Calculation of a mixed color in RGB
Based on this documented response and this alghoritm aware response, I have tryed a simple interface to mix colors using additive and substractive aproach.
You must confirm that primary colors of RGB and CMYK gives you the secondary colors in the first response diagrams:
- Red + Blue = Magenta (on additive)
- Yellow + Cyan = Green (on substractive)
- and so on ...
import javax.swing.*;
import javax.swing.border.BevelBorder;
import javax.swing.border.CompoundBorder;
import javax.swing.border.LineBorder;
import javax.swing.border.MatteBorder;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Hashtable;
import java.util.Vector;
/**
* Color Mixing alghoritms
* User: alberto
* Date: 29/01/13
* Time: 21:28
*/
public class ColorMix {
Vector<JLabel> firstMixColors;
Vector<JLabel> secondMixColors;
JComboBox/*<Mixer>*/ comboBox;
JLabel firstMixColor;
JLabel firstSel;
JLabel secondSel;
JLabel finalColor;
public ColorMix() {
firstMixColors = new Vector<JLabel>();
Vector<Mixer> mixers = new Vector<Mixer>();
mixers.add(new AdditiveMixer());
mixers.add(new SustractiveMixer());
mixers.add(new TertiaryMixer());
mixers.add(new DilutingSustractiveMixer());
comboBox = new JComboBox(new DefaultComboBoxModel(mixers));
firstMixColor = buildColorLabel();
firstSel = buildColorLabel();
secondSel = buildColorLabel();
secondMixColors = new Vector<JLabel>();
secondMixColors.add(firstSel);
secondMixColors.add(secondSel);
finalColor = buildColorLabel();
comboBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
calculateMixes();
}
});
buildGUI();
}
private JLabel buildColorLabel() {
JLabel label = new JLabel();
label.setOpaque(true);
label.setHorizontalAlignment(SwingConstants.CENTER);
label.setHorizontalTextPosition(SwingConstants.CENTER);
label.setBorder(BorderFactory.createLineBorder(Color.BLACK));
label.setPreferredSize(new Dimension(100,25));
return label;
}
public void buildGUI() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.setTitle("Mixing colors");
frame.setLayout(new GridBagLayout());
GridBagConstraints cc = new GridBagConstraints();
cc.fill = GridBagConstraints.BOTH;
cc.insets = new Insets(5, 5, 5, 5);
cc.weightx = .2;
cc.weighty = 1;
frame.getContentPane().add(buildColorPanel(0), cc);
frame.getContentPane().add(buildColorPanel(1), cc);
cc.gridy = 1;
JPanel firstMix = new JPanel(new GridBagLayout());
GridBagConstraints ccCol = new GridBagConstraints();
ccCol.fill = GridBagConstraints.BOTH;
ccCol.insets = new Insets(5, 5, 5, 5);
ccCol.weightx = 1;
ccCol.weighty = 1;
ccCol.gridx = 0;
ccCol.gridy = 0;
ccCol.gridheight = 2;
firstMix.add(firstMixColor, ccCol);
ccCol.fill = GridBagConstraints.HORIZONTAL;
ccCol.weightx = 0.2;
ccCol.weighty = 0.5;
ccCol.gridx = 1;
ccCol.gridy = 0;
ccCol.gridheight = 1;
ccCol.gridwidth = 1;
firstMix.add(new JButton(new AbstractAction("Set First") {
@Override
public void actionPerformed(ActionEvent e) {
setBackgroundToLabel(firstSel, firstMixColor.getBackground());
calculateMixes();
}
}), ccCol);
ccCol.gridx = 1;
ccCol.gridy = 1;
firstMix.add(new JButton(new AbstractAction("Set Second") {
@Override
public void actionPerformed(ActionEvent e) {
setBackgroundToLabel(secondSel, firstMixColor.getBackground());
calculateMixes();
}
}), ccCol);
firstMix.setBorder(BorderFactory.createTitledBorder("Secondary Colors"));
frame.getContentPane().add(firstMix, cc);
cc.weightx = .6;
