<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>4. Arranging actors in a single row or column</title><link rel="stylesheet" type="text/css" href="style.css"><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot"><link rel="home" href="index.html" title="The Clutter Cookbook"><link rel="up" href="layouts.html" title="Chapter 7. Layout management"><link rel="prev" href="layouts-bind-constraint.html" title="3. Binding the size of one actor to the size of another"><link rel="next" href="script.html" title="Chapter 8. Script"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">4. Arranging actors in a single row or column</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="layouts-bind-constraint.html">Prev</a> </td><th width="60%" align="center">Chapter 7. Layout management</th><td width="20%" align="right"> <a accesskey="n" href="script.html">Next</a></td></tr></table><hr></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="layouts-box"></a>4. Arranging actors in a single row or column</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idm140200506926400"></a>4.1. Problem</h3></div></div></div><p>You want to layout several actors in a single row
or column.</p><p>Example use cases:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>Creating an application menu.</p></li><li class="listitem"><p>Showing message subject lines as a list in an
email client.</p></li></ul></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idm140200506922464"></a>4.2. Solution</h3></div></div></div><p>Create a <span class="type">ClutterActor</span> with a
<span class="type">ClutterBoxLayout</span> as its layout manager.</p><p>A <span class="type">ClutterBoxLayout</span> can hold a single row or
column of <span class="type">ClutterActors</span>, and has configurable spacing,
actor alignments, and expand and fill options.</p><p>The code fragment below is excerpted from the
<a class="link" href="layouts-box.html#layouts-box-example-1" title="Example 7.6. Different approaches to setting child layout properties in a ClutterBoxLayout">full example</a>. It
demonstrates how to lay out three rectangles in a vertical
column. A different approach is used to set the <code class="varname">x-fill</code>
property on each rectangle, so each fills the horizontal space in
the layout (each rectangle is 100 pixels wide, while the
box they are inside is 200 pixels wide).</p><div class="informalexample"><pre class="programlisting">/* create a ClutterBoxLayout */
box_layout = clutter_box_layout_new ();
/* configure it to lay out actors vertically */
clutter_box_layout_set_vertical (CLUTTER_BOX_LAYOUT (box_layout), TRUE);
/* put 5px of spacing between actors */
clutter_box_layout_set_spacing (CLUTTER_BOX_LAYOUT (box_layout), 5);
/* actors are packed into this box; we set its width, but
* allow its height to be determined by the children it contains
*/
box = clutter_actor_new ();
clutter_actor_set_layout_manager (box, box_layout);
clutter_actor_set_background_color (box, &box_color);
clutter_actor_set_position (box, 100, 50);
clutter_actor_set_width (box, 200);
/* pack an actor into the layout and set all layout properties on it
* at the same time
*/
yellow = clutter_rectangle_new_with_color (&yellow_color);
clutter_actor_set_size (yellow, 100, 100);
clutter_box_layout_pack (CLUTTER_BOX_LAYOUT (box_layout),
yellow,
FALSE, /* expand */
TRUE, /* x-fill */
FALSE, /* y-fill */
CLUTTER_BOX_ALIGNMENT_START, /* x-align */
CLUTTER_BOX_ALIGNMENT_START); /* y-align */
/* add an actor to the box as a container and set layout properties
* afterwards; the latter is useful if you want to change properties on
* actors already inside a layout, but note that you have to
* pass the function both the layout AND the container
*/
red = clutter_rectangle_new_with_color (&red_color);
clutter_actor_set_size (red, 100, 100);
clutter_actor_add_child (box, blue);
clutter_layout_manager_child_set (box_layout,
CLUTTER_CONTAINER (box),
blue,
"x-fill", TRUE,
NULL);
blue = clutter_rectangle_new_with_color (&blue_color);
clutter_actor_set_size (blue, 100, 100);
clutter_actor_add_child (box, blue);
clutter_layout_manager_child_set (box_layout,
CLUTTER_CONTAINER (box),
blue,
"x-fill", TRUE,
NULL);
/* put the box on the stage */
clutter_actor_add_child (stage, box);</pre></div><p>The result looks like this:</p><div class="screenshot"><div class="mediaobject"><img src="images/layouts-box.png" alt="A simple vertical ClutterBoxLayout"></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idm140200506909648"></a>4.3. Discussion</h3></div></div></div><p><span class="type">ClutterBoxLayout</span> is not a reflowing layout:
that is, if the layout's container changes size, the actors inside
aren't automatically repositioned to occupy or find new positions
in its available area. If you want that behaviour, use
<span class="type">ClutterFlowLayout</span> instead.</p><p>If you want the container to be resizable, but find that
resizing the container obscures its child actors, you could put
the container inside a scrollable area. Then the container's actors
can be scrolled to if they go out of sight.
