CpmlSegment

CpmlPath

typedef cairo_path_t CpmlPath;

This is another name for the cairo_path_t type. Although phisically they are the same struct, CpmlPath conceptually embodies an important difference: it is a cairo path that can embed CPML_ARC primitives. This is not a native cairo primitive and having two different data types is a good way to make clear when a function expect or not embedded arc-to primitives.

CpmlSegment

typedef struct {
        CpmlPath          *path;
        cairo_path_data_t *data;
        int                num_data;
} CpmlSegment;

This is an unobtrusive struct to identify a segment inside a cairo path. Unobtrusive means that the real coordinates are still stored in path: CpmlSegment only provides a way to access them.

cpml_segment_from_cairo ()

cairo_bool_t        cpml_segment_from_cairo             (CpmlSegment *segment,
                                                         CpmlPath *path);

Builds a CpmlSegment from a CpmlPath structure. This operation involves stripping the duplicate CPML_MOVE primitives at the start of the path and setting num_data field to the end of the contiguous line, that is when another CPML_MOVE primitive is found or at the end of the path. A pointer to the source cairo path is kept though.

This function will fail if path is null, empty or if its status member is not CAIRO_STATUS_SUCCESS. Also, the first primitive must be a CPML_MOVE, so no dependency on the cairo context is needed.

cpml_segment_copy ()

void                cpml_segment_copy                   (CpmlSegment *segment,
                                                         const CpmlSegment *src);

Makes a shallow copy of src into segment.

cpml_path_is_empty()

#define             cpml_path_is_empty(cpml_path)

Checks if cpml_path is empty. An invalid path is considered empty.

cpml_segment_reset ()

void                cpml_segment_reset                  (CpmlSegment *segment);

Modifies segment to point to the first segment of the source cairo path.

cpml_segment_next ()

cairo_bool_t        cpml_segment_next                   (CpmlSegment *segment);

Modifies segment to point to the next segment of the source cairo path.

cpml_segment_get_length ()

double              cpml_segment_get_length             (const CpmlSegment *segment);

Gets the whole length of segment.

cpml_segment_put_extents ()

void                cpml_segment_put_extents            (const CpmlSegment *segment,
                                                         CpmlExtents *extents);

Gets the whole extents of segment.

cpml_segment_put_pair_at ()

void                cpml_segment_put_pair_at            (const CpmlSegment *segment,
                                                         double pos,
                                                         CpmlPair *pair);

Gets the coordinates of the point lying on segment at position pos. pos is an homogeneous factor where 0 is the start point, 1 the end point, 0.5 the mid point and so on. The relation 0 < pos < 1 should be satisfied, although some cases accept value outside this range.

cpml_segment_put_vector_at ()

void                cpml_segment_put_vector_at          (const CpmlSegment *segment,
                                                         double pos,
                                                         CpmlVector *vector);

Gets the steepness of the point lying on segment at position pos. pos is an homogeneous factor where 0 is the start point, 1 the end point, 0.5 the mid point and so on. The relation 0 < pos < 1 should be satisfied, although some cases accept value outside this range.

cpml_segment_put_intersections ()

size_t              cpml_segment_put_intersections      (const CpmlSegment *segment,
                                                         const CpmlSegment *segment2,
                                                         size_t n_dest,
                                                         CpmlPair *dest);

Computes the intersections between segment and segment2 and returns the found points in dest. If the intersections are more than n_dest, only the first n_dest pairs are stored in dest.

To get the job done, the primitives of segment are sequentially scanned for intersections with any primitive in segment2. This means segment has a higher precedence over segment2.

cpml_segment_offset ()

void                cpml_segment_offset                 (CpmlSegment *segment,
                                                         double offset);

Offsets a segment of the specified amount, that is builds a "parallel" segment at the offset distance from the original one and returns the result by replacing the original segment.

cpml_segment_transform ()

void                cpml_segment_transform              (CpmlSegment *segment,
                                                         const cairo_matrix_t *matrix);

Applies matrix on all the points of segment.

cpml_segment_reverse ()

void                cpml_segment_reverse                (CpmlSegment *segment);

Reverses segment in-place. The resulting rendering will be the same, but with the primitives generated in reverse order.

It is assumed that segment has yet been sanitized, that is returned by some CPML API function or it is a path yet conforming to the segment rules described by the cpml_segment_from_cairo() function.

cpml_segment_to_cairo ()

void                cpml_segment_to_cairo               (const CpmlSegment *segment,
                                                         cairo_t *cr);

Appends the path of segment to cr. The segment is "flattened", that is CPML_ARC primitives are approximated by one or more CPML_CURVE using cpml_arc_to_cairo(). Check its documentation for further details.

cpml_segment_dump ()

void                cpml_segment_dump                   (const CpmlSegment *segment);

Dumps the specified segment to stdout. Useful for debugging purposes.