High level toolkits might wish to construct a PangoFontDescription and
then set it directly on a ClutterText actor proxy or sub-class.
ClutterText should have a :font-description property to set (and get)
the PangoFontDescription.
http://bugzilla.openedhand.com/show_bug.cgi?id=1960
Commit 92a375ab4 changed the initial value of max_texcoord_attrib_unit
to -1 so that it could disable the texture coord array for the first
texture unit when there are no texture coords used in the vbo. However
max_texcoord_attrib_unit was an unsigned value so this actually became
G_MAXUINT. The disabling loop at the bottom still worked because
G_MAXUINT+1==0 but the check for whether any texture unit is greater
than max_texcoord_attrib_unit was failing so it would always end up
disabling all texture units. This is now fixed by changing
max_texcoord_attrib_unit to be signed.
The commit ecbb7ce41a exposed some issues
when positioning the cursor with the mouse pointer: the selection is
not moved along with the cursor when inserting a single character or a
string.
Also, some freeze_notify() are called too early, leading to decoupling
from their respective thaw_notify().
http://bugzilla.openedhand.com/show_bug.cgi?id=1955
The documentation for ClutterGroup behaviour when setting an explicit
size is not accurate - or, actually, it was accurate by the time
ClutterGroup was first written but has been neglected in the following
release cycles.
To avoid confusion for new users of Clutter the documentation should be
slightly expanded, mentioning the exact semantics of ClutterGroup with
regards to: preferred size, explicitly set size and how to constrain the
visible area of a ClutterGroup to an explicitly set size.
Based on a patch by: Neil Roberts <neil@linux.intel.com>
When we disable the per-actor events delivery Clutter replicates the X11
implicit soft grab for motion events with off-stage. The implicit grab
is done whenever the pointer of a device leaves a window with a button
still pressed; with the implicit grab in place the window still receives
motion events even after the LeaveNotify - until the button is released.
The implicit grab is not honoured in the per-actor event deliver case,
though, so we have a mismatch between two in theory equivalent cases.
Luckily, the fix is pretty trivial: when we check for a motion event
with a stage set but without an actor set, and that has off-stage
coordinates, we arbitrarily set the source to be the stage of the event
and emit the pointer event.
When deciding if a material layer is equal it now compares the GL
target and texture number if the textures are not sliced. This is
needed to get batching across atlased textures.
Cogl accepts a pixel format for both the data in memory and the
internal format to be used for the texture. If they do not match then
it would convert them using the CoglBitmap functions before uploading
the data. However, GL also lets you specify both formats so it makes
more sense to let GL do the conversion. The driver may need the
texture in a specific format so it may end up being converted anyway.
The cogl_texture_upload_data functions have been removed and replaced
with a single function to prepare the bitmap. This will only do the
premultiplication conversion because that is the only part that GL
can't do directly.
The premult part of _cogl_convert_premult has now been split out as
_cogl_convert_premult_status. _cogl_convert_premult has been renamed
to _cogl_convert_format to make it less confusing. The premult
conversion is now done in-place instead of copying the
buffer. Previously it was copying the buffer once for the format
conversion and then copying it again for the premult conversion. The
premult conversion never changes the size of the buffer so it's quite
easy to do in place. We can also use the separated out function
independently.
The internal format of the atlas texture is still set to the
appropriate format so Cogl will disable blending for textures that are
intended to be RGB. This should end up ignoring the alpha channel from
the texture in the atlas. This makes the code slightly easier to
maintain and should also improve the chances of batching.
Since we're allowing allocation cycles saying that calling
queue_relayout() inside an allocation cycle "is not allowed" is kind of
confusing. We should say that "it is not recommended".
* device-manager: (37 commits)
x11: Re-enable XI1 extension keyboards
x11: Always handle core device events before XI events
docs: Documentation fixes for DeviceManager
device-manager: Fix the signals definition
docs: Add sections for InputDevice and DeviceManager
docs: Add clutter_input_device_get_device_name()
tests: Print out the device details on motion
Always register core devices
device: Remove unused is_default member
win32: Experimental implementation of device support
tests: Print the device name, as well as its Id
x11: Fill out the :name property of the InputDevices
device: Add the :name property to InputDevice
x11: Store core devices on the X11 Backend singleton
device: Unset the cursor actor when leaving the stage
device: Add pointer actor getter
x11: Discard the LeaveNotify for off-stage ButtonRelease
device: Do not overwrite the stage for an InputDevice
event: Off-stage button releases have a click count of 1
event: Scroll events do not have click count
...