<a class="link" href="events-mouse-scroll.html" title="3. Detecting mouse scrolling on an actor">This recipe</a> explains
how to make a container scrollable.</p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="idm140200506906128"></a>4.3.1. Layout properties</h4></div></div></div><p><span class="type">ClutterBoxLayout</span> is very flexible, with
several properties which influence the appearance of the
layout and its children. As with other layouts, these properties
are either applicable to the layout itself, or to individual
children of the layout.</p><p>As most of these properties are documented in the API reference,
they aren't covered in much detail here. However, below is a brief
overview of the properties available, as well as details of properties
particular to <span class="type">ClutterBoxLayout</span>.</p><p>The main issue you may face when applying these properties
is understanding how they interact. As this is harder to describe
than to show, you can run the
<a class="link" href="layouts-box.html#layouts-box-example-3" title="Example 7.8. A demonstrator for "toggling and tweaking" a ClutterBoxLayout's properties">example</a>
below to toggle and tweak various properties and see
how they affect the layout's appearance.</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>The "toggle and tweak"
<a class="link" href="layouts-box.html#layouts-box-example-3" title="Example 7.8. A demonstrator for "toggling and tweaking" a ClutterBoxLayout's properties">example</a> sets
child properties (fill, alignment, expand) on all children
of the layout when those properties are changed. If you want
to see the effect of setting these to different values for
<span class="emphasis"><em>each</em></span> child, you will have to experiment
yourself.</p></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a name="idm140200506899616"></a>4.3.1.1. <span class="type">ClutterBoxLayout</span> properties</h5></div></div></div><p><span class="type">ClutterBoxLayout</span> has the following properties
which affect the appearance of all children inside the container.</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>Animation properties are covered separately
<a class="link" href="layouts-box.html#layouts-box-animating-layout-changes" title="4.3.2. Animating layout changes">later</a>.
</p></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><b><code class="varname">vertical</code>; set with
<code class="function">clutter_box_layout_set_vertical()</code>. </b>Set to <code class="constant">TRUE</code> to lay out
child actors in a column; if <code class="constant">FALSE</code>
(the default), actors are laid out horizontally.</p></li><li class="listitem"><p><b><code class="varname">homogeneous</code>; set with
<code class="function">clutter_box_layout_set_homogeneous()</code>. </b>Set to <code class="constant">TRUE</code> to allocate all
child actors the same amount of space in the row or column
(depending on the setting for <code class="varname">vertical</code>).
This overrides per-actor <code class="varname">expand</code> settings
and preferred sizes for child actors. The default value for
this property is <code class="constant">FALSE</code>.</p></li><li class="listitem"><p><b><code class="varname">spacing</code>; set with
<code class="function">clutter_box_layout_set_spacing()</code>. </b>Sets the number of pixels to place between actors
in the layout.</p><p>Note that if you increase spacing too much, actors
may go outside the edges of the layout's container (if
the container has a fixed size).</p></li><li class="listitem"><p><b><code class="varname">pack-start</code>; set with
<code class="function">clutter_box_layout_set_pack_start()</code>. </b>Set <code class="varname">pack-start</code> to
<code class="constant">TRUE</code> to configure the layout to
prepend actors to the row or column; the default is
<code class="constant">FALSE</code>, meaning that actors are
appended to the row or column when added.</p><p>Changing this property on a layout which already has
actors in it will reverse the order of those actors, as
well as changing how new actors are added to the layout.</p></li></ul></div></div><div class="section"><div class="titlepage"><div><div><h5 class="title"><a name="idm140200506879232"></a>4.3.1.2. Child properties</h5></div></div></div><p>These properties apply to individual children within
the layout's container. Each child can have different values
for each of these properties.</p><p>To set properties, you can use
<code class="function">clutter_box_layout_pack()</code> or
<code class="function">clutter_box_pack()</code> (if using a
<span class="type">ClutterBox</span>) while packing actors into the layout.
