So we can keep track of the experimental progress of Cogl 2.0 features
this adds a standalone Cogl 2.0 Reference Manual which doesn't cover
the deprecated 1.x symbols and removes the need for a "Cogl
experimental API" chapter since those sections now make up the main
table of contents.
Since EGA colors are apparently all the rage in other toolkits, Clutter
should not be left out. On top of the usual CGA/EGA palette the static
colors also include the Tango Icon palette, which at least is more
pleasant to the eye.
Static colors are accessed through an enumeration by using
clutter_color_get_static(), or using the short-hand pre-processor
macros.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2066
This exposes the idea of a stack of source materials instead of just
having a single current material. This allows the writing of orthogonal
code that can change the current source material and restore it to its
previous state. It also allows the implementation of new composite
primitives that may want to validate the current source material and
possibly make override changes in a derived material.
* wip/path-constraint:
docs: Add PathConstraint
tests: Add a PathConstraint interactive test
Add ClutterPathConstraint
actor-box: Add setters for origin and size
This function handles a single windows message. The idea is that it
could be used by clutter-gtk to forward on events from a
GdkEventFilter. The function replaces the old message_translate()
function. That function didn't translate the event anymore anyway and
instead it could generate multiple events so
clutter_win32_handle_event seems like a more appropriate name. The
function returns TRUE or FALSE depending on whether the event was
completely handled instead of setting call_window_proc.
The interpolate() method does what it says on the tin: it interpolates
between two colors using the given factor.
ClutterColor uses it to register a progress function for Intervals.
Recipe covers adding handlers for button-press-event and
button-release-event signals on actors, and how to
examine the content of a ClutterButtonEvent via API functions.
The discussion section explains about click count
(the criteria for how clicks get counted, including
distance and time settings); how button numbers are reported;
and how to use ClutterClickAction as an alternative
for press + release in certain scenarios.
The internal copy of JSON-GLib was meant to go away right after the 1.0
release, given that JSON-GLib was still young and relatively unknown.
Nowadays, many projects started depending on this little library, and
distributions ship it and keep it up to date.
Keeping a copy of JSON-GLib means keeping it up to date; unfortunately,
this would also imply updating the code not just for the API but for the
internal implementations.
Starting with the 1.2 release, Clutter preferably dependend on the
system copy; with the 1.4 release we stopped falling back automatically.
The 1.6 cycle finally removes the internal copy and requires a copy of
JSON-GLib installed on the target system in order to compile Clutter.
This recipe explains how to use the three animation
approaches (implicit, State, Animator) to animate movement
of actors.
Includes some guidelines about which approach to use when, with
a full code example for each approach.
The discussion section covers some subtleties around animated
movement; namely: moving actors out of their containers; anchor
points and movement; moving in the depth axis; interactions
between animated movement and constraints.
Added an example showing how to move two actors between
two states (one minimised, one maximised) using ClutterState
to do the movement. Also shows how movement can be mixed
with other animation (in this case, scaling).
This adds a "Cogl deprecated API" chapter to the Cogl reference manual
so we can group all the documentation for deprecated symbols together
instead of having them clutter up the documentation of symbols we would
rather developers used.
The CoglTexture3D API is only available when defining
COGL_ENABLE_EXPERIMENTAL_API so it should be listed in the experimental
section of the API reference.
* cookbook-layouts-bind-constraint:
cookbook: Add recipe about sync'ing actor sizes
cookbook: Example using allocation-changed to sync actor size
cookbook: Simple example to demonstrate bind constraint
cookbook: Example of using a bind constraint for an overlay
The recipe covers how to use ClutterBindConstraint
to bind actor sizes together.
It gives some examples of where this approach is appropriate,
as well as explaining an alternative using allocation-changed
or notify::* signals.
Three examples are given:
1. Resizing a texture to the stage.
2. Resizing a rectangle to act as a transparent overlay on
top of a texture (using constraints).
3. Resizing a rectangle to act as a transparent overlay on
top of a texture, but with a size proportional to the texture
(using a handler connected to allocation-changed signals
emitted by the texture).
An alternative method (not using constraints) to bind
one actor's size and position to another. Used as
an example in the recipe about resizing one actor in
sync with a source actor.
A simple example showing how to scale an actor to the stage.