Added a "selection-bound" notify on clutter_text_clear_selection as it
changes the value.
Added utility function clutter_text_set_positions, in order to
change both cursor position and selection bound inside a
g_object_[freeze/thaw]_notify block
Added g_object_[freeze/thaw]_notify in other functions that changes
both cursor position and selection bound
Solves http://bugzilla.openedhand.com/show_bug.cgi?id=1955
ClutterStage has both set_key_focus() and get_key_focus() methods, but
there is no :key-focus property. This means that it is not possible to
get notifications when the key-focus has changes except by connecting to
both the ::key-focus-in and ::key-focus-out signals and do additional
bookkeeping.
http://bugzilla.openedhand.com/show_bug.cgi?id=1956
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
The TimeoutPool is not used by ClutterTimeline any more, so we need to
remove a sentence from its description. We also need to fix the gtk-doc
syntax errors.
Instead of assigning a new colour to each quad of a batch, the
rectangle debugging code now assigns a new colour to each batch so
that it can be used to visually see what is being batched. The colour
is stored in a global variable that is reset during cogl_clear. This
improves the chances that the same colour will be used for a batch in
the next frames to avoid flickering.
When setting up the state for the vertex buffer,
enable_state_for_drawing_buffer tries to keep track of the highest
numbered texture unit in use. It then disables any texture arrays for
units that were previously enabled if they are greater than that
number. However if there is no texturing in the VBO then the max used
unit would be left at 0 which it would later think meant unit 0 is
still in use so it wouldn't disable it. To fix this it now initialises
the max used unit to -1 which it should interpret as ‘no units are in
use’ so it will later disable the arrays for all units.
Thanks to Jon Mayo for reporting the bug.
http://bugzilla.openedhand.com/show_bug.cgi?id=1957
We were checking the number of texture units against the GL enum that is
used in glGetInteger() to query that number. Let's abstract this in a
little function.
Took the opportunity to dig a bit on the usage of GL limits for the
number of texture (image) units and document our use of them. We'll need
something finer grained if we want to fully exploit texture image units
with a programmable pipeline.
The index field of CoglTextureUnit was never set, leading to the
creation of units with index set to 0. When trying to retrieve a texture
unit by its index (!= 0) with _cogl_get_texture_unit(), a new one was
created as it could not find it back in the list of textures units:
ctx->texture_units.
http://bugzilla.openedhand.com/show_bug.cgi?id=1958
The :opacity property is defined using a GParamSpecUchar. This usually
leads to issues with language bindings that don't have an 'unsigned
char' type and that need to explicitly handle the conversion between
G_TYPE_UCHAR and G_TYPE_INT or G_TYPE_UINT.
The property definition already specifies an interval size of [0, 255]
on the values; more importantly, GObject already implicitly transforms
between G_TYPE_UCHAR and G_TYPE_UINT (the GValue transformation
functions are registered at type system initialization time) so
switching between a GParamSpecUchar and a GParamSpecUint should not be
an ABI break.
I have tested a simple program using the opacity property before and
after the change and I cannot see any run-time warnings related to this
issue.
Be more drastic if the internal state is broken, and assert() if the
expected Alpha and Timeline instances we need are not valid. This
usually implies a library bug or a massive heap corruption.
The Animation code does transformation of values between type A and A'
after checking for compatibility using g_value_type_compatible(). This
is incorrect: compatibility means that the two types can be copied. The
correct conversion should follow:
if (compatible (type (A), type (A')))
copy (A, A');
else
if (transformable (type (A), type (A')))
transform (A, A');
else
error("Unable to trasform type A in A'");
The transformation might still fail, so we need to check for errors
there as well as a fall-through case.
We should not just check for compatibility, but also for the ability to
transform a GValue of type A into another of type A'.
