Display¶

class lsst.afw.display.Display(frame=None, backend=None, *args, **kwargs)¶

Bases: object

Create an object able to display images and overplot glyphs

Parameters:	frame An identifier for the display backend : `str` The backend to use (defaults to value set by setDefaultBackend()) args Arguments to pass to the backend *kwargs Arguments to pass to the backend

Attributes Summary

verbose The backend’s verbosity

Methods Summary

`Buffering`()	Return a class intended to be used with python’s with statement
`close`()
`delAllDisplays`()	Delete and close all known displays
`dot`(symb, c, r[, size, ctype, origin])	Draw a symbol onto the specified display frame
`erase`()	Erase the specified display frame
`flush`()	Flush the buffers
`getActiveCallbackKeys`([onlyActive])	Return all callback keys
`getDefaultBackend`()
`getDefaultFrame`()	Get the default frame for display
`getDisplay`([frame, backend, create, verbose])	Return a specific `Display`, creating it if need be
`getMaskPlaneColor`([name])	Return the color associated with the specified mask plane name
`getMaskTransparency`([name])	Return the current display’s mask transparency
`incrDefaultFrame`()	Increment the default frame for display
`interact`()	Enter an interactive loop, listening for key presses in display and firing callbacks.
`line`(points[, origin, symbs, ctype, size])	Draw a set of symbols or connect points
`maskColorGenerator`([omitBW])	A generator for “standard” colors
`mtv`(data[, title, wcs])	Display an `Image` or `Mask` on a display
`pan`([colc, rowc, origin])	Pan to a location
`scale`(algorithm, min[, max, unit])	Set the range of the scaling from DN in the image to the image display
`setCallback`(k[, func, noRaise])	Set the callback for a key
`setDefaultBackend`(backend)
`setDefaultFrame`([frame])	Set the default frame for display
`setDefaultImageColormap`(cmap)	Set the default colormap for images
`setDefaultMaskPlaneColor`([name, color])	Set the default mapping from mask plane names to colors
`setDefaultMaskTransparency`([…])
`setImageColormap`(cmap)	Set the colormap to use for images
`setMaskPlaneColor`(name[, color])	Request that mask plane name be displayed as color
`setMaskTransparency`([transparency, name])	Specify display’s mask transparency (percent); or `None` to not set it when loading masks
`show`()	Uniconify and Raise display.
`zoom`([zoomfac, colc, rowc, origin])	Zoom frame by specified amount, optionally panning also

Attributes Documentation

verbose¶: The backend’s verbosity

Methods Documentation

Buffering()¶

Return a class intended to be used with python’s with statement

Examples

with display.Buffering():
    display.dot("+", xc, yc)

close()¶

static delAllDisplays()¶: Delete and close all known displays

dot(symb, c, r, size=2, ctype=None, origin=<ImageOrigin.PARENT: 0>, *args, **kwargs)¶

Draw a symbol onto the specified display frame

Parameters:

symb

Possible values are:

"+"

Draw a +

"x"

Draw an x

"*"

Draw a *

"o"

Draw a circle

"@:Mxx,Mxy,Myy"

Draw an ellipse with moments (Mxx, Mxy, Myy) (argument size is ignored)

lsst.afw.geom.ellipses.BaseCore

Draw the ellipse (argument size is ignored). N.b. objects derived from BaseCore include Axes and Quadrupole.

Any other value

Interpreted as a string to be drawn.

c, r

The column and row where the symbol is drawn [0-based coordinates]

size : int

Size of symbol, in pixels

ctype : str

The desired color, either e.g. lsst.afw.display.RED or a color name known to X11

origin : lsst.afw.image.ImageOrigin

Coordinate system for the given positions.

*args

Extra arguments to backend

**kwargs

Extra keyword arguments to backend

erase()¶: Erase the specified display frame

flush()¶: Flush the buffers

getActiveCallbackKeys(onlyActive=True)¶

Return all callback keys

Parameters:	onlyActive : `bool` If `True` only return keys that do something

static getDefaultBackend()¶

static getDefaultFrame()¶: Get the default frame for display

static getDisplay(frame=None, backend=None, create=True, verbose=False, *args, **kwargs)¶

Return a specific Display, creating it if need be

Parameters:

frame: The desired frame (None => use defaultFrame (see setDefaultFrame))
backend : str: create the specified frame using this backend (or the default if None) if it doesn’t already exist. If backend == "", it’s an error to specify a non-existent frame.
create : bool: create the display if it doesn’t already exist.
verbose : bool: Allow backend to be chatty
*args: arguments passed to Display constructor
**kwargs: keyword arguments passed to Display constructor

getMaskPlaneColor(name=None)¶

Return the color associated with the specified mask plane name

Parameters:	name : `str` Desired mask plane; if `None`, return entire dict

getMaskTransparency(name=None)¶: Return the current display’s mask transparency

static incrDefaultFrame()¶: Increment the default frame for display

interact()¶

Enter an interactive loop, listening for key presses in display and firing callbacks.

