Java2D:用线剪裁图形对象

如果有更好的方法,我从来没有遇到过。我能想到的最好的办法就是用三角法使线宽更一致。

好吧,我没有使用setClip()方法就想出了一个很好的解决方案。它包括将背景绘制到中间Graphics2D对象,使用setComposite()指定如何遮罩像素,然后在顶部使用drawLine()绘制线条。一旦我有了这条线,我就通过drawImage把它画回到我原来的图形对象上。下面是一个例子:

BufferedImage mask = g2d.getDeviceConfiguration().createCompatibleImage(width, height, BufferedImage.TRANSLUCENT);
Graphics2D maskGraphics = (Graphics2D) mask.getGraphics();
maskGraphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

maskGraphics.setStroke(new BasicStroke(lineWidth));
maskGraphics.setPaint(Color.BLACK);

// Draw line onto mask surface first.
Point prev = line.get(0);
for(int i = 1; i < line.size(); i++)
{
    Point current = line.get(i);
    maskGraphics.drawLine(prev.x, prev.y, current.x, current.y);
        prev = current;
}

// AlphaComposite.SrcIn:    "If pixels in the source and the destination overlap, only the source pixels
//                          in the overlapping area are rendered."
maskGraphics.setComposite(AlphaComposite.SrcIn);

maskGraphics.setPaint(top);
maskGraphics.fillRect(0, 0, width, referenceY);

maskGraphics.setPaint(bottom);
maskGraphics.fillRect(0, referenceY, width, height);

g2d.drawImage(mask, null, 0, 0);
maskGraphics.dispose();

也许你可以用Stroke.createClippedShape来做这个?(可能需要使用一个区域将笔划形状从原始形状中加/减到原始形状,具体取决于您正试图执行的操作。