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gluas

This package provides the ability to experiment with prototypes and ideas for image processing. One of it's primary purposes is a teaching tool students will use to reimplement, and experiment with, simple image processing operations.

The best documentation for the package is the examples catalog, all of lua, documented at http://www.lua.org/ is avaiable, as well as the following image manipulation functions:

set_hsl (x, y, h, s, l)
set_hsv (x, y, h, s, v)
set_lab (x, y, l, a, b)
set_rgb (x, y, r, g, b)
set_rgba (x, y, r, g, b, a)
set_value (x, y, value)
set_alpha (x, y, alpha)

(lua allows multiple return, I use that to illustrate the return value of the pixel data querying functions)

h,s,l = get_hsl (x, y)
h,s,v = get_hsv (x, y)
l,a,b = get_lab (x, y)
r,g,b = get_rgb (x, y)
r,g,b,a = get_rgba (x, y)
value = get_value (x, y)
alpha = get_alpha (x, y)

flush ()

apply the current processing (which means that pixels retrieved with get_ functions, will get the data set with set_ functions and not original data, useful for multipass implementations,

the global variables width and height are set to the pixel dimensions of the drawable being modified.

progress (amount)

Calling the function progress(val) with a number between 0.0 and 1.0 will give the user feedback about how much of the image is processed.

Animation

An extra feature of gluas is animation, by pressing shift+ctrl+A you can control some additional options. The number of frames generated, and the time value to use when doing a preview.

From within the code the time value can be accessed through the global variable 'time' which varies from 0.0 at the start of the animation to 1.0 at the end of the animation.

To make the animation "ping-pong" insert code similar to

if time>0.5 then

        time=0.5-(time-0.5)
        time=time2
else
        time=time2

end

at the top of your script.

Happy image processing
/pippin