lsst.display.ds9.ds9 Namespace Reference

Classes
class	Ds9Error
class	Buffer
class	Ds9Event
class	DisplayImpl

Functions
def	getXpaAccessPoint ()
def	ds9Version ()
def	selectFrame (frame)
def	ds9Cmd (cmd=None, trap=True, flush=False, silent=True, frame=None, get=False)
def	initDS9 (execDs9=True)

Variables
	file
bool	needShow = True
int	XPA_SZ_LINE = 4096 - 100
	cmdBuffer
	haveGzip = not os.system("gzip < /dev/null > /dev/null 2>&1")
bool	definedCallbacks = True

Function Documentation

ds9Cmd()

def lsst.display.ds9.ds9.ds9Cmd	(		cmd = None,
			trap = True,
			flush = False,
			silent = True,
			frame = None,
			get = False
	)

Issue a DS9 command, raising errors as appropriate.

Parameters
----------
cmd : `str`, optional
    Command to execute.
trap : `bool`, optional
    Trap errors.
flush : `bool`, optional
    Flush the output.
silent : `bool`, optional
    Do not print trapped error messages.
frame : `int`, optional
    Frame number on which to execute command.
get : `bool`, optional
    Return xpa response.

Definition at line 225 of file ds9.py.

def ds9Cmd(cmd=None, trap=True, flush=False, silent=True, frame=None, get=False):
    """Issue a DS9 command, raising errors as appropriate.
 
    Parameters
    ----------
    cmd : `str`, optional
        Command to execute.
    trap : `bool`, optional
        Trap errors.
    flush : `bool`, optional
        Flush the output.
    silent : `bool`, optional
        Do not print trapped error messages.
    frame : `int`, optional
        Frame number on which to execute command.
    get : `bool`, optional
        Return xpa response.
    """
 
    global cmdBuffer
    if cmd:
        if frame is not None:
            cmd = "%s;" % selectFrame(frame) + cmd
 
        if get:
            return xpa.get(None, getXpaAccessPoint(), cmd, "").strip()
 
        # Work around xpa's habit of silently truncating long lines; the value
        # ``5`` provides some margin to handle new lines and the like.
        if cmdBuffer._lenCommands + len(cmd) > XPA_SZ_LINE - 5:
            ds9Cmd(flush=True, silent=silent)
 
        cmdBuffer._commands += ";" + cmd
        cmdBuffer._lenCommands += 1 + len(cmd)
 
    if flush or cmdBuffer._lenCommands >= cmdBuffer._getSize():
        cmd = (cmdBuffer._commands + "\n")
        cmdBuffer._commands = ""
        cmdBuffer._lenCommands = 0
    else:
        return
 
    cmd = cmd.rstrip()
    if not cmd:
        return
 
    try:
        ret = xpa.set(None, getXpaAccessPoint(), cmd, "", "", 0)
        if ret:
            raise IOError(ret)
    except IOError as e:
        if not trap:
            raise Ds9Error("XPA: %s, (%s)" % (e, cmd))
        elif not silent:
            print("Caught ds9 exception processing command \"%s\": %s" % (cmd, e), file=sys.stderr)
 
 

ds9Version()

def lsst.display.ds9.ds9.ds9Version

(

)

Get the version of DS9 in use.

Returns
-------
version : `str`
    Version of DS9 in use.

Definition at line 89 of file ds9.py.

def ds9Version():
    """Get the version of DS9 in use.
 
    Returns
    -------
    version : `str`
        Version of DS9 in use.
    """
    try:
        v = ds9Cmd("about", get=True)
        return v.splitlines()[1].split()[1]
    except Exception as e:
        print("Error reading version: %s" % e, file=sys.stderr)
        return "0.0.0"
 
 
try:
    cmdBuffer

getXpaAccessPoint()

def lsst.display.ds9.ds9.getXpaAccessPoint

(

)

Parse XPA_PORT if set and return an identifier to send DS9 commands.

Returns
-------

xpaAccessPoint : `str`
    Either a reference to the local host with the configured port, or the
    string ``"ds9"``.

