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mutter/clutter/clutter-path.c
Neil Roberts ff92cc9766 Convert clutter_path_get_position to take a gdouble instead of an alpha value 
The gdouble value represents an interval along the path from 0.0 to
1.0. This makes more sense than using an alpha value because paths are
not directly related to ClutterAlphas and the rest of the Clutter API
tends to expose gdouble arguments.
2008-12-16 15:39:53 +00:00

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/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By Matthew Allum <mallum@openedhand.com>
*
* Copyright (C) 2008 Intel Corporation
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* SECTION:clutter-path
* @short_description: An object describing a path with straight lines
* and bezier curves.
*
* A #ClutterPath contains a description of a path consisting of
* straight lines and bezier curves. This can be used in a
* #ClutterBehaviourPath to animate an actor moving along the path.
*
* The path consists of a series of nodes. Each node is one of the
* following four types:
*
* <variablelist>
* <varlistentry><term>%CLUTTER_PATH_MOVE_TO</term>
* <listitem><para>
* Changes the position of the path to the given pair of
* coordinates. This is usually used as the first node of a path to
* mark the start position. If it is used in the middle of a path then
* the path will be disjoint and the actor will appear to jump to the
* new position when animated.
* </para></listitem></varlistentry>
* <varlistentry><term>%CLUTTER_PATH_LINE_TO</term>
* <listitem><para>
* Creates a straight line from the previous point to the given point.
* </para></listitem></varlistentry>
* <varlistentry><term>%CLUTTER_PATH_CURVE_TO</term>
* <listitem><para>
* Creates a bezier curve. The end of the last node is used as the
* first control point and the three subsequent coordinates given in
* the node as used as the other three.
* </para></listitem></varlistentry>
* <varlistentry><term>%CLUTTER_PATH_CLOSE</term>
* <listitem><para>
* Creates a straight line from the last node to the last
* %CLUTTER_PATH_MOVE_TO node. This can be used to close a path so
* that it will appear as a loop when animated.
* </para></listitem></varlistentry>
* </variablelist>
*
* The first three types have the corresponding relative versions
* %CLUTTER_PATH_REL_MOVE_TO, %CLUTTER_PATH_REL_LINE_TO and
* %CLUTTER_PATH_REL_CURVE_TO. These are exactly the same except the
* coordinates are given relative to the previous node instead of as
* direct screen positions.
*
* You can build a path using the node adding functions such as
* clutter_path_add_line_to(). Alternatively the path can be described
* in a string using a subset of the SVG path syntax. See
* clutter_path_add_string() for details.
*
* #ClutterPath is available since Clutter 1.0
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <glib-object.h>
#include <string.h>
#include <stdarg.h>
#include "clutter-path.h"
#include "clutter-types.h"
#include "clutter-bezier.h"
#include "clutter-private.h"
G_DEFINE_TYPE (ClutterPath, clutter_path, G_TYPE_INITIALLY_UNOWNED);
#define CLUTTER_PATH_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE ((obj), CLUTTER_TYPE_PATH, \
ClutterPathPrivate))
#define CLUTTER_PATH_NODE_TYPE_IS_VALID(t) \
((((t) & ~CLUTTER_PATH_RELATIVE) >= CLUTTER_PATH_MOVE_TO \
&& ((t) & ~CLUTTER_PATH_RELATIVE) <= CLUTTER_PATH_CURVE_TO) \
|| (t) == CLUTTER_PATH_CLOSE)
enum
{
PROP_0,
PROP_DESCRIPTION,
PROP_LENGTH
};
typedef struct _ClutterPathNodeFull ClutterPathNodeFull;
struct _ClutterPathNodeFull
{
ClutterPathNode k;
ClutterBezier *bezier;
guint length;
};
struct _ClutterPathPrivate
{
GSList *nodes, *nodes_tail;
gboolean nodes_dirty;
guint total_length;
};
/* Character tests that don't pay attention to the locale */
#define clutter_path_isspace(ch) memchr (" \f\n\r\t\v", (ch), 6)
#define clutter_path_isdigit(ch) ((ch) >= '0' && (ch) <= '9')
static ClutterPathNodeFull *clutter_path_node_full_new (void);
static void clutter_path_node_full_free (ClutterPathNodeFull *node);
static void clutter_path_finalize (GObject *object);
static void
clutter_path_get_property (GObject *gobject,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
