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cookbook: Made docbook element usage consistent

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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.
This commit is contained in:
Elliot Smith 2010-07-06 16:00:33 +01:00
parent fe7385cb7d
commit c108a32c30
4 changed files with 172 additions and 97 deletions
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22
doc/cookbook/actors.xml
View File

@ -23,7 +23,7 @@
with the others: it can be the parent of another actor, or a child of
another actor.</para>
<note><para>The Stage is an actor that can have children but cannot have
<note><para>The stage is an actor that can have children but cannot have
any parent.</para></note>
<para>Actors have different attributes: a position, a size, a
@ -38,7 +38,7 @@
</section>
<section id="actors-allocation-notify">
<title>Knowing when an actor position or size change</title>
<title>Knowing when an actor's position or size changes</title>
<section>
<title>Problem</title>
@ -112,7 +112,9 @@ on_allocation_changed (ClutterActor *actor,
<para>Any change the position and size of an actor will cause a
change in the allocation of the actor itself. This will update the
values of the :x, :y, :width and :height properties as well.</para>
values of the <property>x</property>, <property>y</property>,
<property>width</property> and <property>height</property>
properties as well.</para>
<para>The first technique allows a greater deal of granularity,
allowing you to know what exactly changed. Inside the callback
@ -159,12 +161,13 @@ on_allocation_changed (ClutterActor *actor,
<para>All actors will update these properties when their size
or position change.</para>
<para>Note that the Stage, on the other hand, will not notify on
position changes, so it is not possible to use the :x and :y
<para>Note that the stage, on the other hand, will not notify on
position changes, so it is not possible to use the
<property>x</property> and <property>y</property>
properties to know that the platform-specific window embedding the
stage has been moved &mdash; if the platform supports a windowing
system. In order to achieve that you will have to use backend-specific
API to extract the surface used by the Stage and then platform-specific
API to extract the surface used by the stage and then platform-specific
API to retrieve its coordinates.</para>
</section>
@ -218,12 +221,12 @@ void on_paint (ClutterActor *actor, gpointer user_data);
<title>Discussion</title>
<para>The paint cycle in Clutter works its way recursively from the
Stage through every child.</para>
stage through every child.</para>
<para>Whenever an Actor is going to be painted it will be positioned in
a new frame of reference according to the list of transformations
(scaling, rotation and additional traslations). After that, the "paint"
signal will be emitted.</para>
(scaling, rotation and additional translations). After that, the "paint"
signal will be emitted.</para>d
<para>The "paint" signal is defined as <emphasis>run-last</emphasis>,
that is the signal handlers connected to it using
@ -255,4 +258,3 @@ on_paint (ClutterActor *actor)
</section>
</chapter>

57
doc/cookbook/clutter-cookbook.xml.in
View File

@ -49,9 +49,60 @@
<appendix id="contributing">
<title>Contributing to this document</title>
<para>This document is written in Docbook XML. The source file for this
document is located in the subdirectory "doc/cookbook" of the source
directory of Clutter.</para>
<para>This document is written in
<link url="http://docbook.org/">Docbook XML</link>. The source files
for this document are located in the subdirectory
<filename>doc/cookbook</filename> inside the Clutter source directory.</para>
<para>To maintain some degree of consistency, try to stick to the
following broad guidelines about how to write Docbook for this
cookbook:</para>
<itemizedlist>
<listitem>
<para>If adding a new recipe, use the
<filename>recipe-template.xml</filename> XML file as a basis.
You can find it in the <filename>&lt;clutter_source&gt;/doc/cookbook/</filename>
directory.</para>
</listitem>
<listitem>
<para>Try to indent your XML sensibly using 2 spaces per level
(we're not too strict, but some indentation helps reading
the source).</para>
</listitem>
<listitem>
<para>Stick to a column width of around 80 characters.</para>
</listitem>
<listitem>
<para>Use the &lt;filename&gt; element for file
and directory names.</para>
</listitem>
<listitem>
<para>Use the &lt;property&gt; element for property names
(e.g. GObject properties).</para>
</listitem>
<listitem>
<para>Use the &lt;type&gt; element for GObject class
names.</para>
</listitem>
<listitem>
<para>Use the &lt;constant&gt; element for C defines.</para>
</listitem>
<listitem>
<para>Use the &lt;keycap&gt; element for keys, where
you are referring to what's actually printed on the key, e.g.
