Processing: Creative Coding and Computational Art

Figure 10-30. Tint sketch
Speeding things up with bitwise operations
You might have noticed that this last sketch took some time to render (or maybe your
computer is faster than mine). There is a faster, albeit lower-level, way to manipulate the
individual color components packed inside the color data type. The color data type combines
the individual color components alpha, red, green, and blue into 32 bits of data. The
structure of the color data type looks like this: AAAAAAAARRRRRRRRGGGGGGGG-
BBBBBBBB. Of course, the letters would be replaced by zeros and ones, depending on the
color specified. For example, run the following sketch to see the bit string for blue:
color c = color(0, 0, 255);
println(binary(c));
In the sketch output, the alpha and blue bits are all ones, since I specified maximum value
for blue (255), and alpha is 255 by default. Likewise, the red and green bits are all zeros,
per the original color value I set—color(0, 0, 255).
Bitwise operations allow you to directly manipulate the bits, shifting and even doing
simple mathematical operations on them. Bitwise operations are not for everyone, so
don’t fret if you can’t deal with this approach. However, it’s good to know that the possibility
exists, and they are quite speedy. I provide a detailed overview of bitwise operations
in Appendix B, so you might want to read that before trying these next few sketches. If,
however, you just want to use bitwise operations with a limited understanding of how they
actually work, here’s the highly abridged “recipe” version:
COLOR AND IMAGING
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