5.4 The `graphserv` library

The graphserv library groups low level graphics routines, which fall in three specific categories :

communication channel management routines, used to setup and control the couple of channels used to communciate between a graphics client and its server.
a single piece of code f2x, represeneing the Fortran callabe Xlib interface used by the X window graphics server
low level graphics proper (the y_*.f family) which implement the graphics primitives described in doc TBD

Use also the quick alphabetic index here below to locate the routine of interest.

blkpipecommon	connectserver	deregister	f2x	isregistered
register	y_clear_viewport	y_closeplot	y_colour	y_coordinates
y_draw	y_fill	y_get_cursor	y_lines	y_move
y_openplot	y_page	y_readlut	y_scale	y_text
y_viewport	y_width	y_window	y_write_image	y_writelut

blkpipecommon

Library graphserv Fortran code

Calling sequence EXTERNAL BLKPIPECOMMON

This BLOCK DATA routine is called implicitly by the isregistered call to initialize the PIPECOMMON common block used to keep track of the list of registered graphics servers.
connectserver

Library graphserv Fortran code

Calling sequence CALL CONNECTSERVER(CODE,N,lu1,lu2,IERR)

Arguments CHARACTER*(*) CODE

INTEGER N

INTEGER LU1,LU2

INTEGER IERR

This call establishes the connection to the N-th instance of the graphics server of type CODE (chosen among 'XW'|'BW'|'CP'|'C2'), verifying the correct registration and the existence of the communication channels which are open on a couple of logical units LU1,LU2 (there are always an input and an output channel per server !) using the VOS z_channel routine.
The returned error code IERR can be 0 in case of successful opening or 2 (server not registered), 3 (communication channels not set up correctly) or 5 (VOS error opening communication channels).
deregister

Library graphserv Fortran code

Calling sequence CALL DEREGISTER(CODE,N)

Arguments CHARACTER*(*) CODE

INTEGER N

This call removes the registration entry of the N-th instance of the graphics server of type CODE (chosen among 'XW'|'BW'|'CP'|'C2') from the PIPECOMMON common block and from the XAS environment
f2x

Library graphserv C code

Calling sequence EXTERNAL F2X ... F2C_element=value F2C_element=value ... CALL F2X_routine

Arguments none

This piece of C code is the Fortran-callable Xlib interface used only by the X window server xwserver. All routines are (from the Fortran point of view) argumentless entry points in the same C code file.
All communication with the caller occurs via a struct (actually a couple of them to preserve the usual separation between numeric and character data) seen by the Fortran program as a COMMON block : the caller sets specific elements, call one of the f2x routines (without arguments) and reads any return value in other elements of the COMMON.
All C routines in the f2x.c file share a local set of variables among themselves.
The entry points are the following (for further details see the code) :
- f2x : no-op (for relocation only)
- f2x_init : open display, create and map window, set up graphic context etc.
- f2x_winsize : i/f to XGetGeometry
- f2x_clear : i/f to XClearWindow
- f2x_clearview : i/f to XClearArea
- f2x_clip : i/f to XSetClipRectangles
- f2x_clipoff : i/f to XSetClipMask
- f2x_draw : i/f to XDrawLine
- f2x_polyl : i/f to XDrawLines
- f2x_polyg : i/f to XFillPolygon
- f2x_wrima : i/f to XAddPixel and XPutImage
- f2x_text : i/f to XDrawString
- f2x_colour : i/f to XSetForeground
- f2x_bkg : i/f to XSetBackground
- f2x_attrib : i/f to XSetLineAttributes
- f2x_font : i/f to XSetFont
- f2x_lutquery : i/f to XQueryColors
- f2x_lutalloc : i/f to XAllocColorCells and XStoreColors
- f2x_lutchange : i/f to XStoreColors
- f2x_lutdummy : internal i/f
- f2x_curson : i/f to XWindowEvent etc. (cursor management)
- f2x_disconn : send XSync before disconnecting
- f2x_end : i/f to XCloseDisplay
isregistered

Library graphserv Fortran code

Calling sequence CALL ISREGISTERED(code,n,ok)
IF (OK) THEN ...

Arguments CHARACTER*(*) CODE

INTEGER N

LOGICAL OK

This call verifies a registration entry for the N-th instance of the graphics server of type CODE (chosen among 'XW'|'BW'|'CP'|'C2') is present in the XAS environment, and returns a flag OK=.TRUE. if the server is registered.
Side effects: The environment is loaded in the PIPECOMMON common block while at the same time the index of the server and the next free slot for a server are computed.
register

Library graphserv Fortran code

Calling sequence CALL REGISTER(CODE,N)

Arguments CHARACTER*(*) CODE

INTEGER N

This call records a registration entry of the N-th instance of the graphics server of type CODE (chosen among 'XW'|'BW'|'CP'|'C2') in the next free slot of the PIPECOMMON common block and in the XAS environment
y_clear_viewport