You can also set properties later using
<code class="function">clutter_layout_manager_child_set()</code>
etc. See the <a class="link" href="layouts.html#layouts-introduction" title="1. Introduction">layouts
introduction</a> for more details.</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><code class="varname">x-fill</code> and <code class="varname">y-fill</code>
set whether an actor will fill its allocated horizontal
or vertical space (respectively) within the layout. Setting
these properties only has an effect where an actor is smaller
(on the appropriate fill axes) than the layout's container.</p><p>Note that the actor's actual size is not changed
if it is set to fill: the reported width and height are
unaffected.</p></li><li class="listitem"><p><code class="varname">expand</code> sets whether an actor
will be expanded inside the layout. If
<code class="varname">expand</code> is <code class="constant">TRUE</code>
and <code class="varname">fill</code> is <code class="constant">TRUE</code>
for the orientation axis, the actor is resized to fill
its whole allocation on that axis; if <code class="varname">expand</code>
is <code class="constant">TRUE</code> but <code class="varname">fill</code>
is <code class="constant">FALSE</code>, extra padding is added
around the actor to fill the allocation.</p></li><li class="listitem"><p><code class="varname">x-align</code> and <code class="varname">y-align</code>
set how an actor is aligned within its allocation, in
cases where it doesn't fill that allocation. In practical
terms, these properties come into effect if a child is set
to expand but <code class="varname">fill</code> is set to
<code class="constant">FALSE</code> on the align axis.</p><p>For example, if <code class="varname">expand</code> is
<code class="constant">TRUE</code> but <code class="varname">x-fill</code>
is <code class="constant">FALSE</code>, some padding is added
around the actor to fill its allocation. In this case,
the <code class="varname">x-align</code> property can be set to
align the actor to the left, center or right of the
allocation; any whitespace would be redistributed around
the actor's new position after alignment.</p></li></ul></div><p>These properties are only useful where you have
actors of non-uniform sizes and/or a container which is
either wider or taller (or both) than one or more of the
child actors it contains.</p></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="layouts-box-animating-layout-changes"></a>4.3.2. Animating layout changes</h4></div></div></div><p>If actors are added to a layout, or if the layout's
properties or its children's properties are changed, the
appearance of the layout may also change. The
<code class="varname">use-animations</code> property (set with
<code class="function">clutter_box_layout_set_use_animations()</code>)
determines whether such changes to the layout are animated: if set
to <code class="constant">TRUE</code>, any changes to actor
allocations resulting from the changes (movements, resizings)
are animated.</p><p>If this property is <code class="constant">FALSE</code> (the default)
changes to other properties or addition of new actors will
cause actors to be laid out instantaneously. For example, if
a new actor is prepended with animations on, the new actor is
added to the layout and the other actors shifted to make room
for it; if animations are off, child actors jump to their new
positions at the same instant as the new actor is added.</p><p>To change the appearance of the animations, you can use
<code class="function">clutter_box_layout_set_easing_mode()</code> and
<code class="function">clutter_box_layout_set_duration()</code> (see the
<a class="link" href="animations.html#animations-introduction" title="1. Introduction">animations
introduction</a> for more about easing and duration