Demonstrates ClutterBindConstraint and ClutterAlignConstraint
in a fashion suitable for a short recipe.
Example code which loads an image into a texture, and resizes
the image in response to +/- key presses. The overlay is
a transparent rectangle which is bound to the height and
width of the texture; on clicking the texture, the overlay
is made visible by increasing its opacity.
This demonstrates how to use constraints to simplify code
for resizing an actor which is "dependent" on another actor.
When building actor relative transforms, instead of using the matrix
stack to combine transformations and making assumptions about what is
currently on the stack we now just explicitly initialize an identity
matrix and apply transforms to that.
This removes the full_vertex_t typedef for internal transformation code
and we just use ClutterVertex.
ClutterStage now implements apply_transform like any other actor now
and the code we had in _cogl_setup_viewport has been moved to the
stage's apply_transform instead.
ClutterStage now tracks an explicit projection matrix and viewport
geometry. The projection matrix is derived from the perspective whenever
that changes, and the viewport is updated when the stage gets a new
allocation. The SYNC_MATRICES mechanism has been removed in favour of
_clutter_stage_dirty_viewport/projection() APIs that get used when
switching between multiple stages to ensure cogl has the latest
information about the onscreen framebuffer.
This recipe explains how to "reuse" the same animation
definition for different actors, by creating a new
instance of a "rig" (empty container) and animation
for the rig each time the animation is required.
An actor is then re-parented to the rig and animated
using it, rather than being animated directly.
JSON is used to define the rig + animator, to make
creating new instances of them simpler. The recipe
also discusses various caveats around using this
approach, rather than directly animating an actor.
Modified the "animation reuse" sample code to provide
a simpler example to explain in the recipe.
Also modified variable names to mirror the names used
for the previous "complex animation" example and added
some more comments, to further simplify and support the
recipe.
With some help from pippin, moved variable declarations
into more sensible positions within their functions,
changed a function name, and found a better way
to unref a script once its associated actor has
been destroyed.
Extracted the animation into its own JSON definition,
then create a new script and get the animation each
time a rectangle is clicked.
Removes the need to reparent onto the background and
copy property values to the rectangle after the animation,
and generally much cleaner.
Added an example showing how to reuse a ClutterAnimator
instance to animate multiple actors at different times
using an animatable rig, combined with reparenting.
The keysyms defines in clutter-keysyms.h are generated from the X11 key
symbols headers by doing the equivalent of a pass of sed from XK_* to
CLUTTER_*. This might lead to namespace collisions, down the road.
Instead, we should use the CLUTTER_KEY_* namespace.
This commit includes the script, taken from GDK, that parses the X11
key symbols and generates two headers:
- clutter-keysyms.h: the default included header, with CLUTTER_KEY_*
- clutter-keysyms-compat.h: the compatibility header, with CLUTTER_*
The compat.h header file is included if CLUTTER_DISABLE_DEPRECATED is
not defined - essentially deprecating all the old key symbols.
This does not change any ABI and, assuming that an application or
library is not compiling with CLUTTER_DISABLE_DEPRECATED, the source
compatibility is still guaranteed.
When animating an actor through clutter_actor_animate() and friends we
might want forcibly detach the animation instance from the actor in
order to start a new one - for instance, in response to user
interaction.
Currently, there is no way to do that except in a very convoluted way,
by emitting the ::completed signal and adding a special case in the
signal handlers; this is due to the fact that clutter_actor_animate()
adds more logic than the one added by clutter_animation_set_object(),
so calling set_object(NULL) or unreferencing the animation instance
itself won't be enough.
The right way to approach this is to add a new method to Clutter.Actor
that detaches any eventual Animation currently referencing it.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2051
Uses ClutterAnimator to implement a reasonably complex
animation of a single actor (movement along a path with
simultaneous scaling).
Provides a metaphor for thinking about ClutterAnimator
animations (stage directions) and explains keys and key
frames in some depth. Also compares ClutterAnimator
with other possible approaches to this type of animation
(implicit animations, ClutterState).
Added another JSON example to show how transitions can
be easily overlapped when using ClutterAnimator (two
sequences of 5 transitions, simultaneous with two
sequences of 1 transition).
Modified the C JSON loader program so it can be used with
this example as well.