ClutterPath *path = CLUTTER_PATH (gobject);
switch (prop_id)
{
case PROP_DESCRIPTION:
g_value_take_string (value, clutter_path_get_description (path));
break;
case PROP_LENGTH:
g_value_set_uint (value, clutter_path_get_length (path));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
clutter_path_set_property (GObject *gobject,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
ClutterPath *path = CLUTTER_PATH (gobject);
switch (prop_id)
{
case PROP_DESCRIPTION:
if (!clutter_path_set_description (path, g_value_get_string (value)))
g_warning ("Invalid path description");
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
clutter_path_class_init (ClutterPathClass *klass)
{
GObjectClass *gobject_class = (GObjectClass *) klass;
GParamSpec *pspec;
gobject_class->get_property = clutter_path_get_property;
gobject_class->set_property = clutter_path_set_property;
gobject_class->finalize = clutter_path_finalize;
pspec = g_param_spec_string ("description",
"Description",
"SVG-style description of the path",
"",
CLUTTER_PARAM_READWRITE);
g_object_class_install_property (gobject_class, PROP_DESCRIPTION, pspec);
pspec = g_param_spec_uint ("length",
"Length",
"An approximation of the total length "
"of the path.",
0, G_MAXUINT, 0,
CLUTTER_PARAM_READABLE);
g_object_class_install_property (gobject_class, PROP_LENGTH, pspec);
g_type_class_add_private (klass, sizeof (ClutterPathPrivate));
}
static void
clutter_path_init (ClutterPath *self)
{
self->priv = CLUTTER_PATH_GET_PRIVATE (self);
}
static void
clutter_path_finalize (GObject *object)
{
ClutterPath *self = (ClutterPath *) object;
clutter_path_clear (self);
G_OBJECT_CLASS (clutter_path_parent_class)->finalize (object);
}
/**
* clutter_path_new:
*
* Creates a new #ClutterPath instance with no nodes.
*
* The object has a floating reference so if you add it to a
* #ClutterBehaviourPath then you do not need to unref it.
*
* Return value: the newly created #ClutterPath
*
* Since: 1.0
*/
ClutterPath *
clutter_path_new (void)
{
ClutterPath *self = g_object_new (CLUTTER_TYPE_PATH, NULL);
return self;
}
/**
* clutter_path_new_with_description:
* @desc: a string describing the path
*
* Creates a new #ClutterPath instance with the nodes described in
* @desc. See clutter_path_add_string() for details of the format of
* the string.
*
* The object has a floating reference so if you add it to a
* #ClutterBehaviourPath then you do not need to unref it.
*
* Return value: the newly created #ClutterPath
*
* Since: 1.0
*/
ClutterPath *
clutter_path_new_with_description (const gchar *desc)
{
return g_object_new (CLUTTER_TYPE_PATH,
"description", desc,
NULL);
}
/**
* clutter_path_clear:
* @path: a #ClutterPath
*
* Removes all nodes from the path.
*
* Since: 1.0
*/
void
clutter_path_clear (ClutterPath *path)
{
ClutterPathPrivate *priv = path->priv;
g_slist_foreach (priv->nodes, (GFunc) clutter_path_node_full_free, NULL);
g_slist_free (priv->nodes);
priv->nodes = priv->nodes_tail = NULL;
priv->nodes_dirty = TRUE;
}
/* Takes ownership of the node */
static void
clutter_path_add_node_full (ClutterPath *path,
ClutterPathNodeFull *node)
{
ClutterPathPrivate *priv = path->priv;
GSList *new_node;
new_node = g_slist_prepend (NULL, node);
if (priv->nodes_tail == NULL)
priv->nodes = new_node;
else
priv->nodes_tail->next = new_node;
priv->nodes_tail = new_node;
priv->nodes_dirty = TRUE;
}
/* Helper function to make the rest of teh add_* functions shorter */
static void
clutter_path_add_node_helper (ClutterPath *path,
ClutterPathNodeType type,
int num_coords,
...)
{
ClutterPathNodeFull *node;
int i;
va_list ap;
g_return_if_fail (CLUTTER_IS_PATH (path));
node = clutter_path_node_full_new ();
node->k.type = type;
va_start (ap, num_coords);
for (i = 0; i < num_coords; i++)
{
node->k.points[i].x = va_arg (ap, gint);
node->k.points[i].y = va_arg (ap, gint);
}
va_end (ap);
clutter_path_add_node_full (path, node);
}
/**
* clutter_path_add_move_to:
* @path: a #ClutterPath
* @x: the x coordinate
* @y: the y coordinate
*
* Adds a #CLUTTER_PATH_MOVE_TO type node to the path. This is usually
* used as the first node in a path. It can also be used in the middle
* of the path to cause the actor to jump to the new coordinate.
