00100	  DDCALL and DDJOB  -  A Prototype of a Data Disc Display Spooler.
00200	
00300	                          Bruce g. Baumgart
00400	
00500	
00600	ABSTRACT
00700	
00800		DDJOB creates Data Disc buffers of graphics and TV  pictures.
00900	DDJOB  is  bit  raster  oriented and follows the clear white light of
01000	windowing.      Bit rasters provide a common ground on  which  images
01100	and  graphics  can  be  combined.  Windows provide a way to deal with
01200	image  addressing   (physical   and   logical),   zooming,   scaling,
01300	magnification,   clipping,   cropping,   aspect   ratios  and  buffer
01400	allocation.
01500	
01600		DDJOB waits for letters from DDCALL.    The  DDCALL  routines
01700	are  not III compatible because I have never liked the III very much,
01800	a program that reads III buffers and  sends  appropriate  letters  to
02100	
02200	The require source file statement for declaring these ruotines is:
02300	
02400		REQUIRE "DD[DD,BGB]" SOURCE_FILE;
02500	
02600	At present the mechanisms in DDCALL will load a  distinct  DDJOB  for
02700	each  project programmer as it becomes necessary. For programmer XXX,
02800	the DDJOB is renamed to DDJXXX and is run thru PTY.
     

00100	I. GRAPHICS.
00200	
00300	BEGIN	"TEST1"
00400		REQUIRE "DD[DD,BGB]" SOURCE_FILE;
00500		SETDWN(40,40,350,350);
00600		SETLWN(0,0,1,1);
00700	ERASDD;
00800		AI(-1,-1);
00900		AV( 1,-1);
01000		AV( 1, 1);
01100		AV(-1, 1);
01200		AV(-1,-1);
01300		AI(-0.5,0);AV(+0.5,0);
01400		AI(0,-0.5);AV(0,+0.5);
01500		AI(0,0);ARC(0.75, 6.3, 0);
01600		SHOWDD(0);
01700		DDSTR(0.25, 0.5, 0, "DISPLAY EXAMPLE !");
01800		INCHRW;
01900	END	"TEST1"
02000	
02100		The above program will display a cross within a circle within
02200	a rectangle with a label on your local Data Disc Screen.
     

00100	SUMMARY OF DDCALL ROUTINES
00200	
00300	ERASTV;		Erases the six video synthesizer channels.
00400	ERASDD;		Erases your local data disc screen.
00500	
00600	DPYDD (STRING File; INTEGER ARRAY Swindo, Owindo, Levels);	
00700	
00800		DPYDD gets a TV file from the 2314 and repacks  the  bits  by
00900	levels  and  stores  the  TV  image  and  the  repacked  image on the
01000	Librascope in order to expedite subsequent DPYDD's.    Swindo  is  an
01100	integer  array  [1:4]  containing  the source window:  sx,sy,sdx,sdy.
01200	Owindo is an  integer  array  [1:3]  containing  the  object  window:
01300	ox,oy,magpow. (Windows are explained on page three).
01400	
01500		The Levels array [1:6] contains channel numbers. hannel #0 is
01600	a no operation.   DPYDD  always  sets  the  logical  window  and  the
01700	physical  destination  window,  so  that a DPYDD followed by graphics
01800	primitives results in a combined image properly clipped and scaled.
01900	
02000	SETLWN(real lx,ly,ldx,ldy); Initializes the Graphics Logical Window.
02100	SETDWN(integer dr,dc,dm,dn ); Initializes the Physical Destination Window.
02200	SETWND(real array lwn;integer array dwn); Combines SETLWN and SETDWN.
02300	
02400	The graphics primitives:(details given on page four)
02500	AI(X,Y);AV(X,Y);DOT(X,Y);ARC(R,L,A);RADIAL(R1,R2,A);DMS(dddmmss);
02600	
02700	DDSTR (x,y,chn,str);	Data Disc string at x,y.
02800	DDSTRC(r,c,chn,str);	Data Disc string at row column.
02900	DDTYPE(Y,GLITCHES,LINES);
03000	
03100	SHOWDD(INTEGER  levchn);  Outputs  a  graphics image. Negative levchn
03200	IOR's the image onto the  DD,  Positive  levchn  causes  replacement.
03300	Levchn  itself should be a two digit octal number, Level concatenated
03400	with Channel.
03500	
03600	DRUMDD(frame);
03700		Positive frame numbers cause the next  dd  buffers  shown  by
03800	DPYDD  or  SHOWDD to go to the librascope. Negative frame numbers get
03900	the frame from the librascope and display it.  The zero frame flushes
04000	the  librascope  (well you see there is this chain on the back of the
04100	librascope). Ordinary mortals are limited to 150  frames,  since  the
04200	librascope  can  only  hold  300 frames in all.  Drum frames are like
04300	glass and even if The Ernest Television Crossbar Switch should happen
04400	to  work,  we will still be up against the wall for tracks, so IORing
04500	tracks thru Ernest is not a solution to the glass problem  since  the
04600	number of tracks is so ridiculously small.
04700	
04800	TVSEG(file,segname);
04900		Gets a TV file from the 2314  or  from  the  librascope,  and
05000	makes  an upper segment out of it. Null string segnam flushs the file
05100	off the librascope, null string file name flushs the segment.
     