JPanel panel = new JPanel(new GridBagLayout());
GridBagConstraints ccColor = new GridBagConstraints();
ccColor.fill = GridBagConstraints.BOTH;
ccColor.insets = new Insets(5, 5, 5, 5);
ccColor.weightx = 1;
ccColor.weighty = 1;
panel.add(firstSel, ccColor);
ccColor.gridx = 1;
panel.add(secondSel, ccColor);
ccColor.gridx = 0;
ccColor.gridy = 1;
ccColor.weighty = 0;
ccColor.gridwidth = 2;
panel.add(finalColor, ccColor);
ccColor.gridy = 2;
panel.add(comboBox, ccColor);
panel.setBorder(BorderFactory.createTitledBorder("Tertiary Colors"));
frame.getContentPane().add(panel, cc);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
new ColorMix();
}
private JComponent buildColorPanel(int selectedIndex) {
final JLabel pColor = buildColorLabel();
firstMixColors.add(pColor);
JPanel pSelectColor = new JPanel(new GridBagLayout());
GridBagConstraints cc = new GridBagConstraints();
cc.fill = GridBagConstraints.BOTH;
cc.insets = new Insets(5, 5, 5, 5);
cc.weightx = 1;
cc.weighty = 1;
final JSlider slidRed = buildSlider(pSelectColor, cc);
final JSlider slidGreen = buildSlider(pSelectColor, cc);
final JSlider slidBlue = buildSlider(pSelectColor, cc);
pSelectColor.add(pColor, cc);
final JComboBox comboColores = buildColorCombo();
comboColores.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
Color color = (Color) comboColores.getSelectedItem();
slidRed.setValue(color.getRed());
slidGreen.setValue(color.getGreen());
slidBlue.setValue(color.getBlue());
}
});
comboColores.setSelectedIndex(selectedIndex);
cc.gridy = 1;
cc.gridwidth = 4;
cc.weighty = 0;
pSelectColor.add(comboColores, cc);
ChangeListener changeListener = new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
setBackgroundToLabel(pColor, new Color(slidRed.getValue(), slidGreen.getValue(), slidBlue.getValue()));
calculateMixes();
}
};
slidRed.addChangeListener(changeListener);
slidGreen.addChangeListener(changeListener);
slidBlue.addChangeListener(changeListener);
pSelectColor.setBorder(BorderFactory.createBevelBorder(BevelBorder.LOWERED));
changeListener.stateChanged(null);
return pSelectColor;
}
private JComboBox buildColorCombo() {
Color TRANSPARENT = new Color(0, 0, 0, 0);
Vector<Color> colors = new Vector<Color>();
colors.add(new NamedColor(Color.RED, "Red"));
colors.add(new NamedColor(Color.GREEN, "Green"));
colors.add(new NamedColor(Color.BLUE, "Blue"));
colors.add(new NamedColor(Color.YELLOW, "Yellow"));
colors.add(new NamedColor(Color.MAGENTA, "Magenta"));
colors.add(new NamedColor(Color.CYAN, "Cyan"));
colors.add(new NamedColor(Color.WHITE, "White"));
colors.add(new NamedColor(Color.LIGHT_GRAY, "Light Gray"));
colors.add(new NamedColor(Color.GRAY, "Gray"));
colors.add(new NamedColor(Color.DARK_GRAY, "Dark Gray"));
colors.add(new NamedColor(Color.BLACK, "Black"));
colors.add(new NamedColor(Color.PINK, "Pink"));
colors.add(new NamedColor(Color.ORANGE, "Orange"));
colors.add(new NamedColor(TRANSPARENT, "transparent"));
//http://www.w3schools.com/css/css_colornames.asp
colors.add(new NamedColor(new Color(0xf0f8ff), "aliceblue"));
colors.add(new NamedColor(new Color(0xfaebd7), "antiquewhite"));
colors.add(new NamedColor(new Color(0x00ffff), "aqua"));
colors.add(new NamedColor(new Color(0x7fffd4), "aquamarine"));
colors.add(new NamedColor(new Color(0xf0ffff), "azure"));
colors.add(new NamedColor(new Color(0xf5f5dc), "beige"));
colors.add(new NamedColor(new Color(0xffe4c4), "bisque"));