*
* Since: 1.0
*/
void
clutter_path_add_move_to (ClutterPath *path,
gint x,
gint y)
{
clutter_path_add_node_helper (path, CLUTTER_PATH_MOVE_TO, 1, x, y);
}
/**
* clutter_path_add_rel_move_to:
* @path: a #ClutterPath
* @x: the x coordinate
* @y: the y coordinate
*
* Same as clutter_path_add_move_to() except the coordinates are
* relative to the previous node.
*
* Since: 1.0
*/
void
clutter_path_add_rel_move_to (ClutterPath *path,
gint x,
gint y)
{
clutter_path_add_node_helper (path, CLUTTER_PATH_REL_MOVE_TO, 1, x, y);
}
/**
* clutter_path_add_line_to:
* @path: a #ClutterPath
* @x: the x coordinate
* @y: the y coordinate
*
* Adds a #CLUTTER_PATH_LINE_TO type node to the path. This causes the
* actor to move to the new coordinates in a straight line.
*
* Since: 1.0
*/
void
clutter_path_add_line_to (ClutterPath *path,
gint x,
gint y)
{
clutter_path_add_node_helper (path, CLUTTER_PATH_LINE_TO, 1, x, y);
}
/**
* clutter_path_add_rel_line_to:
* @path: a #ClutterPath
* @x: the x coordinate
* @y: the y coordinate
*
* Same as clutter_path_add_line_to() except the coordinates are
* relative to the previous node.
*
* Since: 1.0
*/
void
clutter_path_add_rel_line_to (ClutterPath *path,
gint x,
gint y)
{
clutter_path_add_node_helper (path, CLUTTER_PATH_REL_LINE_TO, 1, x, y);
}
/**
* clutter_path_add_curve_to:
* @path: a #ClutterPath
* @x1: the x coordinate of the first control point
* @y1: the y coordinate of the first control point
* @x2: the x coordinate of the second control point
* @y2: the y coordinate of the second control point
* @x3: the x coordinate of the third control point
* @y3: the y coordinate of the third control point
*
* Adds a #CLUTTER_PATH_CURVE_TO type node to the path. This causes
* the actor to follow a bezier from the last node to (x3,y3) using
* (x1,y1) and (x2,y2) as control points.
*
* Since: 1.0
*/
void
clutter_path_add_curve_to (ClutterPath *path,
gint x1,
gint y1,
gint x2,
gint y2,
gint x3,
gint y3)
{
clutter_path_add_node_helper (path, CLUTTER_PATH_CURVE_TO, 3,
x1, y1, x2, y2, x3, y3);
}
/**
* clutter_path_add_rel_curve_to:
* @path: a #ClutterPath
* @x1: the x coordinate of the first control point
* @y1: the y coordinate of the first control point
* @x2: the x coordinate of the second control point
* @y2: the y coordinate of the second control point
* @x3: the x coordinate of the third control point
* @y3: the y coordinate of the third control point
*
* Same as clutter_path_add_curve_to() except the coordinates are
* relative to the previous node.
*
* Since: 1.0
*/
void
clutter_path_add_rel_curve_to (ClutterPath *path,
gint x1,
gint y1,
gint x2,
gint y2,
gint x3,
gint y3)
{
clutter_path_add_node_helper (path, CLUTTER_PATH_REL_CURVE_TO, 3,
x1, y1, x2, y2, x3, y3);
}
/**
* clutter_path_add_close:
* @path: a #ClutterPath
*
* Adds a #CLUTTER_PATH_CLOSE type node to the path. This creates a
* straight line from the last node to the last #CLUTTER_PATH_MOVE_TO
* type node.
*
* Since: 1.0
*/
void
clutter_path_add_close (ClutterPath *path)
{
clutter_path_add_node_helper (path, CLUTTER_PATH_CLOSE, 0);
}
static gboolean
clutter_path_parse_number (const gchar **pin, gboolean allow_comma, gint *ret)
{
gint val = 0;
gboolean negative = FALSE;
gint digit_count = 0;
const gchar *p = *pin;
/* Skip leading spaces */
while (clutter_path_isspace (*p))
p++;
/* Optional comma */
if (allow_comma && *p == ',')
{
p++;
while (clutter_path_isspace (*p))
p++;
}
/* Optional sign */
if (*p == '+')
p++;
else if (*p == '-')
{
negative = TRUE;
p++;
}
/* Some digits */
while (clutter_path_isdigit (*p))
{
val = val * 10 + *p - '0';
digit_count++;
p++;
}
/* We need at least one digit */
if (digit_count < 1)
return FALSE;
/* Optional fractional part which we ignore */
if (*p == '.')
