path2d.h

一个用于智能手机的多媒体库适合S60 WinCE的跨平台开发库

/*!
 *	\brief flattens path 
 *
 *	Flattens the path, i.e. transform all bezier curves to lines according to the path flatness.
 *	\param gp the target path
 */
void gf_path_flatten(GF_Path *gp);
/*!
 *	\brief gets flatten copy of path 
 *
 *	Gets a flatten copy of the path.
 *	\param gp the target path
 *	\return the flatten path
 */
GF_Path *gf_path_get_flatten(GF_Path *gp);
/*!
 *	\brief point over path testing
 *
 *	Tests if a point is over a path or not, according to the path filling rule.
 *	\param gp the target path
 *	\param x x-coordinate of the point to check
 *	\param y y-coordinate of the point to check
 *	\return 1 if the point is over the path, 0 otherwise.
 */
Bool gf_path_point_over(GF_Path *gp, Fixed x, Fixed y);

/*!
 *	\brief path init testing
 *
 *	Tests if the path is empty or not.
 *	\param gp the target path
 *	\return 1 if the path is empty, 0 otherwise.
 */
Bool gf_path_is_empty(GF_Path *gp);

/*!
 *	\brief path iterator 
 *
 *	The path iterator object is used to compute the length of a given path as well
 * as transformation matrices along this path.
 */
typedef struct _path_iterator GF_PathIterator;

/*!
 *	\brief path iterator constructor
 *
 *	Creates a new path iterator from a given path
 *	\param gp the target path
 *	\return the path iterator object.
 */
GF_PathIterator *gf_path_iterator_new(GF_Path *gp);
/*!
 *	\brief path iterator destructor
 *
 *	Destructs the path iterator object
 *	\param it the target path iterator
 */
void gf_path_iterator_del(GF_PathIterator *it);

/*!
 *	\brief get path length
 *
 *	Gets a path length from its iterator
 *	\param it the target path iterator
 *	\return the length of the path
 */
Fixed gf_path_iterator_get_length(GF_PathIterator *it);
/*!
 *\brief gets transformation matrix at given point on path
 *
 * Gets the transformation of a given point on the path, given by offset from origin. 
 *The transform is so that a local system is translated to the given point, its x-axis tangent 
 *to the path and in the same direction. The path direction is from first point to last point
 *of the path.
 *	\param it the target path iterator
 *	\param offset length on the path in local system unit
 *	\param follow_tangent indicates if transformation shall be computed if offset indicates a point outside the path (<0 or >path_length). In which case the path shall be virtually extended by the tangent at origin (offset <0) or at end (offset>path_length). Otherwise the transformation is not computed and 0 is returned.
 *	\param mat matrix to be transformed (transformation shall be appended) - the matrix shall not be initialized
 *	\param smooth_edges indicates if discontinuities shall be smoothed. If not set, the rotation angle THETA is the slope (DX/DY) of the current segment found.
 *	\param length_after_point if set and smooth_edges is set, the amount of the object that lies on next segment shall be computed according to length_after_point. 
 \code
  Let:
	len_last: length of current checked segment
	len1: length of all previous segments so that len1 + len_last >= offset then if (offset + length_after_point > len1 + len_last) {
	ratio = (len1 + len_last - offset) / length_after_point;
	then THETA = ratio * slope(L1) + (1-ratio) * slope(L2)

  Of course care must be taken for PI/2 angles and similar situations 
 \endcode

 *	\return 1 if matrix has been updated, 0 otherwise, if failure or if point is out of path without tangent extension.
 */
Bool gf_path_iterator_get_transform(GF_PathIterator *it, Fixed offset, Bool follow_tangent, GF_Matrix2D *mat, Bool smooth_edges, Fixed length_after_point);



/*! brief gets convexity type for a 2D polygon
 *
 * Gets the convexity type of the given 2D polygon
 * \param pts the points of the polygon
 * \param nb_pts number of points in the polygon
 * \return the convexity type of the polygon
*/
u32 gf_polygone2d_get_convexity(GF_Point2D *pts, u32 nb_pts);


/* 2D Path constants */

/*!
 *2D Path point tags
 *	\hideinitializer
 */
enum
{
	/*/! Point is on curve (moveTo, lineTo, end of splines)*/
	GF_PATH_CURVE_ON = 1,
	/*! Point is a contour close*/
	GF_PATH_CLOSE	= 5,
	/*! Point is a quadratic control point*/
	GF_PATH_CURVE_CONIC = 0,
	/*! Point is a cubic control point*/
	GF_PATH_CURVE_CUBIC = 2,
};


/*!
 *2D Path flags
 *	\hideinitializer
 */
enum
{
	/*! Path is filled using the zero-nonzero rule. If not set, filling uses odd/even rule*/
	GF_PATH_FILL_ZERO_NONZERO = 1,
	/*! When set bbox must be recomputed. 
	\note Read only, used to avoid wasting time on bounds calculation*/
	GF_PATH_BBOX_DIRTY = 2,
	/*! Indicates the path is flattened flattened
	\note Read only, used to avoid wasting time on flattening*/
	GF_PATH_FLATTENED = 4,
};

