hidden from the user such that if you call cogl_get_projection you will not
see this scale.
We were ignoring the possibility that the current modelview matrix may flip
the incoming rectangle in which case we didn't calculate a valid scissor
rectangle for clipping.
This fixes: http://bugzilla.o-hand.com/show_bug.cgi?id=1809
(Clipping doesn't work within an FBO)
Cogl's support for offscreen rendering was originally written just to support
the clutter_texture_new_from_actor API and due to lack of documentation and
several confusing - non orthogonal - side effects of using the API it wasn't
really possible to use directly.
This commit does a number of things:
- It removes {gl,gles}/cogl-fbo.{c,h} and adds shared cogl-draw-buffer.{c,h}
files instead which should be easier to maintain.
- internally CoglFbo objects are now called CoglDrawBuffers. A
CoglDrawBuffer is an abstract base class that is inherited from to
implement CoglOnscreen and CoglOffscreen draw buffers. CoglOffscreen draw
buffers will initially be used to support the
cogl_offscreen_new_to_texture API, and CoglOnscreen draw buffers will
start to be used internally to represent windows as we aim to migrate some
of Clutter's backend code to Cogl.
- It makes draw buffer objects the owners of the following state:
- viewport
- projection matrix stack
- modelview matrix stack
- clip state
(This means when you switch between draw buffers you will automatically be
switching to their associated viewport, matrix and clip state)
Aside from hopefully making cogl_offscreen_new_to_texture be more useful
short term by having simpler and well defined semantics for
cogl_set_draw_buffer, as mentioned above this is the first step for a couple
of other things:
- Its a step toward moving ownership for windows down from Clutter backends
into Cogl, by (internally at least) introducing the CoglOnscreen draw
buffer. Note: the plan is that cogl_set_draw_buffer will accept on or
offscreen draw buffer handles, and the "target" argument will become
redundant since we will instead query the type of the given draw buffer
handle.
- Because we have a common type for on and offscreen framebuffers we can
provide a unified API for framebuffer management. Things like:
- blitting between buffers
- managing ancillary buffers (e.g. attaching depth and stencil buffers)
- size requisition
- clearing
This ensures that glViewport is called before the first stage paint.
Previously _clutter_stage_maybe_setup_viewport (which is done before we
start painting) was bailing out without calling cogl_setup_viewport because
the CLUTTER_STAGE_IN_RESIZE flag may be set if the stage was resized before
the first paint. (NB: The CLUTTER_STAGE_IN_RESIZE flag isn't removed until
we get an explicit event back from the X server since the window manager may
choose to deny/alter the resize.)
We now special case the first resize - where the viewport hasn't previously
been initialized and use the requested geometry to initialize the
glViewport without waiting for a reply from the server.
Over time the two cogl-fbo.c files have needlessly diverged as bug fixes or
cleanups went into one version but not the other. This tries to bring them
back in line with each other. It should actually be simple enough to move
cogl-fbo.c to be a common file, and simply not build it for GLES 1.1, so
maybe I'll follow up with such a patch soon.
The comment just said: "Some implementation require a clear before drawing
to an fbo. Luckily it is affected by scissor test." and did a scissored
clear, which is clearly a driver bug workaround, but for what driver? The
fact that it was copied into the gles backend (or vica versa is also
suspicious since it seems unlikely that the workaround is necessary for both
backends.)
We can easily restore the workaround with a better comment if this problem
really still exists on current drivers, but for now I'd rather minimize
hand-wavey workaround code that can't be tested.
Just like CLUTTER_CHECK_VERSION does version checking at compile
time, we need a way to verify the version of the library that we
are linking against. This is mostly needed for language bindings
and for run-time loadable modules -- when we'll get those.
Otherwise you can't use the alpha channel of the vertex colors unless
the material has a texture with alpha or the material's color has
alpha less than 255.
Apparently, on 64bit systems the floating point noise is enough
to screw up the float-to-int truncation.
