;
; NAME:
; 	DICOM_WRITER
;
; VERSION:
;	0.1
;
; PURPOSE:
;	Generate a dicom file from within RSI IDL
; 
; AUTHOR:
;	Bhautik Joshi
;
; EMAIL:
;	bjoshi@geocities.com
;
; HOMEPAGE:
;	http://cow.mooh.org
;
; USE:
;	DICOM_WRITER, filename rows, cols, bpp, image
;
; INPUT:
;	filename - string containing name of dicom file to be written to
;	rows - number of rows in image
;	cols - number of columns in image
;	bpp - number of _bytes_ per pixel in the image
;	image - byte formatted version of image
;
; NOTES ON USAGE:
;	* At the moment the program only writes to a single slice
;	* The input image must be squashed into a 1D array of bytes before
;	  it can be used in dicom_writer
;	* bpp specifies the number of bytes (not bits!!) per pixel
;	* Extra dicom tags can be easily added (see body of program)
;	* There is little to no error-checking at the moment, so be 
;	  careful!
;
; EXAMPLE:
;	Create a horrendously boring byte image and store it in a 
;	dicom file, ~/test.dcm :
;
;	> rows = 20
;	> cols = 20
;	> bpp = 1
;	> image = BYTESCL(indgen(rows,cols))
;	> dicom_writer, ~/test.dcm, rows, cols, bpp, image
;
; HISTORY:
;	Based on Marc O'Briens (marcus@icr.ac.uk) TIFF_to_DICOM.c
;	version 0.1 08-01-2002 - first working version produced
;
; TODO:
;	* Allow for more robust dicom writing
;	* Expand the number of tags written (using DICOM data 
;	  dictionary)
;	* Part 10 compliance (!!!!!!!!!!!)
;
; DISCLAIMER:
; 
; Permission to use, copy, modify, and distribute this software and its
; documentation for any purpose and without fee is hereby granted,
; provided that the above copyright notice appear in all copies and that
; both that copyright notice and this permission notice appear in
; supporting documentation.
;
; This file is provided AS IS with no warranties of any kind.  The author
; shall have no liability with respect to the infringement of copyrights,
; trade secrets or any patents by this file or any part thereof.  In no
; event will the author be liable for any lost revenue or profits or
; other special, indirect and consequential damages.
; 
; The author accepts no responsibility for any action arising from use of 
; this package. The software is not guaranteed to write compliant DICOM
; files. If it causes damage to you or your system, you have been warned -
; this is a work in progress. If it bites your dog, its not my fault. If
; it causes you to curl up on the floor in the foetal position muttering
; about pixies and mushrooms, its not my fault. If it causes you or someone
; else to spontaneously burst into song and dance, its not my fault but
; I'd like to hear about it. You have been warned.
;

pro dicom_writer, filename, rows, cols, bpp, image

;dummy fill-in variables. 
	random= '123456'
	SOPClass = '1.2.840.10008.5.1.4.1.1.20'
	SOPInstance = '1.2.840.10008.5.1.4.1.1.20.1'
	StudyID = '1.2.3.4'
	StudyInstanceUID = SOPInstance + random
	SeriesInstanceUID = StudyInstanceUID
	RelFrameOfReferenceUID = StudyInstanceUID
	SeriesInstanceUID = SeriesInstanceUID + '.1'
	RelFrameOfReferenceUID = RelFrameOfReferenceUID + '.2'
	StudyID = StudyID + 'SIGNA '

;image variables
	Seriesnum=0
	Imagenum=0
	thickness=1.0
	spacing='1.0\\1.0'

	OPENW, 1, filename

; DICOM tags - feel free to add more!

;0008 tags

;MR type	
	WRITEU, 1, BYTE(generate_stringtag('0008'x,'0008'x,'ORIGINAL\\PRIMARY\\OTHER'))
;Instance date
	WRITEU, 1, BYTE(generate_stringtag('0008'x,'0012'x,'20020108'))
;Instance time
	WRITEU, 1, BYTE(generate_stringtag('0008'x,'0013'x,'000000.00000'))
;SOP class
	WRITEU, 1, BYTE(generate_stringtag('0008'x,'0016'x,SOPClass))
;SOP instance
	WRITEU, 1, BYTE(generate_stringtag('0008'x,'0018'x,SOPInstance))
;Modality
	WRITEU, 1, BYTE(generate_stringtag('0008'x,'0060'x,'MR'))
;Manufacturer
	WRITEU, 1, BYTE(generate_stringtag('0008'x,'0070'x,'GE'))
;Study Physicians Name
;	WRITEU, 1, BYTE(generate_stringtag('0008'x,'0012'x,'chewbacca wookiee'))

