/*
* Copyright 2009 Hao Nguyen
*
* 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.
*/
package gwt.g2d.shared;
import gwt.g2d.client.math.MathHelper;
import gwt.g2d.shared.math.Vector2;
import java.io.Serializable;
import java.util.Arrays;
import com.google.gwt.canvas.dom.client.ImageData;
import com.google.gwt.regexp.shared.MatchResult;
import com.google.gwt.regexp.shared.RegExp;
/**
* Stores a color. Color is immutable.
*
* @author hao1300@gmail.com
*/
public class Color implements Serializable {
protected static final double DEFAULT_ALPHA = 1.0;
private static final long serialVersionUID = 5370658935618812361L;
private final String colorCode;
public final int red, green, blue;
public final double alpha;
/**
* Constructor.
*
* @param colorCode the string representing this color.
* @param red red channel [0-255]
* @param green green channel [0-255]
* @param blue blue channel [0-255]
* @param alpha alpha channel [0.0, 1.0]
*/
protected Color(String colorCode, int red, int green, int blue, double alpha) {
this.colorCode = colorCode;
this.red = red;
this.green = green;
this.blue = blue;
this.alpha = alpha;
}
/**
* Represents a color that contains transparency.
* The color code is represented in the form "rgba(r,g,b,a)".
*
* @param red red channel [0-255]
* @param green green channel [0-255]
* @param blue blue channel [0-255]
* @param alpha alpha channel [0.0, 1.0]
*/
public Color(int red, int green, int blue, double alpha) {
this(new StringBuilder(21)
.append("rgba(")
.append(red).append(',')
.append(green).append(',')
.append(blue).append(',')
.append(alpha).append(')')
.toString(),
red, green, blue, alpha);
}
/**
* Construct a web-safe color. The color code is represented in the form
* "#RRGGBB" which represents an RGB color using hexadecimal numbers.
*
* @param red red channel [0-255]
* @param green green channel [0-255]
* @param blue blue channel [0-255]
*/
public Color(int red, int green, int blue) {
StringBuilder stringBuilder = new StringBuilder("#000000");
String hexString = Integer.toHexString(getHexValue(red, green, blue));
colorCode = stringBuilder.replace(
stringBuilder.length() - hexString.length(),
stringBuilder.length(),
hexString).toString();
this.red = red;
this.green = green;
this.blue = blue;
this.alpha = DEFAULT_ALPHA;
}
/**
* Linear interpolation between two colors.
*
* @param value1
* @param value2
* @param amount the amount to interpolate [0.0, 1.0].
* @return a new interpolated color.
*/
public static final Color lerp(Color value1, Color value2, double amount) {
return new Color(
(int) MathHelper.lerp(value1.getR(), value2.getR(), amount),
(int) MathHelper.lerp(value1.getG(), value2.getG(), amount),
(int) MathHelper.lerp(value1.getB(), value2.getB(), amount),
MathHelper.lerp(value1.getAlpha(), value2.getAlpha(), amount));
}
/**
* Linear interpolation between two colors with alpha premultiplication for better
* graphical effects.
*
* @param value1
* @param value2
* @param amount the amount to interpolate [0.0, 1.0].
* @return a new interpolated color.
*/
public static final Color lerpPremultiplied(Color c1, Color c2, double amount) {
double alpha = MathHelper.lerp(c1.getAlpha(), c2.getAlpha(), amount);
return new Color(
(int) (MathHelper.lerp(c1.red * c1.alpha, c2.red * c2.alpha, amount)/alpha),
(int) (MathHelper.lerp(c1.green * c1.alpha, c2.green * c2.alpha, amount)/alpha),
(int) (MathHelper.lerp(c1.blue * c1.alpha, c2.blue * c2.alpha, amount)/alpha),
alpha);
}
/**
* Smooth interpolation between two colors.
*
* @param value1
* @param value2
* @param amount the amount to interpolate [0.0, 1.0].
* @return a new interpolated color.
*/
public static final Color smoothStep(Color value1, Color value2, double amount) {
return new Color(
(int) MathHelper.smoothStep(value1.getR(), value2.getR(), amount),
(int) MathHelper.smoothStep(value1.getG(), value2.getG(), amount),
(int) MathHelper.smoothStep(value1.getB(), value2.getB(), amount),
MathHelper.smoothStep(value1.getAlpha(), value2.getAlpha(), amount));
}
/**
* Gets the string representation of the color.
*/
public final String getColorCode() {
return colorCode;
}
/**
* Gets the value of the red channel.
*
* @return a value between 0 to 255, inclusive.
*/
public final int getR() {
return red;
}
/**
* Gets the value of the green channel.
*
* @return a value between 0 to 255, inclusive.
*/
public final int getG() {
return green;
}
/**
* Gets the value of the blue channel.
*
* @return a value between 0 to 255, inclusive.
*/
public final int getB() {
return blue;
}
/**
* Gets the value of the alpha channel.
*
* @return a value between 0.0 to 1.0, inclusive.
*/
public final double getAlpha() {
return alpha;
}
/**
* Return the color code (identical to getColorCode).
*/
@Override
public final String toString() {
return getColorCode();
}
// regular expressions for parsing a color
private static RegExp PatternRGBA = RegExp.compile("rgba\\(\\s*([0-9]+)\\s*,\\s*([0-9]+)\\s*,\\s*([0-9]+)\\s*,\\s*([0-9]*\\.?[0-9]+)\\s*\\)"); // rgba
private static RegExp PatternRGB = RegExp.compile("rgb\\(\\s*([0-9]+)\\s*,\\s*([0-9]+)\\s*,\\s*([0-9]+)\\s*\\)"); // rgb
private static RegExp PatternHex = RegExp.compile("\\#([0-9a-fA-F][0-9a-fA-F])([0-9a-fA-F][0-9a-fA-F])([0-9a-fA-F][0-9a-fA-F])"); // html color code #XXXXXX
/**
* Parse a color from a color code.
*/
public static final Color parseColor(String s) {
// rgba pattern
MatchResult res = PatternRGBA.exec(s);
if (res != null && res.getGroupCount() == 5) return new Color(Integer.parseInt(res.getGroup(1)), Integer.parseInt(res.getGroup(2)), Integer.parseInt(res.getGroup(3)), Double.parseDouble(res.getGroup(4)));
// rgb pattern
res = PatternRGB.exec(s);
if (res != null && res.getGroupCount() == 4) return new Color(Integer.parseInt(res.getGroup(1)), Integer.parseInt(res.getGroup(2)), Integer.parseInt(res.getGroup(3)));
// hex pattern
res = PatternHex.exec(s);
if (res != null && res.getGroupCount() == 4) return new Color(Integer.parseInt(res.getGroup(1), 16), Integer.parseInt(res.getGroup(2), 16), Integer.parseInt(res.getGroup(3), 16));
// no match
return null;
}
@Override
public final boolean equals(Object obj) {
return (obj instanceof Color) ? equals((Color) obj) : false;
}
public final boolean equals(Color rhs) {
return getR() == rhs.getR() && getG() == rhs.getG() && getB() == rhs.getB()
&& getAlpha() == rhs.getAlpha();
}
@Override
public final int hashCode() {
return Arrays.hashCode(new double[]{getHexValue(red, green, blue), alpha});
}
/**
* Gets the integer value of the given rgb value.
*/
private final int getHexValue(int r, int g, int b) {
return ((r << 16) & 0xFF0000) | ((g << 8) & 0xFF00) | (b & 0xFF);
}
}