{
p++;
digit_count = 0;
while (clutter_path_isdigit (*p))
{
digit_count++;
p++;
}
/* If there is a fractional part then it also needs at least one
digit */
if (digit_count < 1)
return FALSE;
}
*pin = p;
*ret = negative ? -val : val;
return TRUE;
}
static gboolean
clutter_path_parse_description (const gchar *p, GSList **ret)
{
GSList *nodes = NULL;
ClutterPathNodeFull *node;
while (TRUE)
{
/* Skip leading whitespace */
while (clutter_path_isspace (*p))
p++;
/* It is not an error to end now */
if (*p == '\0')
break;
switch (*p)
{
case 'M':
case 'm':
case 'L':
case 'l':
node = clutter_path_node_full_new ();
nodes = g_slist_prepend (nodes, node);
node->k.type = (*p == 'M' ? CLUTTER_PATH_MOVE_TO
: *p == 'm' ? CLUTTER_PATH_REL_MOVE_TO
: *p == 'L' ? CLUTTER_PATH_LINE_TO
: CLUTTER_PATH_REL_LINE_TO);
p++;
if (!clutter_path_parse_number (&p, FALSE, &node->k.points[0].x)
|| !clutter_path_parse_number (&p, TRUE, &node->k.points[0].y))
goto fail;
break;
case 'C':
case 'c':
node = clutter_path_node_full_new ();
nodes = g_slist_prepend (nodes, node);
node->k.type = (*p == 'C' ? CLUTTER_PATH_CURVE_TO
: CLUTTER_PATH_REL_CURVE_TO);
p++;
if (!clutter_path_parse_number (&p, FALSE, &node->k.points[0].x)
|| !clutter_path_parse_number (&p, TRUE, &node->k.points[0].y)
|| !clutter_path_parse_number (&p, TRUE, &node->k.points[1].x)
|| !clutter_path_parse_number (&p, TRUE, &node->k.points[1].y)
|| !clutter_path_parse_number (&p, TRUE, &node->k.points[2].x)
|| !clutter_path_parse_number (&p, TRUE, &node->k.points[2].y))
goto fail;
break;
case 'Z':
case 'z':
node = clutter_path_node_full_new ();
nodes = g_slist_prepend (nodes, node);
p++;
node->k.type = CLUTTER_PATH_CLOSE;
break;
default:
goto fail;
}
}
*ret = g_slist_reverse (nodes);
return TRUE;
fail:
g_slist_foreach (nodes, (GFunc) clutter_path_node_full_free, NULL);
g_slist_free (nodes);
return FALSE;
}
/* Takes ownership of the node list */
static void
clutter_path_add_nodes (ClutterPath *path, GSList *nodes)
{
ClutterPathPrivate *priv = path->priv;
if (priv->nodes_tail == NULL)
priv->nodes = nodes;
else
priv->nodes_tail->next = nodes;
while (nodes)
{
priv->nodes_tail = nodes;
nodes = nodes->next;
}
priv->nodes_dirty = TRUE;
}
/**
* clutter_path_add_string:
* @path: a #ClutterPath
* @str: a string describing the new nodes
*
* Adds new nodes to the end of the path as described in @str. The
* format is a subset of the SVG path format. Each node is represented
* by a letter and is followed by zero, one or three pairs of
* coordinates. The coordinates can be separated by spaces or a
* comma. The types are:
*
* <variablelist>
* <varlistentry><term>M</term>
* <listitem><para>
* Adds a %CLUTTER_PATH_MOVE_TO node. Takes one pair of coordinates.
* </para></listitem></varlistentry>
* <varlistentry><term>L</term>
* <listitem><para>
* Adds a %CLUTTER_PATH_LINE_TO node. Takes one pair of coordinates.
* </para></listitem></varlistentry>
* <varlistentry><term>C</term>
* <listitem><para>
* Adds a %CLUTTER_PATH_CURVE_TO node. Takes three pairs of coordinates.
* </para></listitem></varlistentry>
* <varlistentry><term>z</term>
* <listitem><para>
* Adds a %CLUTTER_PATH_CLOSE node. No coordinates are needed.
