Display

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

Bases: object

Create an object able to display images and overplot glyphs.

Parameters:

frame

An identifier for the display.

backendstr

The backend to use (defaults to value set by setDefaultBackend()).

**kwargs

Arguments to pass to the backend.

Attributes Summary

verbose

The backend's verbosity.

Methods Summary

Buffering()	Return a context manager that will buffer repeated display commands, to e.g.
centroids(catalog, *[, symbol])	Draw the sources from a catalog at their pixel centroid positions as given by getX() and getY().
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 any buffering that may be provided by the backend.
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.
image(data[, title, wcs])	Display an image on a display, with semi-transparent masks overlaid, if available.
incrDefaultFrame()	Increment the default frame for display.
interact()	Enter an interactive loop, listening for key presses or equivalent UI actions in the 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 on a display, with semi-transparent masks overlaid, if available.
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 context manager that will buffer repeated display commands, to e.g. speed up displaying points.

Examples

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

centroids(catalog, *, symbol='o', **kwargs)

Draw the sources from a catalog at their pixel centroid positions as given by getX() and getY().

See dot for an explanation of symbol and available args/kwargs, which are passed to dot.

Parameters:

cataloglsst.afw.table.Catalog

Catalog to display centroids for. Must have valid slot_Centroid.

close()

static delAllDisplays()

Delete and close all known displays.

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

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

sizeint

Size of symbol, in pixels.

ctypestr

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

originlsst.afw.image.ImageOrigin

Coordinate system for the given positions.

**kwargs

Extra keyword arguments to backend.

erase()

Erase the specified display frame.

flush()

Flush any buffering that may be provided by the backend.

getActiveCallbackKeys(onlyActive=True)

Return all callback keys

Parameters:

onlyActivebool

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, **kwargs)

Return a specific Display, creating it if need be.

Parameters:

frame

The desired frame (None => use defaultFrame (see setDefaultFrame)).

backendstr

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.

createbool

create the display if it doesn’t already exist.

verbosebool

Allow backend to be chatty.

**kwargs

keyword arguments passed to Display constructor.

getMaskPlaneColor(name=None)

Return the color associated with the specified mask plane name.

Parameters:

namestr

Desired mask plane; if None, return entire dict.

getMaskTransparency(name=None)

Return the current display’s mask transparency.

image(data, title='', wcs=None)

Display an image on a display, with semi-transparent masks overlaid, if available.

Parameters:

datalsst.afw.image.Exposure or lsst.afw.image.MaskedImage or lsst.afw.image.Image

Image to display; Exposure and MaskedImage will show transparent mask planes.

titlestr, optional

Title for the display window.

wcslsst.afw.geom.SkyWcs, optional

World Coordinate System to align an MaskedImage or Image to; raise an exception if data is an Exposure.

Raises:

RuntimeError

Raised if an Exposure is passed with a non-None wcs when the wcs kwarg is also non-None.

TypeError

Raised if data is an incompatible type.

static incrDefaultFrame()

Increment the default frame for display.

interact()

Enter an interactive loop, listening for key presses or equivalent UI actions in the display and firing callbacks.

Exit with q, CR, ESC, or any equivalent UI action provided in the display. The loop may also be exited by returning True from a user-provided callback function.

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

Draw a set of symbols or connect points

Parameters:

pointslist

A list of (col, row)

originlsst.afw.image.ImageOrigin

Coordinate system for the given positions.

symbsbool 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.

ctypestr

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

sizefloat

Size of points to create if symbs is passed.

maskColorGenerator(omitBW=True)

A generator for “standard” colors.

Parameters:

omitBWbool

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 on a display, with semi-transparent masks overlaid, if available.

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

Coordinates to pan to.

originlsst.afw.image.ImageOrigin

Coordinate system for the given positions.

See also

Display.zoom

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

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

Parameters:

algorithmstr

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).

**kwargs

Optional keyword arguments to the backend.

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

Set the callback for a key.

Backend displays may provide an equivalent graphical UI action, but must make the associated key letter visible in the UI in some way.

Parameters:

kstr

The key to assign the callback to.

funccallable

The callback assigned to k.

noRaisebool

Do not raise if k is already in use.

Returns:

oldFunccallable

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:

cmapstr

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:

namestr 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:

cmapstr

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:

namestr or dict

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

colorstr

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