## gnome-canvas-path-def

gnome-canvas-path-def — Container and functions for manipulating ArtBpaths

## Synopsis

    #include <libgnomecanvas/libgnomecanvas.h>

                        GnomeCanvasPathDef;
    GnomeCanvasPathDef* gnome_canvas_path_def_new           (void);
    GnomeCanvasPathDef* gnome_canvas_path_def_new_sized     (gint length);
    GnomeCanvasPathDef* gnome_canvas_path_def_new_from_bpath
                                                            (ArtBpath *bpath);
    GnomeCanvasPathDef* gnome_canvas_path_def_new_from_static_bpath
                                                            (ArtBpath *bpath);
    GnomeCanvasPathDef* gnome_canvas_path_def_new_from_foreign_bpath
                                                            (ArtBpath *bpath);
    void                gnome_canvas_path_def_ref           (GnomeCanvasPathDef *path);
    void                gnome_canvas_path_def_finish        (GnomeCanvasPathDef *path);
    void                gnome_canvas_path_def_ensure_space  (GnomeCanvasPathDef *path,
                                                             gint space);
    void                gnome_canvas_path_def_copy          (GnomeCanvasPathDef *dst,
                                                             const GnomeCanvasPathDef *src);
    GnomeCanvasPathDef* gnome_canvas_path_def_duplicate     (const GnomeCanvasPathDef *path);
    GnomeCanvasPathDef* gnome_canvas_path_def_concat        (const GSList *list);
    GSList*             gnome_canvas_path_def_split         (const GnomeCanvasPathDef *path);
    GnomeCanvasPathDef* gnome_canvas_path_def_open_parts    (const GnomeCanvasPathDef *path);
    GnomeCanvasPathDef* gnome_canvas_path_def_closed_parts  (const GnomeCanvasPathDef *path);
    GnomeCanvasPathDef* gnome_canvas_path_def_close_all     (const GnomeCanvasPathDef *path);
    void                gnome_canvas_path_def_unref         (GnomeCanvasPathDef *path);
    void                gnome_canvas_path_def_reset         (GnomeCanvasPathDef *path);
    void                gnome_canvas_path_def_moveto        (GnomeCanvasPathDef *path,
                                                             gdouble x,
                                                             gdouble y);
    void                gnome_canvas_path_def_lineto        (GnomeCanvasPathDef *path,
                                                             gdouble x,
                                                             gdouble y);
    void                gnome_canvas_path_def_lineto_moving (GnomeCanvasPathDef *path,
                                                             gdouble x,
                                                             gdouble y);
    void                gnome_canvas_path_def_curveto       (GnomeCanvasPathDef *path,
                                                             gdouble x0,
                                                             gdouble y0,
                                                             gdouble x1,
                                                             gdouble y1,
                                                             gdouble x2,
                                                             gdouble y2);
    void                gnome_canvas_path_def_closepath     (GnomeCanvasPathDef *path);
    void                gnome_canvas_path_def_closepath_current
                                                            (GnomeCanvasPathDef *path);
    ArtBpath*           gnome_canvas_path_def_bpath         (const GnomeCanvasPathDef *path);
    gint                gnome_canvas_path_def_length        (const GnomeCanvasPathDef *path);
    gboolean            gnome_canvas_path_def_is_empty      (const GnomeCanvasPathDef *path);
    gboolean            gnome_canvas_path_def_has_currentpoint
                                                            (const GnomeCanvasPathDef *path);
    void                gnome_canvas_path_def_currentpoint  (const GnomeCanvasPathDef *path,
                                                             ArtPoint *p);
    ArtBpath*           gnome_canvas_path_def_last_bpath    (const GnomeCanvasPathDef *path);
    ArtBpath*           gnome_canvas_path_def_first_bpath   (const GnomeCanvasPathDef *path);
    gboolean            gnome_canvas_path_def_any_open      (const GnomeCanvasPathDef *path);
    gboolean            gnome_canvas_path_def_all_open      (const GnomeCanvasPathDef *path);
    gboolean            gnome_canvas_path_def_any_closed    (const GnomeCanvasPathDef *path);
    gboolean            gnome_canvas_path_def_all_closed    (const GnomeCanvasPathDef *path);

## Description

Convenient container and functions for manipulating ArtBpaths, which are paths defined by line and curve segments.

