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Functions related to reporting a the bounding box of certain inputs are
declared in `gnuastro/box.h`. All coordinates in this header are in
the FITS format (first axis is the horizontal and the second axis is
vertical).

- Function:

*void*

**gal_box_bound_ellipse_extent***(double*`a`

, double`b`

, double`theta_deg`

, double`*extent`

) Return the maximum extent along each dimension of the given ellipse from the center of the ellipse. Therefore this is half the extent of the box in each dimension.

`a`

is the ellipse major axis,`b`

is the minor axis,`theta_deg`

is the position angle in degrees. The extent in each dimension is in floating point format and stored in`extent`

which must already be allocated before this function.

- Function:

*void*

**gal_box_bound_ellipse***(double*`a`

, double`b`

, double`theta_deg`

, long`*width`

) Any ellipse can be enclosed into a rectangular box. The purpose of this function is to give the height and width of that box assuming the center of the ellipse is in the box center.

`a`

is the ellipse major axis,`b`

is the minor axis,`theta_deg`

is the position angle in degrees. The`width`

array will contain the output size in long integer type.`width[0]`

, and`width[1]`

are the number of pixels along the first and second FITS axis. Since the ellipse center is assumed to be in the center of the box, all the values in`width`

will be an odd integer.

- Function:

*void*

**gal_box_border_from_center***(double*`center`

, size_t`ndim`

, long`*width`

, long`*fpixel`

, long`*lpixel`

) Given the center coordinates in

`center`

and the`width`

(along each dimension) of a box, return the coordinates of the first (`fpixel`

) and last (`lpixel`

) pixels. All arrays must have`ndim`

elements (one for each dimension).

- Function:

*int*

**gal_box_overlap***(long*`*naxes`

, long`*fpixel_i`

, long`*lpixel_i`

, long`*fpixel_o`

, long`*lpixel_o`

, size_t`ndim`

) An

`ndim`

-dimensional dataset of size`naxes`

(along each dimension, in FITS order) and a box with first and last (inclusive) coordinate of`fpixel_i`

and`lpixel_i`

is given. This box doesn’t necessarily have to lie within the dataset, it can be outside of it, or only patially overlap. This function will change the values of`fpixel_i`

and`lpixel_i`

to exactly cover the overlap in the input dataset’s coordinates.This function will return 1 if there is an overlap and 0 if there isn’t. When there is an overlap, the coordinates of the first and last pixels of the overlap will be put in

`fpixel_o`

and`lpixel_o`

.

Next: Polygons, Previous: Tessellation library, Up: Gnuastro library [Contents][Index]

GNU Astronomy Utilities 0.5 manual, December 2017.