要求如下:
我们需要将值映射到颜色。所以每个离散值都会有一种颜色。
我们允许用户指定 maxColor
但 NO minColor
但允许他们指定表示色度数的 bin 数。因此,如果选择的 maxColor
是 Color.GREEN
并且 bins= 5
,那么我们希望选择的颜色有 5 种绿色阴影因为最大是最暗的,其余四个将按亮度增加的顺序排列。
//Give me a list of 5 shades of Green with the first argument being the darkest.
List<Color> greenShades = calculateShades(Color.GREEN,5);
//Give me a list of 7 shades of RED with the first argument being the darkest.
List<Color> greenShades = calculateShades(Color.RED,7);
我在用 Java 编码时将问题标记为 Java。但我知道它只是一种算法。因此,用其他语言(如 JavaScript)实现此实现的实现/想法也是可以接受的。
最佳答案
基本概念围绕着基于源的一小部分生成颜色的想法......
也就是说,如果您想要 5 个波段,则每个波段的强度将是最后一个波段强度的 1/5...
public List<Color> getColorBands(Color color, int bands) {
List<Color> colorBands = new ArrayList<>(bands);
for (int index = 0; index < bands; index++) {
colorBands.add(darken(color, (double) index / (double) bands));
}
return colorBands;
}
public static Color darken(Color color, double fraction) {
int red = (int) Math.round(Math.max(0, color.getRed() - 255 * fraction));
int green = (int) Math.round(Math.max(0, color.getGreen() - 255 * fraction));
int blue = (int) Math.round(Math.max(0, color.getBlue() - 255 * fraction));
int alpha = color.getAlpha();
return new Color(red, green, blue, alpha);
}
作为一个快速而讨厌的例子......
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSlider;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class ColorBands {
public static void main(String[] args) {
new ColorBands();
}
public ColorBands() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JPanel bandsPane;
private JSlider slider;
private Timer changeTimer;
public TestPane() {
bandsPane = new JPanel(new GridBagLayout());
slider = new JSlider(1, 100);
setLayout(new BorderLayout());
add(new JScrollPane(bandsPane));
add(slider, BorderLayout.SOUTH);
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
changeTimer.restart();
}
});
changeTimer = new Timer(250, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
int bands = slider.getValue();
List<Color> bandsList = getColorBands(Color.RED, bands);
bandsPane.removeAll();
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.insets = new Insets(1, 1, 1, 1);
for (Color color : bandsList) {
bandsPane.add(new ColorBand(color), gbc);
}
gbc.weighty = 1;
bandsPane.add(new JPanel(), gbc);
revalidate();
repaint();
}
});
changeTimer.setRepeats(false);
slider.setValue(1);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
public List<Color> getColorBands(Color color, int bands) {
List<Color> colorBands = new ArrayList<>(bands);
for (int index = 0; index < bands; index++) {
colorBands.add(darken(color, (double) index / (double) bands));
}
return colorBands;
}
public static Color darken(Color color, double fraction) {
int red = (int) Math.round(Math.max(0, color.getRed() - 255 * fraction));
int green = (int) Math.round(Math.max(0, color.getGreen() - 255 * fraction));
int blue = (int) Math.round(Math.max(0, color.getBlue() - 255 * fraction));
int alpha = color.getAlpha();
return new Color(red, green, blue, alpha);
}
public class ColorBand extends JPanel {
public ColorBand(Color color) {
setBackground(color);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(100, 20);
}
}
}
关于java - 按暗度递减顺序显示相同颜色的 n 个不同阴影的算法,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/18605410/