About existing
plug-ins
Mapping
Mapping is the distortion
of an image. Technically, every pixel in the distorted image is linked
to a corresponding pixel in the original image. The correspondence is
translated in mathematical equations. Some problems arise, such as the
need for interpolation in between pixels and the need for extrapolation
for data that exits the domain.
The methods for
defining mapping available in this plug-in is Analitical definition,
Ordinal Differential Equation definition and Height Map definition.
Also the plug-in
allows the overlaying of several mappings, thus generating all kinds
of simple or complex motion blurs. One can imagine motion blur as keepin
the shutter of a camera open, while photographing the pixels of a canvas,
each one moving on a defined trajectory.
Dynamic Mapping
The
Dynamic Mapping plug-in has the same concept as Mapping: distorting
an image by using a map. However, in DMapping the user may interactively
edit the map by using different tools.
The same problems
regarding interpolation and extrapolation arise, and they are solved
basically in the same way.
The map used for
distorsion can be loaded from or saved to a file, compatible with the
Mapping plug-in.
DMapping also support
bitmaps in 32bit format, including Alpha channel.
The tools available
for editing the map are:
-
Click Mapping - Mapping applyin on mouse click
-
Mouse Mapping (Airbrush style) - Mapping independent of mouse events
-
Freeze - allows selecting a frozen area that is not to be affected
by other mapping tools
-
Undo - allows the partial or complete restoration of the image.
-
Exact applying - allows the applying of a click mapping effect on
an exact contour (rectangle, ellipse, line etc).
-
PDE Simulation - interesting editing of maps using user-defined Partial
Differential Equations
Fractal
The
word fractal originates from the latin "fractus", which means
severed or broken. Fractals are actually a form of chaos. They have many
different forms (IFS, L-Systems, ODE, PDE), but as they were initially
defined by Benoit Mandelbrot, they represent visualizations for stability
analyses of ordinal differential equations (ODE).
What one does if take
a system of ODE, set a fairly large differential step (usually 1) and
the initial conditions. The iterations commence and a response is given
in regard to how long it lasts until the values of the solution exit a
certain region of space. If a certain number of maximum iterations is
reached, the iterations are stopped. So, if the region is exited in the
first iteration, the pixel shall be black and if it remains within the
region until the maximum number of iterations, it is white. For in-between
values, it will have a shade of grey.
The widely-known methods
for rendering these fractals are Julia and Mandelbrot. Both of them colour
each point in space according to how the chaotic system "behaves"
at that point. The Julia method takes the coordinates of the point and
plugs them as initial conditions for the system, as system parameters
remain constant. Mandelbrot is the other way around.
Aside from being beautiful,
fractals have some visual proprieties: they are self-similar and infinitely
irregular. No matter how much it is zoomed in, a fractal still presents
smaller and smaller asperities.
This program allows
the user to set up the chaotic system in detail and to plot it according
to some specific settings.
Partial Differential
Equations
Partial
Differential Equations are a very useful mathematical tool and physics
and other scientific fields. In this case, PDE are used only as a source
of chaos. Initial conditions are loaded from a bitmap file. One must specify
the differential step considered (IT IS HIGHLY RECOMMENDED THAT IT IS
KEPT BELOW 0.5) and the number of steps to be taken. Three channels mean
three different sets of initial conditions, that need to be solved separately
- so each one can be solved with different parameters. By clicking the
"Simulation" button, the resolution of the equation commences
and the solution is progressively displayed as it evolves (using the specified
refresh rate).
Data can be saved
as bitmap, whether the program is used as a plug-in or as stand-alone.
The Wave Equation
is a second order PDE describing the motion of an elastic membrane, initially
deformed as specified by conditions. The waves propagate at a certain
speed (v) and with dynamic damping (loss of energy - k). These two parameters
can be specified for each channel. Also, esential to the form of the solution
are the rectangular boundary conditions, normally set to "Clammed".
However, for diversity, one may attempt setting them on "Wrap"
or "Mirror". It is mathematically possible, though improbable
for the values to be slightly out of range - in this case they will be
truncated. The "Normalize" button brings all values in range,
without truncation.
The Diffusion
Equation describes diffusion in a moving fluid. If fluid speed
is set to zero, the process will result in a progressive blurring, asymptotically
converging to the mean value (or in this case, the mean color). The parameter
v, in this case, is the coefficient of diffusivity and vx and vy respectively
specify the equations of the fluid motion, in regard to time and space.
One should be warned: in this case, if a too large differential step is
specified or if certain parameters become too large, the PDE system may
become unstable and diverge. |