From b41b9034225ab3e49980d9de55c141011b6383b0 Mon Sep 17 00:00:00 2001 From: Taru Karttunen Date: Wed, 30 Mar 2011 16:49:47 +0300 Subject: Import sources from 2011-03-30 iso image - sys/man --- sys/man/1/gview | 204 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 204 insertions(+) create mode 100755 sys/man/1/gview (limited to 'sys/man/1/gview') diff --git a/sys/man/1/gview b/sys/man/1/gview new file mode 100755 index 000000000..1777a3f7d --- /dev/null +++ b/sys/man/1/gview @@ -0,0 +1,204 @@ +.TH GVIEW 1 +.SH NAME +gview \- interactive graph viewer +.SH SYNOPSIS +.B gview +[ +.B -mp +] +[ +.B -l +.I logfile +] +[ +.I files +] +.SH DESCRIPTION +.I Gview +reads polygonal lines or a polygonal line drawing from an +.B ASCII +input file (which defaults to standard input), and views it interactively, +with commands to zoom in and out, perform simple editing operations, and +display information about points and polylines. (Multiple input files are +allowed if you want to overlay several line drawings.) The editing commands can +change the color and thickness of the polylines, delete (or undelete) +some of them, and optionally rotate and move them. It is also possible to +generate an output file that reflects these changes and is in the same format +as the input. +.PP +Since the +.B move +and +.B rotate +commands are undesirable when just viewing a graph, they are only enabled if +.I gview +is invoked with the +.B -m +option. +.PP +The +.B -p +option plots only the vertices of the polygons. +.PP +Clicking on a polyline with button 1 displays the coordinates and a +.I t +value that tells how far along the polyline. +.IR (t =0 +at the first vertex, +.IR t =1 +at the first vertex, +.IR t =1.5 +halfway between the second and third vertices, etc.) The +.B -l +option generates a log file that lists all points selected in this manner. +.PP +The most important interactive operations are to +.I zoom in +by sweeping out a rectangle, or to +.I zoom out +so that everything currently being displayed shrinks to fit in the swept-out +rectangle. Other options on the button 3 menu are +.I unzoom +which restores the coordinate system to the default state where everything +fits on the screen, +.I recenter +which takes a point and makes it the center of the window, and +.I square up +which makes the horizontal and vertical scale factors equal. +.PP +To take a graph of a function where some part is almost linear and +see how it deviates from a straight line, select two points on this +part of the graph (i.e., select one with button 1 and then select the +other) and then use the +.I slant +command on the button 3 menu. +This slants the coordinate system so that the line between the two +selected points appears horizontal (but vertical still means positive +.IR y ). +Then the +.I zoom in +command can be used to accentuate deviations from horizontal. +There is also an +.I unslant +command that undoes all of this and goes back to an unslanted coordinate +system. +.PP +There is a +.I recolor +command on button 3 that lets you select a color and change everything +to have that color, and a similar command on button 2 that only affects +the selected polyline. If the input file uses the +.B Multi(...) +feature explained below, either flavor of +.I recolor +allows you to type a digit in lieu of selecting a color. +.PP +The +.I thick +or +.I thin +command on button 2 changes the thickness of the selected polyline +and there is also an undo command for such edits. +Finally, button 3 has commands to +.I read +a new input file and display it on top of everything else, +.I restack +the drawing order (in case lines of different color are drawn on top of +each other), +.I write +everything into an output file, or +.I exit +the program. +.PP +Each polyline in an input or output file is a space-delimited +.I x +.I y +coordinate pair on a line by itself, and the polyline is a sequence +of such vertices followed by a label. The label could be just a +blank line or it could be a string in double +quotes, or virtually any text that does not contain spaces and is +on a line by itself. The label at the end of the last polyline is +optional. It is not legal to have two consecutive labels, since that +would denote a zero-vertex polyline and each polyline must have at least +one vertex. (One-vertex polylines are useful for scatter plots.) +Under the +.B -l +option, a newline causes the selected polyline's label to appear in +the log file (where it could be seen by invoking +.B tail -f +in another window). + +If the label after a polyline contains the word +.B "Thick" +or a color name +.BR (Red , +.BR Pink , +.BR Dkred , +.BR Orange , +.BR Yellow , +.BR Dkyellow , +.BR Green , +.BR Dkgreen , +.BR Cyan , +.BR Blue , +.BR Ltblue , +.BR Magenta , +.BR Violet , +.BR Gray , +.BR Black , +.BR White ), +whichever color name comes first will be used to color the polyline. +Alternatively, labels can contain +.B Multi +followed by single-letter versions of these names: +.BR (R , +.BR P , +.BR r , +.BR O , +.BR Y , +.BR y , +.BR G , +.BR g , +.BR C , +.BR B , +.BR b , +.BR M , +.BR V , +.BR A , +.BR K , +.BR W , +each optionally preceded by +.BR T ). +Then +.I recolor +followed by a nonzero digit +.I n +selects the +.IR n th +alternative for each polyline. + +.SH EXAMPLE +To see a graph of the function +.IR y = sin( x )/ x , +generate input with an awk script and pipe it into +.IR gview : +.IP +.EX +awk 'BEGIN{for(x=.1;x<500;x+=.1)print x,sin(x)/x}' | gview +.EE +.SH SOURCE +.B /sys/src/cmd/gview.c +.SH SEE ALSO +.IR awk (1), +.IR tail (1) +.SH BUGS +The user interface for the +.I slant +command is counter-intuitive. Perhaps it would be better to have a scheme +for sweeping out a parallelogram. +.PP +The +.B -p +option makes the interactive point selection feature behave strangely, and +is unnecessary since extra blank lines in the input achieve essentially the +same effect. -- cgit v1.2.3