Constants and colors in Util.js

[jessegreenberg]

Related to code review #14 and somewhat related to #20.

It looks like TrigTourScreenView.js uses the default layout bounds, so can constant LAYOUT_BOUNDS be removed from Util.js? If the constant can be removed, I would recommend renaming Util.js to something a little more descriptive like TrigTourColors.js.

For the colors, TAN_COLOR should be pulled from RED_COLORBLIND in PhetColorScheme.js and renamed to RED_COLORBLIND.

SIN_COLOR is documented as color-blind green. I am not familiar with color blind green, did this color test well in colorblind tests? If yes, then I think hex color '#008700' should be moved to PhetColorScheme and documented there.

[jessegreenberg]

UnitCircleView would also benefit from renaming to TrigTourColorScheme because Util would not have to be renamed to UtilTrig.
var UtilTrig = require( 'TRIG_TOUR/trig-tour/view/Util' );

It is a little confusing when the var name does not match the module name. To me, UtilTrig means a file that holds utility trig functions. TrigTourColors would more accurately describe the file

var TrigTourColors = require('TRIG_TOUR/trig-tour/view/TrigTourColors')

[jessegreenberg]

@amanda-phet, are you familiar with the color-blind green that is being used to represent sin? Was this color tested for visibility in color-blind tests?

If it was tested, I think this color should be added to the PhET color scheme. If not, some documentation needs to be changed.

[amanda-phet]

We chose the green while doing color-blind tests, so it does behave well with the red. I'm not sure if the red is exactly color-blind-red. Did you verify the hex code or RGB components? If it is, then feel free to add the green as a good green to go with it!

[jessegreenberg]

I verified that the red in trig-tour has the exact RGB components of RED_COLORBLIND in PhetColorSCheme.

I added the green-colorblind to PhetColorScheme for future use since it pairs well with red-colorblind. That completes this issue, closing.