00100	                          SPECIFIC WINDOWS
00200	
00300	TV file window frame  -  TVM & TVN forever 216 by 288.
00400	
00500		TV  images  contain  so  many rows, TVM, and so many columns,
00600	TVN, and consequently image manipulations must be restricted to these
00700	bounds.  The  number  of  rows and columns is computed from the image
00800	file header, unusually large or negative counts cause the file to  be
00900	ignored.  At our present primitive state of cameras, digitization and
01000	memory I have come to prefer images which contain  216  rows  of  288
01100	columns   of  sixbits  per  pixel,  this  standard  arises  from  the
01200	convenience of dimensions that are divisible by as  many  factors  of
01300	two and three as possible. All images are expanded or truncated to
01400	fit into 216 rows by 288 columns by 6 bits.
01500	
01600	Data Disc window frame  -  DDM & DDN forever 480 by 512.
01700	
01800		The data disc can display 482 lines of 512 bits each, however
01900	for the sake of divisibility by four DDM is only 480 lines.
02000	
02100	Source Window   -  INTEGER SX,SY,SDX,SDY;
02200	
02300		The source window defines a subset of a TV file.
02400	
02500	Object Window  -  INTEGER OX,OY,MAGPOW.
02600	
02700		The object window defines a mapping from a TV file  onto  the
02800	data  disc  screen. OX,OY is where the center of the source window is
02900	to be placed on the screen.  MAGPOW is the logrithm  base  two  of  a
03000	magnification  factor, so each source image pixel gets mapped into
03100	(2↑MAGPOW)↑2 object image pixels.  No interpolation or  smoothing  is
03200	done.
03300	
03400	Logical Window  -  REAL LX,LY,LDX,LDY;
03500	
03600		The logical window defines the address space for the graphics
03700	primitives: DOT, AI, AV, ARC, RADIAL and DDSTR.  
03800	
03900	Data Disc Physical Window or Destination Window  -  INTEGER DR,DC,DM,DN.
04000	
04100		The physical destination window defines the patch of data disc
04200	screen in which the logical window appears.
     

00100	                       THE GRAPHICS PRIMITIVES

00200	
00300	AI(X,Y).................Position Pseudo Beam.
00400	AV(X,Y).................Absolute Vector to new pseudo beam position.
00500	DOT(X,Y)................Absolute point, doesn't affect beam position.
00600	
00700	ARC(R,L,A);
00800		ARC displays an arc of  radius  R  centered  about  the  most
00900	recent  beam position. L is the arc's directed length from a starting
01000	point A radians from the positive X axis, L & A are  in  radians  and
01100	CCW is the positive orientation.
01200	
01300	RADIAL (R1,R2,A);
01400		RADIAL  displays  the  line  segment  which radiates from the
01500	pseudo beam position in the direction A, and lies between the  radii
01600	R1 and R2, the pseudo beam remains fixed unless R1=R2;
01700	
01800	Real DMS (integer dddmmss)
01900		DMS  converts  from  degrees, minutes and seconds to radians.
02000	The argument is a decimal integer ((ddd*100+mm)*100+ss.