colors.add(new NamedColor(new Color(0x000000), "black"));
colors.add(new NamedColor(new Color(0xffebcd), "blanchedalmond"));
colors.add(new NamedColor(new Color(0x0000ff), "blue"));
colors.add(new NamedColor(new Color(0x8a2be2), "blueviolet"));
colors.add(new NamedColor(new Color(0xa52a2a), "brown"));
colors.add(new NamedColor(new Color(0xdeb887), "burlywood"));
colors.add(new NamedColor(new Color(0x5f9ea0), "cadetblue"));
colors.add(new NamedColor(new Color(0x7fff00), "chartreuse"));
colors.add(new NamedColor(new Color(0xd2691e), "chocolate"));
colors.add(new NamedColor(new Color(0xff7f50), "coral"));
colors.add(new NamedColor(new Color(0x6495ed), "cornflowerblue"));
colors.add(new NamedColor(new Color(0xfff8dc), "cornsilk"));
colors.add(new NamedColor(new Color(0xdc143c), "crimson"));
colors.add(new NamedColor(new Color(0x00ffff), "cyan"));
colors.add(new NamedColor(new Color(0x00008b), "darkblue"));
colors.add(new NamedColor(new Color(0x008b8b), "darkcyan"));
colors.add(new NamedColor(new Color(0xb8860b), "darkgoldenrod"));
colors.add(new NamedColor(new Color(0xa9a9a9), "darkgray"));
colors.add(new NamedColor(new Color(0xa9a9a9), "darkgrey"));
colors.add(new NamedColor(new Color(0x006400), "darkgreen"));
colors.add(new NamedColor(new Color(0xbdb76b), "darkkhaki"));
colors.add(new NamedColor(new Color(0x8b008b), "darkmagenta"));
colors.add(new NamedColor(new Color(0x556b2f), "darkolivegreen"));
colors.add(new NamedColor(new Color(0xff8c00), "darkorange"));
colors.add(new NamedColor(new Color(0x9932cc), "darkorchid"));
colors.add(new NamedColor(new Color(0x8b0000), "darkred"));
colors.add(new NamedColor(new Color(0xe9967a), "darksalmon"));
colors.add(new NamedColor(new Color(0x8fbc8f), "darkseagreen"));
colors.add(new NamedColor(new Color(0x483d8b), "darkslateblue"));
colors.add(new NamedColor(new Color(0x2f4f4f), "darkslategray"));
colors.add(new NamedColor(new Color(0x2f4f4f), "darkslategrey"));
colors.add(new NamedColor(new Color(0x00ced1), "darkturquoise"));
colors.add(new NamedColor(new Color(0x9400d3), "darkviolet"));
colors.add(new NamedColor(new Color(0xff1493), "deeppink"));
colors.add(new NamedColor(new Color(0x00bfff), "deepskyblue"));
colors.add(new NamedColor(new Color(0x696969), "dimgray"));
colors.add(new NamedColor(new Color(0x696969), "dimgrey"));
colors.add(new NamedColor(new Color(0x1e90ff), "dodgerblue"));
colors.add(new NamedColor(new Color(0xb22222), "firebrick"));
colors.add(new NamedColor(new Color(0xfffaf0), "floralwhite"));
colors.add(new NamedColor(new Color(0x228b22), "forestgreen"));
colors.add(new NamedColor(new Color(0xff00ff), "fuchsia"));
colors.add(new NamedColor(new Color(0xdcdcdc), "gainsboro"));
colors.add(new NamedColor(new Color(0xf8f8ff), "ghostwhite"));
colors.add(new NamedColor(new Color(0xffd700), "gold"));
colors.add(new NamedColor(new Color(0xdaa520), "goldenrod"));
colors.add(new NamedColor(new Color(0x808080), "gray"));
colors.add(new NamedColor(new Color(0x808080), "grey"));
colors.add(new NamedColor(new Color(0x008000), "green"));
colors.add(new NamedColor(new Color(0xadff2f), "greenyellow"));
colors.add(new NamedColor(new Color(0xf0fff0), "honeydew"));
colors.add(new NamedColor(new Color(0xff69b4), "hotpink"));
colors.add(new NamedColor(new Color(0xcd5c5c), "indianred"));
colors.add(new NamedColor(new Color(0x4b0082), "indigo"));