Library graphserv Fortran code

Calling sequence CALL Y_CLEAR_VIEWPORT(LUS)

Arguments INTEGER LUS(2)

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 8 which causes the graphics viewport to be cleared.
y_closeplot

Library graphserv Fortran code

Calling sequence CALL Y_CLOSEPLOT(LUS)

Arguments INTEGER LUS(2)

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 0 which notifies the server of the disconnection of the client. Note that the communication channel is not closed (that is responsibility of the server, not of the client !).
y_colour

Library graphserv Fortran code

Calling sequence CALL Y_COLOUR(LUS,ICOL)

Arguments INTEGER LUS(2)

INTEGER ICOL

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 105 with operand the colour ICOL, which sets the current "pen colour" to the appropriate value (colours 0-7 are the standard simple colours, while a negative ICOL points to location ABS(ICOL) of the current colour lookup table.
y_coordinates

Library graphserv Fortran code

Calling sequence CALL Y_COORDINATES(LUS,icode)

Arguments INTEGER LUS(2)

INTEGER ICODE

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 103 with operand the colour ICODE, which tells the server to interpret all further coordinates in raw device coordinates (ICODE=0), normalized device coordinates (NDC, 0.0-1.0, ICODE=1), world coordinates (ICODE=2), cm or inch (respectively ICODE=3 or 4)
y_draw

Library graphserv Fortran code

Calling sequence CALL Y_DRAW(LUS,X,Y)

Arguments INTEGER LUS(2)

REAL X,Y

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 3 with operands the coordinates of a point in the current coordinate system X,Y, which tells the server to draw a line from the current point to X,Y.
y_fill

Library graphserv Fortran code

Calling sequence CALL Y_FILL(LUS,N,X,Y)

Arguments INTEGER LUS(2)

INTEGER N

REAL X(N) ,Y(N)

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the polyfill opcode 6 with operands the number of points N, and an array of coordinates in the current coordinate system X,Y, which tells the server to fill (with the current pen colour) the polygon enclosed by points X,Y.
y_get_cursor

Library graphserv Fortran code

Calling sequence CALL Y_GET_CURSOR(LUS,X,Y,A)

Arguments INTEGER LUS(2)

REAL X,Y

CHARACTER A

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 11 (which causes the server to read the current cursor position at a key or button press) and reads from the server output channel the coordinate of the point in the current coordinate system X,Y, and the character of the pressed key A (mouse buttons currently return '?').
y_lines

Library graphserv Fortran code

Calling sequence CALL Y_LINES(LUS,N,X,Y)

Arguments INTEGER LUS(2)

INTEGER N

REAL X(N) ,Y(N)

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the polyline opcode 4 with operands the number of points N, and an array of coordinates in the current coordinate system X,Y, which tells the server to draw (with the current pen colour) a (poly)line connecting points X,Y.
y_move

Library graphserv Fortran code

Calling sequence CALL Y_MOVE(LUS,X,Y)

Arguments INTEGER LUS(2)

REAL X,Y

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 2 with operands the coordinates of a point in the current coordinate system X,Y, which tells the server to move the current point to X,Y.
y_openplot

Library graphserv Fortran code

Calling sequence CALL Y_OPENPLOT(LUS,CODE,N)

Arguments INTEGER LUS(2)

CHARACTER*(*) CODE

INTEGER N

This routine is called by a graphics client to establish a plotting connection (via connectserver) to the N-th instance of the graphics server of type CODE (chosen among 'XW'|'BW'|'CP'|'C2' or ' ' in which case the default server xw1 is used). The couple of logical units LUS, associated to the communication channels, are used in all subsequent graphics calls.
y_page

Library graphserv Fortran code

Calling sequence CALLY_PAGE(LUS)

Arguments INTEGER LUS(2)

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 1 , which causes the server to clear the entire page or screen.
y_readlut

Library graphserv Fortran code

Calling sequence CALL Y_READLUT(LUS,START,NSTEP,ISIGN,R,G,B)

Arguments INTEGER LUS(2)

INTEGER START

INTEGER NSTEP

INTEGER ISIGN

REAL R(NSTEP), G(NSTEP),G(NSTEP)

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 13 (which causes the server to read the current colour lookup table) and reads from the server output channel the red, green and blue components (0.0-1.0) R,G,B of NSTEP locations of the lookup table, starting at location START. The starting location can be relative (ISIGN=+1) to the beginning of the colour table loaded with y_writelut, or absolute (ISIGN=-1), referred to the origin of the system colour table (the XAS colour table loaded with y_writelut occupies only a portion of the typical X colour table).
y_scale

Library graphserv Fortran code

Calling sequence CALL Y_SCALE(LUS,X,Y)

Arguments INTEGER LUS(2)

CHARACTER X,Y ('LIN'|'LOG')

