It was started with the command xdatplot a1.bin.gz &. a1.bin.gz is a sample file you can get from wherever you got xdatplot. The window has three areas: a menu bar across the top, a plot window in the middle displaying data, and a control panel at the bottom.
The menu bar
The menu bar contains three pulldown menus, the File menu, which allows you to read files, save
xdp files, and make printouts, the Analyze menu, which brings up
dialog boxes for setting the units used in
plotting, finding peaks, and filtering the data, and the Marks menu, which allows marks to be read,
saved, or modified by an external program (a filter). In addition, it
has a Help button at the far right, which brings up the help system
you are now using.
The plot window
The plot window shows your data. The axes are labeled with the units
you set in the units dialog. (You can also
set default units; see Customization (X
resources).) The scrollbars on the bottom and right edge allow
you to move around in the data file. There are three ways to use the
scrollbar. First, you can click on the little arrows at the ends.
This will move just a little bit. (You can hold the mouse down to
stream through the file.) Second, you can click in the blank area of
the scrollbar on either side of the raised part. This will move you
by a little less than the width or height of the plot. Third, you can
click on the raised part and drag it somewhere else. That moves you
immediately to the corresponding place in the file.
If you click the mouse anywhere where data are plotted, a red line, the cursor, appears:
You'll notice that numbers also appeared in the t and V fields of the control panel. This gives you a way to read values out. The cursor can also be used to set and clear marks. If the mouse is in the plot window and you type any letter or number, a mark will be placed at the cursor. See keys for more details.
Now click the right mouse button somewhere else in
the plot window. A whole rgion of the plot becomes red:
The region, when it exists, restricts the action of many operations
that would otherwise extend over the whole file. For instance, if you
now do a peak search, it will find peaks only within the red area.
Setting a new cursor cancels the region.
The region is not restricted to one window. You can set the cursor at
one place, scroll the plot to some distant location in the file, and
click the right mouse button to create a region that encompasses all
the area between.
The control panel
The control panel, at the bottom of the main window, is its most
complicated part. It has four areas, from left to right: Time zoom,
Voltage zoom, cursor values, and comment.
The Zoom In and Zoom Out buttons increase and decrease the magnification of the relevant axis by a factor of 1.5. Zoom Way In increases the magnification by a factor of 5. (There is a Zoom Way Out function, but it is accessible only by a keyboard shortcut.) The Full Scale button zooms out so that the whole horizontal or vertical extent of the plot is visible at once. (Note: for big files, it will take quite a while to plot the whole horizontal extent.) The Zoom Out and Full Scale buttons are grayed out if the axis is already full scale, as is the case for the Voltage axis in the above pictures. The Fit Height button in the Voltage zoom area sets the vertical zoom and the vertical scrollbars so that the data in the plotted area exactly fit. If you set the Autofit toggle, the plot will automatically Fit Height whenever you scroll.
The text fields in the zoom areas give the current magnification in pixels/unit. For instance, in the window shown above, one sec is 146 pixels, and 1 pA is 0.272066 pixels. You can select these values by double-clicking and paste them somewhere else (for instance, into the zoom field of another xdatplot window, to set the scales the same). If you type a new value into the field and hit return, the zoom will be set to approximately the value you asked for.
The cursor values fields show the time and Voltage at the current position of the cursor, as described above. You can select them by double-clicking the mouse in the text field, and then paste them somewhere else. The Voltage value is read-only: you can't type into it. But you can type into the t field. If you type a new value and hit return, the cursor will be placed there. The plot window will be scrolled if necessary to show the new cursor.
The rightmost area of the control panel shows any comment attached to the file. Most data acquistion programs allow a text description to be attached; this will be shown in the comment window. You can edit the comment, and the changed text will be saved when you use File Save to create an xdp file.
Leon Avery (leon@eatworms.swmed.edu)