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area.go
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area.go
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package proj
/*
#cgo CFLAGS: -I. -I${SRCDIR}/usr/local/include
#cgo LDFLAGS: -L${SRCDIR}/usr/local/lib -lproj
#include "wrapper.h"
*/
import "C"
// Area contains a opaque object describing an area in which a transformation is performed.
//
type Area struct {
pj *C.PJ_AREA
}
/*
var (
World := NewArea(-180, -90, 180, 90)
)
*/
// NewArea creates an area of use.
// `lonmin` West longitude, in degrees. In [-180,180] range.
// `latmin` South latitude, in degrees. In [-90,90] range.
// `lonmax` East longitude, in degrees. In [-180,180] range.
// `latmax` North latitude, in degrees. In [-90,90] range.
// In the case of an area of use crossing the antimeridian (longitude +/- 180
// degrees), `lonmin` will be greater than `lonmax`.
//
func NewArea ( lonmin float64, latmin float64, lonmax float64, latmax float64) (*Area) {
a := &Area{pj:C.proj_area_create()}
C.proj_area_set_bbox(a.pj, C.double(lonmin), C.double(latmin), C.double(lonmax), C.double(latmax))
return a
}
// DestroyArea deallocates the internal PROJ area pointer
//
func (a *Area) DestroyArea () {
if a != nil {
C.proj_area_destroy((*a).pj)
(*a).pj = nil
}
}
// Handle returns the PROJ internal object to be passed to the PROJ library
//
func (a *Area) Handle () (interface{}) {
return (*a).pj
}
// HandleIsNil returns true when the PROJ internal object is NULL.
//
func (a *Area) HandleIsNil () bool {
return (*a).pj == (*C.PJ_AREA)(nil)
}
/*
// SetBBox sets the bounding box of the area of use.
// In the case of an area of use crossing the antimeridian (longitude +/- 180
// degrees), `lonmin` will be greater than `lonmax`.
//
func (a *Area) SetBBox ( lonmin float64, latmin float64, lonmax float64, latmax float64 ) {
C.proj_area_set_bbox(a.pj, C.double(lonmin), C.double(latmin), C.double(lonmax), C.double(latmax))
}
*/
/* TODO how to destroy opaque object in the end ?
// init package initialisation
//
func init () {
runtime.SetFinalizer(World, func (a *Area) {
a.DestroyArea()
}
}
*/