This describes some of the standard characteristics of all graphical output.
The draw resource is used to toggle on and off various parts of the plot. The plot contains two basic regions. The text label areas above and below the plot and the plot itself. The text labels can appear in six regions around the plot, left, center and right. The plot contains a background map or grid and the data plotted as text, symbols or contours. There is a plot border which is a rectangle surrounding the plot. The other possibility is the radar summary that is separate from data. There are these possible options for draw:
- text - The text labels above and below the plot (all labels and border)
- text_ul - The text label in the upper left
- text_uc - The text label in the upper center
- text_ur - The text label in the upper right
- text_ll - The text label in the lower left
- text_lc - The text label in the lower center
- text_lr - The text label in the lower right
- bord - The plot border
- map - The background map
- grid - The background grid (synonymous with map)
- data - The data plotted as text, symbols or contours
- sum - The radar summary
- all - All of the above
- none - No graphics generated
By default, all draw types are turned on. If any of the above are specified, all types are turned off and only those types listed will be turned on. For example, if the data and map are needed but no text labels, specify:
Draw types can be added and removed by putting a "+" or "-" in front of the draw type. If this is done, the types are not turned off initially. For example, if only the upper right label and border is to be removed, specify:
In some cases, it is necessary for the plotted data to fill the entire window. By default, WXP allots room above and below the plot for labels to be displayed. To turn this feature off, use the "full" plot parameter.
Changing Plot Labels
The label resource is used to change the text labels that appear above and below the plot. Each label must by preceded with a location specifier:
followed by a color ":" and the text. The string may have spaces but the string must be quoted. Underscores can be placed in the string to denote spaces if needed. Multiple labels are separated by commas.
There are special characters that can be used to use date information in the label:
- %D -- full date (hhZ dd mmm yy)
- %V -- full valid date (HH hr valid hhZ dd mmm yy)
- %F -- a forecast hour
label (24 hr)
- %Y -- 4 digit year
- %y -- last two digits of the year
- %m -- the two digit month
- %b -- the three letter month abbreviation
- %d -- the two digit day
- %h -- the two digit hour
- %n -- the two digit minute
- %f -- the forecast hour
- %% -- the percent sign
- _ -- underscore is replaced by a space
Changing Time Zones
By default, WXP displays all times in universal time (UTC).
The programs use
"Z" for the time zone label for simplicity. To
time zone displayed on the plots, use the time_zone resource.
The syntax is
would plot the time in Eastern Standard Time. The "EST" is only for the label. The critical part is the time offset "-5" which is the number of hours from UTC. The result would be a string like "835 EST 14 MAR 10"
To get time to display as AM/PM, add a plus "+" to the beginning of the label "+EST". The result would be "4:00 PM EST 23 MAR 10".
A color bar can be displayed on the image if the "bar" parameter is set. It appears in the lower left corner of the plot and shows the colors used in the color fill plot labeled with their associated values:
If there are too many labels, appropriate ones will be skipped. If colored plotting is enabled, the color bar can also be used. If multicolored/multistyles contour lines are used, the color bar will draw colored lines rather than filled regions. The lines will also reflect the line style.
To set the range of the color bar, specify the max and min values with the "bar:min:max" plot parameter:
If values for the color fills are listed, these
will be used for the
color bar labels exactly as they are listed.
Output to Image Files
There is a GIF image encoder/decoder built into WXP. This allows graphics to be saved in image format for future use and use with web servers. There are three methods for saving images to file:
- Automatically by adding "gif=filename" to the output resource. The filename is either a file name convention tag or an exact filename. There are two wildcards that can be placed in the filename: %p which is the program name/window title and %i which is the index of the image in a loop.
- Automatically through wxploop's
loopset save 0 filename
The same %p and %i wildcards can be used in the filename.
- Manually by hitting <Meta>g in the window. The output will be a file which is the first 5 characters of the window title plus ".gif". The image_path resource value is prepended to the filename. If the image is part of a loop, the image number in the loop is added to the filename "ttttt-##.gif" where ## is the image number starting at 0.
If the program has created a loop of images and the program is looping the images, the image save will save all the images in the loop. If the loop is stopped, only that image is saved to file.
Interlaced GIF Images
To save GIF images in interlaced format, use the "gifinter" plot parameter.
By default, WXP uses a black background with data plotted in green and a map in red. For some applications, it is required for WXP to have white backgrounds. This is especially true for GIF images that go on a web server whose purpose is to be printed. When inverted, only a couple of colors change. First, the background color defaults to white. Any piece of information that is plotted in white is now plotted in black. Those plotted in yellow are now plotted in brown. There are two methods for inverting the image:
- Automatically by specifying "inv" for the plot parameter
or by setting the wxpinverse environment variable:
setenv wxpinverse on
By specifying pscolor for printed output, the colors are automatically inverted.
- Manually by changing the background and specific colors to achieve the desired results.
In some cases, the user may want control over exactly where in the
window the plot is
being displayed. This can be done in a number of ways. One
way is with WXPloop
and the geometry specification. If you are not
using WXPloop, the
geometry relates to the window and not the plot. As a result, the
viewport size can
be specified with the "vp_size" plot parameter.
syntax is: "
coordinates represent the fractional panel coordinates. The dx
represent the fraction of the overall window ( 0 < dx
the panel will use. The x and y are the offsets
measured from the lower
left. For example, to produce a 4 panel plot (2x2) and the current plot
is the upper left,
the geometry would be:
For further information about WXP, email firstname.lastname@example.org
Last updated by Dan Vietor on March 16, 2010