<keycap>Shift</keycap>. If you're referring to the key some
other way (e.g. "the Control key"), don't use
&lt;keycap&gt;.</para>
</listitem>
<listitem>
<para>Use the &lt;function&gt; element for functions;
the style adopted is to give the function name followed by
empty brackets, e.g. <function>clutter_actor_set_size()</function>.
</para>
</listitem>
</itemizedlist>
</appendix>
</book>

97
doc/cookbook/events.xml
View File

@ -70,8 +70,8 @@
</listitem>
<listitem>
<para><emphasis>Solution 2:</emphasis> Use an actor's
ClutterBindingPool to declaratively assign actions to specific
key and modifier combinations.</para>
<type>ClutterBindingPool</type> to declaratively assign
actions to specific key and modifier combinations.</para>
</listitem>
</orderedlist>
@ -80,12 +80,13 @@
<section>
<title>Solution 1</title>
<para>Connect the key-press-event signal for an actor to a callback;
then examine the event in the callback to determine which key and
modifiers were pressed.</para>
<para>Connect the <emphasis>key-press-event</emphasis>
signal for an actor to a callback; then examine the event
in the callback to determine which key and modifiers were
pressed.</para>
<para>First, connect an actor's key-press-event signal
to a callback:</para>
<para>First, connect an actor's
<emphasis>key-press-event</emphasis> signal to a callback:</para>
<informalexample>
<programlisting>
@ -96,7 +97,8 @@ g_signal_connect (actor, "key-press-event", G_CALLBACK (_key_press_cb), NULL);
<para>Then, in the callback, check which key was pressed and which
modifiers were down at the same time. For example, this callback
checks for a press on the up arrow key and whether
the Shift and/or Control key were down:</para>
the <keycap>Shift</keycap> and/or <keycap>Ctrl</keycap>
key were down:</para>
<informalexample>
<programlisting>
@ -110,26 +112,26 @@ _key_press_cb (ClutterActor *actor,
if (CLUTTER_Up == keyval)
{
ClutterModifierType modifiers = clutter_event_get_state (event);
switch (modifiers)
{
case CLUTTER_SHIFT_MASK:
g_debug ("Up and shift pressed");
break;
case CLUTTER_SHIFT_MASK + CLUTTER_CONTROL_MASK:
g_debug ("Up and shift and control pressed");
break;
default:
g_debug ("Up pressed");
break;
}
/* The event was handled, and the emission should stop */
return TRUE;
}
/* The event was not handled, and the emission should continue */
return FALSE;
}
@ -137,33 +139,38 @@ _key_press_cb (ClutterActor *actor,
</informalexample>
<para>Note that Clutter provides a range of key value definitions
(like CLUTTER_Up, used above). These are generated from the list in the
(like <constant>CLUTTER_Up</constant>, used above). These are
generated from the list in the
<ulink url="http://cgit.freedesktop.org/xorg/proto/x11proto/plain/keysymdef.h">X.Org source code</ulink>
(replace "XK" with "CLUTTER" in the definitions there to get the
CLUTTER equivalents; alternatively, look at the clutter-keysyms.h
header file for the list).</para>
CLUTTER equivalents; alternatively, look at the
<filename>clutter-keysyms.h</filename> header file for the
list).</para>
<para>CLUTTER_SHIFT_MASK, CLUTTER_CONTROL_MASK and other modifiers are
defined in the ClutterModifierType enum.</para>
<para><constant>CLUTTER_SHIFT_MASK</constant>,
<constant>CLUTTER_CONTROL_MASK</constant> and other modifiers are
defined in the <type>ClutterModifierType</type> enum.</para>
</section>
<section>
<title>Solution 2</title>
<para>Assign actions to an actor's ClutterBindingPool.
<para>Assign actions to an actor's <type>ClutterBindingPool</type>.
