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.\" RCSid "$Id: ximage.1,v 1.7 2010/01/07 17:54:56 greg Exp $" | 
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greg | 
1.1 | 
.TH XIMAGE 1 10/27/98 RADIANCE | 
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.SH NAME | 
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1.2 | 
ximage - RADIANCE picture display for X window system | 
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1.1 | 
.SH SYNOPSIS | 
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.B ximage | 
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[ | 
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.B \=geometry | 
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.B "\-di display" | 
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.B "\-c ncolors" | 
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.B \-d | 
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.B \-b | 
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.B \-m | 
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.B "\-g gamma" | 
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.B \-f | 
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.B "\-e spec | 
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.BI -o spec | 
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.B "\-t intvl" | 
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.B \-s | 
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] | 
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.B "picture .." | 
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.SH DESCRIPTION | 
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.I Ximage | 
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takes one or more RADIANCE picture files | 
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and displays them on an X server. | 
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The | 
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.I \-c | 
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option specifies the number of colors to use (default fills color table). | 
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The | 
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.I \-d | 
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option turns off color dithering. | 
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The | 
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.I \-b | 
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option displays the image in black and white (greyscale). | 
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The | 
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.I \-m | 
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option forces monochrome output. | 
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The | 
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.I \-g | 
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option specifies the exponent used in gamma correction; | 
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the default value is 2.2. | 
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The | 
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.I \-f | 
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option stores a Pixmap on the server side for faster refresh. | 
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This may not work with large images on some servers. | 
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The | 
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.I \-o | 
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option specifies a sequence of information to print to the standard | 
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output for the 't' command (see below). | 
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The | 
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.I \-t | 
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option specifies a minimum interval (in milliseconds) | 
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between successive ray outputs | 
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in mouse tracking mode (right button pressed). | 
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.PP | 
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The | 
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.I \-e | 
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option specifies an exposure compensation in f-stops (powers of two). | 
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Only integer stops are allowed, for efficiency. | 
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If the special word, | 
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.I auto | 
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is given instead of a number of stops, then | 
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.I ximage | 
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performs an automatic exposure adjustment similar to | 
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.I pcond(1), | 
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compressing the dynamic range of the image to fit | 
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within the dynamic range of the display. | 
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If the special word, | 
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.I human | 
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is given instead, then | 
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.I ximage | 
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performs an exposure adjustment similar to | 
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.I pcond | 
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with the | 
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.I \-s | 
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and | 
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.I \-c | 
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options, which compensate for human contrast and color sensitivity | 
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at the corresponding scene luminance levels. | 
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1.8 | 
This option yields and appearance of the scene on the display that | 
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1.1 | 
closely matches what would be experienced in the real world. | 
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.PP | 
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The | 
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.I \-s | 
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option tells | 
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.I ximage | 
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to display multiple pictures sequentially, rather than all at once. | 
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If no | 
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.I picture | 
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is given, input is read from stdin provided either the | 
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.I \-b | 
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or | 
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.I \-m | 
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option is in effect, or the X server is capable of 24-bit color. | 
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However, many of the commands given below will not work. | 
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.SH COMMANDS | 
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Once a picture is displayed, the user | 
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may perform a number of operations. | 
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Some of the operations make use of an area of interest, defined by pressing | 
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the left mouse button and dragging the cursor over a section of the image. | 
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Pressing the button and immediately releasing it defines a single point as | 
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the area of interest. | 
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A command is a single character. | 
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.TP 10n | 
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.BR q | 
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Quit picture. | 
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(Also Q or ^D.)\0 | 
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.TP 10 | 
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.BR <space> | 
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Redraw the area of interest. | 
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.TP 10 | 
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.BR ^R | 
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Redraw the entire image. | 
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.TP | 
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.BR <return> | 
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Display the radiance averaged over the area of interest. | 
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1.6 | 
The maximum of the three (RGB) channels is reported. | 
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1.1 | 
.TP | 
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.BR l | 
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Display the photometrically-weighted luminance value in the area of interest. | 