## Details

### GnomeCanvasPathDef

    typedef struct _GnomeCanvasPathDef GnomeCanvasPathDef;

This structure should not be accessed directly. Use the functions defined below.

### gnome_canvas_path_def_new ()

    GnomeCanvasPathDef* gnome_canvas_path_def_new           (void);

This function creates a new empty gnome_canvas_path_def.

Returns : | the new canvas path definition.

### gnome_canvas_path_def_new_sized ()

    GnomeCanvasPathDef* gnome_canvas_path_def_new_sized     (gint length);

This function creates a new gnome_canvas_path_def with `length` number of points allocated. It is useful, if you know the exact number of points in path, so you can avoid automatic point array reallocation.

`length` : | number of points to allocate for the path
Returns : | the new canvas path definition

### gnome_canvas_path_def_new_from_bpath ()

    GnomeCanvasPathDef* gnome_canvas_path_def_new_from_bpath
                                                            (ArtBpath *bpath);

This function constructs a new gnome_canvas_path_def and uses the passed `bpath` as the contents. The passed bpath should not be static as the path definition is editable when constructed with this function. Also, passed bpath will be freed with art_free, if path is destroyed, so use it with caution. For constructing a gnome_canvas_path_def from (non-modifiable) bpath use gnome_canvas_path_def_new_from_static_bpath.

`bpath` : | libart bezier path
Returns : | the new canvas path definition that is populated with the passed bezier path, if the `bpath` is bad NULL is returned.

### gnome_canvas_path_def_new_from_static_bpath ()

    GnomeCanvasPathDef* gnome_canvas_path_def_new_from_static_bpath
                                                            (ArtBpath *bpath);

This function constructs a new gnome_canvas_path_def and references the passed `bpath` as its contents. The gnome_canvas_path_def returned from this function is to be considered static and non-editable (meaning you cannot change the path from what you passed in `bpath`). The bpath will not be freed, if path will be destroyed, so use it with caution.

`bpath` : | libart bezier path
Returns : | the new canvas path definition that references the passed `bpath`, or if the path is bad NULL is returned.

### gnome_canvas_path_def_new_from_foreign_bpath ()

    GnomeCanvasPathDef* gnome_canvas_path_def_new_from_foreign_bpath
                                                            (ArtBpath *bpath);

This function constructs a new gnome_canvas_path_def and duplicates the contents of the passed `bpath` in the definition.

`bpath` : | libart bezier path
Returns : | the newly created gnome_canvas_path_def or NULL if the path is invalid.

### gnome_canvas_path_def_ref ()

    void                gnome_canvas_path_def_ref           (GnomeCanvasPathDef *path);

Increment the reference count of the GnomeCanvasPathDef.

`path` : | a GnomeCanvasPathDef

### gnome_canvas_path_def_finish ()

    void                gnome_canvas_path_def_finish        (GnomeCanvasPathDef *path);

Trims dynamic point array to exact length of path.

`path` : | a GnomeCanvasPathDef

### gnome_canvas_path_def_ensure_space ()

    void                gnome_canvas_path_def_ensure_space  (GnomeCanvasPathDef *path,
                                                             gint space);

This function ensures that enough space for `space` points is allocated at the end of the path.

`path` : | a GnomeCanvasPathDef
`space` : | number of points to guarantee are allocated at the end of the path.

### gnome_canvas_path_def_copy ()

    void                gnome_canvas_path_def_copy          (GnomeCanvasPathDef *dst,
                                                             const GnomeCanvasPathDef *src);

This function copies the contents `src` to `dest`. The old `dest` path array is freed and `dest` is marked as non-static (editable), regardless of the status of `src`.

`dst` : | a GnomeCanvasPathDef where the contents of `src` will be stored.
`src` : | a GnomeCanvasPathDef whose contents will be copied it `src`.

### gnome_canvas_path_def_duplicate ()

    GnomeCanvasPathDef* gnome_canvas_path_def_duplicate     (const GnomeCanvasPathDef *path);

This function duplicates the passed `path`. The new path is marked as non-static regardless of the state of original.

`path` : | a GnomeCanvasPathDef to duplicate
Returns : | a GnomeCanvasPathDef which is a duplicate of `path`.

### gnome_canvas_path_def_concat ()

    GnomeCanvasPathDef* gnome_canvas_path_def_concat        (const GSList *list);

This function concatenates a list of GnomeCanvasPathDefs into one newly created GnomeCanvasPathDef.