* </para></listitem></varlistentry>
* </variablelist>
*
* The M, L and C commands can also be specified in lower case which
* means the coordinates are relative to the previous node.
*
* For example, to move an actor in a 100 by 100 pixel square centered
* on the point 300,300 you could use the following path:
*
* <informalexample>
* <programlisting>
* M 250,350 l 0 -100 L 350,250 l 0 100 z
* </programlisting>
* </informalexample>
*
* If the path description isn't valid %FALSE will be returned and no
* nodes will be added.
*
* Return value: %TRUE is the path description was valid or %FALSE
* otherwise.
*
* Since: 1.0
*/
gboolean
clutter_path_add_string (ClutterPath *path, const gchar *str)
{
GSList *nodes;
g_return_val_if_fail (CLUTTER_IS_PATH (path), FALSE);
if (clutter_path_parse_description (str, &nodes))
{
clutter_path_add_nodes (path, nodes);
return TRUE;
}
else
return FALSE;
}
/**
* clutter_path_add_node:
* @path: a #ClutterPath
* @node: a #ClutterPathNode
*
* Adds @node to the end of the path.
*
* Since: 1.0
*/
void
clutter_path_add_node (ClutterPath *path,
const ClutterPathNode *node)
{
ClutterPathNodeFull *node_full;
g_return_if_fail (CLUTTER_IS_PATH (path));
g_return_if_fail (node != NULL);
g_return_if_fail (CLUTTER_PATH_NODE_TYPE_IS_VALID (node->type));
node_full = clutter_path_node_full_new ();
node_full->k = *node;
clutter_path_add_node_full (path, node_full);
}
/**
* clutter_path_get_n_nodes:
* @path: a #ClutterPath
*
* Retrieves the number of nodes in the path.
*
* Return value: the number of nodes.
*
* Since: 1.0
*/
guint
clutter_path_get_n_nodes (ClutterPath *path)
{
ClutterPathPrivate *priv;
g_return_val_if_fail (CLUTTER_IS_PATH (path), 0);
priv = path->priv;
return g_slist_length (priv->nodes);
}
/**
* clutter_path_get_node:
* @path: a #ClutterPath
* @index: the node number to retrieve
* @node: a location to store a copy of the node
*
* Retrieves the node of the path indexed by @index.
*
* Since: 1.0
*/
void
clutter_path_get_node (ClutterPath *path,
guint index,
ClutterPathNode *node)
{
ClutterPathNodeFull *node_full;
ClutterPathPrivate *priv;
g_return_if_fail (CLUTTER_IS_PATH (path));
priv = path->priv;
node_full = g_slist_nth_data (priv->nodes, index);
g_return_if_fail (node_full != NULL);
*node = node_full->k;
}
/**
* clutter_path_get_nodes:
* @path: a #ClutterPath
*
* Returns a #GSList of #ClutterPathNode<!-- -->s. The list should be
* freed with g_slist_free(). The nodes are owned by the path and
* should not be freed. Altering the path may cause the nodes in the
* list to become invalid so you should copy them if you want to keep
* the list.
*
* Return value: a list of nodes in the path.
*
* Since: 1.0
*/
GSList *
clutter_path_get_nodes (ClutterPath *path)
{
ClutterPathPrivate *priv;
g_return_val_if_fail (CLUTTER_IS_PATH (path), NULL);
priv = path->priv;
return g_slist_copy (priv->nodes);
}
/**
* clutter_path_foreach:
* @path: a #ClutterPath
* @callback: the function to call with each node
* @user_data: user data to pass to the function
*
* Calls a function for each node of the path.
*
* Since: 1.0
*/
void
clutter_path_foreach (ClutterPath *path,
ClutterPathCallback callback,
gpointer user_data)
{
ClutterPathPrivate *priv;
g_return_if_fail (CLUTTER_IS_PATH (path));
priv = path->priv;
g_slist_foreach (priv->nodes, (GFunc) callback, user_data);
}
/**
* clutter_path_insert_node:
* @path: a #ClutterPath
* @index: offset of where to insert the node
* @node: the node to insert
*
* Inserts @node into the path before the node at the given offset. If
* @index is negative it will append the node to the end of the path.
