explain about wrapping hexadecimal colors

Author: monkstone

external_library/java/pixel_flow/README.md

@@ -33,3 +33,15 @@ end
 # init skylight renderer
 @skylight = DwSkyLight.new(context, scene_display, mat_scene_bounds)
 ```
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+In [antialiasing.rb][anti] if we just use the overloaded `color` method, jruby complains of overloaded method but guesses right and chooses the correct java signature (float, float, float). Mainly to show how we can do it, we provide an alias method `color_float` that avoids the look up cost in detecting the correct signature, this is not generally important if you can put up with the warning.
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+The ControlP5 library is overly complicated and does not seem to work well with JRubyArt, the built in `control_panel` is much simpler to use. If you must use ControlP5 see [examples][p5] and the revised [basic_fluid.rb][basic]
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+NB: where processing sketches use `fill(hexadecimal)` etc in propane we must wrap hexadecimal with color `fill(color(hexadecimal))` (_otherwise fill etc will complain of int too big_)
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+[anti]:https://github.com/ruby-processing/JRubyArt-examples/blob/master/external_library/java/PixelFlow/anti_aliasing.rb
+[p5]:https://github.com/ruby-processing/JRubyArt-examples/tree/master/external_library/java/controlP5
+[basic]:https://github.com/ruby-processing/propane-examples/blob/master/external_library/java/pixel_flow/fluid_basic.rb