Question

我在这里显然错过了一个重要的概念。我已经使用鼠标事件编写代码来在现有的BufferedImage上绘制边界（多边形）。以下是相关部分：

public void paintComponent(Graphics g) 
{
    super.paintComponent(g);  //Paint parent's background

    //G3 displays the BufferedImage "Drawing" with each paint
    Graphics2D G3 = (Graphics2D)g;
    G3.drawImage(this.Drawing, 0, 0, null);
    G3.dispose();
} 

public void updateDrawing()
{               
    int x0, y0, x1, y1; // Vertex coordinates
    Line2D.Float seg;
    // grafix is painting the mouse drawing to the BufferedImage "Drawing"     
    if(this.pts.size() > 0)
    {                   
        for(int ip = 0; ip < pts.size(); ip++)
        {
            x0 = (int)this.pts.get(ip).x;
            y0 = (int)this.pts.get(ip).y;
            this.grafix.drawRect(x0 - this.sqw/2, y0 - this.sqh/2, + this.sqw, this.sqh);
            if (ip > 0)
            {
                x1 = (int)this.pts.get(ip-1).x;
                y1 = (int)this.pts.get(ip-1).y; 
                this.grafix.drawLine(x1, y1, x0, y0);
                seg = new Line2D.Float(x1, y1, x0, y0);
                this.segments.add(seg);
            }
        }
    }
    repaint();
}

接下来的两个例程由鼠标事件调用：左键单击获取下一个点，右键单击关闭该区域。

public void getNextPoint(Point2D p)
{
    this.isDrawing = true;
    Point2D.Float next = new Point2D.Float();
    next.x = (float) p.getX();
    next.y = (float) p.getY();
    this.pts.add(next);
    updateDrawing();
}

public void closeBoundary()
{
    //Connects the last point to the first point to close the loop
    Point2D.Float next = new Point2D.Float(this.pts.get(0).x, this.pts.get(0).y);
    this.pts.add(next);
    this.isDrawing = false;
    updateDrawing();
}

一切正常，我可以用我的绘图保存图像： image with drawing 顶点列表（pts）和线段（段）都是描述区域/形状/多边形的。我希望仅从原始图像中提取包含在边界内的区域。也就是说，我计划通过移动所有像素来创建一个新的BufferedImage，测试它们是否属于图中并保留它们。所以我想根据我在绘制形状时收集的点和段创建一个AREA。一切都说：创建一个AREA变量和＆＃34; getPathIterator＆＃34;。但是什么形状？我的AREA变量将为空。路径迭代器如何访问列表中的点？

我也遍布文学和本网站。我错过了什么。

Answer 1

感谢haraldK的建议。在我看到你的帖子之前，我得出了类似的结论：使用绘制操作中顶点的Arraylist，我通过循环遍历在“绘制”操作期间创建的点列表来填充称为“轮廓”的“Path2D.Float”对象。使用这个“轮廓”对象，我实例化了一个名为“干涉图”的区域。为了检查我的工作，我从区域创建了另一个PathIterator，“PI”，并将区域“干涉图”分解为“段”，将结果发送到控制台。我展示了以下代码：

private void mnuitmKeepInsideActionPerformed(java.awt.event.ActionEvent evt)                                                 
{                                                     
    // Keeps the inner area of interest
    // Vertices is the "pts" list from Class MouseDrawing (mask)
    // It is already a closed path
    ArrayList<Point2D.Float> vertices = 
            new ArrayList<>(this.mask.getVertices()); 
    this.contour = new Path2D.Float(Path2D.WIND_NON_ZERO);

    // Read the vertices into the Path2D variable "contour"
    this.contour.moveTo((float)vertices.get(0).getX(), 
        (float)vertices.get(0).getY()); //Starting location

    for(int ivertex = 1; ivertex < vertices.size(); ivertex++)
    {
        this.contour.lineTo((float)vertices.get(ivertex).getX(), 
            (float)vertices.get(ivertex).getY());                           
    }      
    this.interferogram = new Area(this.contour);        
    PathIterator PI = this.interferogram.getPathIterator(null);

    //Test print out the segment types and vertices for debug
    float[] p = new float[6];
    int icount = 0;
    while( !PI.isDone())
    {
        int type = PI.currentSegment(p);
        System.out.print(icount);
        System.out.print(" Type " + type);
        System.out.print(" X " + p[0]);
        System.out.println(" Y " + p[1]);
        icount++;
        PI.next();
    }

    BufferedImage masked = Mask(this.image_out, this.interferogram);
    // Write image to file for debug
    String dir;
    dir = System.getProperty("user.dir");
    dir = dir + "\\00masked.png";
    writeImage(masked, dir, "PNG");

}

接下来，我使用以下代码将遮罩应用于测试每个像素的图像以包含在该区域中：

public BufferedImage Mask(BufferedImage BIM, Area area)
{
    /** Loop through the pixels in the image and test each one for inclusion
    *   within the area.
    *   Change the colors of those outside
    **/

    Point2D p = new Point2D.Double(0,0);
    // rgb should be white
    int rgb = (255 << 24);
    for (int row = 0; row < BIM.getWidth(); row++)
    {
        for (int col = 0; col < BIM.getHeight(); col++)
        {
            p.setLocation(col, row);
            if(!area.contains(p))
            {
                BIM.setRGB(col, row, rgb);
            }
        }
    }
    return BIM;
}
public static BufferedImage deepCopy(BufferedImage B2M) 
{
    ColorModel cm = B2M.getColorModel();
    boolean isAlphaPremultiplied = cm.isAlphaPremultiplied();
    WritableRaster raster = B2M.copyData(B2M.getRaster()
            .createCompatibleWritableRaster());
    return new BufferedImage(cm, raster, isAlphaPremultiplied, null);
}

这很漂亮（我很惊讶！）除了一个细微的细节：该区域的线条出现在蒙面图像的外面。为了解决这个问题，我在绘画操作之前复制了原始（调整大小）的图像。非常感谢user1050755（2014年11月）我在本网站上发现的常规 deepCopy 。将我的蒙版应用于复制的图像会导致我想要的原始图像部分没有蒙版线。结果如附图所示。我被激怒了！ masked image

如何使用PathIterator创建Area对象？

1 个答案: