Processing: Creative Coding and Computational Art

When working in a 3D coordinate system, you just add another axis, called z, which follows
the same rules I’ve been discussing for 2D. The z-axis goes into the screen and is perpendicular
to both the x- and y-axes—but rest assured, for now you only need to deal with the
x- and y-axes.
One other issue to consider when dealing with coordinate systems is local vs. world coordinates.
For example, when you draw a rectangle on the screen at (100, 100), you can think
of the rectangle living on the screen world at pixel address (100, 100). However, let’s imagine
you then want to put a small circle on the rectangle 3 pixels to the right of the rectangle’s
left edge and 3 pixels down from its top edge. What is the circle’s screen pixel
address? You can consider the circle’s world address as (103, 103), and the circle’s local
address, in relation to the rectangle, as (3, 3). Now this may sound a little confusing and
like an obscure point, but it is something that comes up fairly often. For example, it is
often easier to work with a local coordinate system when you are assembling components
on a larger structure. If you are drawing windows on a house, isn’t it easier to just worry
about where the windows fit in relation to the rectangle of the of building, rather than
keeping track of where the windows are in relation to the edges of the screen? This way, if
you ever move the building, the windows will stay in the right place in relationship to the
building.
Anatomy of an image
COMPUTER GRAPHICS, THE FUN, EASY WAY
A computer screen is (very simply put) a matrix, or grid, made up of rows and columns of
pixels that can each glow a certain color, giving the illusion, when enough pixels are glowing
the right color, of a continuous tone image (e.g., a photograph). Fortunately, the resolution
of most of our monitors is high enough and the refresh rate fast enough to allow
this matrix of pixels and constant screen redrawing to remain hidden, giving the illusion of
image persistence—you see what looks like a still, smooth image. When you zoom way
into an image in a program like Photoshop, you can see the pixel matrix, made up of little
blocks of color. If you look under a magnifying glass at printed materials, you can also see
a matrix of dots of color that, when zoomed back out, creates the same illusion of a continuous
image as on a monitor. Some well-known artists, such as Roy Lichtenstein and
Chuck Close, both exploited this phenomenon in their paintings, albeit in very different
ways. Lichtenstein painted the dot pattern as an explicit visual element in his pop art work,
directly referencing the commercial printing process. Close utilized a matrix structure originally
as a production tool, dividing his images up, similar to a monitor, into small rectangular
cells. Eventually his work began incorporating the grid as an explicit element as well.
Refresh rate is the rate at which the monitor redraws the screen image. Although images
on a screen look constant, they’re not. If you’ve ever shot video of your television, you’ve
probably seen the screen flickering or jumping. The frequency of the video camera’s
refresh rate and the frequency of the monitor’s refresh rate are not synchronized, allowing
you to catch the screen refreshing. Properties like screen resolution and refresh rates
are hardware-dependent and determined by the monitor and video card in your computer.
You can usually select from numerous monitor display configurations through system
control panels to change these properties, but actually communicating directly with
the video card or monitor through the code you write in Processing is lower level than you
go. Java does have a DisplayMode class, allowing you the ability to mess with this stuff
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