Exit with q, CR, ESC, or any other callback function that returns a True value.

line(points, origin=<ImageOrigin.PARENT: 0>, symbs=False, ctype=None, size=0.5)¶

Draw a set of symbols or connect points

Parameters:

points : list

a list of (col, row)

origin : lsst.afw.image.ImageOrigin

Coordinate system for the given positions.

symbs : bool or sequence

If symbs is True, draw points at the specified points using the desired symbol, otherwise connect the dots.

If symbs supports indexing (which includes a string – caveat emptor) the elements are used to label the points

ctype : str

ctype is the name of a color (e.g. ‘red’)

size : float

maskColorGenerator(omitBW=True)¶

A generator for “standard” colors

Parameters:	omitBW : `bool` Don’t include `BLACK` and `WHITE`

Examples

colorGenerator = interface.maskColorGenerator(omitBW=True)
for p in planeList:
    print p, next(colorGenerator)

mtv(data, title='', wcs=None)¶

Display an Image or Mask on a display

Notes

Historical note: the name “mtv” comes from Jim Gunn’s forth imageprocessing system, Mirella (named after Mirella Freni); The “m” stands for Mirella.

pan(colc=None, rowc=None, origin=<ImageOrigin.PARENT: 0>)¶

Pan to a location

Parameters:	colc, rowc the coordinates to pan to origin : `lsst.afw.image.ImageOrigin` Coordinate system for the given positions.

See also

Display.zoom

scale(algorithm, min, max=None, unit=None, *args, **kwargs)¶

Set the range of the scaling from DN in the image to the image display

Parameters:	algorithm : `str` Desired scaling (e.g. “linear” or “asinh”) min Minimum value, or “minmax” or “zscale” max Maximum value (must be `None` for minmax\|zscale) unit Units for min and max (e.g. Percent, Absolute, Sigma; `None` if min==minmax\|zscale) args Optional arguments to the backend *kwargs Optional keyword arguments to the backend

setCallback(k, func=None, noRaise=False)¶

Set the callback for a key

Parameters:	k The key to assign the callback to func : callable The callback assigned to `k` noRaise : `bool`
Returns:	oldFunc : callable The callback previously assigned to `k`.

static setDefaultBackend(backend)¶

static setDefaultFrame(frame=0)¶: Set the default frame for display

static setDefaultImageColormap(cmap)¶

Set the default colormap for images

Parameters:	cmap : `str` Name of colormap, as interpreted by the backend

Notes

The only colormaps that all backends are required to honor (if they pay any attention to setImageColormap) are “gray” and “grey”

static setDefaultMaskPlaneColor(name=None, color=None)¶

Set the default mapping from mask plane names to colors

Parameters:	name : `str` or `dict` name of mask plane, or a dict mapping names to colors If name is `None`, use the hard-coded default dictionary color Desired color, or `None` if name is a dict

static setDefaultMaskTransparency(maskPlaneTransparency={})¶

setImageColormap(cmap)¶

Set the colormap to use for images

Parameters:	cmap : `str` Name of colormap, as interpreted by the backend

Notes

The only colormaps that all backends are required to honor (if they pay any attention to setImageColormap) are “gray” and “grey”

setMaskPlaneColor(name, color=None)¶

Request that mask plane name be displayed as color

Parameters:

name : str or dict

Name of mask plane or a dictionary of name -> colorName

color : str

The name of the color to use (must be None if name is a dict)

Colors may be specified as any X11-compliant string (e.g. "orchid"), or by one of the following constants in lsst.afw.display : BLACK, WHITE, RED, BLUE, GREEN, CYAN, MAGENTA, YELLOW.

If the color is “ignore” (or IGNORE) then that mask plane is not displayed

The advantage of using the symbolic names is that the python interpreter can detect typos.

setMaskTransparency(transparency=None, name=None)¶: Specify display’s mask transparency (percent); or None to not set it when loading masks

show()¶

Uniconify and Raise display.

Notes

Throws an exception if frame doesn’t exit

zoom(zoomfac=None, colc=None, rowc=None, origin=<ImageOrigin.PARENT: 0>)¶: Zoom frame by specified amount, optionally panning also

Navigation

Display¶