colors.add(new NamedColor(new Color(0xfffff0), "ivory"));
colors.add(new NamedColor(new Color(0xf0e68c), "khaki"));
colors.add(new NamedColor(new Color(0xe6e6fa), "lavender"));
colors.add(new NamedColor(new Color(0xfff0f5), "lavenderblush"));
colors.add(new NamedColor(new Color(0x7cfc00), "lawngreen"));
colors.add(new NamedColor(new Color(0xfffacd), "lemonchiffon"));
colors.add(new NamedColor(new Color(0xadd8e6), "lightblue"));
colors.add(new NamedColor(new Color(0xf08080), "lightcoral"));
colors.add(new NamedColor(new Color(0xe0ffff), "lightcyan"));
colors.add(new NamedColor(new Color(0xfafad2), "lightgoldenrodyellow"));
colors.add(new NamedColor(new Color(0xd3d3d3), "lightgray"));
colors.add(new NamedColor(new Color(0xd3d3d3), "lightgrey"));
colors.add(new NamedColor(new Color(0x90ee90), "lightgreen"));
colors.add(new NamedColor(new Color(0xffb6c1), "lightpink"));
colors.add(new NamedColor(new Color(0xffa07a), "lightsalmon"));
colors.add(new NamedColor(new Color(0x20b2aa), "lightseagreen"));
colors.add(new NamedColor(new Color(0x87cefa), "lightskyblue"));
colors.add(new NamedColor(new Color(0x778899), "lightslategray"));
colors.add(new NamedColor(new Color(0x778899), "lightslategrey"));
colors.add(new NamedColor(new Color(0xb0c4de), "lightsteelblue"));
colors.add(new NamedColor(new Color(0xffffe0), "lightyellow"));
colors.add(new NamedColor(new Color(0x00ff00), "lime"));
colors.add(new NamedColor(new Color(0x32cd32), "limegreen"));
colors.add(new NamedColor(new Color(0xfaf0e6), "linen"));
colors.add(new NamedColor(new Color(0xff00ff), "magenta"));
colors.add(new NamedColor(new Color(0x800000), "maroon"));
colors.add(new NamedColor(new Color(0x66cdaa), "mediumaquamarine"));
colors.add(new NamedColor(new Color(0x0000cd), "mediumblue"));
colors.add(new NamedColor(new Color(0xba55d3), "mediumorchid"));
colors.add(new NamedColor(new Color(0x9370d8), "mediumpurple"));
colors.add(new NamedColor(new Color(0x3cb371), "mediumseagreen"));
colors.add(new NamedColor(new Color(0x7b68ee), "mediumslateblue"));
colors.add(new NamedColor(new Color(0x00fa9a), "mediumspringgreen"));
colors.add(new NamedColor(new Color(0x48d1cc), "mediumturquoise"));
colors.add(new NamedColor(new Color(0xc71585), "mediumvioletred"));
colors.add(new NamedColor(new Color(0x191970), "midnightblue"));
colors.add(new NamedColor(new Color(0xf5fffa), "mintcream"));
colors.add(new NamedColor(new Color(0xffe4e1), "mistyrose"));
colors.add(new NamedColor(new Color(0xffe4b5), "moccasin"));
colors.add(new NamedColor(new Color(0xffdead), "navajowhite"));
colors.add(new NamedColor(new Color(0x000080), "navy"));
colors.add(new NamedColor(new Color(0xfdf5e6), "oldlace"));
colors.add(new NamedColor(new Color(0x808000), "olive"));
colors.add(new NamedColor(new Color(0x6b8e23), "olivedrab"));
colors.add(new NamedColor(new Color(0xffa500), "orange"));
colors.add(new NamedColor(new Color(0xff4500), "orangered"));
colors.add(new NamedColor(new Color(0xda70d6), "orchid"));
colors.add(new NamedColor(new Color(0xeee8aa), "palegoldenrod"));
colors.add(new NamedColor(new Color(0x98fb98), "palegreen"));
colors.add(new NamedColor(new Color(0xafeeee), "paleturquoise"));
colors.add(new NamedColor(new Color(0xd87093), "palevioletred"));
colors.add(new NamedColor(new Color(0xffefd5), "papayawhip"));
colors.add(new NamedColor(new Color(0xffdab9), "peachpuff"));
colors.add(new NamedColor(new Color(0xcd853f), "peru"));