The solution is to round up by 0.5 and then use floorf(). This
gives predictable and correct results on both 32bit and 64bit
systems.
When calling remove_child_meta() we check if there is a LayoutMeta
already attached to the Actor, and if that LayoutMeta matches the
(manager, container, actor) tuple. If the LayoutMeta does not match,
though, we create a new LayoutMeta instance -- in order to remove it
right afterwards.
Instead of doing this, we can simply check for a matching LayoutMeta
and if present, remove it.
In case of an existing, non-matching LayoutMeta, we're left with a
dangling instance, but it does not matter: the removal happens in the
unparenting phase of a ClutterContainer, so either the Actor will be
destroyed and thus the LayoutMeta will be disposed along with it; or
it will be parented to another container, and thus the LayoutMeta
will be replaced.
A ClutterBox might not have a ClutterLayoutManager instance
associated -- for instance, during destruction. We should check
for one before calling methods on it.
When cogl_texture_new_from_data() fails in clutter_texture_set_from_data()
and no GError is provided, the clutter app will segfault when dereferencing
the GError ** and emitting LOAD_FINISHED signal.
Based on a patch by: Haakon Sporsheim <haakon.sporsheim@gmail.com>
http://bugzilla.openedhand.com/show_bug.cgi?id=1806
Some changes to make COGL pass distcheck with Automake 1.11 and
anal-retentiveness turned up to 11.
The "major" change is the flattening of the winsys/ part of COGL,
which is built directly inside libclutter-cogl.la instead of an
intermediate libclutter-cogl-winsys.la object.
Ideally, the whole COGL should be flattened out using a
quasi-non-recursive Automake layout; unfortunately, the driver/
sub-section ships with identical targets and Automake cannot
distinguish GL and GLES objects.
If an actor calls directly or indirectly clutter_actor_queue_relayout()
on itself from within the allocate() implementation it will cause a
relayout cycle. This is usually a condition that should be checked by
ClutterActor and we should emit a warning if it is verified.
ClutterActor should check whether the current instance is being
destroyed and avoid performing operations like:
• queueing redraws
• queueing relayouts
It should also warn if the actor is being parented to an actor
currently being destroyed.
When showing a warning in the state checks we perform to verify that
the invariants are maintained when showing, mapping and realizing, we
should also print out the name of the actor failing the checks. If the
actor has no name, the GType name should be used as a fallback.
When defining an Alpha in ClutterScript we should allow setting
the alpha function by using a custom property. This makes it
possible to have both:
{
"id" : "behaviour-1",
"type" : "ClutterBehaviourDepth",
"alpha" : { "timeline" : "timeline-1", "function" : "alpha_func" },
...
}
And:
{
"id" : "alpha-1",
"type" : "ClutterAlpha",
"timeline" : "timeline-1",
"function" : "alpha_func"
},
{
"id" : "behaviour-1",
"type" : "ClutterBehaviourDepth",
"alpha" : "alpha-1",
...
}
The latter allows defining a single alpha function for multiple
behaviours.
The block that allows setting a GObject property holding an object
instance is conditionally depending on the USE_PIXBUF define. This
makes it impossible to reference an object inside ClutterScript on
platforms not using GdkPixbuf.
When an actor is hidden, the parent actor is not required to
size request or allocate it. (ClutterGroup does, but, for example,
NbtkBoxLayout doesn't.) This means that the
needs_width_request/needs_height_request/needs_allocate can be
stale when we go to show it again - they are set for the actor
but not the parent. Explicitly setting them to FALSE avoids
clutter_actor_relayout() improperly short-circuiting.
http://bugzilla.openedhand.com/show_bug.cgi?id=1831
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
The change in commit 3bbc96e17e moved the
:text property setter to use set_text_internal(); this function does not
invalidate the Layout cache and does not queue a relayout, thus breaking
the behaviour of ClutterText when setting the contents of the actor using
the property.
http://bugzilla.openedhand.com/show_bug.cgi?id=1851
Since we no longer depend on the GL matrix API in Cogl we can remove a lot
of wrapper code from the GLES 2 backend. This is particularly nice given
that there was no code shared between the cogl-matrix-stack API and gles2
wrappers so we had a lot of duplicated logic.