Notes
-----
If you don't have XPA_PORT set, the usual xpans tricks will be played
when we return ``"ds9"``.

Definition at line 61 of file ds9.py.

def getXpaAccessPoint():
    """Parse XPA_PORT if set and return an identifier to send DS9 commands.
 
    Returns
    -------
 
    xpaAccessPoint : `str`
        Either a reference to the local host with the configured port, or the
        string ``"ds9"``.
 
    Notes
    -----
    If you don't have XPA_PORT set, the usual xpans tricks will be played
    when we return ``"ds9"``.
    """
    xpa_port = os.environ.get("XPA_PORT")
    if xpa_port:
        mat = re.search(r"^DS9:ds9\s+(\d+)\s+(\d+)", xpa_port)
        if mat:
            port1, port2 = mat.groups()
 
            return "127.0.0.1:%s" % (port1)
        else:
            print("Failed to parse XPA_PORT=%s" % xpa_port, file=sys.stderr)
 
    return "ds9"
 
 

initDS9()

def lsst.display.ds9.ds9.initDS9

(

execDs9 = True

)

Initialize DS9.

Parameters
----------
execDs9 : `bool`, optional
    If DS9 is not running, attempt to execute it.

Definition at line 282 of file ds9.py.

def initDS9(execDs9=True):
    """Initialize DS9.
 
    Parameters
    ----------
    execDs9 : `bool`, optional
        If DS9 is not running, attempt to execute it.
    """
    try:
        xpa.reset()
        ds9Cmd("iconify no; raise", False)
        ds9Cmd("wcs wcsa", False)         # include the pixel coordinates WCS (WCSA)
 
        v0, v1 = ds9Version().split('.')[0:2]
        global needShow
        needShow = False
        try:
            if int(v0) == 5:
                needShow = (int(v1) <= 4)
        except Exception:
            pass
    except Ds9Error as e:
        if not re.search('xpa', os.environ['PATH']):
            raise Ds9Error('You need the xpa binaries in your path to use ds9 with python')
 
        if not execDs9:
            raise Ds9Error
 
        import distutils.spawn
        if not distutils.spawn.find_executable("ds9"):
            raise NameError("ds9 doesn't appear to be on your path")
        if "DISPLAY" not in os.environ:
            raise RuntimeError("$DISPLAY isn't set, so I won't be able to start ds9 for you")
 
        print("ds9 doesn't appear to be running (%s), I'll try to exec it for you" % e)
 
        os.system('ds9 &')
        for i in range(10):
            try:
                ds9Cmd(selectFrame(1), False)
                break
            except Ds9Error:
                print("waiting for ds9...\r", end="")
                sys.stdout.flush()
                time.sleep(0.5)
            else:
                print("                  \r", end="")
                break
 
        sys.stdout.flush()
 
        raise Ds9Error
 
 

selectFrame()

def lsst.display.ds9.ds9.selectFrame

(

frame

)

Convert integer frame number to DS9 command syntax.

Parameters
----------
frame : `int`
    Frame number

Returns
-------
frameString : `str`

Definition at line 210 of file ds9.py.

def selectFrame(frame):
    """Convert integer frame number to DS9 command syntax.
 
    Parameters
    ----------
    frame : `int`
        Frame number
 
    Returns
    -------
    frameString : `str`
    """
    return "frame %d" % (frame)
 
 

Variable Documentation

cmdBuffer

lsst.display.ds9.ds9.cmdBuffer

Definition at line 207 of file ds9.py.

definedCallbacks

bool lsst.display.ds9.ds9.definedCallbacks = True

Definition at line 697 of file ds9.py.

file

lsst.display.ds9.ds9.file

Definition at line 39 of file ds9.py.

haveGzip

lsst.display.ds9.ds9.haveGzip = not os.system("gzip < /dev/null > /dev/null 2>&1")

Definition at line 638 of file ds9.py.

needShow

bool lsst.display.ds9.ds9.needShow = True

Definition at line 47 of file ds9.py.

XPA_SZ_LINE

int lsst.display.ds9.ds9.XPA_SZ_LINE = 4096 - 100

Definition at line 109 of file ds9.py.