Intel CE3100 and CE4100 have several planes (framebuffers) and a
hardware blender to blend the planes togeteher to produce the final
image.
clutter_cex100_set_plane() lets you configure which framebuffer clutter
will use for its rendering.
*** This is an API change ***
The create_target() virtual function should return a CoglHandle to a
texture; clutter_offscreen_effect_get_target(), instead, returns a
CoglMaterial to be painted in the implementation of the paint_target()
virtual function.
Instead of equating textures with materials, and confusing the user of
the API, we should mark the difference more prominently.
First of all, we should return a CoglMaterial* (now that we have that
as a public type) in get_target(); having handles all over the place
does not make it easier to distinguish the semantics of the virtual
functions.
Then we should rename create_target() to create_texture(), to make it
clear that what should be returned is a texture that is used as the
backing for the offscreen framebuffer.
Added a recipe explaining how to connect signals to handlers
in the JSON definition used by ClutterScript; also shows
how to connect the signals in code once the JSON has been
loaded.
Includes guidelines on writing handlers (i.e. need to use
-export-dynamic and non-static functions) and example
which connects a handler for motion events on a rectangle.
GEnum nicknames can be used to set properties in JSON
definitions, so added a callout to the JSON example explaining
this, and showing how to derive the nickname for an enumeration
value.
Modified the example code to use nicknames as well.
As JSON can make use of nicknames for GEnum properties,
mentioned this in the table mapping C property values
to their JSON equivalents (as the nick name is a much
shorter and cleaner way of setting a property in JSON).
Wrote an introduction to using ClutterScript with JSON. Focus
is on explaining why you might want to use it, basic principles
of operation (with annotated JSON sample), and how to map
data types from C to JSON.
Written simultaneously with a short recipe (uses the same sample
code) showing how to load a JSON file and retrieve objects
from it in code.
Commented the ClutterScript example so it can be used
inline as part of the recipe, rather than as an
example in the appendix (it's too simple to warrant
a separate appendix).
New script chapter needs an introduction.
While writing the introduction, also slightly changed the
emphasis of the recipe (towards refactoring an existing
application to use ClutterScript) and incorporated example
code into documentation.
Set a parameter on the XSLT transform so that callout elements
are rendered as text rather than graphics (removes the need
to add callout graphics to the build).
There was too much in the example code to cover in a single
recipe, so I trimmed it down to demonstrate simple
UI building (no constraints, effects, animations, or signals).
Added a simple script and program to load it, to support
recipe on ClutterScript for UI definitions.
Also amended the Makefile (following the pattern of
the tests/interactive Makefile) to enable signal
connection from ClutterScript by passing -export-dynamic
to linker.
* elliot/cookbook-textures-crossfade:
cookbook: Use GdkPixbuf instead of getting data from a texture
cookbook: Added a recipe for cross-fading between two images
cookbook: Modified COGL example for consistency
cookbook: Added video of two texture cross-fade
cookbook: Removed unused constant
cookbook: Renamed front/back to top/bottom in cross-fade example
cookbook: Don't need to set keep-aspect-ratio for simple example
cookbook: Modified ordering of statements in cross-fade example
cookbook: Added a longer slideshow example
cookbook: Made code examples more consistent
cookbook: Added example code for texture cross-fading
Post-release version bump to 1.3.13
Release Clutter 1.3.12 (developers snapshot)
Conflicts:
doc/cookbook/examples/Makefile.am
Added a recipe about handling enter, leave, and motion events
on an actor.
Gives some pointers to data available from motion events,
explains a bit about stage-relative and actor-relative coords,
and covers how overlapping actors and reactivity of actors
can affect events occurring.
Examples include a simple scribble app showing how to integrate
pointer events into a more useful context.
Added another example (used for a screenshot) to demonstrate
how pointer events pass through non-reactive actors and how
depth ordering affects whether an actor will emit a pointer
motion signal.
Use clutter_event_get_coords() to get x and y position,
rather than casting to the right event type then directly
accessing members of the event struct.
Decided might be better to cover crossing and motion under
a broader "pointer motion" recipe, so renamed the example
(which only shows pointer crossing event handling).
It can be useful to be able to forcibly break the grab set up by the
ClickAction. The newly added release() method provides a mechanism to
release the grab and unset the :held state of the ClickAction.