Usually compatibility is enough, especially if types can be
introspected beforehand; some times, though, we also need to check for
transformability as a type can provide the transformation functions
necessary for the operation.
The commit 1c69c61745 which improved the
protection against timeline removals during the master clock advancement
was only doing half the job - and actually broke the chaining of
animations inside the ::completed signal.
We cannot simply take a reference on the timelines and still use the list
held by the master clock because the do_tick() might result in the
creation of a new timeline, which gets added at the end of the list with
no reference increase and thus gets disposed at the end of the iteration.
We also cannot steal the master clock timelines list because a timeline
might be removed as the direct result of do_tick() and remove_timeline()
would not find the timeline, failing and leaving a dangling pointer
behind.
For this reason we copy the list of timelines out of the one that the
Master Clock holds, take a reference on each timeline, advance them all,
release the reference and free the list.
The extension keyboard support in XInput 1.x is hopelessly broken.
Nevertheless, it's possible to use some bits of it, as we prefer the
core keyboard events to the XInput events, thus at least having proper
handling for X11 key events on the Stage window.
The XI 1.0 layer is complementary to the X11 core devices handling; this
means that core events will still be emitted for the core pointer and
keyboard devices, and that secondary (floating) devices should be
handled on top of that.
Thus, the XI event handling code should be executed (if explicitly
compiled in and enabled) if the core device events have not been parsed.
Note: this is going away with XI2, which completely replaces both core and
XI1 events.
Even with XInput support we should always register core devices. This
allows us to handle enter and leave events correctly on the Stage and
to have a working XInput 1.x support in Clutter.
Mostly lifted from the core pointer and keyboard X11 backend support.
The win32 backend registers two devices (a core pointer and a core
keyboard) and assigns them to the event structure when doing the
translation from native events to Clutter events.
Thanks to: Samuel Degrande <Samuel.Degrande@lifl.fr> for testing this
patch.
Instead of overloading the device id of 0 and 1 we should treat the core
devices as special, and have a pointer inside the X11 backend singleton
structure, for fast access.
When an InputDevice leaves a stage we set the stage member of
InputDevice to NULL. We should also unset the cursor_actor (as the
device is obviously not on an actor any more).
When the device re-enters the Stage the ENTER/LEAVE event generation
machinery will then be able to emit the ENTER event on the Stage.
If the user presses a button on a pointer device and then moves out the
Stage X11 will emit the following events:
LeaveNotify ➔ MotionNotify ... ➔ ButtonRelease ➔ LeaveNotify
The second LeaveNotify differs from the first by the state field.
Unfortunately, ClutterCrossingEvent doesn't have a modifier_state field
like other events, so we cannot provide a way for programmatically
distinguishing them from a Clutter perspective. This is also an X11-ism
we might not even want to replicate on every backend with sane
enter/leave semantics.
For this reason we should check inside the X11 event processing if the
pointer device has already left the Stage and ignore the second
LeaveNotify.
The Stage field of an InputDevice is set by the backend, whenever the
pointer enters or leaves the Stage. The Stage should not overwrite the
stage field for every event it processes.
The previous state for the device is used by the click count machinery
and we should not be overwriting it at every event; instead, we should
use a parallel storage for the current state coming from the windowing
system.
The device manager does not need to update the state of the devices
when the user has disabled the delivery of motion events to actors:
the events will always be delivered as they are to the stage.
The LEAVE/ENTER event pairs should be queued during the InputDevice
update process, when we change the actor under the device pointer.
This commit cleans up the event emission code inside clutter-main.c
and the logic of the event processing.
The InputDevice objects stores pointer coordinates, state, stage and
the actor under the cursor, so if the current backend provides us with
one attached to the Event structure then we want the InputDevice itself
to update its state and give us the ClutterActor underneath the
pointer's cursor.
Even when we are not using XInput we now have fallback devices; the
X11 backend should always assign the default devices when translating
the X events to Clutter events.
Use the device manager to store the input devices. Also, provide
two fallback devices when initializing the X11 backend: device 0
for the pointer and device 1 for the keyboard.
Previously the atlas textures were being created with whatever format
the first sub texture is in. Only three formats are supported so this
only matters if the first texture is a premultiplied alpha
texture. Instead it now masks out the premultiplied bit so that the
textures are always either RGB_888 or RGBA_8888.