The indirection through this API isn't necessary since we no longer
arbitrate between the OpenGL matrix API and Cogl's client side API. Also it
doesn't help to maintain an OpenGL style matrix mode API for internal use
since it's awkward to keep restoring the MODELVIEW mode and easy enough to
directly work with the matrix stacks of interest.
This replaces use of the _cogl_current_matrix API with direct use of the
_cogl_matrix_stack API. All the unused cogl_current_matrix API is removed
and the matrix utility code left in cogl-current-matrix.c was moved to
cogl.c.
This cache of the gl matrix mode lets us avoid repeat calls to glMatrixMode
in _cogl_matrix_stack_flush_to_gl when we have lots of sequential modelview
matrix modifications.
This goes a bit further than the previous patch, and as a special case
we now simply represent identity matrices using a boolean, and only
lazily initialize them when they need to be modified.
The journal always uses an identity matrix since it uses software
transformation. Currently it manually uses glLoadMatrix since previous
experimentation showed that the cogl-matrix-stack gave bad performance, but
it would be nice to fix performance so we only have to care about one path
for loading matrices.
For the common case where we do:
cogl_matrix_stack_push()
cogl_matrix_stack_load_identity()
we were effectively initializing the matrix 3 times. Once due to use of
g_slice_new0, then we had a cogl_matrix_init_identity in
_cogl_matrix_state_new for good measure, and then finally in
cogl_matrix_stack_load_identity we did another cogl_matrix_init_identity.
We don't use g_slice_new0 anymore, _cogl_matrix_state_new is documented as
not initializing the matrix (instead _cogl_matrix_stack_top_mutable now
takes a boolean to choose if new stack entries should be initialised) and so
we now only initialize once in cogl_matrix_stack_load_identity.
This relates back to an earlier commitment to stop using the OpenGL matrix
API which is considered deprecated. (ref 54159f5a1d)
The new texture matrix stacks are hung from a list of (internal only)
CoglTextureUnit structures which the CoglMaterial code internally references
via _cogl_get_texure_unit ().
So we would be left with only the cogl-matrix-stack code being responsible
for glMatrixMode, glLoadMatrix and glLoadIdentity this commit updates the
journal code so it now uses the matrix-stack API instead of GL directly.
• Fix list_stages() and peek_stages() documentation
• Fix clutter_text_set_preedit_string() arguments in the header
to match source and documentation
• Add clutter_units_cm() to the private section for Units
• Rename the LayoutManager section
• Add FlowLayout:homogeneous accessors
* layout-manager: (50 commits)
docs: Reword a link
layout, docs: Add more documentation to LayoutManager
layout, docs: Fix description of Bin properties
layout, bin: Use ceilf() instead of casting to int
layout, docs: Add long description for FlowLayout
layout, box: Clean up
layout, box: Write long description for Box
layout, docs: Remove unused functions
layout: Document BoxLayout
layout: Add BoxLayout, a single line layout manager
layout: Report the correct size of FlowLayout
layout: Resizing the stage resizes the FlowLayout box
layout: Use the get_request_mode() getter in BinLayout
layout: Change the request-mode along with the orientation
actor: Add set_request_mode() method
[layout] Remove FlowLayout:wrap
[layout] Rename BinLayout and FlowLayout interactive tests
[layout] Skip invisible children in FlowLayout
[layout] Clean up and document FlowLayout
[layout] Snap children of FlowLayout to column/row
...
The layout manager reference should have some documentation on how
to use a LayoutManager object inside a container and how to implement
a LayoutManager sub-class correctly.
The JSON conditional rules can be moved outside the introspection
conditional ones to avoid a nested check, as all the JSON rules do
is setting up variables that may or may not be used.
The Journal can be considered a standalone component, so even though
it's currently only used to log quads, it seems better to split it
out into its own file.
