我如何用线性插值和链表来制作颜色渐变

Question

我目前正在尝试使彩虹轨迹跟随您的鼠标。我用Linkedlist来绘制我的鼠标点，以便追踪。轨迹本身看起来很完美，只是轨迹上的颜色看起来不对。我想让他们慢慢融入彼此。有人告诉我使用线性插值，在研究了一段时间后，似乎它会工作，我只是不知道如何实现它。

这是我到目前为止的代码:

import impsoft.bots.ColorBot;
import impsoft.scripting.ibot.interfaces.AutoPaint;
import impsoft.scripting.types.ColorScript;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.util.Deque;
import java.util.LinkedList;
import impsoft.scripting.ibot.structs.XY;
import impsoft.scripting.types.ColorSkeltonScriptable;
import impsoft.scripting.types.parallel.scriptjobs.ScriptJob;

public class MouseTrail extends ColorScript implements AutoPaint {
     public MouseTrail(ColorBot c) {
      super(c);
     }
    public void script() throws InterruptedException {
     while(true) {
         mt.setSize(500);
         mt.exec();
      sleep(100);
     }
    }
    public static String name = "Mouse trail test";
    public static String author = "Llaver";
    public static String description = "test for mouse trail";
    public static double version = 1.00;

public class MouseTrail2 extends ScriptJob implements AutoPaint {

    private int size;
    private final ColorSkeltonScriptable cs;
    private final Deque<XY> trail = new LinkedList<XY>();
    private final Color[] rainbow = new Color[]{
            Color.RED, Color.YELLOW, Color.GREEN, Color.CYAN, Color.BLUE, Color.magenta
        };
    public MouseTrail2(ColorSkeltonScriptable cs) {
        super(cs);
        this.cs = cs;
    }
    public void setSize(int s) {
        size = s;
        s = 200;
    }
    public void runV() {
        try {
            while (true) {
                synchronized (trail) {
                    if (trail.size() >= size) {
                        trail.pop();
                    }
                    trail.offer(cs.getCurrentMouseXY());
                }
                sleep(1);
            }
        } catch (InterruptedException e) {
        }
    }
    @Override
    public void paint(Graphics g) {
        final Graphics2D g2d = (Graphics2D) g;
        g2d.setStroke(new BasicStroke(3, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND));
        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        synchronized (trail) {
                float perc;
                int idx;
                for(int i = 1 ; i < trail.size() - 1 ; i++){
        XY current = ((LinkedList<XY>) trail).get(i);
        XY next = ((LinkedList<XY>) trail).get(i - 1);
        perc = ((float)i / trail.size()) * 100f;
       idx = Math.round((perc * (float)rainbow.length) / 100f);
       if(idx >= rainbow.length)idx -= 1;       
       g2d.setColor(rainbow[idx]);
        g.drawLine(current.x, current.y, next.x, next.y);
    }
            }
        }
    }

@Override
public void paint(Graphics arg0) {  
}
private MouseTrail2 mt = new MouseTrail2(this);
}

一些图片:

这是我现在拥有的:

http://img11.imageshack.us/img11/3031/mousetrailhavenow.png

这就是我想要得到的:

http://img594.imageshack.us/img594/7381/mousetrailtryingtoget.png

这样能让我更清楚一点吗?

Answer 1

为了得到你想要的效果，你可能需要创建一个自定义的渐变绘画，沿着一个轴跨越色相的色域，沿着另一个轴跨越alpha透明度的范围。作为一个相关的例子，这个KineticModel使用一个RadialGradientPaint来创建一个GradientImage实例数组。在每张图像中，alpha从中心的0xff(1.0)到外围的0x3f(0.25)呈径向变化。

附录:根据您的图片，只需将图形上下文的Stroke设置为合适的宽度，将油漆设置为颜色查找表(clut)和drawLine()中的下一个色调。你可以改变色调，保持饱和度和亮度不变。

float N = 360;
Queue<Color> clut = new LinkedList<Color>();
for (int i = 0; i < N; i++) {
    clut.add(Color.getHSBColor(i / N, 1, 1));
}

你必须决定何时根据空间或时间改变颜色。对于后者，javax.swing.Timer是个不错的选择。