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 104 with a couple of 0 or 1 operands, which tells the server to plot all further data converting to linear or logarithmic scale as specified for the X,Y axes by the appropriate 'LIN' or 'LOG' codes.
y_text

Library graphserv Fortran code

Calling sequence CALL Y_TEXT(LUS,STRING,IFONT)

Arguments INTEGER LUS(2)

CHARACTER*(*) STRING

INTEGER IFONT

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 110 with operand a font number IFONT, followed by opcode 7 with operands the length of a string STRING, and the character string itself. This causes the server to write at the current position the text string in the wished font.
Font indexes are server dependent and are controlled by entries in a server specific font listing file
y_viewport

Library graphserv Fortran code

Calling sequence CALL Y_VIEWPORT(LUS,X1,X2,Y1,Y2)

Arguments INTEGER LUS(2)

REAL X1,X2,Y1,Y2

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 101 with operands the coordinates of two points in the current coordinate system X1,Y1 and X2,Y2, which are intepreted as the corners of the new viewport.
y_width

Library graphserv Fortran code

Calling sequence CALL Y_WIDTH(LUS,WIDTH)

Arguments INTEGER LUS(2)

REAL WIDTH

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 106 with operand the line width WIDTH, which tells the server to draw all further lines in the (server dependent) width.
y_window

Library graphserv Fortran code

Calling sequence CALL Y_WINDOW(LUS,X1,X2,Y1,Y2)

Arguments INTEGER LUS(2)

REAL X1,X2,Y1,Y2

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 102 with operands the coordinates of two points in the current coordinate system X1,Y1 and X2,Y2, which are intepreted as the corners of the new plotting window, then sends an opcode 103 with operand 2, to force the coordinate system into world coordinates.
y_write_image

Library graphserv Fortran code

Calling sequence CALL Y_WRITE_IMAGE(LUS,DATA,ILEN)

Arguments INTEGER LUS(2)

CHARACTER*(ILEN) DATA

INTEGER ILEN

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 9 with operands the number of bytes ILEN (max 4096) and a byte string and DATA, which cause the server to display one image line. The image DATA shall be prescaled in values ranging 0-255 (or less) pointing to colours in the current colour lookup table.
y_writelut

Library graphserv Fortran code

Calling sequence CALL Y_WRITELUT(LUS,START,NSTEP,R,G,B)

Arguments INTEGER LUS(2)

INTEGER START

INTEGER NSTEP

REAL R(NSTEP), G(NSTEP),G(NSTEP)

This routine sends to the graphics server at the other end of the communication channels attached to logical units LUS the opcode 10 (which causes the server to write values into the current colour lookup table) and loads the red, green and blue components (0.0-1.0) R,G,B into NSTEP locations of the lookup table (LUT), starting at location START. The start and step parameters are interpreted by the server as follows :
- START=0 NSTEP.NE.0
  allocates (or reallocates) a new contiguous LUT segment wherever the X server likes to, or redefines entire LUT for the Postscript servers.
- START.NE.0 NSTEP.NE.0
  redefines the content of part of the current LUT, i.e. loads NSTEP values after relative START.
- START.NE.0 NSTEP=0
  assigns explicitly location START in the X server colour table as start for the XAS LUT (unused for Postscript servers)
- START=0 NSTEP=0 (query call),
  writes on terminal the current LUT (relative location 0) start in the X server colour table (unused for Postscript servers)

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sax.iasf-milano.inaf.it/Xashelp/Prog/lib.4.html :: original creation 2002 Sep 04 18:25:55 CEST :: last edit 2002 Sep 04 18:25:55 CEST

Library	graphserv	Fortran code
Calling sequence	EXTERNAL BLKPIPECOMMON

Library	graphserv	C code
Calling sequence	`EXTERNAL F2X ... F2C_element=value F2C_element=value ... CALL F2X_routine`
Arguments	none

Library	graphserv	Fortran code
Calling sequence	`CALL CONNECTSERVER(CODE,N,lu1,lu2,IERR)`
Arguments	`CHARACTER()`	`CODE`
	`INTEGER`	`N`
	`INTEGER`	`LU1,LU2`
	`INTEGER`	`IERR`

Library	graphserv	Fortran code
Calling sequence	CALL ISREGISTERED(code,n,ok) IF (OK) THEN ...
Arguments	`CHARACTER()`	`CODE`
	`INTEGER`	`N`
	`LOGICAL`	`OK`

Library	graphserv	Fortran code
Calling sequence	`CALL Y_FILL(LUS,N,X,Y)`
Arguments	`INTEGER`	`LUS(2)`
	`INTEGER`	`N`
	`REAL`	`X(N) ,Y(N)`

Library	graphserv	Fortran code
Calling sequence	`CALL Y_GET_CURSOR(LUS,X,Y,A)`
Arguments	`INTEGER`	`LUS(2)`
	`REAL`	`X,Y`
	`CHARACTER`	`A`

5.4 The graphserv library

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5.4 The `graphserv` library