colors.add(new NamedColor(new Color(0xffc0cb), "pink"));
colors.add(new NamedColor(new Color(0xdda0dd), "plum"));
colors.add(new NamedColor(new Color(0xb0e0e6), "powderblue"));
colors.add(new NamedColor(new Color(0x800080), "purple"));
colors.add(new NamedColor(new Color(0xff0000), "red"));
colors.add(new NamedColor(new Color(0xbc8f8f), "rosybrown"));
colors.add(new NamedColor(new Color(0x4169e1), "royalblue"));
colors.add(new NamedColor(new Color(0x8b4513), "saddlebrown"));
colors.add(new NamedColor(new Color(0xfa8072), "salmon"));
colors.add(new NamedColor(new Color(0xf4a460), "sandybrown"));
colors.add(new NamedColor(new Color(0x2e8b57), "seagreen"));
colors.add(new NamedColor(new Color(0xfff5ee), "seashell"));
colors.add(new NamedColor(new Color(0xa0522d), "sienna"));
colors.add(new NamedColor(new Color(0xc0c0c0), "silver"));
colors.add(new NamedColor(new Color(0x87ceeb), "skyblue"));
colors.add(new NamedColor(new Color(0x6a5acd), "slateblue"));
colors.add(new NamedColor(new Color(0x708090), "slategray"));
colors.add(new NamedColor(new Color(0x708090), "slategrey"));
colors.add(new NamedColor(new Color(0xfffafa), "snow"));
colors.add(new NamedColor(new Color(0x00ff7f), "springgreen"));
colors.add(new NamedColor(new Color(0x4682b4), "steelblue"));
colors.add(new NamedColor(new Color(0xd2b48c), "tan"));
colors.add(new NamedColor(new Color(0x008080), "teal"));
colors.add(new NamedColor(new Color(0xd8bfd8), "thistle"));
colors.add(new NamedColor(new Color(0xff6347), "tomato"));
colors.add(new NamedColor(new Color(0x40e0d0), "turquoise"));
colors.add(new NamedColor(new Color(0xee82ee), "violet"));
colors.add(new NamedColor(new Color(0xf5deb3), "wheat"));
colors.add(new NamedColor(new Color(0xffffff), "white"));
colors.add(new NamedColor(new Color(0xf5f5f5), "whitesmoke"));
colors.add(new NamedColor(new Color(0xffff00), "yellow"));
colors.add(new NamedColor(new Color(0x9acd32), "yellowgreen"));
JComboBox comboBox = new JComboBox(new DefaultComboBoxModel(colors));
comboBox.setRenderer(new DefaultListCellRenderer() {
protected Color backgroundColor = Color.BLACK;
{
setBorder(new CompoundBorder(
new MatteBorder(2, 5, 2, 5, Color.white)
, new LineBorder(Color.black)));
}
public Component getListCellRendererComponent(JList list, Object obj,
int row, boolean sel, boolean hasFocus) {
if (obj instanceof Color)
backgroundColor = (Color) obj;
setText(obj.toString());
return this;
}
public void paint(Graphics g) {
setBackground(backgroundColor);
super.paint(g);
}
});
return comboBox;
}
class NamedColor extends Color {
private String name;
NamedColor(Color color, String name) {
super(color.getRed(), color.getGreen(), color.getBlue());
this.name = name;
}
@Override
public String toString() {
return name;
}
}
private void calculateMixes() {
calculateFirstMix();
calculateSecondMix();
}
private void calculateFirstMix() {
calculateMix(firstMixColors, firstMixColor);
}
private void calculateSecondMix() {
calculateMix(secondMixColors, finalColor);
}
private void calculateMix(Vector<JLabel> mixColors, JLabel finalColor) {
Color bg = ((Mixer) comboBox.getSelectedItem()).calculateMix(mixColors);
setBackgroundToLabel(finalColor, bg);
}
private void setBackgroundToLabel(JLabel label, Color color) {
label.setBackground(color);
label.setText(color.getRed() + "," + color.getGreen() + "," + color.getBlue());
}
interface Mixer {