A binding pool stores mappings from a key press (either a single key
or a key plus modifiers) to actions; an action is simply a callback
function with a specific signature.</para>
<para>While this approach is trickier to implement, it is more
flexible and removes the drudgery of writing branching code to
handle different key presses. See the Discussion section for
more details.</para>
handle different key presses. See the
<link linkend="events-handling-key-events-discussion">Discussion</link>
section for more details.</para>
<para>To use this approach with an actor which will receive key press
events, first get that actor's binding pool. In the example below,
we're using the binding pool for the default ClutterStage:</para>
we're using the binding pool for the default
<type>ClutterStage</type>:</para>
<informalexample>
<programlisting>
@ -176,8 +183,9 @@ binding_pool = clutter_binding_pool_get_for_class (stage_class);
</informalexample>
<para>Next, install actions into the binding pool. For example, to
install an action bound to the up arrow key, which calls the _move_up
function when that key is pressed, you would do:</para>
install an action bound to the up arrow key, which calls the
<function>_move_up()</function> function when that key is pressed,
you would do:</para>
<informalexample>
<programlisting>
@ -191,8 +199,10 @@ clutter_binding_pool_install_action (binding_pool,
</programlisting>
</informalexample>
<para>Another example, binding up + Shift + Control to an action which
calls _move_up_shift_control when activated:</para>
<para>Another example, binding up arrow +
<keycap>Shift</keycap> + <keycap>Ctrl</keycap> to an action
which calls <function>_move_up_shift_control()</function> when
activated:</para>
<informalexample>
<programlisting>
@ -206,8 +216,8 @@ clutter_binding_pool_install_action (binding_pool,
</programlisting>
</informalexample>
<para>The function called when an action is activated looks like this
(for _move_up):</para>
<para>The function called when an action is activated looks
like this (for <function>_move_up()</function>):</para>
<informalexample>
<programlisting>
@ -223,8 +233,8 @@ _move_up (GObject *instance,
</programlisting>
</informalexample>
<para>Then bind the key-press-event for the actor (in our case,
the stage) to a callback:</para>
<para>Then bind the <emphasis>key-press-event</emphasis> signal
for the actor (in our case, the stage) to a callback:</para>
<informalexample>
<programlisting>
@ -258,13 +268,13 @@ _key_press_cb (ClutterActor *actor,
</programlisting>
</informalexample>
<para>Now, when a key plus modifiers that has been bound to an action
is pressed on the actor, the appropriate action is activated.</para>
<para>Now, when a key + modifiers that have been bound to an action
are pressed on the actor, the appropriate action is activated.</para>
</section>
</section>
<section>
<section id="events-handling-key-events-discussion">
<title>Discussion</title>
<section>
@ -285,9 +295,10 @@ _key_press_cb (ClutterActor *actor,
<para>In addition, Solution 2 lets you write a single callback to
handle all key press events for all actors. This callback could then
use clutter_binding_pool_find (as in the example code) to determine
which binding pool to activate (depending on which actor received the
key press event).</para>
use <function>clutter_binding_pool_find()</function>
(as in the example code) to determine which binding pool to
activate (depending on which actor received the key press
event).</para>
<para>Finally, a binding pool allows you to block and unblock actions.
This means you can make the response to a key press event conditional
@ -305,17 +316,19 @@ _key_press_cb (ClutterActor *actor,
<itemizedlist>
<listitem>
<para>A ClutterKeyEvent contains only a <emphasis>single</emphasis>
key value, plus possibly one or more modifier keys (like Shift,
Control, Alt etc.). There are no functions in the
Clutter API which return events for tracking near-simultaneous
presses on multiple keys.</para>
<para>A <type>ClutterKeyEvent</type> contains only a
<emphasis>single</emphasis> key value, plus possibly one
or more modifier keys (like <keycap>Shift</keycap>,
<keycap>Ctrl</keycap>, <keycap>Alt</keycap> etc.).
There are no functions in the Clutter API which return
events for tracking near-simultaneous presses on multiple
keys.</para>
</listitem>
<listitem>
<para>By default, the stage receives all key events.