Rewrote example for single texture + COGL to use
a GdkPixbuf to load images, rather than reading data
out of another CoglTexture.
The data is then loaded from the pixbuf to a region of
the CoglTexture (as before).
The recipe covers a two texture approach (using the Clutter API)
and a single texture approach (using COGL).
It also discusses issues with cross-fading between images of
different sizes with the COGL API, and gives a longer
example of cycling through multiple images in a slideshow
application.
Added a video showing the two texture cross-fade.
Modified the example code to animate on key press, so
this video could be captured.
Also altered the stage size to minimise the video size.
Front/back seems like the wrong terminology when discussing
actors arranged in layers. Top/bottom fits better with Clutter
API function names and other recipes, so renamed variables.
Cross-fading between two images is straightforward,
but cycling between more than two is more efficient
if done by copying COGL textures between the
two textures, rather than trying to reposition the
textures.
The example demonstrates how to reuse a pair of
textures to cycle through multiple images.
Modified the code example for the Clutter API version
of the cross-fade to use the same command line
as the COGL version.
This also simplifies the explanation in the recipe.
Also made the COGL code sample more consistent with
the Clutter API code sample.
Added simple image viewer which loads image file names
from a directory, displays the first one, then displays
the next in the list with each key press. Uses the
primitive fade front in/fade back out approach.
Also adapted Emmanuele's example code which uses Cogl
to produce a similar effect, but within a single texture.
This code loads two images specified on the command
line and cross-fades between them.
The tests/accessibility, tests/micro-bench and the examples directory
in the coobook create a lot of non-installed binaries. Since we know who
they are, and we ignore them, we can auto-generate the ignore files as
well.
The rest of Clutter is covered by the main ignore file.
* elliot/cookbook-events-mouse-scroll:
cookbook: Cleaning up grammar and wording in mouse scroll recipe
cookbook: Added more explanation about setting y coord on scrollable
cookbook: Mentioned the animation in the sample code
cookbook: Included video of the scroll example running
cookbook: Made stage slightly smaller for scroll event example
cookbook: Added video showing scrollable actor
cookbook: Added walk through of code example for mouse scroll
cookbook: Fixed link to example in mouse scroll recipe
cookbook: Simplified full scroll example
cookbook: Improved wording and formatting in mouse scroll intro.
cookbook: Handle all possible mouse scroll directions
cookbook: Build mouse scroll example with cookbook
cookbook: Cleaned up redundant comments in code example
cookbook: Added xmlns for XInclude to events docbook file
cookbook: Added basic mouse scroll recipe
This removes all references to SDL in the build instructions as the
backend is no longer available. The OpenGL version required is only
1.2 not 1.4. The Windows build instructions were out of date and have
been replaced with a link to the wiki instead.
Instead of exposing an API that provides an OpenGL state machine style
where you first have to bind the program to the context using
cogl_program_use() followed by updating uniforms using
cogl_program_uniform_xyz we now have uniform setter methods that take an
explicit CoglHandle for the program.
This deprecates cogl_program_use and all the cogl_program_uniform
variants and provides the following replacements:
cogl_program_set_uniform_1i
cogl_program_set_uniform_1f
cogl_program_set_uniform_int
cogl_program_set_uniform_float
cogl_program_set_uniform_matrix
Added some extra explanation, referencing the sample code, to
try to make the scrollable actor example easier to follow. Basically
demonstrates the principles described in the paragraph about
setting the y coordinate for the scrollable actor, but using actual
numbers.
A TableLayout is a layout manager that allocates its children in rows
and columns. Each child is assigned to a cell (or more if a cell span
is set).
The supported child properties are:
• x-expand and y-expand: if this cell with try to allocate the
available extra space for the table.
• x-fill and y-fill: if the child will get all the space available in
the cell.
• x-align and y-align: if the child does not fill the cell, then
where the child will be aligned inside the cell.
• row-span and col-span: number of cells the child will allocate for
itself.
Also, the TableLayout has row-spacing and col-spacing for specifying
the space in pixels between rows and between columns.
We also include a simple test of the layout manager, and the
documentation updates.