The win32 backend now handles the WM_SETCURSOR message and sets a
fully transparent cursor if the cursor-visible property has been
cleared on the stage. The icon is stored in the library via a resource
file. The instance handle for the DLL is needed to load the resource
so there is now a DllMain function to grab the handle.
g_list_foreach has better protection against the current node being
removed. This will happen for example if someone calls
clutter_container_foreach(container, clutter_actor_destroy). This was
causing valgrind errors for the conformance tests which do just that.
When uploading texture data it was just calling cogl_texture_set_data
on the large texture. This would attempt to convert the data to the
format of the large texture. All of the textures with alpha channels
are stored together regardless of whether they are premultiplied so
this was causing premultiplied textures to be unpremultiplied
again. It now just uploads the data ignoring the premult bit of the
format so that it only gets converted once.
With the atlas texture backend ensuring the mipmaps can make it become
a completely different texture which will have different texture
coordinates or may even be sliced. Therefore we need to ensure the
mipmaps before deciding which quads to log in the journal. This adds a
new private function to cogl-material which ensures the mipmaps if
needed.
The sub texture backend doesn't work well as a completely general
texture backend because for example when rendering with cogl_polygon
it needs to be able to tranform arbitrary texture coordinates without
reference to the other coordintes. This can't be done when the texture
coordinates are a multiple of one because sometimes the coordinate
should represent the left or top edge and sometimes it should
represent the bottom or top edge. For example if the s coordinates are
0 and 1 then 1 represents the right edge but if they are 1 and 2 then
1 represents the left edge.
Instead the sub-textures are now documented not to support coordinates
outside the range [0,1]. The coordinates for the sub-region are now
represented as integers as this helps avoid rounding issues. The
region can no longer be a super-region of the texture as this
simplifies the code quite a lot.
There are two new texture virtual functions:
transform_quad_coords_to_gl - This transforms two pairs of coordinates
representing a quad. It will return FALSE if the coordinates can
not be transformed. The sub texture backend uses this to detect
coordinates that require repeating which causes cogl-primitives
to use manual repeating.
ensure_non_quad_rendering - This is used in cogl_polygon and
cogl_vertex_buffer to inform the texture backend that
transform_quad_to_gl is going to be used. The atlas backend
migrates the texture out of the atlas when it hits this.
When calculating the next integer position for negative coordinates it
would not increment if the position is already a multiple of one so we
need to manually add one.
When try_creating_fbo fails it returns 0 to report the error and if it
succeeds it returns ‘flags’. However cogl_offscreen_new_to_texture
also passes in 0 for the flags as the last fallback to create the fbo
with nothing but the color buffer. In that case it will return 0
regardless of whether it succeeded so the last fallback will always be
considered a failure.
To fix this it now just returns a gboolean to indicate whether it
succeeded and the flags used for each attempt is assigned when passing
the argument rather than from the return value of the function.
Also if the only configuration that succeeded was with flags==0 then
it would always try all combinations because last_working_flags would
also be zero. To avoid this it now uses a separate gboolean to mark
whether we found a successful set of flags.
http://bugzilla.openedhand.com/show_bug.cgi?id=1873
Use the newly-added profiling timers inside the master clock dispatch
function to see how much time we spend:
• in the whole function
• in the event processing for each stage
• in the timeline advancement
Reading back the texture data in unrealize does not seem like a
desirable feature any more, clutter has evolved a lot since it was
implemented.
What's wrong with it now:
* It takes *a lot* of time to read the data back with glReadPixel(),
* When several textures share the same CoglTexture, the same data can
be read back multiple times,
* If the underlying material uses multiple texture units, only the
first one was copied back,
* In ClutterCairoTexture, we end up having two separate copies of the
data,
* GL actually manages texture memory accross system/video memory
for us!
For all the reasons above, let's get rid of the glReadPixel() in
Texture::unrealize()
Fixes: OHB#1842
Since 755cce33a7 the framebuffer code is using the GL enums
GL_DEPTH_ATTACHMENT and GL_DEPTH_COMPONENT16. These aren't available
directly under GLES except with the OES suffix so we need to define
them manually as we do with the other framebuffer constants.