properties).</p><p>The <a class="link" href="layouts-box.html#layouts-box-example-3" title="Example 7.8. A demonstrator for "toggling and tweaking" a ClutterBoxLayout's properties">"toggle and tweak"
example</a> uses animation for layout changes, and can give
you some idea of what to expect in your own animated layouts.</p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="idm140200506850080"></a>4.4. Full examples</h3></div></div></div><div class="example"><a name="layouts-box-example-1"></a><p class="title"><b>Example 7.6. Different approaches to setting child layout properties
in a <span class="type">ClutterBoxLayout</span></b></p><div class="example-contents"><pre class="programlisting">#include <stdlib.h>
#include <clutter/clutter.h>
static const ClutterColor stage_color = { 0x33, 0x33, 0x55, 0xff };
static const ClutterColor box_color = { 0xff, 0xff, 0xff, 0xff };
static const ClutterColor yellow_color = { 0xaa, 0xaa, 0x00, 0xff };
static const ClutterColor red_color = { 0xff, 0x00, 0x00, 0xff };
static const ClutterColor blue_color = { 0x00, 0x00, 0xff, 0xff };
int
main (int argc,
char *argv[])
{
ClutterActor *stage;
ClutterLayoutManager *box_layout;
ClutterActor *box;
ClutterActor *yellow;
ClutterActor *red;
ClutterActor *blue;
if (clutter_init (&argc, &argv) != CLUTTER_INIT_SUCCESS)
return 1;
stage = clutter_stage_new ();
clutter_actor_set_size (stage, 400, 400);
clutter_stage_set_color (CLUTTER_STAGE (stage), &stage_color);
g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
/* create a ClutterBoxLayout */
box_layout = clutter_box_layout_new ();
/* configure it to lay out actors vertically */
clutter_box_layout_set_vertical (CLUTTER_BOX_LAYOUT (box_layout), TRUE);
/* put 5px of spacing between actors */
clutter_box_layout_set_spacing (CLUTTER_BOX_LAYOUT (box_layout), 5);
/* actors are packed into this actor; we set its width, but
* allow its height to be determined by the children it contains
*/
box = clutter_actor_new ();
clutter_actor_set_layout_manager (box, box_layout);
clutter_actor_set_background_color (box, CLUTTER_COLOR_White);
clutter_actor_set_position (box, 100, 50);
clutter_actor_set_width (box, 200);
/* pack an actor into the layout and set all layout properties on it
* at the same time
*/
yellow = clutter_actor_new ();
clutter_actor_set_background_color (yellow, CLUTTER_COLOR_Yellow);
clutter_actor_set_size (yellow, 100, 100);
clutter_box_layout_pack (CLUTTER_BOX_LAYOUT (box_layout),
yellow,
FALSE, /* expand */
TRUE, /* x-fill */
FALSE, /* y-fill */
CLUTTER_BOX_ALIGNMENT_START, /* x-align */
CLUTTER_BOX_ALIGNMENT_START); /* y-align */
/* add an actor to the box as a container and set layout properties
* afterwards; the latter is useful if you want to change properties on
* actors already inside a layout, but note that you have to
* pass the function both the layout AND the container
*/
red = clutter_actor_new ();
clutter_actor_set_background_color (red, CLUTTER_COLOR_Red);
clutter_actor_set_size (red, 100, 100);
clutter_actor_add_child (box, red);
clutter_layout_manager_child_set (box_layout,
CLUTTER_CONTAINER (box),
red,
"x-fill", TRUE,
NULL);
blue = clutter_actor_new ();
clutter_actor_set_background_color (blue, CLUTTER_COLOR_Blue);
clutter_actor_set_size (blue, 100, 100);
clutter_actor_add_child (box, blue);
clutter_layout_manager_child_set (box_layout,
CLUTTER_CONTAINER (box),
blue,
"x-fill", TRUE,
NULL);
/* put the box on the stage */
clutter_actor_add_child (stage, box);
clutter_actor_show (stage);
clutter_main ();
return EXIT_SUCCESS;
}
</pre></div></div><br class="example-break"><div class="example"><a name="layouts-box-example-2"></a><p class="title"><b>Example 7.7. A simple <span class="type">ClutterBoxLayout</span> menu</b></p><div class="example-contents"><pre class="programlisting">#include <stdlib.h>
