Changes between Initial Version and Version 1 of DVO_Intro

Timestamp:

May 18, 2009, 11:02:23 PM (17 years ago)

Author:

rodney

Comment:

Initial Revision (s.r.)

DVO_Intro

@@ +1 @@
+= DVO Language anad Display Tools =
+
+This is a general introduction to the DVO shell and some of its graphics functionality.  The dvo commands are taken from the transcript of Gene Magnier's dvo demo at the IPP Workshop, 18 May, 2009. 
+
+* dvo is a shell environment, like bash or csh
+* command line editing is emacs-like
+
+== Getting help ==
+** three commands :  'help'  '?' '??'
+** 'help' gives a list of help topics.  The 'help' output is incomplete/nonexistant for many commands
+** '?'  - brief description of commands,  generated automatically from comments in the code
+*** (Use 'which' to get '?' like help for a single command)
+** '??' - shows currently defined variables 
+
+==== Useful help topics ====
+Some help items provide an overview of major functions, instead of a
+specific command.  Try these:
+
+{{{
+dvo: help Variables
+dvo: help Math
+dvo: help Graphics
+dvo: help Kii
+}}}
+
+
+== Variables ==
+ * set and access scalar variables with $ prefix
+ * Enclose math expressions in { }
+
+{{{
+dvo: $a = 5
+dvo: $b = "hello there"
+dvo: echo $a
+dvo: echo $b
+dvo: echo {6*$a} {-2.5*log(10000)} ; echo $a
+dvo: echo $a; $a = 10; echo $a
+}}}
+
+== Shell Escapes ==
+ * Do shell escapes with "bang" (!) or 'exec' 
+ * exec is necessary for macro files b/c '!' is a comment char
+ * use backticks (`) to store the results of a command line execution
+ in a dvo variable
+
+{{{
+dvo: !ls
+dvo: exec ls
+dvo: $word = `ls`
+dvo: echo $word
+}}}
+
+
+=== Lists : ===
+Lists are collections of scalar variables.  Can contain a mix of types.
+Start a list definition with the 'list' command, end it with a line
+containing only 'end'.
+Use 'help list' for more info
+
+{{{
+dvo: list fooList
+>> 5.6
+>> tada 
+>> 19
+>> end
+}}}
+
+The contents of a list are accessible as scalar variables with names
+derived from the list name. 
+
+{{{
+dvo: ??
+fooList:0 = 5.6
+fooList:1 = tada 
+fooList:2 = 19
+fooList:n = 3
+}}}
+
+
+You can collect the output of a command line expression directly into
+a list by using the '-x' option
+{{{
+dvo: list files -x "ls"
+dvo: echo $files:n
+12
+dvo: for i 0 $files:n
+>> echo $files:$i
+>> end
+}}}
+
+You can break a string into substrings, using whitespace delimiters:
+
+{{{
+dvo: $test = adaopdaow aeiaoiepoa fsdp eaoeap
+dvo: list word -split 
+>> $test adaopdaow aeiaoiepoa fsdp eaoeap
+dvo: for i 0 $word:n
+>> echo $word:$i
+>> end
+}}}
+
+== for loops ==
+ * for <iterator> <start> <end> <incr>
+ * close the loop with 'end'
+
+{{{
+dvo: for i 0 10 2 
+>> echo $i
+>> end
+0
+2
+4
+6
+8
+}}}
+
+{{{
+dvo: for i 0 $fooList:n
+>> echo $fooList:$i
+>> end
+5.6
+tada
+19
+}}}
+
+
+= Macros =
+ * see 'help macro'
+ *      warning : scope is not restricted 
+        **  variables defined in macros can conflict with variables 
+          set at higher levels if they have the same name
+ * flow control functions are available (for, if, break, 
+
+{{{
+dvo: macro example
+> for i 0 $0
+> echo $i
+> end
+> end
+dvo: example a b c
+0
+1
+2
+3
+}}}
+
+= Vectors =
+ * the command to make an index vector is 'create'
+ * see 'help create'
+ * build vectors from other vectors using 'set'
+
+{{{
+dvo: create x 0 1000
+dvo: echo x[0]
+dvo: echo x[200]
+dvo: echo {4*x[5]}
+dvo: set y = x^2
+dvo: echo x[5] y[5]
+}}}
+
+== Image display ==
+
+ * device -n <name> : instantiate a device with name <name>
+ **   any graphics command will accept -n <name> to send output to that
+  window (as opposed to the current window)
+
+ * set style options to adjust line width, color, point size, etc.
+ * see 'help style' for gory details. 
+ * use 'label' to put labels on the +x +y -x or -y axes.  
+
+ * Text commands can have sub- or superscript with '_' and '^',
+where the subscript is terminated  by '|'
+
+
+* Read an image: 
+{{{
+rd image simtest.fits 
+}}}
+
+* image interaction tools :
+**  cursor:             see 'help cursor'
+**  star :       get stats from the position where the cursor is, 
+
+== Plotting in a Graphics Window ==
+
+* region        : define a region on the sky for plotting in. 
+** see 'help region'
+
+* plot vs cplot :  
+**  plot just plots in the x-y coord system 
+**  cplot plots in the currently defined coord system
+
+* csystem : convert vectors between coordinate systems 
+
+{{{
+ dev -n 1
+ region 
+ create R 0 360 1 
+ set D = zero(R)
+ csystem G C R D
+ cplot R D
+}}}
+
+== Read vectors from a file ==
+* for reading from an Ascii file see 'help read'
+* for reading from a fits table use 'read -fits'
+
+
+== interactive work with a cmf and fits file ==
+
+* plotting vector data on top of an image
+* vload : load x,y vectors as an overlay onto a graphics window (can set plot styles)
+* vzload : load x,y vectors into an overlay with point sizes set by a z vector 
+* available overlays: red, green, blue,  yellow  (can be toggled on and off with buttons in the Kapa window)
+