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diff --git a/pkg/plot/doc/pvector.hlp b/pkg/plot/doc/pvector.hlp new file mode 100644 index 00000000..34ab1590 --- /dev/null +++ b/pkg/plot/doc/pvector.hlp @@ -0,0 +1,191 @@ +.help pvector Oct91 plot +.ih +NAME +pvector -- plot an arbitrary vector in a 2D image +.ih +USAGE +pvector image x1 y1 x2 y2 +.ih +PARAMETERS +.ls image +Input image containing data to be plotted. +.le +.ls x1, y1 +Starting coordinates of the vector to be plotted. +.le +.ls x2, y2 +Ending coordinates of the vector to be plotted. +.le +.ls xc, yc +The center coordinates of the vector to be plotted if the position +angle \fItheta\fR is defined. +.le +.ls width = 1 +Number of pixels perpendicular to the vector to average. +.le +.ls theta = INDEF +The postion angle of the vector to be plotted measured counter-clockwise +from the positive x axis. Theta must be between 0.0 and 360.0 degrees. +If theta is specified, the \fIxc\fR, and \fIyc\fR parameters +must be specified instead of the starting and ending coordinates +as in examples 3 and 4. +.le +.ls length = INDEF +The length of the vector to be plotted if \fItheta\fR is defined. The +default is to plot the vector from one edge of the frame to another. +.le +.ls boundary = constant +The type of boundary extension. The boundary extension options are: +.ls nearest +Use the value of the nearest boundary pixel. +.le +.ls constant +Use a constant value. +.le +.ls reflect +Generate a value by reflecting around the boundary. +.le +.ls wrap +Generate a value by wrapping around to the opposite side of the image. +.le +.le +.ls constant = 0. +The constant for constant valued boundary extension. +.le +.ls vec_output = "" +File or image name if output vector is desired. If this parameter is +non-null, then the computed vector will be output to the named file of +the type specified by the \fIout_type\fR parameter. If set to STDOUT +or STDERR, a listing of the pixels (i.e. text format) will be output to +either of these streams. Plotting is disabled if vector output is selected. +.le +.ls out_type = "text" +Type of output format (image|text). If an image is created, then a new +header keyword, "VSLICE", will be appended to the new image describing +the endpoints of the vector, the width, and the parent image name. The +parent image header will be copied to the new image. +.le +.ls wx1 = 0., wx2 = 0., wy1 = 0., wy2 = 0. +The range of world coordinates to be included in the plot. If the +range of values in x or y is zero, the plot is automatically scaled from the +minimum to maximum data values along the degenerate axis. +.le +.ls vx1 = 0., vx2 = 0., vy1 = 0., vy2 = 0. +NDC coordinates (0-1) of the device plotting window. If not set by user, +a suitable viewport which allows sufficient room for all labels is used. +.le +.ls pointmode = no +Plot individual points instead of a continuous line? +.le +.ls marker = "box" +Marker or line type to be drawn. If \fBpointmode\fR = yes the markers are +"point", "box", "cross", "plus", "circle", "hebar", "vebar", "hline", +"vline" or "diamond". Any other value defaults to "box". If drawing lines, +\fBpointmode\fR = no, the values are "line", "lhist", "bhist". Any other +value defaults to "line". "bhist" (box histogram) draws lines to the +bottom of the graph while "lhist" does not. In both cases the +horizontal histogram lines run between the half way points (reflected +at the ends). +.le +.ls szmarker = 0.005 +The size of the marker drawn when \fBpointmode\fR = yes. +.le +.ls logx = no, logy = no +Draw the x or y axis in log units, versus linear? +.le +.ls xlabel = "", ylabel = "" +The x-axis and y-axis labels. +.le +.ls title = "imtitle" +Title for plot. If not changed from the default, the title string from the +image header, appended with the vector endpoints, is used. +.le +.ls majrx = 5, minrx = 5, majry = 5, minry = 5 +The number of major and minor divisions along the x or y axis. +.le +.ls round = no +Round axes up to nice values? +.le +.ls fill = yes +Fill the output viewport regardless of the device aspect ratio? +.le +.ls append = no +Append to an existing plot? +.le +.ls device = "stdgraph" +Output device. +.le +.ih +DESCRIPTION +Plot an arbitrary vector of data from an image. The vector can be +specified by either defining the two endpoints of the vector or +by specifying the center position, length and position angle of the vector. +The user can specify +the plot size and placement, the scaling and labeling of axes. Data can be +plotted as a continuous line or individual points with a specified marker. +Optionally, the computed vector may be output to a named image or text file +(as specified by the \fIvec_output\fR and \fIout_type\fR parameters). + +The vector is extracted as a straight line between the given +coordinates, sampled at a spacing along that line equivalent to that +between adjacent pixels in the x or y direction (e.g. the length of a +diagonal endpoint vector from a square image is n*sqrt(2)). +It is possible to specify an averaging width +which determines how many pixels perpendicular to the vector are averaged. +This averaging window is centered +on the vector pixel. When this window is greater than one pixel, it +is possible that the extraction process might try to exceed the +image boundary, in which case the specified type of boundary extension +is employed. The extraction algorithm uses bilinear interpolation to +evaluate points at non-integral pixel positions. + +If \fBappend\fR is enabled, previous values for \fBbox\fR, +\fBfill\fR, \fBround\fR, the plotting viewport (\fBvx1\fR, \fBvx2\fR, +\fBvy1\fR, \fBvy2\fR), and the plotting window (\fBwx1\fR, \fBwx2\fR, +\fBwy1\fR, \fBwy2\fR) are used. + +If the plotting viewport was not set by the user, \fBpvector\fR +automatically sets a viewport centered on the device. The default value +of \fBfill\fR = yes means the plot spans equal amounts of NDC space in +x and y. Setting +the value of \fBfill\fR to "no" means the viewport will be adjusted so +that the square plot will span equal physical lengths in x and y +when plotted. That is, when \fBfill = no\fR, a unity aspect ratio is +enforced, and plots +appear square regardless of the device aspect ratio. On devices with non +square full device viewports (e.g., the vt640), a plot drawn by \fIpvector\fR +appears extended in the x direction unless \fBfill\fR = no. + +.ih +EXAMPLES +1. Plot from the lower left to upper right of 512 square image crab.5009. + + cl> pvector crab.5009 1. 1. 512. 512. + +2. Plot the same vector but with the sampling width = 3. + + cl> pvector crab.5009 1. 1. 512. 512. width=3 + +3. Plot a vector in same image with center position 256, 256, and a position +angle of 45 degrees which extends from one edge of the frame to the other. + + cl> pvector crab.5009 0. 0. 0. 0. 256. 256. theta=45. + or + cl> pvector crab.5009 xc=256. xc=256. theta=45. + + +4. Plot the above vector with a length of 100 pixels. + + cl> pvector crab.5009 0. 0. 0. 0. 256. 256. theta=45. length=100. + or + cl> pvector crab.5009 xc=256. xc=256. theta=45. length=100. +.ih +TIME REQUIREMENTS +It takes approximately 6.7 cpu seconds to compute and plot the twenty +pixel wide diagonal of a 512 square real image. (VAX/VMS 750 with fpa). +.ih +BUGS +.ih +SEE ALSO +prow, pcol, prow, pcols +.endhelp |