Represents a color in the RGBA color space. This representation is designed
for simplicity of conversion to and from color representations in various
languages over compactness. For example, the fields of this representation
can be trivially provided to the constructor of java.awt.Color in Java; it
can also be trivially provided to UIColor's +colorWithRed:green:blue:alpha
method in iOS; and, with just a little work, it can be easily formatted into
a CSS rgba() string in JavaScript. This reference page doesn't have
information about the absolute color space that should be used to interpret
the RGB value—for example, sRGB, Adobe RGB, DCI-P3, and BT.2020. By default,
applications should assume the sRGB color space. When color equality needs to
be decided, implementations, unless documented otherwise, treat two colors as
equal if all their red, green, blue, and alpha values each differ by at most
1e-5. Example (Java): import com.google.type.Color; // ... public static
java.awt.Color fromProto(Color protocolor) { float alpha =
protocolor.hasAlpha() ? protocolor.getAlpha().getValue() : 1.0; return new
java.awt.Color( protocolor.getRed(), protocolor.getGreen(),
protocolor.getBlue(), alpha); } public static Color toProto(java.awt.Color
color) { float red = (float) color.getRed(); float green = (float)
color.getGreen(); float blue = (float) color.getBlue(); float denominator =
255.0; Color.Builder resultBuilder = Color .newBuilder() .setRed(red /
denominator) .setGreen(green / denominator) .setBlue(blue / denominator); int
alpha = color.getAlpha(); if (alpha != 255) { result.setAlpha( FloatValue
.newBuilder() .setValue(((float) alpha) / denominator) .build()); } return
resultBuilder.build(); } // ... Example (iOS / Obj-C): // ... static UIColor*
fromProto(Color* protocolor) { float red = [protocolor red]; float green =
[protocolor green]; float blue = [protocolor blue]; FloatValue* alpha_wrapper
= [protocolor alpha]; float alpha = 1.0; if (alpha_wrapper != nil) { alpha =
[alpha_wrapper value]; } return [UIColor colorWithRed:red green:green
blue:blue alpha:alpha]; } static Color* toProto(UIColor* color) { CGFloat
red, green, blue, alpha; if (![color getRed:&red green:&green blue:&blue
alpha:&alpha]) { return nil; } Color* result = [[Color alloc] init]; [result
setRed:red]; [result setGreen:green]; [result setBlue:blue]; if (alpha <=
0.9999) { [result setAlpha:floatWrapperWithValue(alpha)]; } [result
autorelease]; return result; } // ... Example (JavaScript): // ... var
protoToCssColor = function(rgb_color) { var redFrac = rgb_color.red || 0.0;
var greenFrac = rgb_color.green || 0.0; var blueFrac = rgb_color.blue || 0.0;
var red = Math.floor(redFrac * 255); var green = Math.floor(greenFrac * 255);
var blue = Math.floor(blueFrac * 255); if (!('alpha' in rgb_color)) { return
rgbToCssColor(red, green, blue); } var alphaFrac = rgb_color.alpha.value ||
0.0; var rgbParams = [red, green, blue].join(','); return ['rgba(',
rgbParams, ',', alphaFrac, ')'].join(''); }; var rgbToCssColor =
function(red, green, blue) { var rgbNumber = new Number((red << 16) | (green
<< 8) | blue); var hexString = rgbNumber.toString(16); var missingZeros = 6 -
hexString.length; var resultBuilder = ['#']; for (var i = 0; i <
missingZeros; i++) { resultBuilder.push('0'); }
resultBuilder.push(hexString); return resultBuilder.join(''); }; // ...