#include <clutter/clutter.h>
#define FONT "Sans 20px"
static const ClutterColor stage_color = { 0x33, 0x33, 0x55, 0xff };
static const ClutterColor yellow_color = { 0xaa, 0xaa, 0x00, 0xff };
static const ClutterColor black_color = { 0x00, 0x00, 0x00, 0xff };
static void
menu_run_option (ClutterActor *actor,
ClutterEvent *event,
gpointer user_data)
{
g_debug ("%s pressed", (gchar *) user_data);
}
static void
menu_add_option (ClutterBox *menu,
gchar *text,
gchar *shortcut)
{
ClutterActor *entry;
entry = clutter_box_new (clutter_bin_layout_new (CLUTTER_BIN_ALIGNMENT_CENTER,
CLUTTER_BIN_ALIGNMENT_CENTER));
clutter_box_set_color (CLUTTER_BOX (entry), &black_color);
clutter_actor_set_width (entry, 250);
clutter_actor_set_reactive (entry, TRUE);
clutter_box_pack (CLUTTER_BOX (entry),
clutter_text_new_full (FONT, text, &yellow_color),
"x-align", CLUTTER_BIN_ALIGNMENT_START,
NULL);
clutter_box_pack (CLUTTER_BOX (entry),
clutter_text_new_full (FONT, shortcut, &yellow_color),
"x-align", CLUTTER_BIN_ALIGNMENT_END,
NULL);
clutter_container_add_actor (CLUTTER_CONTAINER (menu), entry);
g_signal_connect (entry,
"button-press-event",
G_CALLBACK (menu_run_option),
text);
}
static void
menu_toggle (ClutterActor *actor,
ClutterEvent *event,
gpointer user_data)
{
ClutterAnimation *animation;
ClutterActor *menu = CLUTTER_ACTOR (user_data);
if (clutter_actor_get_animation (menu))
return;
if (clutter_actor_get_opacity (menu) > 0)
{
animation = clutter_actor_animate (menu, CLUTTER_EASE_OUT_CUBIC, 200,
"opacity", 0,
NULL);
/* hide the menu once it is fully transparent */
g_signal_connect_swapped (animation,
"completed",
G_CALLBACK (clutter_actor_hide),
menu);
}
else
{
clutter_actor_show (menu);
clutter_actor_animate (menu, CLUTTER_EASE_OUT_CUBIC, 200,
"opacity", 255,
NULL);
}
}
int
main (int argc,
char *argv[])
{
ClutterActor *stage;
ClutterActor *button;
ClutterLayoutManager *menu_layout;
ClutterActor *menu;
if (clutter_init (&argc, &argv) != CLUTTER_INIT_SUCCESS)
return 1;
stage = clutter_stage_new ();
clutter_actor_set_size (stage, 400, 400);
clutter_stage_set_color (CLUTTER_STAGE (stage), &stage_color);
g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
/* button */
button = clutter_box_new (clutter_bin_layout_new (CLUTTER_BIN_ALIGNMENT_CENTER,
CLUTTER_BIN_ALIGNMENT_CENTER));
clutter_actor_set_width (button, 100);
clutter_actor_set_position (button, 50, 50);
clutter_actor_set_reactive (button, TRUE);
clutter_box_set_color (CLUTTER_BOX (button), &black_color);
clutter_box_pack (CLUTTER_BOX (button),
clutter_text_new_full (FONT, "Edit", &yellow_color),
"x-align", CLUTTER_BIN_ALIGNMENT_FILL,
"y-align", CLUTTER_BIN_ALIGNMENT_FILL,
NULL);
/* menu */
menu_layout = clutter_box_layout_new ();
clutter_box_layout_set_homogeneous (CLUTTER_BOX_LAYOUT (menu_layout), TRUE);
clutter_box_layout_set_vertical (CLUTTER_BOX_LAYOUT (menu_layout), TRUE);
clutter_box_layout_set_spacing (CLUTTER_BOX_LAYOUT (menu_layout), 2);
menu = clutter_box_new (menu_layout);
clutter_box_set_color (CLUTTER_BOX (menu), &yellow_color);
menu_add_option (CLUTTER_BOX (menu), "Undo", "Ctrl-z");
menu_add_option (CLUTTER_BOX (menu), "Redo", "Ctrl-Shift-z");
menu_add_option (CLUTTER_BOX (menu), "Cut", "Ctrl-x");
menu_add_option (CLUTTER_BOX (menu), "Copy", "Ctrl-c");
menu_add_option (CLUTTER_BOX (menu), "Paste", "Ctrl-v");
/* align left-hand side of menu with left-hand side of button */
clutter_actor_add_constraint (menu, clutter_align_constraint_new (button,
CLUTTER_ALIGN_X_AXIS,
0.0));
/* align top of menu with the bottom of the button */
clutter_actor_add_constraint (menu, clutter_bind_constraint_new (button,
CLUTTER_BIND_Y,
clutter_actor_get_height (button)));
/* hide the menu until we're ready to animate it in */
clutter_actor_set_opacity (menu, 0);
clutter_actor_hide (menu);
/* clicking on the button toggles the menu */
