private/google/type/color.proto
// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
syntax = "proto3";
package google.type;
import "google/protobuf/wrappers.proto";
option cc_enable_arenas = true;
option go_package = "google.golang.org/genproto/googleapis/type/color;color";
option java_multiple_files = true;
option java_outer_classname = "ColorProto";
option java_package = "com.google.type";
option objc_class_prefix = "GTP";
// Represents a color in the RGBA color space. This representation is designed
// for simplicity of conversion to/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, as well.
//
// Note: this proto does not carry information about the absolute color space
// that should be used to interpret the RGB value (e.g. sRGB, Adobe RGB,
// DCI-P3, BT.2020, etc.). By default, applications SHOULD assume the sRGB color
// space.
//
// Note: when color equality needs to be decided, implementations, unless
// documented otherwise, will treat two colors to be 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('');
// };
//
// // ...
message Color {
// The amount of red in the color as a value in the interval [0, 1].
float red = 1;
// The amount of green in the color as a value in the interval [0, 1].
float green = 2;
// The amount of blue in the color as a value in the interval [0, 1].
float blue = 3;
// The fraction of this color that should be applied to the pixel. That is,
// the final pixel color is defined by the equation:
//
// pixel color = alpha * (this color) + (1.0 - alpha) * (background color)
//
// This means that a value of 1.0 corresponds to a solid color, whereas
// a value of 0.0 corresponds to a completely transparent color. This
// uses a wrapper message rather than a simple float scalar so that it is
// possible to distinguish between a default value and the value being unset.
// If omitted, this color object is to be rendered as a solid color
// (as if the alpha value had been explicitly given with a value of 1.0).
google.protobuf.FloatValue alpha = 4;
}