To make another actor receive key events, use
clutter_stage_set_key_focus:</para>
<function>clutter_stage_set_key_focus()</function>:</para>
<informalexample>
<programlisting>

93
doc/cookbook/textures.xml
View File

@ -27,8 +27,8 @@
<section>
<title>Solution</title>
<para>Create a ClutterCairoTexture, then draw onto the Cairo context
it wraps using the Cairo API:</para>
<para>Create a <type>ClutterCairoTexture</type>, then draw onto
the Cairo context it wraps using the Cairo API:</para>
<informalexample>
<programlisting>
@ -64,9 +64,11 @@ cairo_destroy (cr);
<section>
<title>Discussion</title>
<para>A ClutterCairoTexture is a standard ClutterActor, so it can be
added to ClutterContainers (e.g. a ClutterStage or ClutterGroup),
animated, resized etc. in the usual ways.</para>
<para>A <type>ClutterCairoTexture</type> is a standard
<type>ClutterActor</type>, so it can be added to a
<type>ClutterContainer</type> (e.g. a <type>ClutterStage</type>
or <type>ClutterGroup</type>), animated, resized etc. in the
usual ways.</para>
<para>Other useful operations:</para>
@ -74,24 +76,24 @@ cairo_destroy (cr);
<listitem>
<para><emphasis>To draw on part of the texture:</emphasis>
use <function>clutter_cairo_texture_create_region</function> to
use <function>clutter_cairo_texture_create_region()</function> to
retrieve a Cairo context for the region you want to draw on.</para>
</listitem>
<listitem>
<para><emphasis>To clear existing content from a texture:</emphasis>
use <function>clutter_cairo_texture_clear</function>.</para>
use <function>clutter_cairo_texture_clear()</function>.</para>
<para>You may need to do this as the texture reuses the same
Cairo context each time you call
<function>clutter_cairo_texture_create</function> or
<function>clutter_cairo_texture_create_region</function>.</para>
<function>clutter_cairo_texture_create()</function> or
<function>clutter_cairo_texture_create_region()</function>.</para>
</listitem>
<listitem>
<para><emphasis>To resize the Cairo context wrapped
by a texture</emphasis>, use
<function>clutter_cairo_texture_set_surface_size</function>.</para>
<function>clutter_cairo_texture_set_surface_size()</function>.</para>
</listitem>
</itemizedlist>
@ -145,10 +147,11 @@ cairo_destroy (cr);
</informalexample>
<para>Note that if the page is larger than the Cairo context,
some of it might not be visible. Similarly, if the ClutterCairoTexture
is larger than the stage, some of that might not be visible. So you
may need to do some work to make the ClutterCairoTexture fit
inside the stage properly (e.g. resize the stage), and/or some work
some of it might not be visible. Similarly, if the
<type>ClutterCairoTexture</type> is larger than the stage,
some of that might not be visible. So you
may need to do some work to make the <type>ClutterCairoTexture</type>
fit inside the stage properly (e.g. resize the stage), and/or some work
to make the PDF page sit inside the Cairo context (e.g. scale the PDF
page or put it inside a scrollable actor).</para>
@ -174,8 +177,8 @@ cairo_destroy (cr);
<para>Set the texture to keep the aspect ratio of the
underlying image (so it doesn't distort when it's scaled); use
the actor's request-mode property to set the correct
geometry management (see the discussion section); then
the actor's <property>request-mode</property> property to set
the correct geometry management (see the discussion section); then
resize the texture along one dimension (height or width).
Now, when an image is loaded into the texture, the image is
scaled to fit the set height or width; the other dimension
@ -210,20 +213,20 @@ clutter_texture_set_from_file (CLUTTER_TEXTURE (texture),
<section>
<title>Discussion</title>
<para>The request mode for an actor determines how
geometry requisition is performed; in this case, this
<para>The <property>request-mode</property> for an actor
determines how geometry requisition is performed; in this case, this
includes how scaling is applied if you change the actor's
width or height. There are two possible values for
request-mode:</para>
<orderedlist>
<listitem>
<para>If set to <emphasis>CLUTTER_REQUEST_HEIGHT_FOR_WIDTH</emphasis>
<para>If set to <constant>CLUTTER_REQUEST_HEIGHT_FOR_WIDTH</constant>
(the default), changing the width causes the height
to be scaled by the same factor as the width.</para>
</listitem>
<listitem>
<para>If set to <emphasis>CLUTTER_REQUEST_WIDTH_FOR_HEIGHT</emphasis>,
<para>If set to <constant>CLUTTER_REQUEST_WIDTH_FOR_HEIGHT</constant>,
changing the height causes the width to be scaled by the
same factor as the height.</para>
</listitem>
@ -231,21 +234,22 @@ clutter_texture_set_from_file (CLUTTER_TEXTURE (texture),
<para>In the example above, the texture is set to keep its
aspect ratio then fixed to a width of 300 pixels; the
request-mode is set to CLUTTER_REQUEST_HEIGHT_FOR_WIDTH. If a
standard, photo-sized image in landscape orientation were
request-mode is set to <constant>CLUTTER_REQUEST_HEIGHT_FOR_WIDTH</constant>.