`list` : | a GSList of GnomeCanvasPathDefs to concatenate into one new path.
Returns : | a new GnomeCanvasPathDef

### gnome_canvas_path_def_split ()

    GSList*             gnome_canvas_path_def_split         (const GnomeCanvasPathDef *path);

This function splits the passed `path` into a list of GnomeCanvasPathDefs which represent each segment of the origional path. The path is split when ever an ART_MOVETO or ART_MOVETO_OPEN is encountered. The closedness of resulting paths is set accordingly to closedness of corresponding segment.

`path` : | a GnomeCanvasPathDef
Returns : | a list of GnomeCanvasPathDef(s).

### gnome_canvas_path_def_open_parts ()

    GnomeCanvasPathDef* gnome_canvas_path_def_open_parts    (const GnomeCanvasPathDef *path);

This function creates a new GnomeCanvasPathDef that contains all of the open segments on the passed `path`.

`path` : | a GnomeCanvasPathDef
Returns : | a new GnomeCanvasPathDef that contains all of the open segemtns in `path`.

### gnome_canvas_path_def_closed_parts ()

    GnomeCanvasPathDef* gnome_canvas_path_def_closed_parts  (const GnomeCanvasPathDef *path);

This function returns a new GnomeCanvasPathDef that contains the all of close parts of passed `path`.

`path` : | a GnomeCanvasPathDef
Returns : | a new GnomeCanvasPathDef that contains all of the closed parts of passed `path`.

### gnome_canvas_path_def_close_all ()

    GnomeCanvasPathDef* gnome_canvas_path_def_close_all     (const GnomeCanvasPathDef *path);

This function closes all of the open segments in the passed path and returns a new GnomeCanvasPathDef.

`path` : | a GnomeCanvasPathDef
Returns : | a GnomeCanvasPathDef that contains the contents of `path` but has modified the path is fully closed

### gnome_canvas_path_def_unref ()

    void                gnome_canvas_path_def_unref         (GnomeCanvasPathDef *path);

Decrease the reference count of the passed `path`. If the reference count is < 1 the path is deallocated.

`path` : | a GnomeCanvasPathDef

### gnome_canvas_path_def_reset ()

    void                gnome_canvas_path_def_reset         (GnomeCanvasPathDef *path);

This function clears the contents of the passed `path`.

`path` : | a GnomeCanvasPathDef

### gnome_canvas_path_def_moveto ()

    void                gnome_canvas_path_def_moveto        (GnomeCanvasPathDef *path,
                                                             gdouble x,
                                                             gdouble y);

This function adds starts new subpath on `path`, and sets its starting point to `x` and `y`. If current subpath is empty, it simply changes its starting coordinates to new values.

`path` : | a GnomeCanvasPathDef
`x` : | x coordinate
`y` : | y coordinate

### gnome_canvas_path_def_lineto ()

    void                gnome_canvas_path_def_lineto        (GnomeCanvasPathDef *path,
                                                             gdouble x,
                                                             gdouble y);

This function add a line segment to the passed `path` with the specified `x` and `y` coordinates.

`path` : | a GnomeCanvasPathDef
`x` : | x coordinate
`y` : | y coordinate

### gnome_canvas_path_def_lineto_moving ()

    void                gnome_canvas_path_def_lineto_moving (GnomeCanvasPathDef *path,
                                                             gdouble x,
                                                             gdouble y);

This functions adds a new line segment with loose endpoint to the path, or if endpoint is already loose, changes its coordinates to `x`, `y`. You can change the coordinates of loose endpoint as many times as you want, the last ones set will be fixed, if you continue line. This is useful for handling drawing with mouse.

`path` : | a GnomeCanvasPathDef
`x` : | x coordinate
`y` : | y coordinate

### gnome_canvas_path_def_curveto ()

    void                gnome_canvas_path_def_curveto       (GnomeCanvasPathDef *path,
                                                             gdouble x0,
                                                             gdouble y0,
                                                             gdouble x1,
                                                             gdouble y1,
                                                             gdouble x2,
                                                             gdouble y2);

This function adds a bezier curve segment to the path definition.

