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clutter/clutter/clutter-path.c

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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:
*
* - %CLUTTER_PATH_MOVE_TO, 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.
* - %CLUTTER_PATH_LINE_TO, creates a straight line from the previous
* point to the given point.
* - %CLUTTER_PATH_CURVE_TO, 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.
* -%CLUTTER_PATH_CLOSE, 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.
*
* 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 <string.h>
#include <stdarg.h>
#include <math.h>
#include <glib-object.h>
#include "clutter-path.h"
#include "clutter-types.h"
#include "clutter-bezier.h"
#include "clutter-private.h"
#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,
PROP_LAST
};
static GParamSpec *obj_props[PROP_LAST];
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_value_transform_path_string (const GValue *src,
GValue *dest);
static void clutter_value_transform_string_path (const GValue *src,
GValue *dest);
G_DEFINE_BOXED_TYPE (ClutterPathNode, clutter_path_node,
clutter_path_node_copy,
clutter_path_node_free);
G_DEFINE_TYPE_WITH_CODE (ClutterPath,
clutter_path,
G_TYPE_INITIALLY_UNOWNED,
G_ADD_PRIVATE (ClutterPath)
CLUTTER_REGISTER_VALUE_TRANSFORM_TO (G_TYPE_STRING, clutter_value_transform_path_string)
CLUTTER_REGISTER_VALUE_TRANSFORM_FROM (G_TYPE_STRING, clutter_value_transform_string_path));
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);
obj_props[PROP_DESCRIPTION] = pspec;
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);
obj_props[PROP_LENGTH] = pspec;
g_object_class_install_property (gobject_class, PROP_LENGTH, pspec);
}
static void
clutter_path_init (ClutterPath *self)
{
self->priv = clutter_path_get_instance_private (self);
}
static void
clutter_value_transform_path_string (const GValue *src,
GValue *dest)
{
gchar *string = clutter_path_get_description (src->data[0].v_pointer);
g_value_take_string (dest, string);
}
static void
clutter_value_transform_string_path (const GValue *src,
GValue *dest)
{
ClutterPath *new_path;
new_path = clutter_path_new_with_description (g_value_get_string (src));
g_value_take_object (dest, new_path);
}
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;
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)
{
g_return_if_fail (CLUTTER_IS_PATH (path));
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)
{
g_return_if_fail (CLUTTER_IS_PATH (path));
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)
{
g_return_if_fail (CLUTTER_IS_PATH (path));
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)
{
g_return_if_fail (CLUTTER_IS_PATH (path));
clutter_path_add_node_helper (path, CLUTTER_PATH_REL_LINE_TO, 1, x, y);
}
/**
* clutter_path_add_curve_to:
* @path: a #ClutterPath
* @x_1: the x coordinate of the first control point
* @y_1: the y coordinate of the first control point
* @x_2: the x coordinate of the second control point
* @y_2: the y coordinate of the second control point
* @x_3: the x coordinate of the third control point
* @y_3: 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 (@x_3, @y_3) using
* (@x_1, @y_1) and (@x_2,@y_2) as control points.
*
* Since: 1.0
*/
void
clutter_path_add_curve_to (ClutterPath *path,
gint x_1,
gint y_1,
gint x_2,
gint y_2,
gint x_3,
gint y_3)
{
g_return_if_fail (CLUTTER_IS_PATH (path));
clutter_path_add_node_helper (path, CLUTTER_PATH_CURVE_TO, 3,
x_1, y_1,
x_2, y_2,
x_3, y_3);
}
/**
* clutter_path_add_rel_curve_to:
* @path: a #ClutterPath
* @x_1: the x coordinate of the first control point
* @y_1: the y coordinate of the first control point
* @x_2: the x coordinate of the second control point
* @y_2: the y coordinate of the second control point
* @x_3: the x coordinate of the third control point
* @y_3: 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 x_1,
gint y_1,
gint x_2,
gint y_2,
gint x_3,
gint y_3)
{
g_return_if_fail (CLUTTER_IS_PATH (path));
clutter_path_add_node_helper (path, CLUTTER_PATH_REL_CURVE_TO, 3,
x_1, y_1,
x_2, y_2,
x_3, y_3);
}
/**
* 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)
{
g_return_if_fail (CLUTTER_IS_PATH (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)
{
ClutterPathNodeFull *node;
GSList *nodes = NULL;
if (p == NULL || *p == '\0')
return FALSE;
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:
*
* - `M`: Adds a %CLUTTER_PATH_MOVE_TO node. Takes one pair of coordinates.
* - `L`: Adds a %CLUTTER_PATH_LINE_TO node. Takes one pair of coordinates.
* - `C`: Adds a %CLUTTER_PATH_CURVE_TO node. Takes three pairs of coordinates.
* - `z`: Adds a %CLUTTER_PATH_CLOSE node. No coordinates are needed.
*
* 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:
*
* |[
* M 250,350 l 0 -100 L 350,250 l 0 100 z
* ]|
*
* 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);
g_return_val_if_fail (str != NULL, 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_add_cairo_path:
* @path: a #ClutterPath
* @cpath: a Cairo path
*
* Add the nodes of the Cairo path to the end of @path.