When we implement atlas textures we will probably want to use the spans API
to handle texture repeating so it doesn't make sense to leave the code in
cogl-texture-2d-sliced.c. Since it's a standalone set of data structures
and algorithms it also seems reasonable to split out from cogl-texture.
cogl-texture-2d-sliced provides an implementation of CoglTexture and this
seperation lays the foundation for potentially supporting atlas textures,
pixmap textures (as in GLX_EXT_texture_from_pixmap) and fast-path
GL_TEXTURE_{1D,2D,3D,RECTANGLE} textures in a maintainable fashion.
cogl-primitives.c was previously digging right into CoglTextures so it could
manually iterate the texture slices for texturing quads and polygons and
because we were missing some state getters we were lazily just poking into
the structures directly.
This adds some extra state getter functions, and adds a higher level
_cogl_texture_foreach_slice () API that hopefully simplifies the way in
which sliced textures may be used to render primitives. This lets you
specify a rectangle in "virtual" texture coords and it will call a given
callback for each slice that intersects that rectangle giving the virtual
coords of the current slice and corresponding "real" texture coordinates for
the underlying gl texture.
At the same time a noteable bug in how we previously iterated sliced
textures was fixed, whereby we weren't correctly handling inverted texture
coordinates. E.g. with the previous code if you supplied texture coords of
tx1=100,ty1=0,tx2=0,ty2=100 (inverted along y axis) that would result in a
back-facing quad, which could be discarded if using back-face culling.
The descriptions for gl_handle and gl_target were inverted.
Thanks to Young-Ho Cha for spotting that.
Signed-off-by: Robert Bragg <robert@linux.intel.com>
As part of an incremental process to have Cogl be a standalone project we
want to re-consider how we organise the Cogl source code.
Currently this is the structure I'm aiming for:
cogl/
cogl/
<put common source here>
winsys/
cogl-glx.c
cogl-wgl.c
driver/
gl/
gles/
os/ ?
utils/
cogl-fixed
cogl-matrix-stack?
cogl-journal?
cogl-primitives?
pango/
The new winsys component is a starting point for migrating window system
code (i.e. x11,glx,wgl,osx,egl etc) from Clutter to Cogl.
The utils/ and pango/ directories aren't added by this commit, but they are
noted because I plan to add them soon.
Overview of the planned structure:
* The winsys/ API is the API that binds OpenGL to a specific window system,
be that X11 or win32 etc. Example are glx, wgl and egl. Much of the logic
under clutter/{glx,osx,win32 etc} should migrate here.
* Note there is also the idea of a winsys-base that may represent a window
system for which there are multiple winsys APIs. An example of this is
x11, since glx and egl may both be used with x11. (currently only Clutter
has the idea of a winsys-base)
* The driver/ represents a specific varient of OpenGL. Currently we have "gl"
representing OpenGL 1.4-2.1 (mostly fixed function) and "gles" representing
GLES 1.1 (fixed funciton) and 2.0 (fully shader based)
* Everything under cogl/ should fundamentally be supporting access to the
GPU. Essentially Cogl's most basic requirement is to provide a nice GPU
Graphics API and drawing a line between this and the utility functionality
we add to support Clutter should help keep this lean and maintainable.
* Code under utils/ as suggested builds on cogl/ adding more convenient
APIs or mechanism to optimize special cases. Broadly speaking you can
compare cogl/ to OpenGL and utils/ to GLU.
* clutter/pango will be moved to clutter/cogl/pango
How some of the internal configure.ac/pkg-config terminology has changed:
backendextra -> CLUTTER_WINSYS_BASE # e.g. "x11"
backendextralib -> CLUTTER_WINSYS_BASE_LIB # e.g. "x11/libclutter-x11.la"
clutterbackend -> {CLUTTER,COGL}_WINSYS # e.g. "glx"
CLUTTER_FLAVOUR -> {CLUTTER,COGL}_WINSYS
clutterbackendlib -> CLUTTER_WINSYS_LIB
CLUTTER_COGL -> COGL_DRIVER # e.g. "gl"
Note: The CLUTTER_FLAVOUR and CLUTTER_COGL defines are kept for apps
As the first thing to take advantage of the new winsys component in Cogl;
cogl_get_proc_address() has been moved from cogl/{gl,gles}/cogl.c into
cogl/common/cogl.c and this common implementation first trys
_cogl_winsys_get_proc_address() but if that fails then it falls back to
gmodule.
