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<html>
<head>
<title>ANIMATION</title>
</head>
<body bgcolor="#ffffff" link="#330099" alink="#FF3300" vlink="#330099">
<a href="xpphelp.html">Contents</a>
<hr>
<H1>
Toons
</H1>
To create an animation, just do the following:
<P>
<UL>
<LI>Run the numerical simulation for however long you need it or run it once the toon is loaded.
<p>
<LI>Using a text editor create a description of the animation using
the little scripting language described <a href="#script"> below </a>.
<p>
<LI>Click on the <TT>(V)iew axes</TT> <TT>(T)oon</TT> menu item from the
main XPP window to bring up the <a href="#awin"> animation window</a>.
<p>
<LI>Click on the <TT>File</TT> item in the animation window that pops
up and give it the name of your script file.
<p>
<LI>If the file is OK, click on <TT>Go</TT> item and the animation will
begin.
<p>
<li> Click on the little box in the upper right for animation on the fly -- the animation runs along with the simulation!
</UL>
<H2><A NAME="awin">
The animation window</A>
</H2>
A resizeable window will pop up when you choose the <TT>Toon</TT> item
form the <TT>Viewaxes</TT> submenu. This has 10 buttons on it. They are
<UL>
<LI><B>File</B> Click on this to load a new animation
file. Hereafter, I will call these <B>ani</B> files. The usual
extension will be <B>filename.ani</B>.
<p>
<LI><B>Go</B> Click on here after you have loaded an ani file and it
will run.
<p>
<LI><B>Reset</B> This moves the animation back to the beginning
<p>
<LI><B>Fast</B> speeds up the animation
<p>
<LI><B>Slow</B> slows it down
<p>
<LI><B>Pause</B> pauses the animation. <B>Go</B> restarts it from
where it started. This is very sluggish and it takes a long time to
respond to it. I hope to fix this someday.
<p>
<LI><B>Skip</B> sets the numbers of frames to skip
<p>
<LI><B>»»»»</B> Move forward one frame
<p>
<LI><B>««««</B> Move back one frame
<p>
<LI><B>Mpeg</B> Store a series of ppm files for use with the
mpeg_encode program. This takes a ton of disk space. Better yet, use
the <B>anigif</B> option which creates an animated gif file. 600
frames can be as little as 500K so it wont eat up disk space.
</LI>
</UL>
Some computer systems cannot produce the required amount of graphics
memory for a pixmap and if this happens, you cannot currently run the
animation. You will be told this and the animation window will never
appear.
<P>
<HR>
<H2><A NAME="script">
DASL: Dynamical Animation Scripting Language</A>
</H2>
In order to use the animation components of XPP, you must first
describe the animation that you want to do. This is done by creating a
script with a text editor that describes the animation. You describe
the coordinates and colors of a number of simple geometric
objects. The coordinates and colors of these objects can depend on the
values of the variables (both regular and fixed, but not auxiliary) at
a given time. The animation then runs through the output of the
numerical solution and draws the objects based on that output. I will
first list all the commands and then give some examples.
<P>
Basically,
there are two different types of objects: (i) transient and (ii)
permanent. Transient objects have coordinates that are recomputed at
every time as they are changing with the output of the
simulation. Permanent objects are computed once and are fixed through
the duration of the simulation. The objects themselves are simple
geometric figures and text that can be put together to form the
animation.
<P>
Each line in the script file consists of a command or object followed
by a list of coordinates that must be separated by semicolons. For
some objects, there are other descriptors which can be optional.
Since color is important in visualization, there are two ways a color
can be described. Either as a formula which is computed to yield a
number between 0 and 1 or as an actual color name started with the
dollar sign symbol, $. The <TT>ani</TT> file consists of a lines of
commands and objects which are loaded into XPP and played back on the
animation window. Here are the commands:
<DL>
<DT></DT>
<DD><B>dimension</B> xlo;ylo;xhi;yho
<p></dd>
<DT></DT>
<DD><B>speed</B> delay
<p></dd>
<DT></DT>
<DD><B>transient</B>
<p></dd>
<DT></DT>
<DD><B>permanent</B>
<p></dd>
<DT></DT>
<DD><B>line</B> x1;y1;x2;y2;color;thickness
<p></dd>
<DT></DT>
<DD><B>rline</B> x1;y1;color;thickness
<p></dd>
<DT></DT>
<DD><B>rect</B> x1;y1;x2;y2;color;thickness
<p></dd>
<DT></DT>
<DD><B>frect</B> x1;y1;x2;y2;color
<p></dd>
<DT></DT>
<DD><B>circ</B> x1;y1;rad;color;thickness
<p></dd>
<DT></DT>
<DD><B>fcirc</B> x1;y1;rad;color
<p></dd>
<DT></DT>
<DD><B>ellip</B> x1;y1;rx;ry;color;thickness
<p></dd>
<DT></DT>
<DD><B>fellip</B> x1;y1;rx;ry;color
<p></dd>
<DT></DT>
<DD><B>comet</B> x1;y1;type;n;color
<p></dd>
<DT></DT>
<DD><B>text</B> x1;y1;s
<p></dd>
<DT></DT>
<DD><B>vtext</B> x1;y1;s;z
<p></dd>
<DT></DT>
<DD><B>settext</B> size;font;color
<p></dd>
<DT></DT>
<DD><B>end</B>
<p></dd>
</DL>
<P>
All commands can be abbreviated to their first three letters and case
is ignored. At startup the dimension of the animation window in user
coordinates is (0,0) at the bottom left and (1,1) at the top
right. Thus the point (0.5,0.5) is the center no matter what the
actual size of the window on the screen. <B>Color</B> is described by either
a floating point number between 0 and 1 with 0 corresponding to red
and 1 to violet. When described as a floating point number, it can be
a formula that depends on the variables. In all the commands, the
color is optional <EM>except</EM> <B>settext.</B> The other way of
describing color is to use names which all start with the $
symbol. The names are:
<B>$WHITE, $RED, $REDORANGE, $ORANGE, $YELLOWORANGE,
$YELLOW, $YELLOWGREEN, $GREEN, $BLUEGREEN,
$BLUE,$PURPLE, $BLACK</B>.