The TableLayout was implemented starting from MxTable and
ClutterBoxLayout.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2038
Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
Layout managers are using the same code to allocate a child while taking
into consideration:
• horizontal and vertical alignment
• horizontal and vertical fill
• the preferred minimum and natural size, depending
on the :request-mode property
• the text direction for the horizontal alignment
• an offset given by the fixed position properties
Given the amount of code involved, and the amount of details that can go
horribly wrong while copy and pasting such code in various classes - let
alone various projects - Clutter should provide an allocate() variant
that does the right thing in the right way. This way, we have a single
point of failure.
Added a new recipe for creating a non-rectangular
actor using ClutterPath (aka "shaped pick") and
the Cogl primitives API.
Also cleaned up XML alignment in the actors.xml
file.
It's a XSL FAQ to be able to chomp text nodes and we just have to copy
and paste a XSLT 1.0 solution from:
http://dpawson.co.uk/xsl/sect2/N8321.html#d11325e833
Let's then empower our cookbook customization layer to chomp text nodes,
children of programlisting.
The generated cookbook files (either HTML or PDF) do not only depend on
clutter-cookbok.xml but also on all the chapters that compose the
cookbook. Add this dependency to the Makefile rules to have make rebuild
the book when a chapter changes.
Since XML_FILES is now the list of source files, move recipe-template.xml
to EXTRA_DIST.
New recipe covering how to animate rotation of
an actor (in all axes).
Covers various factors affecting rotation animation
(like orientation of axes, parent rotation/orientation),
as well as trying to make rotations easier to visualise
(e.g. describing how rotation direction is affected by
those factors, how a rotation can be expected to look
when animated). Uses implicit animations for code examples.
Also refers to a full code example which uses ClutterState.
The simple key press example in the cookbook used a brittle
and incorrect switch statement to test modifier values. Instead,
use logical "&" of the state with the modifiers we're interested
in to check which keys were pressed.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2223
The cookbook should also include fully functional code examples. We can
even XInclude them into the docbook XML itself.
The examples should be built with the coobook, so that we can always
make sure they are up to date.
* elliot/cookbook-include-videos:
cookbook: Tweak so that videos sit inside a paragraph for better spacing
docs: Note the P_() macro in the HACKING file
cookbook: Added support for inline video
Conflicts:
doc/cookbook/Makefile.am
Explains how to make an actor transparent so that other actors
are visible through it.
Also explains a bit more generally about opacity and how
it's computed from the actor, container, and color; and how actor
visibility is affected by depth (fog) and depth order.
Amended Makefile to copy content of videos directory into
installation directories. Also copies videos and images
into the html/ directory during the build, so that the
built cookbook can be viewed locally (for testing without
having to install).
Added an XSLT template to transform Docbook <inlinemediaobject>
elements into HTML 5 <video> elements, with a fallback to
link to the video displayed for browsers without HTML 5 support.
Added note to "Contributing" appendix explaining how to put
video into a recipe.
Some apps or some use cases don't need to clear the stage on immediate
rendering GPUs. A media player playing a fullscreen video or a
tile-based game, for instance.
These apps are redrawing the whole screen, so we can avoid clearing the
color buffer when preparing to paint the stage, since there is no
blending with the stage color being performed.
We can add an private set of hints to ClutterStage, and expose accessors
for each potential hint; the first hint is the 'no-clear' one.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2058
This adds a publicly exposed experimental API for a 3D texture
backend. There is a feature flag which can be checked for whether 3D
textures are supported. Although we require OpenGL 1.2 which has 3D
textures in core, GLES only provides them through an extension so the
feature can be used to detect that.
The textures can be created with one of two new API functions :-
cogl_texture_3d_new_with_size
and
cogl_texture_3d_new_from_data
There is also internally a new_from_bitmap function. new_from_data is
implemented in terms of this function.
The two constructors are effectively the only way to upload data to a
3D texture. It does not work to call glTexImage2D with the
GL_TEXTURE_3D target so the virtual for cogl_texture_set_region does
nothing. It would be possible to make cogl_texture_get_data do
something sensible like returning all of the images as a single long
image but this is not currently implemented and instead the virtual
just always fails. We may want to add API specific to the 3D texture
backend to get and set a sub region of the texture.
