; HLPTVIEW
;---------------------------------------------------------------
;! Interactive display of cube in 3 transpositions - run-time help
;# Task TV ANALYSIS IMAGE-UTIL INTERACTIVE
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;;  Copyright (C) 2018-2019
;;  Associated Universities, Inc. Washington DC, USA.
;;
;;  This program is free software; you can redistribute it and/or
;;  modify it under the terms of the GNU General Public License as
;;  published by the Free Software Foundation; either version 2 of
;;  the License, or (at your option) any later version.
;;
;;  This program is distributed in the hope that it will be useful,
;;  but WITHOUT ANY WARRANTY; without even the implied warranty of
;;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;  GNU General Public License for more details.
;;
;;  You should have received a copy of the GNU General Public
;;  License along with this program; if not, write to the Free
;;  Software Foundation, Inc., 675 Massachusetts Ave, Cambridge,
;;  MA 02139, USA.
;;
;;  Correspondence concerning AIPS should be addressed as follows:
;;         Internet email: aipsmail@nrao.edu.
;;         Postal address: AIPS Project Office
;;                         National Radio Astronomy Observatory
;;                         520 Edgemont Road
;;                         Charlottesville, VA 22903-2475 USA
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OFF TRANS
This option turns off any black-and-white enhancements done in TVTRANSF.
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OFF PSEUDO
This options turns of any color enhancements done in TVPSEUDO or
TVPHLAME.  Has no effect if the image is in black and white.
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TVTRANSF
This option allows you to set the black-and-white transfer function
using the TV cursor to control intercept and slope.  Buttons A and B
turn a plot of the LUT on and off, button C reverses the sign of the
slope, and button D ends the enhancement and returns to the menu.
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TVPSEUDO
This option allows you to set the color transfer function using the TV
cursor.  Button A loops through all possible RGB triangles, button B
selects a circle in hue (which is very useful for phase displays),
button C selects several color contours, and button D ends the
enhancement and returns to the menu.  As in AIPS, the TV cursor is used
to adjust the colors within the selected function.  Instructions appear
on the message screen.
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TVPHLAME
This option allows you to set the color transfer function using the TV
cursor and a flame-like color scheme.  Buttons A and B cycle through the
sequence of all possible color combinations, while buttons C and D end
the enhancement and return to the menu.  The TV cursor X position
adjusts the image intensity at which the color turns more white, while
the Y position adjusts the way colors add (the gamma).  Instructions
appear on the message screen.
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LABEL IMAGES?
This option lets you cycle from no axis labels on the gray-scale images
to labeling the gray scale images (as adverb LTYPE=7), to labeling the
grey-scale images with ticks extended to form a coordinate grid, and
back to no label.  The labels are updated whenever windows or planes
are changed.  The labels show celestial coordinates and, if CBPLOT was
set, the Clean beam is displayed in the selected corner of the two
XY images.
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SET REF RANGE
This option lets you chose the pixel intensity range to be displayed for
the reference image.  A prompt will display the allowed range and
request two values to be entered in the input terminal window.  If the
first value is less than the second, the new range will be used.  If the
first value is >= the second, then the full pixel range of the reference
image will be used.
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SET SPEC RANGE
This option lets you chose the pixel intensity range to be displayed for
the SPECTRUM PLOTS.  A prompt will display the allowed range and request
two values to be entered in the input terminal window.  If the first
value is less than the second, the new range will be used.  If the first
value is >= the second, then the full pixel range of the reference image
will be used.
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SET CUBE RANGE
This option lets you chose the pixel intensity range to be displayed for
the 3 cube images.  A prompt will display the allowed range and
request two values to be entered in the input terminal window.  If the
first value is less than the second, the new range will be used.  If the
first value is >= the second, then the full pixel range of the cube
images will be used.
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ROAM
This option allows you to select which planes are displayed.  Move the
TV cursor to one of the images and move it around.  If you are in the
reference image or the Ra-Dec-Freq image (lower left), then the planes
displayed in the two right-hand images, Freq-Ra-Dec and FREQ-Dec-RA,
will respond to the cursor position.  The plane number displayed will
appear above the images on the right-hand side.  If you are in the
Freq-Ra-Dec image (upper right), then the lower images will respond to
the cursor position, changing the Freq plane in the lower left and the
Ra plane in the lower right.  If you are in the Freq-Dec-Ra image
(lower right), then the image at the lower left will respond to the
cursor X position (Freq) and the image at the upper right will respond
to the cursor Y position (Dec), changing the appropriate planes in both
displays.  Hit button C or D to exit.
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SET WINDOW
This option allows you to set the window into the TV image that you wish
to view.  That sub-image will be blown up to fill as much of the area
reserved for the grey-scale (INNAME) image as possible.  This option
first requires you to select one of the images by moving the cursor into
the image and pressing any button.  The you set the window into that
image in a manner similar to TVWINDOW in AIPS.  Any button marks the BLC
on the image, switching you to setting TRC.  Thereafter, buttons A and
B switch between setting BLC and TRC and buttons C and D set the
window, reload the image and return to the menu.  Instructions appear
on the message screen.   Note that the cursor position cannot be moved
off the currently visible image window.  The window in the reference
image affects only that image.  A window into any of the other 3 cube
images will affect two of the three images.
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RESET WINDOW
This option lets you set the visible window into the grey-scale image
to include the whole field.  You must first move the cursor to the
desired image and press any button.  Then any window set in that image
will be reset to the full image.  The image will be re-displayed using
pixel increments large enough to fit the full image into the part of the
screen reserved for that image.  Note that the image is interpolated
if possible and sub-sampled if necessary to fit the available area.
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CURVALUE
This option lets you examine the intensities as a function of pixel
number in any of the grey-scale images and spectral plots.  Move the
cursor to select the image pixel desired or the spectral channel.  You
may move the cursor freely between the images and spectra on display.
HIt button C or D to exit.
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ROTATE
This option allows you to rotate the image cube in RA-Dec around the
reference pixel.  You will be prompted to enter a rotation angle
clockwise in degrees from the input terminal window.  The reference and
cube images will then be rotated accordingly and re-displayed.  Note
that pixels in the rotated image not present in the input image will be
blanked.  Rotating the image back will not restore the blanked pixels.
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TV ROTATE
This option allows you to rotate the image cube in RA-Dec around the
reference pixel.  The TV display will show the reference image in a
full-screen version or, if there is no reference image, the current
selected plane of the Ra-Dec-Freq image.  A small green line will
appear.  Move one end of the line to the end of the desired slice, then
hit buttons A, B, or C to move to set the position of the other end of
desired slice.  Buttons A, B, and C switch between ends.  Button D is
used to end the interaction.  The angle of the slice will be determined
and used as the rotation angle to rotate the reference and cube images.
Note that pixels in the rotated image not present in the input image
will be blanked.  Rotating the image back will not restore the blanked
pixels.
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RELOAD IMAGES
This option allows you to restore the input images to the state that
they were in at the beginning.  The rotation options will cause some
of the image pixels to be blanked, a condition that will not be
corrected by reversing the rotation.  The only way to get the pixels
back is to reload the images and start over.  The planes selected by
any ROAM are retained in the display.
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EXIT
This option allows you to exit the task.
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