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1.1 | 
This assumes that the image was correctly computed in terms of | 
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luminance. | 
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.TP | 
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.BR c | 
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1.6 | 
Display the color in the area of interest, as adjusted by the current | 
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exposure setting. | 
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1.1 | 
.TP | 
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.BR p | 
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Display the x and y location of the cursor. | 
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.TP | 
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.BR i | 
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Identify identical pixels by assigning a random color at the cursor position. | 
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This is useful for displaying contours, especially when combined | 
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1.5 | 
with the \-b option. | 
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1.1 | 
.TP | 
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.BR t | 
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Print information about the pixel under the cursor | 
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according to the string following the | 
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.I \-o | 
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command line option. | 
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The valid characters for this option correspond roughly to the other | 
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.I ximage | 
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commands: | 
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.IP | 
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o       ray origin | 
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.IP | 
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d       ray direction | 
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.IP | 
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v       radiance value | 
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.IP | 
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l       luminance value | 
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.IP | 
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p       pixel position | 
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.IP | 
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greg | 
1.5 | 
The default output is "\-ood", which prints | 
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greg | 
1.1 | 
the ray origin and direction. | 
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This can be used as input to rtrace(1) to get additional information | 
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about the image (ie. pipe the output of ximage into rtrace). | 
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Pressing the middle mouse button is equivalent to typing the 't' key. | 
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Pressing and holding the right mouse button is equivalent to | 
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continuously pressing the 't' key. | 
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.TP | 
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.BR = | 
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Adjust the exposure to the area of interest. | 
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A crude adjustment is made immediately, and the number of stops | 
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is printed while the colors are resampled. | 
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After a few seconds to a minute, the final image is redisplayed. | 
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If the area of interest is already within 1/2 stop of the ideal, | 
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no adjustment is made. | 
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.TP | 
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.BR @ | 
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Same as '=' command, only the exposure is adjusted to provide | 
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roughly the same visibility for the selected region | 
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on screen as a viewer would experience | 
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in the actual space. | 
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Like the 'l' command, this adjustment assumes that the image | 
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has been correctly computed in terms of luminance. | 
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(See also the 'h' command, below.) | 
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.TP | 
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.BR a | 
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Perform automatic exposure compensation, as if | 
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.I ximage | 
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were started with the | 
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.I "\-e auto" | 
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option. | 
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If a rectangular area has been selected, the pixels in this region | 
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will be emphasized in the histogram, offering this area exposure preference. | 
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(Each pixel within the rectangle will be weighted as 21 outside pixels.) | 
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.TP | 
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.BR h | 
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Perform human expsoure compensation, as if | 
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.I ximage | 
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were started with the | 
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.I "\-e human" | 
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option. | 
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See the 'a' command above regarding pixel weighting. | 
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.TP | 
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.BR 0 | 
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Reset the origin to the upper left corner of the image. | 
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This command is used to restore the original image position after | 
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using the shift or control key with the mouse to relocate the image | 
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within the frame (see below). | 
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.TP | 
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.BR f | 
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Switch on the fast redraw option | 
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.I (\-f), | 
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loading the image pixmap over to the server side. | 
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This command is useful when network delays are causing slow image | 
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refresh, and the user didn't notice it until after | 
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.I ximage | 
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was started. | 
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.TP | 
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.BR F | 
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Switch off the fast redraw option. | 
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This frees up some memory on the server, as well as the color table | 
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for other windows. | 
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.PP | 
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In addition to the commands listed above, the control or shift key may | 
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be held while the cursor is dragged to reposition the image within the | 
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window. | 
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.SH "X RESOURCES" | 
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radiance.gamma  the default gamma correction value | 
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.SH ENVIRONMENT | 
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DISPLAY_GAMMA           the default gamma correction value | 
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.SH AUTHORS | 
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Greg Ward | 
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.br | 
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Anat Grynberg (Paris) | 
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.br | 
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Philip Thompson (MIT) | 
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.SH "SEE ALSO" | 
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aedimage(1), normtiff(1), pcond(1), pfilt(1), rpict(1), rtrace(1), | 
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greg | 
1.4 | 
rvu(1), xglaresrc(1), xshowtrace(1) |