g_signal_connect (button, "button-press-event", G_CALLBACK (menu_toggle), menu);
clutter_container_add_actor (CLUTTER_CONTAINER (stage), menu);
clutter_container_add_actor (CLUTTER_CONTAINER (stage), button);
clutter_actor_show (stage);
clutter_main ();
return EXIT_SUCCESS;
}
</pre></div></div><br class="example-break"><div class="example"><a name="layouts-box-example-3"></a><p class="title"><b>Example 7.8. A demonstrator for "toggling and tweaking" a
<span class="type">ClutterBoxLayout's</span> properties</b></p><div class="example-contents"><pre class="programlisting">/*
* Experiment with permutations of layout properties for a ClutterBoxLayout
*
* See the text (in brackets) at the bottom of the application
* window for available key presses
*/
#include <stdlib.h>
#include <clutter/clutter.h>
#define STAGE_SIDE 510
#define BOX_SIDE STAGE_SIDE * 0.75
#define RED_SIDE STAGE_SIDE / 4
#define GREEN_SIDE STAGE_SIDE / 8
#define BLUE_SIDE STAGE_SIDE / 16
typedef struct
{
ClutterLayoutManager *box_layout;
ClutterActor *box;
ClutterActor *status_display;
gboolean x_fill;
gboolean y_fill;
gboolean expand;
ClutterBoxAlignment x_align;
ClutterBoxAlignment y_align;
} State;
static const ClutterColor stage_color = { 0x33, 0x33, 0x55, 0xff };
static const ClutterColor box_color = { 0x66, 0x66, 0x00, 0xff };
static const ClutterColor red_color = { 0xff, 0x00, 0x00, 0xff };
static const ClutterColor green_color = { 0x00, 0xff, 0x00, 0xff };
static const ClutterColor blue_color = { 0x00, 0x00, 0xff, 0xff };
static const ClutterColor white_color = { 0xff, 0xff, 0xff, 0xff };
static GValue
gboolean_to_gvalue (gboolean value)
{
GValue gval = {0};
g_value_init (&gval, G_TYPE_BOOLEAN);
g_value_set_boolean (&gval, value);
return gval;
}
static GValue
alignment_to_gvalue (ClutterBoxAlignment value)
{
GValue gval = {0};
g_value_init (&gval, G_TYPE_INT);
g_value_set_int (&gval, value);
return gval;
}
static gchar*
alignment_as_string (ClutterBoxAlignment value)
{
gchar *align_string = "start ";
switch (value)
{
case CLUTTER_BOX_ALIGNMENT_CENTER:
align_string = "center";
break;
case CLUTTER_BOX_ALIGNMENT_END:
align_string = "end ";
break;
case CLUTTER_BOX_ALIGNMENT_START:
align_string = "start ";
break;
}
return align_string;
}
static ClutterBoxAlignment
get_next_alignment (ClutterBoxAlignment alignment)
{
alignment++;
if (alignment > CLUTTER_BOX_ALIGNMENT_CENTER)
alignment = CLUTTER_BOX_ALIGNMENT_START;
return alignment;
}
static void
show_status (State *state)
{
ClutterText *text = CLUTTER_TEXT (state->status_display);
ClutterBoxLayout *box_layout = CLUTTER_BOX_LAYOUT (state->box_layout);
gboolean homogeneous = clutter_box_layout_get_homogeneous (box_layout);
gboolean vertical = clutter_box_layout_get_vertical (box_layout);
gchar *message = g_strdup_printf ("x_fill (x): %s\t\t\t"
"y_fill (y): %s\n"
"expand (e): %s\t\t"
"homogeneous (h): %s\n"
"spacing (+/-): %dpx\t\t"
"vertical (v): %s\n"
"x_align (right): %s\t"
"y_align (up): %s",
(state->x_fill ? "true" : "false"),
(state->y_fill ? "true" : "false"),
(state->expand ? "true" : "false"),
(homogeneous ? "true" : "false"),
clutter_box_layout_get_spacing (box_layout),
(vertical ? "true" : "false"),
alignment_as_string (state->x_align),
alignment_as_string (state->y_align));
clutter_text_set_text (text, message);
g_free (message);
}
static void
set_property_on_layout_children (State *state,
const gchar *property,
GValue value)
{
ClutterActor *actor;
ClutterContainer *container = CLUTTER_CONTAINER (state->box);
ClutterLayoutManager *manager = CLUTTER_LAYOUT_MANAGER (state->box_layout);
GList *actors = clutter_container_get_children (container);
for (; actors; actors = actors->next)
{
actor = CLUTTER_ACTOR (actors->data);
clutter_layout_manager_child_set_property (manager,
container,
actor,
property,
&value);
}
g_list_free (actors);
}