/*!
 * 2D Polygon convexity type
 *	\hideinitializer
 */
enum
{
	/*! Polygon is either complex or unknown*/
	GF_POLYGON_COMPLEX,
	/*! Polygon is complex, starting in counter-clockwise order*/
	GF_POLYGON_COMPLEX_CCW,
	/*! Polygon is complex, starting in clockwise order*/
	GF_POLYGON_COMPLEX_CW,
	/*! Polygon is a counter-clockwise convex polygon*/
	GF_POLYGON_CONVEX_CCW,
	/*! Polygon is a clockwise convex polygon*/
	GF_POLYGON_CONVEX_CW,
	/*! Polygon is a convex line (degenerated path with all segments aligned)*/
	GF_POLYGON_CONVEX_LINE
};

/*!
 * Stencil alignment type for outlining
 *	\hideinitializer
 */
enum
{	
	/*! outline is centered on the path (default)*/
	GF_PATH_LINE_CENTER = 0,
	/*! outline is inside the path*/
	GF_PATH_LINE_INSIDE,
	/*! outline is outside the path*/
	GF_PATH_LINE_OUTSIDE,
};

/*!
 * Line cap type for outlining
 *	\hideinitializer
 */
enum
{
	/*! End of line is flat (default)*/
	GF_LINE_CAP_FLAT = 0,
	/*! End of line is round*/
	GF_LINE_CAP_ROUND,
	/*! End of line is square*/
	GF_LINE_CAP_SQUARE,
	/*! End of line is triangle*/
	GF_LINE_CAP_TRIANGLE,
};

/*!
 * Line join type for outlining
 *	\hideinitializer
 */
enum
{
	/*! Line join is a miter join (default)*/
	GF_LINE_JOIN_MITER = 0,
	/*! Line join is a round join*/
	GF_LINE_JOIN_ROUND,
	/*! Line join is a bevel join*/
	GF_LINE_JOIN_BEVEL,
	/*! Line join is a miter then bevel join*/
	GF_LINE_JOIN_MITER_SVG
};

/*!
 * Dash types for outlining
 *	\hideinitializer
 */
enum
{
	/*! No dashing is used (default)*/
	GF_DASH_STYLE_PLAIN = 0,
	/*! Predefined dash pattern is used*/
	GF_DASH_STYLE_DASH,
	/*! Predefined dot pattern is used*/
	GF_DASH_STYLE_DOT,
	/*! Predefined dash-dot pattern is used*/
	GF_DASH_STYLE_DASH_DOT,
	/*! Predefined dash-dash-dot pattern is used*/
	GF_DASH_STYLE_DASH_DASH_DOT,
	/*! Predefined dash-dot-dot pattern is used*/
	GF_DASH_STYLE_DASH_DOT_DOT,
	/*! Custom pattern is used. Dash lengths are given in percentage of the pen width*/
	GF_DASH_STYLE_CUSTOM,
	/*! Custom pattern is used. Dash lengths are given in the same unit as the pen width*/
	GF_DASH_STYLE_CUSTOM_ABS,
};


/*!\brief Custom dash pattern
 *
 *The custom dash pattern object is used to specify custom dashes when outlining a path.
 */
typedef struct
{
	/*! Number of dashes in the pattern*/
	u32 num_dash;
	/*! Value of the pattern dashes. Unit depends on the dash type*/
	Fixed *dashes;
} GF_DashSettings;

/*!\brief Pen properties 
 *
 *The pen properties object is used to specify several parameters used when building
 *the vectorial outline of a path.
 */
typedef struct
{
	/*! The width of the outline*/
	Fixed width;
	/*! The style of the lines ends*/
	u8 cap;
	/*! The style of the lines joins*/
	u8 join;
	/*! The alignment of the outline with regard to the path*/
	u8 align;
	/*! The dash style of the line*/
	u8 dash;
	/*! The miter limit of the line joins*/
	Fixed miterLimit;
	/*! The initial dash offset in the outline. All points before this offset will be 
	* ignored when building the outline*/
	Fixed dash_offset;
	/*! The dash pattern used for curstom dashing*/
	GF_DashSettings *dash_set;
	/*! The author-specified path length. Ignored if <= 0*/
	Fixed path_length;
} GF_PenSettings;

/*! brief builds the vectorial outline of a path
 *
 * Builds the vectorial outline of a path for the given settings. The outline of a path is a path.
 * \param path the desired path to outline
 * \param pen the properties of the virtual pen used for outlining
 * \return the outline of the path 
*/
GF_Path *gf_path_get_outline(GF_Path *path, GF_PenSettings pen);


/*! @} */

#ifdef __cplusplus
}
#endif


#endif	/*_GF_PATH2D_H_*/