;0010 tags

;Patient name
	WRITEU, 1, BYTE(generate_stringtag('0010'x,'0010'x,'Jabba the Hutt'))
;Patient ID
	WRITEU, 1, BYTE(generate_stringtag('0010'x,'0020'x,'TK247'))
;Patient birth date
	WRITEU, 1, BYTE(generate_stringtag('0010'x,'0030'x,'20010820'))
;Patient sex
	WRITEU, 1, BYTE(generate_stringtag('0010'x,'0040'x,'M'))


;0018 tags

;Acquisition type
	WRITEU, 1, BYTE(generate_stringtag('0018'x,'0023'x,'2D'))
;Slice thickness
	WRITEU, 1, BYTE(generate_stringtag('0018'x,'0050'x,STRING(thickness)))

;0020 tags

;Study instance
	WRITEU, 1, BYTE(generate_stringtag('0020'x,'000D'x,StudyInstanceUID))
;Series instance UID
	WRITEU, 1, BYTE(generate_stringtag('0020'x,'000E'x,SeriesInstanceUID))
;StudyID
	WRITEU, 1, BYTE(generate_stringtag('0020'x,'0010'x,StudyID))
;Series number
	WRITEU, 1, BYTE(generate_stringtag('0020'x,'0011'x,STRING(seriesnum)))
;Image number
	WRITEU, 1, BYTE(generate_stringtag('0020'x,'0013'x,STRING(imagenum)))

;0028 tags

;samples per pixel
	WRITEU, 1, BYTE(generate_UStag('0028'x,'0002'x,1))
;Photometric interpretation
	WRITEU, 1, BYTE(generate_stringtag('0028'x,'0004'x,'MONOCHROME2'))
;Rows in image
	WRITEU, 1, BYTE(generate_UStag('0028'x,'0010'x,rows))
;Columns in image
	WRITEU, 1, BYTE(generate_UStag('0028'x,'0011'x,rows))
;pixel spacing
	WRITEU, 1, BYTE(generate_stringtag('0028'x,'0030'x,spacing))
;bits allocated per sample
	WRITEU, 1, BYTE(generate_UStag('0028'x,'0100'x,bpp*8))
;bits stored per sample
	WRITEU, 1, BYTE(generate_UStag('0028'x,'0101'x,bpp*8))
;high bit
	WRITEU, 1, BYTE(generate_UStag('0028'x,'0102'x,(bpp*8)-1))
;pixel representation
	WRITEU, 1, BYTE(generate_UStag('0028'x,'0103'x,'0000'x))

;write image data
	imsize=rows*cols*bpp

	WRITEU, 1, BYTE(generate_pixeltag('7FE0'x,'0010'x,imsize))

	WRITEU, 1, BYTE(image)

	CLOSE, 1
end


;write any tag
function generate_anytag, group, element, data

	rs=[getbytes(group,2),getbytes(element,2)]

;correct to even length if necessary
	bs=BYTE(data)
	nl=n_elements(bs)
	if ((nl mod 2) ne 0) then begin
		bs=[bs,BYTE(0)]
		nl=nl+1
	end
;size of field
	rs=[rs,getbytes(nl,2)]
;padding
	rs=[rs,[0,0]]
;string itself
	rs=[rs,bs]

	return, rs
end

;generate string tag
function generate_stringtag, group, element, string
	return, generate_anytag(group, element, BYTE(string))
end

;generate binary element (unsigned short) tag
function generate_UStag, group, element, val
	param=getbytes(val,2)
	return, generate_anytag(group,element,param)
end

;generate pixel tag
function generate_pixeltag, group, element, val
	return, [getbytes(group,2),getbytes(element,2), getbytes(val,4)]
end

;generate unsigned long tag
function generate_ULtag, group, element, val
	param=getbytes(val,4)
	return, generate_anytag(group,element,param)
end

;convert a value, val, that is num bytes long, into 
;a series of ordered bytes
function getbytes, val, num
	ret=BYTARR(num)
	offset=0
;work in big endian ONLY
	;val=swap_endian(val)
	byteorder,val,/SWAP_IF_LITTLE_ENDIAN 
	for i=0,(num-1) do begin
		tmpres=BYTE(ISHFT(val, offset) AND 255)
		ret[i]=tmpres
		offset=offset-8
	endfor

	return, ret
end