java - 使用线条创建填充桶工具

Question

我想使用我拥有的线条类为我的程序制作一个填充桶工具。我的填充桶会记录填充一个区域所需绘制的所有线条，例如:

/image/FJx3j.png - 在此图像中，我点击的点是红色圆圈，它会为每条线找到 2 个点(起点和终点)。我显然没有画出所有的线条，但这就是我所拥有的基本概念。

我遇到的问题是图像最终看起来像这样，但我不明白为什么。 /image/1o1Sb.jpg

这是我查找到目前为止所有行的代码:

公共(public)类 FillBucket{

private BufferedImage image;
private Fill currentFill;
private Line currentLine;

private Queue<Point> pointsToVisit;

@Override
public void mousePressed(Point point) {
    super.mousePressed(point);

    if(pointIsOnCanvas(point)) {
        image = new BufferedImage(getCanvas().getPreferredSize().width, getCanvas().getPreferredSize().height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = (Graphics2D) image.getGraphics();
        getCanvas().paint(g2);

        currentFill = new Fill(getColor());
        pointsToVisit = new LinkedList<>();
        createPoints(point, image.getRGB(point.x, point.y));

        getCanvas().addDrawable(currentFill);
        getCanvas().repaint();
    }
}

private void createPoints(Point clickedPoint, int clickedColor) {
    pointsToVisit.add(clickedPoint);

    while(!pointsToVisit.isEmpty()) {
        Point testPoint = pointsToVisit.poll();

        if(testPoint.x > 0 && testPoint.x < image.getWidth() && testPoint.y > 0 && testPoint.y < image.getHeight() 
                && image.getRGB(testPoint.x, testPoint.y) == clickedColor) {
            while(testPoint.x > 0 && image.getRGB(testPoint.x, testPoint.y) == clickedColor) {
                testPoint.x--;
            }
            currentLine = new Line(getColor(), 5);
            currentLine.addPoint(new Point(testPoint));
            while(testPoint.x < image.getWidth() && image.getRGB(testPoint.x, testPoint.y) == clickedColor) {
                pointsToVisit.add(new Point(testPoint.x, testPoint.y+1));
                pointsToVisit.add(new Point(testPoint.x, testPoint.y-1));

                image.setRGB(testPoint.x, testPoint.y, getColor().getRGB());
                testPoint.x++;
            }
            currentLine.addPoint(new Point(testPoint));
            currentFill.addLine(currentLine);
        }
    }
}

}

这是我的线路类的基础知识:

public class Line {
private List<Point> points;
private int width;

/**
 * Create a Line
 * @param color - The color of the line
 * @param width - The width of the line
 */
public Line(Color color, int width){
    points = new LinkedList<>();
    setColor(color);
    setWidth(width);
}

/**
 * Add a Point to the Line
 * @param p - The Point to add to the Line 
 */
public void addPoint(Point p) {
    points.add(p);
}

@Override
public void draw(Graphics2D g2) {
    super.draw(g2);
    g2.setStroke(new BasicStroke(getWidth(), BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
    for(int i=1; i<points.size(); i++)
        g2.drawLine(points.get(i-1).x, points.get(i-1).y, points.get(i).x, points.get(i).y);
}

}

这是我的 Fill 类:

public class Fill{

List<Line> lines;

/**
 * Create a Fill
 * @param color - The Color of the Fill
 */
public Fill(Color color){
    lines = new LinkedList<>();
    setColor(color);
}

/**
 * Add a Line to the Fill
 * @param l - The Line to add
 */
public void addLine(Line l) {
    lines.add(l);
}

@Override
public void draw(Graphics2D g2) {
    super.draw(g2);
    for(Line l: lines) {
        l.draw(g2);
    }
}

如有任何帮助，我们将不胜感激，谢谢。

Answer 1

您需要将 createPoints(...) 函数更改为如下所示:

private void createPoints(Point clickedPoint, int clickedColor) {
    pointsToVisit.add(clickedPoint);

    while(!pointsToVisit.isEmpty()) {
        Point testPoint = pointsToVisit.poll();

        if(testPoint.x >= 0 && testPoint.x < image.getWidth() && testPoint.y >= 0 && testPoint.y < image.getHeight() 
            && image.getRGB(testPoint.x, testPoint.y) == clickedColor) {
            while(testPoint.x > 0 && image.getRGB(testPoint.x-1, testPoint.y) == clickedColor) {
                testPoint.x--;
            }
            currentLine = new Line(getColor(), 5);
            currentLine.addPoint(new Point(testPoint));

            pointsToVisit.add(new Point(testPoint.x, testPoint.y+1));
            pointsToVisit.add(new Point(testPoint.x, testPoint.y-1));

            image.setRGB(testPoint.x, testPoint.y, getColor().getRGB());

            while(testPoint.x < image.getWidth()-1 && image.getRGB(testPoint.x+1, testPoint.y) == clickedColor) {
                pointsToVisit.add(new Point(testPoint.x, testPoint.y+1));
                pointsToVisit.add(new Point(testPoint.x, testPoint.y-1));

                image.setRGB(testPoint.x, testPoint.y, getColor().getRGB());
                testPoint.x++;
            }
            currentLine.addPoint(new Point(testPoint));
            currentFill.addLine(currentLine);
        }
    }
}

(我在 if 条件中撒了几个 = 符号，以便您也可以单击图像的左上角，还有几个 +1 和 -1 到您的 while 条件中以修复接下来描述的错误)

基本上，在第一个 while 循环之后发生的情况是，您要么位于图像的左边缘，在这种情况下一切正常，要么您的 testPoint 指向第一个不是的像素等于 clickedColor ，在这种情况下，您的第二个 while 循环将立即终止。

顺便说一句:如果您单击已设置为填充颜色的点(即，如果 clickedColor == getColor())，您的代码可能会锁定。