These macros used to define Cogl wrappers for the GLenum values. There are
now Cogl enums everywhere in the API where these were required so we
shouldn't need them anymore. They were in the public headers but as
they are not neccessary and were not in the API docs for Clutter 1.0
it should be safe to remove them.
Using the ::event signal to match the CLUTTER_DELETE event type (and
block the stage destruction) can be costly, since it means checking
every single event.
The ::delete-event signal is similar in spirit to any other specialized
signal handler dealing with events, and retains the same semantics.
If a user supplied multiple groups of texture coordinates with
cogl_rectangle_with_multitexture_coords() then we would repeatedly log only
the first group in the journal. This fixes that bug and adds a conformance
test to verify the fix.
Thanks to Gord Allott for reporting this bug.
The Intel drivers in Mesa 7.6 (and possibly earlier versions) don't
support creating FBOs with a stencil buffer but without a depth
buffer. This reworks framebuffer allocation so that we try a number
of fallback options before failing.
The options we try in order are:
- the same options that were sucessful last time if available
- combined depth and stencil
- separate depth and stencil
- just stencil, no depth
- just depth, no stencil
- neither depth or stencil
Allow the user of the ClutterMedia interface to specify a Pango font
description to display subtitles. Even if the underlying implementation
of the interface does not natively use Pange, it must be capable of
parsing the grammar that pango_font_description_from_string() accepts.
Some source files should not be passed through the introspection parser,
as they are fully private and do not expose any valuable API.
Also the clutter-profile.h header is private and should not be
installed.
We weren't taking a reference on the texture to be used as the color buffer
for offscreen rendering, so it was possible to free the texture leaving the
framebuffer in an inconsistent state.
This adds gives Cogl a dedicated UProf context which will be linked together
with Clutter's context during clutter_init_real().
Initial timers cover _cogl_journal_flush and _cogl_journal_log_quad
You can explicitly ask for a report of Cogl statistics by exporting
COGL_PROFILE_OUTPUT_REPORT=1 but since the context is linked with Clutter's
the statisitcs will also be shown in the automatic Clutter reports.
This suspends and resumes all uprof timers and counters except while dealing
with picking, so as to give more focused statistics.
Be aware that there are still some issues with this profile option since
there are a few special case counters and timers that shouldn't be
suspended; noteably the frame counters are incorrect so the per frame stats
can't be trusted.
As we have for debugging, this adds the ability to control profiling flags
either via the command line or an environment variable.
The first option added is CLUTTER_PROFILE=disable-report
This also changes the reporting to be opt-out so you don't need to export
CLUTTER_PROFILE_OUTPUT_REPORT=1 to see a report but you can use
CLUTTER_PROFILE=disable-report to disable it if desired.
UProf is a small library that aims to help applications/libraries provide
domain specific reports about performance. It currently provides high
precision timer primitives (rdtsc on x86) and simple counters, the ability
to link statistics between optional components at runtime and makes report
generation easy.
This adds initial accounting for:
- Total mainloop time
- Painting
- Picking
- Layouting
- Idle time
The timing done by uprof is of wall clock time. It's not based on stochastic
samples we simply sample a counter at the start and end. When dealing with
the complexities of GPU drivers and with various kinds of IO this form of
profiling can be quite enlightening as it will be able to represent where
your application is blocking unlike tools such as sysprof.
To enable uprof accounting you must configure Clutter with --enable-profile
and have uprof-0.2 installed from git://git.moblin.org/uprof
If you want to see a report of statistics when Clutter applications exit you
should export CLUTTER_PROFILE_OUTPUT_REPORT=1 before running them.
Just a final word of caution; this stuff is new and the manual nature of
adding uprof instrumentation means it is prone to some errors when modifying
code. This just means that when you question strange results don't rule out
a mistake in the instrumentation. Obviously though we hope the benfits out
weigh e.g. by focusing on very key stats and by having automatic reporting.
Since asking for ARGB by default is still somewhat experimental on X11
and not every toolkit or complex widgets (like WebKit) still do not like
dealing with ARGB visuals, we should switch back to RGB by default - now
that at least we know it works.