<P>
The <B>transient</B> and <B>permanent</B> declarations tell the animator
whether the coordinates have to be evaluated at every time or if they
are fixed for all time. The default when the file is loaded is <B>transient.</B> Thus, these are just toggles between the two different
types of objects.
<P>
The number following the <B>speed</B> declaration must be a nonnegative
integer. It tells tha animator how many milliseconds to wait between
pictures.
<P>
The <B>dimension</B> command requires 4 numbers following it. They are
the coordinates of the lower left corner and the upper right. The
defaults are (0,0) and (1,1).
<P>
The <B>settext</B> command tells the animator what size and color to
make the next text output. The size must be an integer, <B>{
0,1,2,3,4 } </B> with 0 the smallest and 4 the biggest. The font is
either <B>roman</B> or <B>symbol.</B> The color must be a named color
and not one that is evaluated.
<P>
The remaining ten commands all put something on the screen.
<UL>
<LI><B>line x1;y1;x2;y2;color;thickness </B> draws a line from <B>(x1,y1)</B>
to <B>(x2,y2)</B> in user coordinates. These four numbers can be any
expression that involves variables and fixed variables from your
simulation. They are evaluated at each time step (unless the line is
<B>permanent</B>) and this is scaled to be drawn in the window. The
<B>color</B> is optional and can either be a named color or an
expression that is to be evaluated. The <B>thickness</B> is also
optional but if you want to include this, you must include the <B>color</B> as well. <B>thickness</B> is any nonnegative integer and will
result in a thicker line.
<P>
</LI>
<LI><B>rline x1;y1;color;thickness </B> is similar to the <B>line</B>
command, but a line is drawn from the endpoints of the last line drawn
to <B>(xold+x1,yold+y1)</B> which becomes then new last point. All other options
are the same. This is thus a ``relative'' line.
<P>
</LI>
<LI><B>rect x1;y1;x2;y2;color;thickness </B> draws a rectangle with
lower corner <B>(x1,y1)</B> to upper corner <B>(x2,y2)</B> with optional
color and thickness.
<P>
</LI>
<LI><B>frect x1;y1;x2;y2;color </B> draws a filled rectangle with
lower corner <B>(x1,y1)</B> to upper corner <B>(x2,y2)</B> with optional
color.
<P>
</LI>
<LI><B>circ x1;y1;rad;color;thick </B> draws a circle with radius <B>rad</B>
centered at <B>(x1,y1)</B> with optional
color and thickness.
<P>
</LI>
<LI><B>fcirc x1;y1;rad;color </B> draws a filled circle with radius <B>rad</B>
centered at <B>(x1,y1)</B> with optional color.
<P>
</LI>
<LI><B>ellip x1;y1;rx;ry;color </B> draws an ellipse with radii <B>rx,ry</B>
centered at <B>(x1,y1)</B> with optional
color and thickness.
<P>
</LI>
<LI><B>fellip x1;y1;rx;ry;color </B> draws a filled ellipse with
radii <B>rx,ry</B> centered at <B>(x1,y1)</B> with optional
color.
<P>
</LI>
<LI><B>comet x1;y1;type;n;color</B> keeps a history of the last <TT>n</TT> points drawn and renders them in the optional <TT>color</TT>. If <TT>type</TT> is non-negative, then the last n points are drawn as a line with
thickness in pixels of the magnitude of <TT>type</TT>. If <TT>type</TT> is
negative, filled circles are drawn with a radius of <TT>-thick</TT> in
pixels.
<P>
</LI>
<LI><B>text x1;y1;s</B> draws a string <B>s</B> at position <B>(x1,y1)</B> with the current color and text properties. Only the
coordinates can depend on the current values.
<P>
</LI>
<LI><B>vtext x1;y1;s;z</B> draws a string <B>s</B> followed by
the floating point value <B>z</B> at position <B>(x1,y1)</B> with the current color and text properties. Thus, you can
print out the current time or value of a variable at any given time.
</LI>
</UL>
<P>
<EM>REMARK.</EM> As with lines in ODE files, it is possible to create
arrays of commands using the cobination of the <B>[i1..i2] </B>
construction. Some examples are shown below.
|