Color calculateMix(Vector<JLabel> colores);
}
/**
* Implement a additive mix of colors
*/
static class AdditiveMixer implements Mixer {
public Color calculateMix(Vector<JLabel> colores) {
int red = 0;
int green = 0;
int blue = 0;
for (int i = 0; i < colores.size(); i++) {
Color background = colores.get(i).getBackground();
red += background.getRed();
green += background.getGreen();
blue += background.getBlue();
}
return new Color(Math.min(255, red), Math.min(255, green), Math.min(255, blue));
}
@Override
public String toString() {
return "Additive";
}
}
/**
* Implement a sustractive mix of colors
*/
static class SustractiveMixer implements Mixer {
public Color calculateMix(Vector<JLabel> colores) {
int red = 1;
int green = 1;
int blue = 1;
for (int i = 0; i < colores.size(); i++) {
Color background = colores.get(i).getBackground();
red *= background.getRed();
green *= background.getGreen();
blue *= background.getBlue();
}
return new Color(Math.min(255, red / 255), Math.min(255, green / 255), Math.min(255, blue / 255));
}
@Override
public String toString() {
return "Sustractive";
}
}
/**
* Implement a diluting/sustractive mix of colors
*/
static class DilutingSustractiveMixer implements Mixer {
public Color calculateMix(Vector<JLabel> colores) {
int red = 0;
int green = 0;
int blue = 0;
for (int i = 0; i < colores.size(); i++) {
Color background = colores.get(i).getBackground();
red += Math.pow(255 - background.getRed(), 2);
green += Math.pow(255 - background.getGreen(), 2);
blue += Math.pow(255 - background.getBlue(), 2);
}
return new Color(Math.min(255, (int)Math.sqrt(red / colores.size())), Math.min(255, (int)Math.sqrt(green / colores.size())), Math.min(255, (int)Math.sqrt(blue / colores.size())));
}
@Override
public String toString() {
return "Diluting/Sustractive";
}
}
/**
* Implement a diluting/sustractive mix of colors
*/
static class TertiaryMixer implements Mixer {
public Color calculateMix(Vector<JLabel> colores) {
Color background1 = colores.get(0).getBackground();
int red = background1.getRed();
int green = background1.getGreen();
int blue = background1.getBlue();
Color background2 = colores.get(1).getBackground();
red -= background2.getRed();
green -= background2.getGreen();
blue -= background2.getBlue();
return new Color(Math.min(255, background1.getRed() - (red/2)), Math.min(255, background1.getGreen() - (green/2)), background1.getBlue() - (blue/2));
}
@Override
public String toString() {
return "Tertiary";
}
}
private JSlider buildSlider(JPanel container, GridBagConstraints upperCC) {
JPanel panel = new JPanel(new GridBagLayout());
GridBagConstraints cc = new GridBagConstraints();
cc.fill = GridBagConstraints.BOTH;
cc.insets = new Insets(5, 5, 5, 5);
cc.weightx = 1;
cc.weighty = 0.7;
final JSlider slider = new JSlider(JSlider.VERTICAL, 0, 255, 0);
slider.setFont(new Font("Serif", Font.PLAIN, 4));
Hashtable<Integer, JLabel> labels = new Hashtable<Integer, JLabel>();
labels.put(0, new JLabel("0"));
labels.put(128, new JLabel("128"));
labels.put(255, new JLabel("255"));
panel.add(slider, cc);
final JTextField field = new JTextField();
field.setEditable(false);
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
field.setText(String.valueOf(slider.getValue()));
}
});
cc.gridx = 0;
cc.gridy = 1;
cc.weighty = 0;
panel.add(field, cc);
slider.setLabelTable(labels);
slider.setPaintLabels(true);
container.add(panel, upperCC);