*
* Since: 1.0
*/
void
clutter_path_add_cairo_path (ClutterPath *path,
const cairo_path_t *cpath)
{
int num_data;
const cairo_path_data_t *p;
g_return_if_fail (CLUTTER_IS_PATH (path));
g_return_if_fail (cpath != NULL);
/* Iterate over each command in the cairo path */
for (num_data = cpath->num_data, p = cpath->data;
num_data > 0;
num_data -= p->header.length, p += p->header.length)
{
switch (p->header.type)
{
case CAIRO_PATH_MOVE_TO:
g_assert (p->header.length >= 2);
clutter_path_add_move_to (path, p[1].point.x, p[1].point.y);
break;
case CAIRO_PATH_LINE_TO:
g_assert (p->header.length >= 2);
clutter_path_add_line_to (path, p[1].point.x, p[1].point.y);
break;
case CAIRO_PATH_CURVE_TO:
g_assert (p->header.length >= 4);
clutter_path_add_curve_to (path,
p[1].point.x, p[1].point.y,
p[2].point.x, p[2].point.y,
p[3].point.x, p[3].point.y);
break;
case CAIRO_PATH_CLOSE_PATH:
clutter_path_add_close (path);
}
}
}
static void
clutter_path_add_node_to_cairo_path (const ClutterPathNode *node,
gpointer data)
{
cairo_t *cr = data;
switch (node->type)
{
case CLUTTER_PATH_MOVE_TO:
cairo_move_to (cr, node->points[0].x, node->points[0].y);
break;
case CLUTTER_PATH_LINE_TO:
cairo_line_to (cr, node->points[0].x, node->points[0].y);
break;
case CLUTTER_PATH_CURVE_TO:
cairo_curve_to (cr,
node->points[0].x, node->points[0].y,
node->points[1].x, node->points[1].y,
node->points[2].x, node->points[2].y);
break;
case CLUTTER_PATH_REL_MOVE_TO:
cairo_rel_move_to (cr, node->points[0].x, node->points[0].y);
break;
case CLUTTER_PATH_REL_LINE_TO:
cairo_rel_line_to (cr, node->points[0].x, node->points[0].y);
break;
case CLUTTER_PATH_REL_CURVE_TO:
cairo_rel_curve_to (cr,
node->points[0].x, node->points[0].y,
node->points[1].x, node->points[1].y,
node->points[2].x, node->points[2].y);
break;
case CLUTTER_PATH_CLOSE:
cairo_close_path (cr);
}
}
/**
* clutter_path_to_cairo_path:
* @path: a #ClutterPath
* @cr: a Cairo context
*
* Add the nodes of the ClutterPath to the path in the Cairo context.
*
* Since: 1.0
*/
void
clutter_path_to_cairo_path (ClutterPath *path,
cairo_t *cr)
{
g_return_if_fail (CLUTTER_IS_PATH (path));
g_return_if_fail (cr != NULL);
clutter_path_foreach (path, clutter_path_add_node_to_cairo_path, cr);
}
/**
* 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: (out): 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: (transfer container) (element-type Clutter.PathNode): 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: (scope call): 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);
g_return_val_if_fail (str != NULL, 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), NULL);
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 guint
clutter_path_node_distance (const ClutterKnot *start,
const ClutterKnot *end)
{
gint64 x_d, y_d;
float 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;
x_d = end->x - start->x;
y_d = end->y - start->y;
t = floorf (sqrtf ((x_d * x_d) + (y_d * y_d)));
return (guint) t;
}
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: (out): 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:
if (node->length == 0)
*position = node->k.points[2];
else
{
_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;
}
G_DEFINE_BOXED_TYPE (ClutterKnot, clutter_knot,
clutter_knot_copy,
clutter_knot_free);
/**
* clutter_knot_copy:
* @knot: a #ClutterKnot
*
* Makes an allocated copy of a knot.
*
* Return value: the copied knot.
*
* Since: 0.2
*/
ClutterKnot *
clutter_knot_copy (const ClutterKnot *knot)
{
if (G_UNLIKELY (knot == NULL))
return NULL;
return g_slice_dup (ClutterKnot, knot);
}
/**
* clutter_knot_free:
* @knot: a #ClutterKnot
*
* Frees the memory of an allocated knot.
*
* Since: 0.2
*/
void
clutter_knot_free (ClutterKnot *knot)
{
if (G_LIKELY (knot != NULL))
g_slice_free (ClutterKnot, knot);
}
/**
* clutter_knot_equal:
* @knot_a: First knot
* @knot_b: Second knot
*
* Compares to knot and checks if the point to the same location.
*
* Return value: %TRUE if the knots point to the same location.
*
* Since: 0.2
*/
gboolean
clutter_knot_equal (const ClutterKnot *knot_a,
const ClutterKnot *knot_b)
{
g_return_val_if_fail (knot_a != NULL, FALSE);
g_return_val_if_fail (knot_b != NULL, FALSE);
if (knot_a == knot_b)
return TRUE;
return knot_a->x == knot_b->x && knot_a->y == knot_b->y;
}
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