If a standard, photo-sized image in landscape orientation were
loaded into it (2848 pixels wide x 2136 high), it would be scaled
down to 300 pixels wide; then, its height would be scaled by the
same factor as the width (i.e. scaled down to 225 pixels).</para>
<para>With request-mode set to CLUTTER_REQUEST_WIDTH_FOR_HEIGHT,
<para>With request-mode set to
<constant>CLUTTER_REQUEST_WIDTH_FOR_HEIGHT</constant>,
you would get the same effect by setting the height first;
then, computation of the width for the scaled image would be
based on the scaling factor applied to its height instead.</para>
<para>You can work out which side of the source image is longest using
clutter_texture_base_size() to get its width and height. This can
be useful when trying to scale images with different orientations
to fit into uniform rows or columns:</para>
<function>clutter_texture_base_size()</function> to get its
width and height. This can be useful when trying to scale images
with different orientations to fit into uniform rows or columns:</para>
<informalexample>
<programlisting>
@ -259,8 +263,9 @@ clutter_texture_get_base_size (CLUTTER_TEXTURE (texture), &width, &height);
</informalexample>
<note><para>If you explicitly set the size (both width and height)
of a texture with clutter_actor_set_size() (or
with clutter_actor_set_width() and clutter_actor_set_height()), any
of a texture with <function>clutter_actor_set_size()</function> (or
with <function>clutter_actor_set_width()</function> and
<function>clutter_actor_set_height()</function>), any
image loaded into the texture is automatically stretched/shrunk to
fit the texture. This is the case regardless of any other settings
(like whether to keep aspect ratio).</para></note>
@ -285,7 +290,8 @@ clutter_texture_get_base_size (CLUTTER_TEXTURE (texture), &width, &height);
<section>
<title>Solution</title>
<para>Create a ClutterTexture directly from an image file:</para>
<para>Create a <type>ClutterTexture</type> directly from an
image file:</para>
<informalexample>
<programlisting>
@ -378,11 +384,12 @@ if (error != NULL)
<itemizedlist>
<listitem>
<para>Call g_thread_init() (from the GLib library) prior
to calling clutter_init(), so that a local thread is used
to load the file, rather than the main loop. (Note that
this is not necessary if you're using GLib version >= 2.24,
since GObject initializes threading with the type system.)</para>
<para>Call <function>g_thread_init()</function> (from the
GLib library) prior to calling <function>clutter_init()</function>,
so that a local thread is used to load the file, rather
than the main loop. (Note that this is not necessary if
you're using GLib version >= 2.24, since GObject
initializes threading with the type system.)</para>
</listitem>
<listitem>
<para>Set the texture to load data asynchronously.</para>
@ -462,16 +469,18 @@ main (int argc, char *argv[])
<itemizedlist>
<listitem>
<para>Various GNOME libraries provide image data in GdkPixbuf
structures; clutter-gtk has functions for
creating or setting a texture from a GdkPixbuf:
gtk_clutter_texture_new_from_pixbuf()
and gtk_clutter_texture_set_from_pixbuf() respectively.</para>
<para>Various GNOME libraries provide image data in
<type>GdkPixbuf</type> structures; clutter-gtk has
functions for creating or setting a texture from a
<type>GdkPixbuf</type>:
<function>gtk_clutter_texture_new_from_pixbuf()</function>
and <function>gtk_clutter_texture_set_from_pixbuf()</function>
respectively.</para>
</listitem>
<listitem>
<para>If you have raw RGB pixel data, ClutterTexture also has
the clutter_texture_set_from_rgb_data() method for loading
it.</para>
<para>If you have raw RGB pixel data, <type>ClutterTexture</type>
also has a <function>clutter_texture_set_from_rgb_data()</function>
function for loading it.</para>
</listitem>
</itemizedlist>