return slider;
}
}
Basically, This operations are like logic AND and logic OR. (Well not exactly)
- On additive alghoritm, the colors overlap, but for every primary it can only be 255 (Logic OR operation)
- On Substractive alghoritm, if some primary is not present, the result will not have that (CYAN has no RED, YELLOW has no BLUE: you get GREEN) (Logic AND Operation)
Based on this you can obtain tertiary colors from mix of primary and secundary colors, so I make a tiny implementation which works pretty well:
NewColor.R = Color1.R - (Color1.R - Color2.R)/2
NewColor.G = Color1.G - (Color1.G - Color2.G)/2
NewColor.B = Color1.B - (Color1.B - Color2.B)/2
There is also an diluting/substractive alghoritm mentioned on second cited response, but I cannot say what It is based on, just added to test.
The best explanation is that the RGB color model is somewhat unintuitive for us humans.
It's perfectly logical for a video display device (such as a monitor or television) that only knows how to display colors by mixing varying amounts of 3 pre-defined colors: red, green, and blue. But that's not how you and I learned to mix colors in grade school.
In RGB, the color white is represented as (255, 255, 255), which equates to "all on." The full value for each of the red, green, and blue color components is displayed, which creates such a high light intensity that we perceive the color as white. Conversely, the color black (0, 0, 0) is the "default" state of the display device—when no color light is displayed ("0"), the result is black, or the absence of color.
When you fully mix yellow (255, 255, 0) and blue (0, 0, 255), you get the color represented by (255, 255, 255), or white. When you multiply white by 0.5, you get a gray color, because 255 * 0.5 = 127.
It's probably more of an anomaly than anything that you get the expected result when mixing red and yellow. Red + yellow is (510, 255, 0), so when you multiply that by 0.5, you get orange (255, 127, 0).
It turns out that what you and I learned in grade school is really more accurately known as a subtractive color model, versus the additive color model used by RGB. Looking at the two diagrams at the bottom, you'll see the RGB color model (additive) on the left, versus the CMYK color model (subtractive) on the right. You should be able to immediately see the problem. Using a subtractive color model instead will produce the results that you want.
EDIT: Of course, that's easier said than done. That is, even if you adopt the CMYK color model instead of RGB (which is already difficult, because conversions from RGB to CMYK are heavily device-dependent and far from straightforward), this will probably still not satisfy the urge to mix pure blue (0, 0, 255) with pure yellow (255, 255, 0) and get green. CMYK uses cyan, magenta, and yellow as the 3 primary colors, instead of red, yellow, and blue. And you have a lot of work ahead of you if you want to go about implementing the RYB color model in the language of your choice.
I don't know of any such algorithm to combine RGB colors realistically. I was attempting in my answer to explain why it would be impossible, or extremely difficult at the very least. You could leave this question open a few more days and see if anyone else has any ideas, but I'd go ahead and start on that look-up table if you need to stick with the RGB model. ;-)