;\begin{verbatim} function alignstr, dummy ;+ ; NAME: alignstr ; PURPOSE: Initialize the alignment structure ; CALLING SEQUENCE: ; a = alignstr() ; EXPLANATION: ; a.object: a string, the information on the object image to be aligned ; (for example, a file name) ; a.reference: a string, the information on the reference image ; a.ref_origin: a two-element float array, ; the origin in the reference image coordinates ; a.obj_origin: a two-element float array, ; the origin in the object image coordinates ; a.rotation: a float scalar, the counterclockwise ; angle of the horizontal ("x") direction of the ; object image frame measured with respect to ; the horizontal("x") direction of the reference image frame ; (in radians) ; a.ref_aspect: a float scalar, the ratio of the physical size of ; a reference image pixel measured in the ; horizontal direction to that measured in the vertical ; direction ; a.obj_aspect: a float scalar, the ratio of the physical size of ; an object image pixel measured in the ; horizontal direction to that measured in the vertical ; direction ; a.scale: a float scalar, the ratio of the physical size of ; an object image pixel measured in the horizontal direction ; to that of a reference pixel measured in the vertical ; direction ; a.flip: a two-element array, the flipping parameters which have a value ; of either 1 or -1. ;- return, {align, $ object: '', $ reference: '', $ ref_origin: [0.,0.], $ obj_origin: [0.,0.], $ rotation: 0., $ ref_aspect: 1., $ obj_aspect: 1., $ scale: 1., $ flip: [1,1] } end ;\end{verbatim}