Fly*_*wat 6 c# algorithm flood-fill
这是周末,这意味着我可以玩我的爱好项目了.
我已经厌倦了手工创建测试级别,所以我想我会从引擎开发中休息并在级别编辑器上工作:
关卡编辑http://gfilter.net/junk/Editor.JPG
我想在编辑器中实现泛洪填充算法,它就像在绘图程序中一样工作.有没有人有任何关于哪种技术对我有用的指示？
级别只是一个2d数组,因此可以认为它与位图真的相同.
谢谢!
维基百科的文章非常好.只要您的网格很小,几乎任何东西都可以工作.
今年秋天早些时候,我在1000万像素扫描图像上做了一些洪水填充.(问题是要去除在复印机上扫描的书页的黑边.)在这种情况下,只有两种颜色,所以我基本上把问题看作是在无向图中搜索,每个像素连接到它的邻居四个指南针方向.我维护了一个单独的位图来跟踪访问过的像素.
主要调查结果如下
不要尝试递归深度优先搜索.你真的想要一个明确的数据结构.
辅助队列使用的空间比堆栈少得多.空间减少约四十倍.换句话说,更喜欢广度优先搜索到深度优先搜索.
同样,这些发现仅适用于具有多个百万像素的网格.在一个很好的小网格上,就像问题中显示的那样,任何简单的算法都应该有效.
我们必须为学校编程:
1: stuff the start pixel into a queue, note its color. note it as added.
2: begin picking a pixel off the queue. If it's similar to the start pixel:
2: put all its neighbours into the queue
for each added pixel, note it's added. if already noted for a pixel, don't
add it anymore.
3: color it with the destination color.
3: nonempty => jump back to 2
4: empty => we are finished
根据我们是8邻居还是4邻居,我们检查所有8个相邻像素,或仅检查某个像素左/右或上/下的像素.这是代码(使用ImageJ.我删除了一些不相关的代码).我希望它有意义,它是Java.只是提出问题:
public class Uebung1_2 implements PlugInFilter, MouseListener {
private ImageProcessor ip;
boolean[] state;
int[] pixels;
Queue<Integer> nextPixels;
int threshould;
/**
* adds one pixel to the next-pixel queue only if it's not
* already added.
*/
void addNextPixel(int p) {
if(!state[p]) {
nextPixels.add(p);
state[p] = true;
}
}
boolean pixelsSimilar(int color1, int color2) {
int dr = Math.abs(((color1 >> 16) & 0xff) -
((color2 >> 16) & 0xff));
int dg = Math.abs(((color1 >> 8) & 0xff) -
((color2 >> 8) & 0xff));
int db = Math.abs(((color1 >> 0) & 0xff) -
((color2 >> 0) & 0xff));
return ((double)(dr + dg + db) / 3.0) <= threshould;
}
/**
* actually does the hard work :)
* @param x the x position from which to start filling
* @param y the y position from which to start filling
*/
private void doFill(int x, int y, boolean connect8) {
// first, add the start pixel
int width = ip.getWidth(),
height = ip.getHeight();
/* for 8bit, we just gonna take the median of rgb */
Color colorC = ij.gui.Toolbar.getForegroundColor();
int color = colorC.getRGB();
int firstPixel = ip.get(x, y);
// go on with the mainloop
addNextPixel(y * width + x);
while(!nextPixels.isEmpty()) {
int nextPixel = nextPixels.remove();
int pixel = pixels[nextPixel];
if(pixelsSimilar(pixel, firstPixel)) {
// yay it matches. put the neighbours.
int xN = nextPixel % width,
yN = nextPixel / width;
/* the three pixels above */
if(yN - 1 >= 0) {
if(connect8) {
if(xN + 1 < width) {
addNextPixel(nextPixel - width + 1);
}
if(xN - 1 >= 0) {
addNextPixel(nextPixel - width - 1);
}
}
addNextPixel(nextPixel - width);
}
/* pixels left and right from the current one */
if(xN > 0) {
addNextPixel(nextPixel - 1);
}
if(xN + 1 < width) {
addNextPixel(nextPixel + 1);
}
/* three pixels below */
if(yN + 1 < height) {
if(connect8) {
if(xN + 1 < width) {
addNextPixel(nextPixel + width + 1);
}
if(xN - 1 >= 0) {
addNextPixel(nextPixel + width - 1);
}
}
addNextPixel(nextPixel + width);
}
/* color it finally */
pixels[nextPixel] = color;
}
}
}
@Override
public void run(ImageProcessor ip) {
ij.WindowManager.getCurrentImage().getCanvas().addMouseListener(this);
this.ip = ip;
this.pixels = (int[])ip.getPixels();
this.state = new boolean[ip.getPixelCount()];
this.nextPixels = new LinkedList<Integer>();
}
@Override
public int setup(String arg0, ImagePlus arg1) {
return DOES_RGB;
}
@Override
public void mouseClicked(MouseEvent e) {
ij.WindowManager.getCurrentWindow().getCanvas().removeMouseListener(this);
ij.gui.GenericDialog g = new GenericDialog("Please enter parameters");
g.addChoice("connection", new String[]{"4-connect", "8-connect"}, "8-connect");
g.addNumericField("Threshould (0..255)", 0.0, 3);
g.showDialog();
boolean connect8 = g.getNextChoice().equals("8-connect");
threshould = (int) g.getNextNumber();
doFill(e.getX(), e.getY(), connect8);
ij.WindowManager.getCurrentImage().draw();
}
}