*
* Since: 1.0
*/
void
clutter_path_insert_node (ClutterPath *path,
gint index,
const ClutterPathNode *node)
{
ClutterPathPrivate *priv;
ClutterPathNodeFull *node_full;
g_return_if_fail (CLUTTER_IS_PATH (path));
g_return_if_fail (node != NULL);
g_return_if_fail (CLUTTER_PATH_NODE_TYPE_IS_VALID (node->type));
priv = path->priv;
node_full = clutter_path_node_full_new ();
node_full->k = *node;
priv->nodes = g_slist_insert (priv->nodes, node_full, index);
if (priv->nodes_tail == NULL)
priv->nodes_tail = priv->nodes;
else if (priv->nodes_tail->next)
priv->nodes_tail = priv->nodes_tail->next;
priv->nodes_dirty = TRUE;
}
/**
* clutter_path_remove_node:
* @path: a #ClutterPath
* @index: index of the node to remove
*
* Removes the node at the given offset from the path.
*
* Since: 1.0
*/
void
clutter_path_remove_node (ClutterPath *path,
guint index)
{
ClutterPathPrivate *priv;
GSList *node, *prev = NULL;
g_return_if_fail (CLUTTER_IS_PATH (path));
priv = path->priv;
for (node = priv->nodes; node && index--; node = node->next)
prev = node;
if (node)
{
clutter_path_node_full_free (node->data);
if (prev)
prev->next = node->next;
else
priv->nodes = node->next;
if (node == priv->nodes_tail)
priv->nodes_tail = prev;
g_slist_free_1 (node);
priv->nodes_dirty = TRUE;
}
}
/**
* clutter_path_replace_node:
* @path: a #ClutterPath
* @index: index to the existing node
* @node: the replacement node
*
* Replaces the node at offset @index with @node.
*
* Since: 1.0
*/
void
clutter_path_replace_node (ClutterPath *path,
guint index,
const ClutterPathNode *node)
{
ClutterPathPrivate *priv;
ClutterPathNodeFull *node_full;
g_return_if_fail (CLUTTER_IS_PATH (path));
g_return_if_fail (node != NULL);
g_return_if_fail (CLUTTER_PATH_NODE_TYPE_IS_VALID (node->type));
priv = path->priv;
if ((node_full = g_slist_nth_data (priv->nodes, index)))
{
node_full->k = *node;
priv->nodes_dirty = TRUE;
}
}
/**
* clutter_path_set_description:
* @path: a #ClutterPath
* @str: a string describing the path
*
* Replaces all of the nodes in the path with nodes described by
* @str. See clutter_path_add_string() for details of the format.
*
* If the string is invalid then %FALSE is returned and the path is
* unaltered.
*
* Return value: %TRUE is the path was valid, %FALSE otherwise.
*
* Since: 1.0
*/
gboolean
clutter_path_set_description (ClutterPath *path, const gchar *str)
{
GSList *nodes;
g_return_val_if_fail (CLUTTER_IS_PATH (path), FALSE);
if (clutter_path_parse_description (str, &nodes))
{
clutter_path_clear (path);
clutter_path_add_nodes (path, nodes);
return TRUE;
}
else
return FALSE;
}
/**
* clutter_path_get_description:
* @path: a #ClutterPath
*
* Returns a newly allocated string describing the path in the same
* format as used by clutter_path_add_string().
*
* Return value: a string description of the path. Free with g_free().
*
* Since: 1.0
*/
gchar *
clutter_path_get_description (ClutterPath *path)
{
ClutterPathPrivate *priv;
GString *str;
GSList *l;
g_return_val_if_fail (CLUTTER_IS_PATH (path), FALSE);
priv = path->priv;
str = g_string_new ("");
for (l = priv->nodes; l; l = l->next)
{
ClutterPathNodeFull *node = l->data;
gchar letter = '?';
gint params = 0;
gint i;
switch (node->k.type)
{
case CLUTTER_PATH_MOVE_TO:
letter = 'M';
params = 1;
break;
case CLUTTER_PATH_REL_MOVE_TO:
letter = 'm';
params = 1;
break;
case CLUTTER_PATH_LINE_TO:
letter = 'L';
params = 1;
break;
case CLUTTER_PATH_REL_LINE_TO:
letter = 'l';
params = 1;
break;
case CLUTTER_PATH_CURVE_TO:
letter = 'C';
params = 3;
break;
case CLUTTER_PATH_REL_CURVE_TO:
letter = 'c';
params = 3;