For applications (and toolkit integration libraries) that want to enable
the ClutterStage:use-alpha property there is a new function:
void clutter_x11_set_use_argb_visual (gboolean use_argb);
which needs to be called before clutter_init().
The CLUTTER_DISABLE_ARGB_VISUAL environment variable can still be used
to force this value off at run-time.
Currently, ClutterActor detects a relayout cycle (an actor causing a
relayout to be queued from within an allocate() function) and aborts
after printing out a warning. This might be a little bit too anal
retentive, and it currently breaks GTK+ embedding inside clutter-gtk
so we should probably relax the behaviour a bit. Now we just emit the
warning but we still go ahead with the relayout.
When Clutter tries to pick an ARGB visual it tried to set the
GLX_TRANSPARENT_TYPE attribute of the FBConfig to
GLX_TRANSPARENT_RGB. However the code to do this was broken so that it
was actually trying to set the non-existant attribute number 0x8008
instead. Mesa silently ignored this so it appeared as if it was
working but the Nvidia drivers do not like it.
It appears that the TRANSPARENT_TYPE attribute is not neccessary for
getting an ARGB visual anyway and instead it is intended to support
color-key transparency. Therefore we can just remove it and get all of
the FBConfigs. Then if we need an ARGB visual we can just walk the
list to look for one with depth == 32.
The fbconfig is now stored in a single variable instead of having a
separate variable for the rgb and rgba configs because the old code
only ever retrieved one of them anyway.
Previously when the markup property is set it would generate an
attribute list from the markup and then merge it with the attributes
from the attribute property and store it as the effective
attributes. The markup attributes and the marked up text would then be
forgotten. This breaks if the application then later changes the
attributes property because it would try to regenerate the effective
attributes from the markup text but the stored text no longer contains
any markup. If the original markup text happened to contain entities
like '<' they would end up causing parse errors because they would
be converted to the actual symbols.
To fix this the attributes from the markup are now stored
independently from the effective attributes. The effective attributes
are now regenerated if either set of attributes changes right before a
layout is created.
http://bugzilla.openedhand.com/show_bug.cgi?id=1940
Destroy the dummy XImage we create even on success.
http://bugzilla.openedhand.com/show_bug.cgi?id=1918
Based on a patch by: Carlos Martín Nieto <carlos@cmartin.tk>
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
PropertyInfo should store a copy of the JsonNodes it references, so
that property_info_free() can safely dispose them, and we can reference
values across different UI definition data.
The implicit timeline parsing code is not copying the JsonNode; this
leads to a double free in some cases, which is masked by the GSlice
allocator and produces a heap corruption later on.
Allow the user of the ClutterMedia interface to specify an external (as
in not multiplexed with the audio/video streams) location of a subtitle
stream.
Both the ::insert-text and ::delete-text are "action" signals, that is
signals that are safe to (and should) be emitted using g_signal_emit()
directly.
A timeline advancement might cause another timeline to be
destroyed, which will likely lead to a segmentation fault.
Before advancing the timelines we should take a reference
on them - just like we do for the stages before doing
event processing. This will prevent dispose() from running
until the end of the advancement.
http://bugzilla.openedhand.com/show_bug.cgi?id=1854
Apparently, calling g_set_prgname() multiple times is not allowed
anymore, and hence clutter_init_* calls should not do that. Though this
is really GLib's fault - and a massive nuisance for us - we should
prolly comply to avoid the test suite dying on us.
* animate-layout-manager:
layout-manager: Document the animation support
layout-manager: Rewind the timeline in begin_animation()
box-layout: Remove the allocations hash table
docs: Clean up the README file
layout: Let begin_animation() return the Alpha
box-layout: Add knobs for controlling animations
box-layout: Animate layout properties
layout: Add animation support to LayoutManager
Add ActorBox animation methods
Add a section inside the LayoutManager class API reference documenting,
with examples, how to implement animation support inside a layout
manager sub-class.
If the default implementation begin_animation() is called twice then we
should rewind the timeline, as well as updating its duration and the
easing mode of the alpha.
