## GogChartMap GogChartMap |

## Synopsis

                        GogChartMap;
                        GogChartMapPolarData;
    double              gog_chart_map_2D_derivative_to_view (GogChartMap *map,
                                                             double deriv,
                                                             double x,
                                                             double y);
    void                gog_chart_map_2D_to_view            (GogChartMap *map,
                                                             double x,
                                                             double y,
                                                             double *u,
                                                             double *v);
    void                gog_chart_map_free                  (GogChartMap *map);
    GogAxisMap *        gog_chart_map_get_axis_map          (GogChartMap *map,
                                                             unsigned int index);
    GogChartMapPolarData * gog_chart_map_get_polar_parms    (GogChartMap *map);
    gboolean            gog_chart_map_is_valid              (GogChartMap *map);
    GOPath *            gog_chart_map_make_close_path       (GogChartMap *map,
                                                             double const *x,
                                                             double const *y,
                                                             int n_points,
                                                             GogSeriesFillType fill_type);
    GOPath *            gog_chart_map_make_path             (GogChartMap *map,
                                                             double const *x,
                                                             double const *y,
                                                             int n_points,
                                                             GOLineInterpolation interpolation,
                                                             gboolean skip_invalid,
                                                             gpointer data);
    GogChartMap *       gog_chart_map_new                   (GogChart *chart,
                                                             GogViewAllocation const *area,
                                                             GogAxis *axis0,
                                                             GogAxis *axis1,
                                                             GogAxis *axis2,
                                                             gboolean fill_area);
    void                gog_chart_map_view_to_2D            (GogChartMap *map,
                                                             double x,
                                                             double y,
                                                             double *u,
                                                             double *v);

## Object Hierarchy

      GBoxed
       +----GogChartMap

## Description

## Details

### GogChartMap

    typedef struct _GogChartMap GogChartMap;

### GogChartMapPolarData

    typedef struct {
    	double cx, cy;
    	double rx, ry;
    	double th0, th1;
    } GogChartMapPolarData;

double `cx`; | center horizontal position.
double `cy`; | center vertical position.
double `rx`; | available horizontal space from the center.
double `ry`; | available vertical space from the center.
double `th0`; | start angle.
double `th1`; | end angle.

### gog_chart_map_2D_derivative_to_view ()

    double              gog_chart_map_2D_derivative_to_view (GogChartMap *map,
                                                             double deriv,
                                                             double x,
                                                             double y);

Converts a 2D slope from data space to canvas space. It is only implemented for xy maps.

`map` : | a GogChartMap
`deriv` : | the slope in data space
`x` : | data x value
`y` : | data y value
Returns : | the slope in canvas space or go_nan.

### gog_chart_map_2D_to_view ()

    void                gog_chart_map_2D_to_view            (GogChartMap *map,
                                                             double x,
                                                             double y,
                                                             double *u,
                                                             double *v);

Converts a 2D coordinate from data space to canvas space.

`map` : | a GogChartMap
`x` : | data x value
`y` : | data y value
`u` : | placeholder for x converted value
`v` : | placeholder for y converted value

### gog_chart_map_free ()

    void                gog_chart_map_free                  (GogChartMap *map);

Frees `map` object.

`map` : | a GogChartMap

### gog_chart_map_get_axis_map ()

    GogAxisMap *        gog_chart_map_get_axis_map          (GogChartMap *map,
                                                             unsigned int index);

Convenience function which returns one of the associated axis_map.

Valid values are in range [0..2].

`map` : | a GogChartMap
`index` : | axis index
Returns : | a GogAxisMap. [transfer none]

### gog_chart_map_get_polar_parms ()

    GogChartMapPolarData * gog_chart_map_get_polar_parms    (GogChartMap *map);

Convenience function for retrieving data related to polar plot layout.

`map` : | a GogChartMap
Returns : | a GogChartMapPolarData struct. [transfer none]

### gog_chart_map_is_valid ()

    gboolean            gog_chart_map_is_valid              (GogChartMap *map);

Tests if `map` was correctly initializied, i.e. if all associated axis_map are valid (see `gog_axis_map_is_valid()` ).

given to gog_chart_map_new.

`map` : | a GogChartMap
Returns : | `TRUE` if `map` is valid.

### gog_chart_map_make_close_path ()

    GOPath *            gog_chart_map_make_close_path       (GogChartMap *map,
                                                             double const *x,
                                                             double const *y,
                                                             int n_points,
                                                             GogSeriesFillType fill_type);

`map` : | a GogChartMap
`x` : | x data
`y` : | y data
`n_points` : | number of points
`fill_type` : | fill type
Returns : | a new GOPath using `x` and `y` data, with respect to `fill_type`.

### gog_chart_map_make_path ()

    GOPath *            gog_chart_map_make_path             (GogChartMap *map,
                                                             double const *x,
                                                             double const *y,
                                                             int n_points,
                                                             GOLineInterpolation interpolation,
                                                             gboolean skip_invalid,
                                                             gpointer data);

`map` : | a GogChartMap
`x` : | x data
`y` : | y data
`n_points` : | number of points
`interpolation` : | interpolation type
`skip_invalid` : | whether to ignore invalid data or interrupt the interpolation
Returns : | a new GOPath using `x` and `y` data, each valid point being connected with respect to `interpolation`.

### gog_chart_map_new ()

    GogChartMap *       gog_chart_map_new                   (GogChart *chart,
                                                             GogViewAllocation const *area,
                                                             GogAxis *axis0,
                                                             GogAxis *axis1,
                                                             GogAxis *axis2,
                                                             gboolean fill_area);

Creates a new GogChartMap, used for conversion from data space to canvas space.

`chart` : | a GogChart
`area` : | area allocated to chart
`axis0` : | 1st dimension axis
`axis1` : | 2nd dimension axis
`axis2` : | 3rd dimension axis
`fill_area` : | does chart fill allocated area
Returns : | a new GogChartMap object. [transfer full]

### gog_chart_map_view_to_2D ()

    void                gog_chart_map_view_to_2D            (GogChartMap *map,
                                                             double x,
                                                             double y,
                                                             double *u,
                                                             double *v);

Converts a 2D coordinate from canvas space to data space.

`map` : | a GogChartMap
`x` : | data x value
`y` : | data y value
`u` : | placeholder for x converted value
`v` : | placeholder for y converted value