break;
case CLUTTER_PATH_CLOSE:
letter = 'z';
params = 0;
break;
}
if (str->len > 0)
g_string_append_c (str, ' ');
g_string_append_c (str, letter);
for (i = 0; i < params; i++)
g_string_append_printf (str, " %i %i",
node->k.points[i].x,
node->k.points[i].y);
}
return g_string_free (str, FALSE);
}
static gint
clutter_path_node_distance (const ClutterKnot *start,
const ClutterKnot *end)
{
gint t;
g_return_val_if_fail (start != NULL, 0);
g_return_val_if_fail (end != NULL, 0);
if (clutter_knot_equal (start, end))
return 0;
t = (end->x - start->x) * (end->x - start->x) +
(end->y - start->y) * (end->y - start->y);
/*
* If we are using limited precision sqrti implementation, fallback on
* clib sqrt if the precission would be less than 10%
*/
#if INT_MAX > CLUTTER_SQRTI_ARG_10_PERCENT
if (t <= COGL_SQRTI_ARG_10_PERCENT)
return cogl_sqrti (t);
else
return COGL_FLOAT_TO_INT (sqrt(t));
#else
return cogl_sqrti (t);
#endif
}
static void
clutter_path_ensure_node_data (ClutterPath *path)
{
ClutterPathPrivate *priv = path->priv;
/* Recalculate the nodes data if has changed */
if (priv->nodes_dirty)
{
GSList *l;
ClutterKnot last_position = { 0, 0 };
ClutterKnot loop_start = { 0, 0 };
ClutterKnot points[3];
priv->total_length = 0;
for (l = priv->nodes; l; l = l->next)
{
ClutterPathNodeFull *node = l->data;
gboolean relative = (node->k.type & CLUTTER_PATH_RELATIVE) != 0;
switch (node->k.type & ~CLUTTER_PATH_RELATIVE)
{
case CLUTTER_PATH_MOVE_TO:
node->length = 0;
/* Store the actual position in point[1] */
if (relative)
{
node->k.points[1].x = last_position.x + node->k.points[0].x;
node->k.points[1].y = last_position.y + node->k.points[0].y;
}
else
node->k.points[1] = node->k.points[0];
last_position = node->k.points[1];
loop_start = node->k.points[1];
break;
case CLUTTER_PATH_LINE_TO:
/* Use point[1] as the start point and point[2] as the end
point */
node->k.points[1] = last_position;
if (relative)
{
node->k.points[2].x = (node->k.points[1].x
+ node->k.points[0].x);
node->k.points[2].y = (node->k.points[1].y
+ node->k.points[0].y);
}
else
node->k.points[2] = node->k.points[0];
last_position = node->k.points[2];
node->length = clutter_path_node_distance (node->k.points + 1,
node->k.points + 2);
break;
case CLUTTER_PATH_CURVE_TO:
/* Convert to a bezier curve */
if (node->bezier == NULL)
node->bezier = _clutter_bezier_new ();
if (relative)
{
int i;
for (i = 0; i < 3; i++)
{
points[i].x = last_position.x + node->k.points[i].x;
points[i].y = last_position.y + node->k.points[i].y;
}
}
else
memcpy (points, node->k.points, sizeof (ClutterKnot) * 3);
_clutter_bezier_init (node->bezier,
last_position.x, last_position.y,
points[0].x, points[0].y,
points[1].x, points[1].y,
points[2].x, points[2].y);
last_position = points[2];
node->length = _clutter_bezier_get_length (node->bezier);
break;
case CLUTTER_PATH_CLOSE:
/* Convert to a line to from last_point to loop_start */
node->k.points[1] = last_position;
node->k.points[2] = loop_start;
last_position = node->k.points[2];
node->length = clutter_path_node_distance (node->k.points + 1,
node->k.points + 2);
break;
}
priv->total_length += node->length;
}
priv->nodes_dirty = FALSE;
}
}
/**
* clutter_path_get_position:
* @path: a #ClutterPath
* @progress: a position along the path as a fraction of its length
* @position: location to store the position
*
* The value in @progress represents a position along the path where
* 0.0 is the beginning and 1.0 is the end of the path. An
* interpolated position is then stored in @position.
*
* Return value: index of the node used to calculate the position.
