Added user-friendly support for commonly used colors

[patrick9958]

I've assembled a list of 140 preset colors so that instead of typing, for example, theaterChase(strip.Color(20,34,16), delayval), users can type theaterChase(TEAL, delayval). Both options for typing colors are available to users and the function will work either way. I've also put all 140 colors into the keywords.txt file and marked them as KEYWORD2 so users know it will be recognized as a valid color by Arduino. I've already written code and tested it on two separate LED ring models.

I have changed the Adafruit_Neopixel.h file only by adding the #include "hexadecimal_colors_to_strings.h" at the top. I have added a new hexadecimal_colors_to_strings.h file in the directory as well. This file defines a list of 140 commonly used colors along with their hex values.

On top of that, I added a new example file called colors.ino in which I demonstrate how these colors can be used.

[ladyada]

great start! can you remove all changes to NeoPixel.cpp and .h? you dont need to include the colors header file there and cpp has some white space changes (which i'd like to not have in this PR!)

[patrick9958]

First of all, sorry for taking so long to get back to you. Secondly, I removed all changes to the Neopixel.h and .cpp files. However, when you remove the include reference to the hexadecimal_colors_to_strings.h in the .h file, colors.ino does not compile (reflected by the failed build) because TEAL, YELLOW, and MAROON are now not declared. I could put the library include for the hexadecimal_colors_to_strings.h file at the top of the example but that would kind of defeat the purpose of integrating it within the Adafruit Neopixel library. Let me know how you want me to move forward.

[lights0123]

I'd like to see these constants namespaced, either by prefixing them with NEO_ or doing something like this:

namespace NeoColors {
  const uint32_t BLACK = 0x000000
  const uint32_t NAVY = 0x000080
}

Because otherwise any user sketches with any of these names won't work anymore. I've seen a couple of LCD graphics libraries that have these same constants, and those sketches won't work anymore without modifying either library (or adding hundreds of #undefs). This also allows sketches to just add using namespace NeoColors; if they aren't using anything that has a conflict to just use the short name.

[patrick9958]

I have the #include <stdint.h> at the top of the hexadecimal_colors_to_strings.h file because Arduino was not recognizing uint32_t as a type but the example colors.ino file still won't compile because the hexadecimals.h file isn't included anywhere

[ladyada]

please ping when this compiles and passes travis CI

[abhinuvpitale]

You need to include "hexadecimal_to_string.h" header