This moves most of cogl-context.{c.h} to cogl/common with some driver
specific members now living in a CoglContextDriver struct. Driver specific
context initialization and typedefs now live in
cogl/{gl,gles}/cogl-context-driver.{c,h}
Driver specific members can be found under ctx->drv.stuff
This splits the limited components that differed between
cogl/{gl,gles}/cogl-texture.c into new {gl,gles}/cogl-texture-driver.c files
and the rest that can now be shared into cogl/common/cogl-texture.c
Most of clutter_stage_egl_realize was renamed to
_clutter_stage_egl_try_realize which now takes a cookie indicating which
fallback number should tried next. clutter_stage_egl_realize now keeps
trying to realize with successive fallback numbers until it succeeds or runs
out of fallbacks.
The only fallback supported for now is for hardware with no stencil buffer
support.
This replaces calls to the old (glx 1.2) functions glXChooseVisual,
glXCreateContext, glXMakeCurrent with the 1.3+ fbconfig varients
glXChooseFBConfig, glXCreateNewContext, glXMakeContextCurrent.
The only backend that tried to implement offscreen stages was the GLX backend
and even this has apparently be broken for some time without anyone noticing.
The property still remains and since the property already clearly states that
it may not work I don't expect anyone to notice.
This simplifies quite a bit of the GLX code which is very desireable from the
POV that we want to start migrating window system code down to Cogl and the
simpler the code is the more straight forward this work will be.
In the future when Cogl has a nicely designed API for framebuffer objects then
re-implementing offscreen stages cleanly for *all* backends should be quite
straightforward.
for the marshal files $(srcdir) was getting prefixed twice since my last
commit (2cc88f1140) since it was already being prefixed including
Makefile.am. The problem with prefixing it in the includer file though is
that the Make variable substitutions like :.list=.h mean we end up
generating into the $(srcdir). This removes the prefix added in
clutter/Makefile.am
We were also missing a $(srcdir) prefix when setting EXTRA_DIST
When validating a new GValue against the ClutterParamSpecUnits, we issue
a warning when the units do not match with both the new value and the
unit we expect to have. Unfortunately we were printing the unit of the
new value twice and not the unit of the ParamSpec.
http://bugzilla.openedhand.com/show_bug.cgi?id=1846
This is really useful when trying to animate GTypes that haven't
registered any progress function. Instead of silently not working it
will warn the developer.
http://bugzilla.openedhand.com/show_bug.cgi?id=1845
To be able to animate CLUTTER_TYPE_UNITS properties we need to register
the GType and its progress function against the ClutterInterval code.
The two ClutterUnits defining the interval can use different units, the
resulting unit will always be in pixels, so calculating a progress
between 10px and 4cm is valid.
http://bugzilla.openedhand.com/show_bug.cgi?id=1844
When computing the pixels value of a ClutterUnits value we should
be caching the value to avoid recomputing for every call of
clutter_units_to_pixels(). We already have a flag telling us to
return the cached value, but we miss the mechanism to evict the
cache whenever the Backend settings affecting the conversion, that
is default font and resolution, change.
In order to implement the eviction we can use a "serial"; the
Backend will have an internal serial field which we retrieve and
put inside the ClutterUnits structure (we split one of the two
64 bit padding fields into two 32 bit fields to maintain ABI); every
time we call clutter_units_to_pixels() we compare the units serial
with that of the Backend; if they match and pixels_set is set to
TRUE then we just return the stored pixels value. If the serials
do not match then we unset the pixels_set flag and recompute the
pixels value.
