# Copyright 2019 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
#
#     https://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.


module Google
  module Type
    # 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.
    #
    # 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('');
    #     };
    #
    #     // ...
    # @!attribute [rw] red
    #   @return [Float]
    #     The amount of red in the color as a value in the interval [0, 1].
    # @!attribute [rw] green
    #   @return [Float]
    #     The amount of green in the color as a value in the interval [0, 1].
    # @!attribute [rw] blue
    #   @return [Float]
    #     The amount of blue in the color as a value in the interval [0, 1].
    # @!attribute [rw] alpha
    #   @return [Google::Protobuf::FloatValue]
    #     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).
    class Color; end
  end
end