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.\" RCSid "$Id: ximage.1,v 1.4 2004/01/01 19:31:45 greg Exp $" |
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.TH XIMAGE 1 10/27/98 RADIANCE |
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.SH NAME |
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ximage - RADIANCE picture display for X window system |
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.SH SYNOPSIS |
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.B ximage |
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[ |
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.B \=geometry |
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][ |
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.B "\-di display" |
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][ |
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.B "\-c ncolors" |
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][ |
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.B \-d |
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][ |
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.B \-b |
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][ |
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.B \-m |
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][ |
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.B "\-g gamma" |
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][ |
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.B \-f |
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][ |
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.B "\-e spec |
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][ |
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.BI -o spec |
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][ |
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.B "\-t intvl" |
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][ |
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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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This option yeilds and appearance of the scene on the display that |
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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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.TP |
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.BR l |
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Display the luminance value in the area of interest. |
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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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Display the color in the area of interest. |
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.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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with the \-b option. |
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.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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The default output is "\-ood", which prints |
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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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rvu(1), xglaresrc(1), xshowtrace(1) |