The BoxLayout uses a HashTable to map the latest stable allocation of
each child, in order to use that as the initial value during an
animation; this in spite of already having a perfectly valid per-child
storage as part of the layout manager: ClutterBoxChild.
The last stable allocation should be stored inside the ClutterBoxChild
instead of having it in the private data for ClutterBoxLayout. The
access remains O(1), since there is a 1:1 mapping between child and
BoxChild instances, but we save a little bit of memory and we avoid
keeping aroud allocations for old children.
* stage-use-alpha:
tests: Use accessor methods for :use-alpha
stage: Add accessors for :use-alpha
tests: Allow setting the stage opacity in test-paint-wrapper
stage: Premultiply the stage color
stage: Composite the opacity with the alpha channel
glx: Always request an ARGB visual
stage: Add :use-alpha property
materials: Get the right blend function for alpha
ClutterActor checks, when destroying and reparenting, if the parent
actor implements the Container interface, and automatically calls the
remove() method to perform a clean removal.
Actors implementing Container, though, might have internal children;
that is, children that are not added through the Container API. It is
already possible to iterate through them using the Container API to
avoid breaking invariants - but calling clutter_actor_destroy() on
these children (even from the Container implementation, and thus outside
of Clutter's control) will either lead to leaks or to segmentation
faults.
Clutter needs a way to distinguish a clutter_actor_set_parent() done on
an internal child from one done on a "public" child; for this reason, a
push/pop pair of functions should be available to Actor implementations
to mark the section where they wish to add internal children:
➔ clutter_actor_push_internal ();
...
clutter_actor_set_parent (child1, parent);
clutter_actor_set_parent (child2, parent);
...
➔ clutter_actor_pop_internal ();
The set_parent() call will automatically set the newly added
INTERNAL_CHILD private flag on each child, and both
clutter_actor_destroy() and clutter_actor_unparent() will check for the
flag before deciding whether to call the Container's remove method.
When beginning a new animation for a LayoutManager, the implementation
should return the ClutterAlpha used. This allows controlling the
timeline and/or modifying the animation parameters on the fly.
ClutterLayoutManager does not have any state associated with it, and
defers all the state to its sub-classes.
The BoxLayout is thus in charge of controlling:
• whether or not animations should be used
• the duration of the animation
• the easing mode of the animation
By adding three new properties:
• ClutterBoxLayout:use-animations
• ClutterBoxLayout:easing-duration
• ClutterBoxLayout:easing-mode
And their relative accessors pairs we can make BoxLayout decide whether
or not, and with which parameters, call the begin_animation() method of
ClutterLayoutManager.
The test-box-layout has been modified to reflect this new functionality,
by checking the key-press event for the 'a' key symbol to toggle the use
of animations.
Use the newly added animation support inside LayoutManager to animate
between state changes of the BoxLayout properties.
The implementation is based on equivalent code from Mx, written by:
Thomas Wood <thomas.wood@intel.com>
In order to animate a fluid layout we cannot use the common animation
code paths as they will override the size request and allocation paths
that are handled by the layout manager itself.
One way to introduce animations in the allocation sequence is to use a
Timeline and an Alpha to compute a progress value and then use that
value to interpolate an ActorBox between the initial and final states of
the animation - with the initial state being the last allocation of the
child prior to the animation start, and the final state the allocation
of the child at the end; for every frame of the Timeline we then queue a
relayout on the layout manager's container, which will result in an
animation.
ClutterLayoutManager is the most likely place to add a generic API for
beginning and ending an animation, as well as the place to provide a
default code path to create the ancillary Timeline and Alpha instances
needed to drive the animation.
A LayoutManager sub-class will need to:
• call clutter_layout_manager_begin_animation() whenever it should
animate between two states, for instance: whenever a layout property
changes value;
• eventually override begin_animation() and end_animation() in case
further state needs to be set up, and then chain up to the default
implementation provided by LayoutManager;
• if a completely different implementation is required, the layout
manager sub-class should override begin_animation(), end_animation()
and get_animation_progress().
Inside the allocate() implementation the sub-class should also
interpolate between the last known allocation of a child and the newly
computed allocation.