All of those three functions can throw a GError. This will happen if
the GPU does not support 3D textures or it does not support NPOTs and
an NPOT size is requested. It will also fail if the FBO extension is
not supported and the COGL_TEXTURE_NO_AUTO_MIPMAP flag is not
given. This could be avoided by copying the code for the
GL_GENERATE_MIPMAP TexParameter fallback, but in the interests of
keeping the code simple this is not yet done.
This adds a couple of functions to cogl-texture-driver for uploading
3D data and querying the 3D proxy
texture. prep_gl_for_pixels_upload_full now also takes sets the
GL_UNPACK_IMAGE_HEIGHT parameter so that 3D textures can have padding
between the images. Whenever 3D texture is uploading, both the height
of the images and the height of all of the data is specified (either
explicitly or implicilty from the CoglBitmap) so that the image height
can be deduced by dividing by the depth.
There are many places in the texture backend that need to do
conversion using the CoglBitmap code. Currently none of these
functions can throw an error but they do return a value to indicate
failure. In future it would make sense if new texture functions could
throw an error and in that case they would want to use a CoglBitmap
error if the failure was due to the conversion. This moves the
internal CoglBitmap error from the quartz backend to be public in
cogl-bitmap.h so that it can be used in this way.
* elliot/cookbook-consistency:
cookbook: Fixed typo
cookbook: Fix build so CSS files get installed
cookbook: Moved paragraph where it logically belongs
cookbook: Added some judicious note elements
cookbook: Added more information for contributors
cookbook: Link out to docbook site
cookbook: Made docbook element usage consistent
cookbook: Additional selectors in CSS stylesheet
cookbook: Copy the CSS file into the HTML build directory
Introduces basic concepts (timelines, alphas, frames)
common to different parts of the Clutter animation API.
Gives a high level overview of the three different
approaches to animation (implicit, ClutterAnimator,
ClutterState).
Added a new recipe (based on the skeleton in the
animations section of the cookbook) about inverting
an animation by reversing the direction of its timeline.
Uses clutter_actor_animate() as the basic approach,
but mentions ClutterState and ClutterAnimator as well.
This adds a new API call to enable point sprite coordinate generation
for a material layer:
void
cogl_material_set_layer_point_sprite_coords_enabled (CoglHandle material,
int layer_index,
gboolean enable);
There is also a corresponding get function.
Enabling point sprite coords simply sets the GL_COORD_REPLACE of the
GL_POINT_SPRITE glTexEnv when flusing the material. There is no
separate application control for glEnable(GL_POINT_SPRITE). Instead it
is left permanently enabled under the assumption that it has no affect
unless GL_COORD_REPLACE is enabled for a texture unit.
http://bugzilla.openedhand.com/show_bug.cgi?id=2047
* cally-merge:
cally: Add introspection generation
cally: Improving cally doc
cally: Cleaning CallyText
cally: Refactoring "window:create" and "window:destroy" emission code
cally: Use proper backend information on CallyActor
cally: Check HAVE_CONFIG_H on cally-util.c
docs: Fix Cally documentation
cally: Clean up the headers
Add binaries of the Cally examples to the ignore file
docs: Add Cally API reference
Avoid to load cally module on a11y examples
Add accessibility tests
Initialize accessibility support on clutter_init
Rename some methods and includes to avoid -Wshadow warnings
Cally initialization code
Add Cally
I had changed the build so CSS files get put into
the HTML build directory; but done it in such
a way that they were then being ignored during
install. Fixed this.
There was a note about constants for keys and
where they are defined in Clutter header files; but
the sentence about where key modifiers are defined
was outside the note. Logically, they belong
together.
In some cases, there were blocks of text which
were really asides/interrupts to the flow, but
which weren't explicitly marked as such. I fixed
them by turning them into <note> blocks.
Made usage of docbook elements consistent across
recipes; to ensure the conventions are kept by others,
added a section about how to write and style recipes.
Make Cally follow the single-include header file policy of Clutter and
Cogl; this means making cally.h the single include header, and requires
a new cally-main.h file for the functions defined by cally.h.
Also:
• clean up the licensing notice and remove the FSF address;
• document the object structures (instance and class);
• G_GNUC_CONST-ify the get_type() functions;
• reduce the padding for CallyActor sub-classes;
• reduce the amount of headers included.