*
* Since: 1.0
*/
guint
clutter_path_get_position (ClutterPath *path,
gdouble progress,
ClutterKnot *position)
{
ClutterPathPrivate *priv;
GSList *l;
guint point_distance, length = 0, node_num = 0;
ClutterPathNodeFull *node;
g_return_val_if_fail (CLUTTER_IS_PATH (path), 0);
g_return_val_if_fail (progress >= 0.0 && progress <= 1.0, 0);
priv = path->priv;
clutter_path_ensure_node_data (path);
/* Special case if the path is empty, just return 0,0 for want of
something better */
if (priv->nodes == NULL)
{
memset (position, 0, sizeof (ClutterKnot));
return 0;
}
/* Convert the progress to a length along the path */
point_distance = progress * priv->total_length;
/* Find the node that covers this point */
for (l = priv->nodes;
l->next && point_distance >= (((ClutterPathNodeFull *) l->data)->length
+ length);
l = l->next)
{
length += ((ClutterPathNodeFull *) l->data)->length;
node_num++;
}
node = l->data;
/* Convert the point distance to a distance along the node */
point_distance -= length;
if (point_distance > node->length)
point_distance = node->length;
switch (node->k.type & ~CLUTTER_PATH_RELATIVE)
{
case CLUTTER_PATH_MOVE_TO:
*position = node->k.points[1];
break;
case CLUTTER_PATH_LINE_TO:
case CLUTTER_PATH_CLOSE:
if (node->length == 0)
*position = node->k.points[1];
else
{
position->x = (node->k.points[1].x
+ ((node->k.points[2].x - node->k.points[1].x)
* (gint) point_distance / (gint) node->length));
position->y = (node->k.points[1].y
+ ((node->k.points[2].y - node->k.points[1].y)
* (gint) point_distance / (gint) node->length));
}
break;
case CLUTTER_PATH_CURVE_TO:
_clutter_bezier_advance (node->bezier,
point_distance * CLUTTER_BEZIER_MAX_LENGTH
/ node->length,
position);
break;
}
return node_num;
}
/**
* clutter_path_get_length:
* @path: a #ClutterPath
*
* Retrieves an approximation of the total length of the path.
*
* Return value: the length of the path.
*
* Since: 1.0
*/
guint
clutter_path_get_length (ClutterPath *path)
{
g_return_val_if_fail (CLUTTER_IS_PATH (path), 0);
clutter_path_ensure_node_data (path);
return path->priv->total_length;
}
static ClutterPathNodeFull *
clutter_path_node_full_new (void)
{
return g_slice_new0 (ClutterPathNodeFull);
}
static void
clutter_path_node_full_free (ClutterPathNodeFull *node)
{
if (node->bezier)
_clutter_bezier_free (node->bezier);
g_slice_free (ClutterPathNodeFull, node);
}
/**
* clutter_path_node_copy:
* @node: a #ClutterPathNode
*
* Makes an allocated copy of a node.
*
* Return value: the copied node.
*
* Since: 1.0
*/
ClutterPathNode *
clutter_path_node_copy (const ClutterPathNode *node)
{
return g_slice_dup (ClutterPathNode, node);
}
/**
* clutter_path_node_free:
* @node: a #ClutterPathNode
*
* Frees the memory of an allocated node.
*
* Since: 1.0
*/
void
clutter_path_node_free (ClutterPathNode *node)
{
if (G_LIKELY (node))
g_slice_free (ClutterPathNode, node);
}
/**
* clutter_path_node_equal:
* @node_a: First node
* @node_b: Second node
*
* Compares two nodes and checks if they are the same type with the
* same coordinates.
*
* Return value: %TRUE if the nodes are the same.
*
* Since: 1.0
*/
gboolean
clutter_path_node_equal (const ClutterPathNode *node_a,
const ClutterPathNode *node_b)
{
guint n_points, i;
g_return_val_if_fail (node_a != NULL, FALSE);
g_return_val_if_fail (node_b != NULL, FALSE);
if (node_a->type != node_b->type)
return FALSE;
switch (node_a->type & ~CLUTTER_PATH_RELATIVE)
{
case CLUTTER_PATH_MOVE_TO: n_points = 1; break;
case CLUTTER_PATH_LINE_TO: n_points = 1; break;
case CLUTTER_PATH_CURVE_TO: n_points = 3; break;
case CLUTTER_PATH_CLOSE: n_points = 0; break;
default: return FALSE;
}
for (i = 0; i < n_points; i++)
if (node_a->points[i].x != node_b->points[i].x
|| node_a->points[i].y != node_b->points[i].y)
return FALSE;
return TRUE;
}
GType
clutter_path_node_get_type (void)
{
static GType our_type = 0;
if (G_UNLIKELY (!our_type))
{
our_type =
g_boxed_type_register_static (I_("ClutterPathNode"),
(GBoxedCopyFunc) clutter_path_node_copy,
(GBoxedFreeFunc) clutter_path_node_free);
}
return our_type;
}
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