`path` : | a GnomeCanvasPathDef
`x0` : | first control point x coordinate
`y0` : | first control point y coordinate
`x1` : | second control point x coordinate
`y1` : | second control point y coordinate
`x2` : | end of curve x coordinate
`y2` : | end of curve y coordinate

### gnome_canvas_path_def_closepath ()

    void                gnome_canvas_path_def_closepath     (GnomeCanvasPathDef *path);

This function closes the last subpath of `path`, adding a ART_LINETO to subpath starting point, if needed and changing starting pathcode to ART_MOVETO

`path` : | a GnomeCanvasPathDef

### gnome_canvas_path_def_closepath_current ()

    void                gnome_canvas_path_def_closepath_current
                                                            (GnomeCanvasPathDef *path);

This function closes the last subpath by setting the coordinates of the endpoint of the last segment (line or curve) to starting point.

`path` : | a GnomeCanvasPathDef

### gnome_canvas_path_def_bpath ()

    ArtBpath*           gnome_canvas_path_def_bpath         (const GnomeCanvasPathDef *path);

This function returns a ArtBpath that consists of the path definition.

`path` : | a GnomeCanvasPathDef
Returns : | ArtBpath

### gnome_canvas_path_def_length ()

    gint                gnome_canvas_path_def_length        (const GnomeCanvasPathDef *path);

This function returns the length of the path definition. Not Euclidian length of the path but rather the number of points on the path.

`path` : | a GnomeCanvasPathDef
Returns : | integer, number of points on the path.

### gnome_canvas_path_def_is_empty ()

    gboolean            gnome_canvas_path_def_is_empty      (const GnomeCanvasPathDef *path);

This function is a boolean test to see if the path is empty, meaning containing no line segments.

`path` : | a GnomeCanvasPathDef
Returns : | boolean, indicating if the path is empty.

### gnome_canvas_path_def_has_currentpoint ()

    gboolean            gnome_canvas_path_def_has_currentpoint
                                                            (const GnomeCanvasPathDef *path);

This function is a boolean test checking to see if the path has a current point defined. Current point will be set by line operators, and cleared by closing subpath.

`path` : | a GnomeCanvasPathdef
Returns : | boolean, indicating if the path has a current point defined.

### gnome_canvas_path_def_currentpoint ()

    void                gnome_canvas_path_def_currentpoint  (const GnomeCanvasPathDef *path,
                                                             ArtPoint *p);

Stores the current point of the path definition in the passed ArtPoint `p`.

`path` : | a GnomeCanvasPathDef
`p` : | a ArtPoint where to store the current point

### gnome_canvas_path_def_last_bpath ()

    ArtBpath*           gnome_canvas_path_def_last_bpath    (const GnomeCanvasPathDef *path);

This function returns pointer to the last ArtBpath segment in the path definition.

`path` : | a GnomeCanvasPathDef
Returns : | ArtBpath, being the last segment in the path definition or null if no line segments have been defined.

### gnome_canvas_path_def_first_bpath ()

    ArtBpath*           gnome_canvas_path_def_first_bpath   (const GnomeCanvasPathDef *path);

This function returns the first ArtBpath point in the definition.

`path` : | a GnomeCanvasPathDef
Returns : | ArtBpath being the first point in the path definition or null if no points are defined

### gnome_canvas_path_def_any_open ()

    gboolean            gnome_canvas_path_def_any_open      (const GnomeCanvasPathDef *path);

This function returns a boolean value indicating if the path has any open segments.

`path` : | a GnomeCanvasPathDef
Returns : | boolean, indicating if the path has any open segments.

### gnome_canvas_path_def_all_open ()

    gboolean            gnome_canvas_path_def_all_open      (const GnomeCanvasPathDef *path);

This function returns a boolean value indicating if the path only contains open segments.

`path` : | a GnomeCanvasPathDef
Returns : | boolean, indicating if the path has all open segments.

### gnome_canvas_path_def_any_closed ()

    gboolean            gnome_canvas_path_def_any_closed    (const GnomeCanvasPathDef *path);

This function returns a boolean valid indicating if the path has any closed segements.

`path` : | a GnomeCanvasPathDef
Returns : | boolean, indicating if the path has any closed segments.

### gnome_canvas_path_def_all_closed ()

    gboolean            gnome_canvas_path_def_all_closed    (const GnomeCanvasPathDef *path);

This function returns a boolean value indicating if the path only contains closed segments.

`path` : | a GnomeCanvasPathDef
Returns : | boolean, indicating if the path has all closed segments.