We can verify this by adding a simple test unit checking that
by changing the resolution of ClutterBackend we get different
pixel values for 1 em.
http://bugzilla.openedhand.com/show_bug.cgi?id=1843
Input Methods require to be able to set a "pre-edit string", that is
a string that it's just displayed into the Text actor without being
committed to the actor's buffer. The string might require custom Pango
attributes, and an update of the cursor position.
Casting a float to int to truncate it before assigning the value
to a float again is wrong. We should use ceilf() instead which
does what we want to achieve (rounding up the size to avoid
sub-pixel positioning of children).
* Use g_list_foreach() instead of iterating over the list inside
the destruction sequence, since we are causing the widgets to be
implicitly removed from the list via the destroy() call.
* Use g_signal_connect_swapped() and spare us from a callback.
FlowLayout should compute the correct height for the assigned width when
in horizontal flow, and the correct width for the assigned height when
in vertical flow. This means pre-computing the number of lines inside
the get_preferred_width() and get_preferred_height(). We can then cache
the computed column width and row height, cache them inside the layout
and then use them when allocating the children.
When changing the orientation of a FlowLayout, the associated
container should also change its request mode. A horizontally
flowing layout has a height depending on the width, since it
will reflow vertically; similarly, a vertically reflowing layout
will have a width depending on the height.
The :wrap property is not implemented, and mostly useless: the
FlowLayout is a reflowing grid. This means that if it receives
less than the preferred width or height in the flow direction
then it should always reflow.
Use the column and row size to align each child; with :homogeneous
set to TRUE, or with children with the same size, the FlowLayout
will behave like a reflowing grid.
FlowLayout is a layout manager that arranges its children in a
reflowing line; the orientation controls the major axis for the
layout: horizontal, for reflow on the Y axis, and vertical, for
reflow on the X axis.
The BinLayout should store a pointer to the Container that it is
using it as the layout manager.
This allows us to fix the API and drop the additional Container
arguments from set_alignment() and get_alignment().
This also allows us to add a ClutterBinLayout::add() method which
adds an actor and sets the alignment policies without dealing with
variadic arguments functions and GValue (de)marshalling.
Use the LayoutManager API to set a back pointer to the Box actor
inside the LayoutManager used by the box.
This also allows us to replace the LayoutManager on a Box, since
the LayoutManager will be able to replace all the metadata if
needed.
The LayoutManager implementation might opt to take a back pointer
to the Container that is using the layout instance; this allows
direct access to the container itself from within the implementation.
The ClutterBox::add method is a simple wrapper around the Container
add_actor() method and the LayoutManager layout properties API. It
allows adding an actor to a Box and setting the layout properties in
one call.
If the LayoutManager used by the Box does not support layout properties
then the add() method short-circuits out.
Along with the varargs version of the method there's also a vector-based
variant, for language bindings to use.
Instead of overloading ClutterChildMeta with both container and layout
metadata and delegate to every LayoutManager implementation to keep a
backpointer to the layout manager instance, we can simply subclass
ChildMeta into LayoutMeta and presto! everything works out pretty well
for everyone.
Each actor managed by a BinLayout policy should reside inside its
own "layer", with horizontal and vertical alignment. The :x-align
and :y-align properties of the BinLayout are the default alignment
policies, which are copied to each new "layer" when it is created.
The set_alignment() and get_alignment() methods of BinLayout can
be changed to operate on a specific "layer".
The whole machinery uses the new ChildMeta support inside the
LayoutManager base abstract class.
The ChildMeta object is a storage for child-container properties,
that is properties that exist only when an actor is inside a specific
container. The LayoutManager delegate class should also have
layout-specific properties -- so, for this job, we can "recycle"
ChildMeta as the storage.
Emit the ::layout-changed when the BinLayout alignment policies change.
This will result in a queue_relayout() on the containers using the
BinLayout layout manager.
* Use ::layout-changed to queue a relayout when the layout changes
* Destroy the Box children when destroying the Box
* Allow getting the layout manager from the Box
