Farbe abziehen

[Network]

Hallo,

Ich habe festgestellt wenn man auf ein transparentes Bild die "fillRect()" Methode anwendet mit einer Farbe die Halbtransparent ist und dann nochmal, addieren sich die Farben.
Also man zeichnet ein blaues Quadrat darauf mit der Transparenz 10% und dann nochmal, ist auf dem Bild ein blaues Quadrat mit der Transparenz 20%.

Meine Frage: Geht das auch anderst herum? Also das man eine Farbe abzieht, anstatt sie hinzuzufügen.
=> Dass man wieder ein blaues Quadrat Transparenz 10% erhält.

Vielen Dank
Gruß TMN

 

[Marco13]

Man kann das AlphaComposite (Java Platform SE 6) setzen. Zugegeben: Ich finde die visuellen Auswirkungen dazu auch etwas... unintuitiv, und probiere dann einfach alle durch, bis ich den passenden Effekt habe Ein bißchen helfen die Bilder in der Mitte von glBlendFunc ? DGL Wiki

 

[Michael...]

Hier eine Demo zu den Wirkungsweisen der verschiedenen vordefinierten Kombinationsregeln aus Filthy Rich Clients, Addison Wesley Verlag bzw. Filthy Rich Clients

/*
 * Copyright (c) 2007, Romain Guy
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *   * Neither the name of the TimingFramework project nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import java.awt.AlphaComposite;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Composite;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.lang.reflect.Field;
import javax.swing.JComboBox;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

/**
 *
 * @author Romain Guy
 */
public class AlphaCompositesApplication extends JFrame {
    private CompositePainter painter;
    private JSlider opacity;
    private JComboBox composites;
    
    public AlphaCompositesApplication() {
        super("Alpha Composites");
        
        add(painter = new CompositePainter(), BorderLayout.CENTER);
        
        JPanel panel = new JPanel(new FlowLayout(FlowLayout.LEADING));
        panel.add(buildCompositeSelector());
        panel.add(buildOpacitySelector());
        add(panel, BorderLayout.SOUTH);
        
        setSize(400, 300);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    
    private Component buildOpacitySelector() {
        opacity = new JSlider(0, 100, 50);
        opacity.addChangeListener(new ChangeListener() {
            public void stateChanged(ChangeEvent changeEvent) {
                changeComposite();
            }
        });
        JPanel panel = new JPanel();
        panel.add(new JLabel("0%"));
        panel.add(opacity);
        panel.add(new JLabel("100%"));
        return panel;
    }
    
    private Component buildCompositeSelector() {
        composites = new JComboBox(new String[] {
            "CLEAR",
            "DST", "DST_ATOP", "DST_IN", "DST_OUT", "DST_OVER",
            "SRC", "SRC_ATOP", "SRC_IN", "SRC_OUT", "SRC_OVER",
            "XOR"
        });
        composites.setSelectedItem("SRC");
        composites.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent actionEvent) {
                changeComposite();
            }
        });
        return composites;
    }
    
    private void changeComposite() {
        String rule = composites.getSelectedItem().toString();
        try {
            Field ruleField = AlphaComposite.class.getDeclaredField(rule);
            AlphaComposite composite = AlphaComposite.getInstance(ruleField.getInt(null),
                (float) opacity.getValue() / 100.0f);
            painter.setComposite(composite);
        } catch (SecurityException ex) {
            ex.printStackTrace();
        } catch (NoSuchFieldException ex) {
            ex.printStackTrace();
        } catch (IllegalArgumentException ex) {
            ex.printStackTrace();
        } catch (IllegalAccessException ex) {
            ex.printStackTrace();
        }
    }
    
    private final class CompositePainter extends JComponent {
        private AlphaComposite composite = AlphaComposite.getInstance(
            AlphaComposite.SRC, 0.5f);

        @Override
        protected void paintComponent(Graphics g) {
            BufferedImage image = new BufferedImage(getWidth(), getHeight(),
                BufferedImage.TYPE_INT_ARGB);
            Graphics2D g2 = image.createGraphics();
            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
            
            g2.setColor(Color.BLUE);
            g2.fillRect(4 + (getWidth() / 4), 4, getWidth() / 2, getHeight() - 8);
            g2.setColor(Color.RED);
            g2.setComposite(composite);
            g2.fillOval(40, 40, getWidth() - 80, getHeight() - 80);
            g2.dispose();
            
            g.drawImage(image, 0, 0, null);
        }

        private void setComposite(AlphaComposite composite) {
            this.composite = composite;
            repaint();
        }
    }
    
    public static void main(String... args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new AlphaCompositesApplication().setVisible(true);
            }
        });
    }
}

 

[Network]

Das Programm hat sehr geholfen, Danke. Es hilft um einiges den Text dazu besser zu verstehen!