## GogAxisMap

GogAxisMap

## Synopsis

    #include <gog-axis.h>

                        GogAxisMap;
    GogAxisMap*         gog_axis_map_new                    (GogAxis *axis,
                                                             double offset,
                                                             double length);
    double              gog_axis_map                        (GogAxisMap *map,
                                                             double value);
    double              gog_axis_map_to_view                (GogAxisMap *map,
                                                             double value);
    double              gog_axis_map_derivative_to_view     (GogAxisMap *map,
                                                             double value);
    double              gog_axis_map_from_view              (GogAxisMap *map,
                                                             double value);
    gboolean            gog_axis_map_finite                 (GogAxisMap *map,
                                                             double value);
    double              gog_axis_map_get_baseline           (GogAxisMap *map);
    void                gog_axis_map_get_extents            (GogAxisMap *map,
                                                             double *start,
                                                             double *stop);
    void                gog_axis_map_get_bounds             (GogAxisMap *map,
                                                             double *minimum,
                                                             double *maximum);
    void                gog_axis_map_free                   (GogAxisMap *map);
    gboolean            gog_axis_map_is_valid               (GogAxisMap *map);
    gboolean            gog_axis_map_is_inverted            (GogAxisMap *map);

## Description

## Details

### GogAxisMap

    typedef struct _GogAxisMap GogAxisMap;

### gog_axis_map_new ()

    GogAxisMap*         gog_axis_map_new                    (GogAxis *axis,
                                                             double offset,
                                                             double length);

Creates a GogAxisMap for data mapping to plot window. offset and length are optional parameters to be used with gog_axis_map_to_view in order to translates data coordinates into canvas space.

`axis` : | a GogAxis
`offset` : | start of plot area.
`length` : | length of plot area.
Returns : | a newly allocated GogAxisMap.

### gog_axis_map ()

    double              gog_axis_map                        (GogAxisMap *map,
                                                             double value);

Converts `value` to plot coordinates. A value in [0,1.0] range means a data within axis bounds.

`map` : | a GogAxisMap
`value` : | value to map to plot space.
Returns : | mapped value.

### gog_axis_map_to_view ()

    double              gog_axis_map_to_view                (GogAxisMap *map,
                                                             double value);

Converts value from data space to canvas space, using offset and length parameters given to gog_axis_map_new.

`map` : | a GogAxisMap
`value` : | value to map to canvas space
Returns : | a value in canvas coordinates

### gog_axis_map_derivative_to_view ()

    double              gog_axis_map_derivative_to_view     (GogAxisMap *map,
                                                             double value);

`map` : | a GogAxisMap
`value` : | value to map to canvas space
Returns : | the derivative of the mapping expression at value.

### gog_axis_map_from_view ()

    double              gog_axis_map_from_view              (GogAxisMap *map,
                                                             double value);

Converts value from canvas space to data space.

`map` : | a GogAxisMap
`value` : | value to unmap from canvas space.
Returns : | value in data coordinates

### gog_axis_map_finite ()

    gboolean            gog_axis_map_finite                 (GogAxisMap *map,
                                                             double value);

Tests whether `value` is valid for the given `map`.

`map` : | a GogAxisMap
`value` : | value to test
Returns : | `TRUE` if value means something

### gog_axis_map_get_baseline ()

    double              gog_axis_map_get_baseline           (GogAxisMap *map);

`map` : | a GogAxisMap
Returns : | the baseline for `map`, in view coordinates, clipped to offset and offset+length, where offset and length are the parameters of gog_axis_map_new.

### gog_axis_map_get_extents ()

    void                gog_axis_map_get_extents            (GogAxisMap *map,
                                                             double *start,
                                                             double *stop);

Gets start and stop for the given axis map in data coordinates. If axis is not inverted, start = minimum and stop = maximum. If axis is invalid, it'll return arbitrary bounds.

Any of `start` and `stop` may be NULL.

`map` : | a GogAxisMap
`start` : | location to store start for this axis
`stop` : | location to store stop for this axis

### gog_axis_map_get_bounds ()

    void                gog_axis_map_get_bounds             (GogAxisMap *map,
                                                             double *minimum,
                                                             double *maximum);

Gets bounds for the given axis map in data coordinates. If axis is invalid, it'll return arbitrary bounds.

Any of `minimum` and `maximum` may be NULL.

`map` : | a GogAxisMap
`minimum` : | location to store minimum for this axis
`maximum` : | location to store maximum for this axis

### gog_axis_map_free ()

    void                gog_axis_map_free                   (GogAxisMap *map);

Frees GogAxisMap object.

`map` : | a GogAxisMap

### gog_axis_map_is_valid ()

    gboolean            gog_axis_map_is_valid               (GogAxisMap *map);

Tests if `map` was correctly initialized, i.e. if bounds are valid.

`map` : | a GogAxisMap
Returns : | `TRUE` if map is valid

### gog_axis_map_is_inverted ()

    gboolean            gog_axis_map_is_inverted            (GogAxisMap *map);

`map` : | a GogAxisMap
Returns : | `TRUE` is the axis is inverted;