static void
toggle_x_fill (GObject *instance,
const gchar *action_name,
guint key_val,
ClutterModifierType modifiers,
gpointer user_data)
{
State *state = (State *) user_data;
state->x_fill = !state->x_fill;
set_property_on_layout_children (state,
"x-fill",
gboolean_to_gvalue (state->x_fill));
}
static void
toggle_y_fill (GObject *instance,
const gchar *action_name,
guint key_val,
ClutterModifierType modifiers,
gpointer user_data)
{
State *state = (State *) user_data;
state->y_fill = !state->y_fill;
set_property_on_layout_children (state,
"y-fill",
gboolean_to_gvalue (state->y_fill));
}
static void
toggle_expand (GObject *instance,
const gchar *action_name,
guint key_val,
ClutterModifierType modifiers,
gpointer user_data)
{
State *state = (State *) user_data;
state->expand = !state->expand;
set_property_on_layout_children (state,
"expand",
gboolean_to_gvalue (state->expand));
}
static void
rotate_x_alignment (GObject *instance,
const gchar *action_name,
guint key_val,
ClutterModifierType modifiers,
gpointer user_data)
{
State *state = (State *) user_data;
state->x_align = get_next_alignment (state->x_align);
set_property_on_layout_children (state,
"x-align",
alignment_to_gvalue (state->x_align));
}
static void
rotate_y_alignment (GObject *instance,
const gchar *action_name,
guint key_val,
ClutterModifierType modifiers,
gpointer user_data)
{
State *state = (State *) user_data;
state->y_align = get_next_alignment (state->y_align);
set_property_on_layout_children (state,
"y-align",
alignment_to_gvalue (state->y_align));
}
static void
toggle_vertical (GObject *instance,
const gchar *action_name,
guint key_val,
ClutterModifierType modifiers,
gpointer user_data)
{
State *state = (State *) user_data;
ClutterBoxLayout *box_layout = CLUTTER_BOX_LAYOUT (state->box_layout);
gboolean vertical = clutter_box_layout_get_vertical (box_layout);
clutter_box_layout_set_vertical (box_layout, !vertical);
}
static void
toggle_homogeneous (GObject *instance,
const gchar *action_name,
guint key_val,
ClutterModifierType modifiers,
gpointer user_data)
{
State *state = (State *) user_data;
ClutterBoxLayout *box_layout = CLUTTER_BOX_LAYOUT (state->box_layout);
gboolean homogeneous = clutter_box_layout_get_homogeneous (box_layout);
clutter_box_layout_set_homogeneous (box_layout, !homogeneous);
}
static void
increase_spacing (GObject *instance,
const gchar *action_name,
guint key_val,
ClutterModifierType modifiers,
gpointer user_data)
{
State *state = (State *) user_data;
ClutterBoxLayout *box_layout = CLUTTER_BOX_LAYOUT (state->box_layout);
guint spacing = clutter_box_layout_get_spacing (box_layout) + 5;
clutter_box_layout_set_spacing (box_layout, spacing);
}
static void
decrease_spacing (GObject *instance,
const gchar *action_name,
guint key_val,
ClutterModifierType modifiers,
gpointer user_data)
{
State *state = (State *) user_data;
ClutterBoxLayout *box_layout = CLUTTER_BOX_LAYOUT (state->box_layout);
guint spacing = clutter_box_layout_get_spacing (box_layout);
if (spacing >= 5)
clutter_box_layout_set_spacing (box_layout, spacing - 5);
}
static gboolean
key_pressed_cb (ClutterActor *actor,
ClutterEvent *event,
gpointer user_data)
{
State *state = (State *) user_data;
ClutterBindingPool *pool;
gboolean return_value;
pool = clutter_binding_pool_find (G_OBJECT_TYPE_NAME (actor));
return_value = clutter_binding_pool_activate (pool,
clutter_event_get_key_symbol (event),
clutter_event_get_state (event),
G_OBJECT (actor));
show_status (state);
return return_value;
}
int
main (int argc,
char *argv[])
{
ClutterActor *stage;
GObjectClass *stage_class;
ClutterBindingPool *binding_pool;
ClutterActor *red;
ClutterActor *green;
ClutterActor *blue;
State *state = g_new0 (State, 1);
if (clutter_init (&argc, &argv) != CLUTTER_INIT_SUCCESS)
return 1;
state->x_fill = FALSE;
state->y_fill = FALSE;
state->expand = FALSE;