ClutterActorBox should have an interpolate() method that allows to
compute the intermediate values between two states, given a progress
value, e.g.:
clutter_actor_box_interpolate (start, end, alpha, &result);
Another utility method, useful for layout managers, is a modifier
that clamps the members of the actor box to the nearest integer
value.
When getting signals from higher level toolkits, occasionally
one wants access to the underlying event; say for a Button
widget's "clicked" signal, to get the keyboard state.
Rather than having all of the highlevel widgets emit
ClutterEvent just for the more unusual use cases,
add a global function to access the event state.
http://bugzilla.openedhand.com/show_bug.cgi?id=1888
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
Old-style X11 terminals require that even modern X11 send KeyPress
and KeyRelease pairs when auto-repeating. For this reason modern(-ish)
API like XKB has a way to detect auto-repeat and do a single KeyRelease
at the end of a KeyPress sequence.
The newly added check emulates XKB's detectable auto-repeat by peeking
the next event after a KeyRelease and checking if it's a KeyPress for
the same key and timestamp - and then ignoring the KeyRelease if it
matches.
If a Stage has been set to use a foreign Window then Clutter should not
be managing it; calling XWithdrawWindow and XMapWindow should be
reserved to the windows we manage ourselves.
Some actor implementation might avoid imposing any layout on their
children. The Actor base class usually assumes some sort of layout
management is in place, so it will queue relayouts when, for instance,
an actor is shown or is hidden. If the parent of the actor does not
impose any layout, though, showing or hiding one of its children will
not affect the layout of the others.
An example of this kind of container is ClutterGroup.
By adding a new Actor flag, CLUTTER_ACTOR_NO_LAYOUT, and by making
the Group actor set it on itself, the Actor base class can now decide
whether or not to queue a relayout. The flag is not meant to be used
by application code, and should only be set when implementing a new
container.
http://bugzilla.openedhand.com/show_bug.cgi?id=1838
When the texture is in the atlas, ensuring the mipmaps can effectively
make it become a completely different texture so we should do this
before getting the GL handle.
Mipmaps don't work very well in the current atlas because there is not
enough padding between the textures. If ensure_mipmaps is called it
will now create a new texture and migrate the atlased texture to
it. It will use the same blit mechanism as when migrating so it will
try to use an FBO for a fast blit. However if this is not possible it
will end up downloading the data for the entire atlas which is not
ideal.
When reorganizing the textures, we can avoid downloading the entire
texture data if we bind the source texture in a framebuffer object and
copy the destination using glCopyTexSubImage2D. This is also
implemented using a much faster path in Mesa.
Currently it is calling the GL framebuffer API directly but ideally it
would use the Cogl offscreen API. However there is no way to tell Cogl
not to create a stencil renderbuffer which seems like a waste in this
situation.
If FBOs are not available it will fallback to reading back the entire
texture data as before.
This adds a 'dump-atlas-image' debug category. When enabled, CoglAtlas
will use Cairo to create a png which visualizes the leaf rectangles of
the atlas.
This adds an 'atlas' category to the COGL_DEBUG environment
variable. When enabled Cogl will display messages when textures are
added to the atlas and when the atlas is reorganized.
When space can't be found in the atlas for a new texture it will now
try to reorganize the atlas to make space. A new CoglAtlas is created
and all of the textures are readded in decreasing size order. If the
textures still don't fit then the size of the atlas is doubled until
either we find a space or we reach the texture size limits. If we
successfully find an organization that fits then all of the textures
will be migrated to a new texture. This involves copying the texture
data into CPU memory and then uploading it again. Potentially it could
eventually use a PBO or an FBO to transfer the image without going
through the CPU.
The algorithm for laying out the textures works a lot better if the
rectangles are added in order so we might eventually want some API for
creating multiple textures in one go to avoid reorganizing the atlas
as far as possible.
This adds a CoglAtlas type which is a data structure that keeps track
of unused sub rectangles of a larger rectangle. There is a new atlased
texture backend which uses this to put multiple textures into a single
larger texture.
Currently the atlas is always sized 256x256 and the textures are never
moved once they are put in. Eventually it needs to be able to
reorganise the atlas and grow it if necessary. It also needs to
migrate the textures out of the atlas if mipmaps are required.
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.
