xvx - X Windows VisionX image display.

xvx [-display <displayname>] [-geometry <geometryspec>] [-H] [if=] [xp=] [yp=] [lut=] [nc=] [-newcmap] [-clean] [-shared] [-img] [+x,y] [t=] [-M] [-v] [-D] [xl= yl= xh= yh=] [-tk]

Xvx is an X-Windows VisionX display command. On color mapped displays Xvx attempt to be efficient about allocating color-table entries. By default it will try to allocate only 128 colors, and multiple copies of xvx will share common colors. The lookup tables are dynamically selected depending on the window the cursor is in. To resize the window one can use his/her favorite window manager. The size of the image will be adjusted, using pixel replication or sampling.

xvx handles bit and byte images, truecolor images, color-map images and image sets. It will use error diffusion to display a grayscale image on a monochrome screen, and it will create a byte image from a bit-plane image to display it on a color screen. Truecolor images are dithered for display on an 8-bit pseudocolor display.

If xvx is given a VisionX file that does not contain one of the above image formats it will display a menu which enables the user to select how the data is to be displayed.

The following keystrokes are available in the image window:

q

quits the program.

M

magnifies the image by 2.

m

shrinks the image by 2.

o

Sets image and the image window to their original size

g

decrement the gamma setting by 0.025 (brightens image)

G

increment the gamma setting by 0.025 (darkens image)

r

set the gamma to its original value 1.0

f

advances to the next image in an image set

F

automatically displays 1 complete cycle of all the images in the image set beginning and ending with the current frame

b

changes the view to the previous image in an image set

B

automatically displays 1 complete cycle of all the images in the image set (in reverse) beginning and ending with the current frame

c

advance to the next image in the sequence until the end then reverse.

h

moves subregion bounding box left.

j

moves subregion bounding box down.

k

moves subregion bounding box up.

l

moves subregion bounding box right.

H

expands subregion bounding box horizontally.

J

expands subregion bounding box vertically.

K

shrinks subregion bounding box vertically.

L

shrinks subregion bounding box horizontally.

a

set the color map to the default values.

z

set the color map to the zheat color table.

x

spawn a new xvx to display a selected region; region selection must have been previously made with the right mouse button.

X

similar to the x command except that the extracted region, if smaller than 256 X 256, is magnified by an integer amount to just fit into a 256 x 256 screen window.

s

save the displayed image to a specified file (image.vx is the default). If a region has been selected by the right mouse button then just the selected region is saved (segment.vx is the default file name in this case).

d

dumps the window to a specified file (dump.vx is the default) as a gray scale image.

D

dumps the window to a specified file (dump.vx is the default) as a pseudocolor image.

p

pops up a window that has controls to change the colormap. The window has three sliders. The left one changes the minimum value of the colormap, the middle one changes the maximum value of the colormap, and the right one controls the gamma (non-linear rate of change of the colors). There are two more sub-windows. The bottom right one displays the colormap, and the bottom left one shows a histogram of the image and a histogram of the R, G, B values of the colormap. Pressing the middle button on the image window, will display a line on the histogram window, indicating the gray value of the point selected. There are also two buttons. One of them pops down a menu for selecting different colormaps, and the other closes the colormap window. The colormap manipulation widget is only supported on 8 bit displays.

-display <displayname>

Use the specified X server for output.

-geometry <geometryspec>

Standard X-windows window placement/size.

LEFT button

Display the current location and pixel value of the mouse.

MIDDLE button

displays a menu of functions that xvx can perform on the data file.

RIGHT button

Dragging with the right button selects a subregion of the image. See the x and s keystroke commands above.

LEFT button with SHIFT key

If no subregion is selected, print the current pixel value. If a subregion is selected, print the dimensions of the subregion as "xl= yl= xh= yh=" and dimensions are displayed on the image.

MIDDLE button with SHIFT key

If no subregion is selected, print the current location and pixel value. If a subregion is selected, print the dimensions of the subregion as "xl= yl= xh= yh=" and dimensions are displayed on the image.

RIGHT button with SHIFT key

If no subregion is selected, print the current location. If a subregion is selected, print the dimensions of the subregion as "xl= yl= xh= yh=" and dimensions are displayed on the image.

if=<filename>

Open the image in <filename>, otherwise, read standard input.

xl= yl= xh= yh=

set initial subregion bounding box.

nc=

Set the number of colors to be used to display the image. On a monochrome or a true color (24 bit) display this flag has no effect, but on an 8 bit pseudo color device, it sets the number of colors that are going to be allocated. The default is 128 colors. Colors are allocated from the Root Colormap, as readonly and shareable. If xvx cannot get enough colors, then it allocates a new colormap, copies the first 64 entries from the root colormap, and then uses the rest. One can force xvx to allocate all the colors on an eight bit display by specifying nc=256, but this is not encouraged, since it will make most other windows unusable. If nc > 128 then xvx always allocates a new colormap.

-newcmap

forces allocation of a new private colormap.

-clean

so we don’t barf. (under development)

-shared

use root colormap.

-img

use image coordinates; i.e. with the coordinate origin

in the top left rather than bottom left corner.

+x,y

Set the x,y offset of the image in addition to the X-Windows geometry spec

xp=

Set the x offset of the image in addition to the X-Windows geometry spec

yp=

Set the y offset of the image in addition to the X-Windows geometry spec

lut=

Use filename as the default lookup table.

t=

Set the title of the image window to the string specified.

-M

Do not display the image, just invoke the VisionX command menu.

m=

Set the intiial magnification.

-v

Set verbose output mode.

-D

Set debug output mode.

-tk

send TK style pixel and subregion bounding box information to stdout.

X(1X)

Christos S. Zoulas, A. P. Reeves and R. J. Prokop