state->x_align = CLUTTER_BOX_ALIGNMENT_START;
stage = clutter_stage_new ();
clutter_actor_set_size (stage, STAGE_SIDE, STAGE_SIDE);
clutter_stage_set_color (CLUTTER_STAGE (stage), &stage_color);
g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
/* for key bindings */
stage_class = G_OBJECT_GET_CLASS (stage);
binding_pool = clutter_binding_pool_get_for_class (stage_class);
clutter_binding_pool_install_action (binding_pool,
"toggle-expand",
CLUTTER_KEY_e,
0,
G_CALLBACK (toggle_expand),
state,
NULL);
clutter_binding_pool_install_action (binding_pool,
"toggle-x-fill",
CLUTTER_KEY_x,
0,
G_CALLBACK (toggle_x_fill),
state,
NULL);
clutter_binding_pool_install_action (binding_pool,
"toggle-y-fill",
CLUTTER_KEY_y,
0,
G_CALLBACK (toggle_y_fill),
state,
NULL);
clutter_binding_pool_install_action (binding_pool,
"toggle-vertical",
CLUTTER_KEY_v,
0,
G_CALLBACK (toggle_vertical),
state,
NULL);
clutter_binding_pool_install_action (binding_pool,
"toggle-homogeneous",
CLUTTER_KEY_h,
0,
G_CALLBACK (toggle_homogeneous),
state,
NULL);
clutter_binding_pool_install_action (binding_pool,
"rotate-x-alignment",
CLUTTER_KEY_Right,
0,
G_CALLBACK (rotate_x_alignment),
state,
NULL);
clutter_binding_pool_install_action (binding_pool,
"rotate-y-alignment",
CLUTTER_KEY_Up,
0,
G_CALLBACK (rotate_y_alignment),
state,
NULL);
clutter_binding_pool_install_action (binding_pool,
"increase-spacing",
CLUTTER_KEY_plus,
CLUTTER_SHIFT_MASK,
G_CALLBACK (increase_spacing),
state,
NULL);
clutter_binding_pool_install_action (binding_pool,
"decrease-spacing",
CLUTTER_KEY_minus,
0,
G_CALLBACK (decrease_spacing),
state,
NULL);
/* rectangles inside the layout */
red = clutter_rectangle_new_with_color (&red_color);
clutter_actor_set_size (red, RED_SIDE, RED_SIDE);
green = clutter_rectangle_new_with_color (&green_color);
clutter_actor_set_size (green, GREEN_SIDE, GREEN_SIDE);
blue = clutter_rectangle_new_with_color (&blue_color);
clutter_actor_set_size (blue, BLUE_SIDE, BLUE_SIDE);
/* the layout */
state->box_layout = clutter_box_layout_new ();
clutter_box_layout_set_use_animations (CLUTTER_BOX_LAYOUT (state->box_layout),
TRUE);
state->box = clutter_box_new (state->box_layout);
clutter_box_set_color (CLUTTER_BOX (state->box), &box_color);
clutter_actor_set_size (state->box, BOX_SIDE, BOX_SIDE);
clutter_actor_add_constraint (state->box,
clutter_align_constraint_new (stage, CLUTTER_ALIGN_X_AXIS, 0.5));
clutter_actor_add_constraint (state->box,
clutter_align_constraint_new (stage, CLUTTER_ALIGN_Y_AXIS, 0.1));
/* text to show status */
state->status_display = clutter_text_new ();
clutter_text_set_color (CLUTTER_TEXT (state->status_display), &white_color);
clutter_actor_set_size (state->status_display,
STAGE_SIDE,
STAGE_SIDE * 0.2);
clutter_actor_set_position (state->status_display,
(STAGE_SIDE - BOX_SIDE) / 2,
STAGE_SIDE * 0.8);
/* set text for initial state */
show_status (state);
/* connect key presses to a callback on the binding pool */
g_signal_connect (stage,
"key-press-event",
G_CALLBACK (key_pressed_cb),
state);
/* pack UI */
clutter_container_add (CLUTTER_CONTAINER (state->box), red, green, blue, NULL);
clutter_container_add (CLUTTER_CONTAINER (stage),
state->box,
state->status_display,
NULL);
/* show stage */
clutter_actor_show (stage);
clutter_main ();
/* clean up */
g_object_unref (binding_pool);
g_free (state);
return EXIT_SUCCESS;
}
</pre></div></div><br class="example-break"></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="layouts-bind-constraint.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="layouts.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="script.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">3. Binding the size of one actor to the size of another </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 8. Script</td></tr></table></div></body></html>