通过重写PolylineConnection.outlineShape()方法优化连线显示

最新推荐文章于 2025-01-18 16:02:57 发布

原创最新推荐文章于 2025-01-18 16:02:57 发布 · 842 阅读

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#布线优化 #outlineShape #PolylineConnection

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本文介绍了一种优化连线显示的方法，通过重写PolylineConnection的outlineShape()方法，在不改变线的数据情况下改变线的显示样式，避免了增加额外的位置数据和为创建线的handle增加负担。该方法全局生效，适用于连线水平竖直分布的情况。

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之前:通过修改线本身的位置的pointList 来实现.为连线增加拐角圆滑修饰.

这样有很多弊端.

后来发现这个方法分享给大家.

outlineShape()是根据线的pointList返回需要绘制线的pointList. 所以我们可以通过重写这个方法在不改变线数据的情况线,改变线的显示样式.

好处:1.不为连线增加额外的位置数据.(简化数据)

2. 不为创建线改变的handle增加负担

3.全局生效.

一下是代码: 限于连线时水平竖直分布的.

import org.eclipse.draw2d.Graphics;
import org.eclipse.draw2d.PolylineConnection;
import org.eclipse.draw2d.geometry.Point;
import org.eclipse.draw2d.geometry.PointList;

public class CustomPolylineConnection extends PolylineConnection {
	private static final int OFFSET = 2;

	@Override
	protected void outlineShape(Graphics g) {
		PointList points = getPoints();
		if (points.size() <= 2) {
			super.outlineShape(g);
		} else if (points.size() > 2)// 存在拐点的情况
		{
			PointList shoulderPoints = new PointList();
			shoulderPoints.addPoint(points.getFirstPoint());
			for (int i = 1; i < points.size() - 1; i++)// 遍历除两端的点,添加肩膀
			{
				Point forwardPoint = points.getPoint(i - 1);
				Point anglePoint = points.getPoint(i);
				Point nextPoint = points.getPoint(i + 1);
				if (forwardPoint.x == anglePoint.x) // 竖直线
				{
					if (forwardPoint.y < anglePoint.y) // 向下
					{
						shoulderPoints.addPoint(anglePoint.x, anglePoint.y
								- OFFSET);
					} else if (forwardPoint.y > anglePoint.y) // 向上
					{
						shoulderPoints.addPoint(anglePoint.x, anglePoint.y
								+ OFFSET);
					}

					// anglePoint 和 nextPoint是水平线
					if (anglePoint.x < nextPoint.x) { // 向右
						shoulderPoints.addPoint(anglePoint.x + OFFSET,
								anglePoint.y);
					} else if (anglePoint.x > nextPoint.x) // 向左
					{
						shoulderPoints.addPoint(anglePoint.x - OFFSET,
								anglePoint.y);
					}
				} else if (forwardPoint.y == anglePoint.y) // 水平线
				{
					if (forwardPoint.x < anglePoint.x) // 向右
					{
						shoulderPoints.addPoint(anglePoint.x - OFFSET,
								anglePoint.y);
					} else if (forwardPoint.x > anglePoint.x) // 向左
					{
						shoulderPoints.addPoint(anglePoint.x + OFFSET,
								anglePoint.y);
					}

					// anglePoint 和 nextPoint是竖直线
					if (anglePoint.y < nextPoint.y) { // 向下
						shoulderPoints.addPoint(anglePoint.x, anglePoint.y
								+ OFFSET);
					} else if (anglePoint.y > nextPoint.y) { // 向上
						shoulderPoints.addPoint(anglePoint.x, anglePoint.y
								- OFFSET);
					}
				}
			}
			shoulderPoints.addPoint(points.getLastPoint());
			g.drawPolyline(shoulderPoints);
		}
	}
}

效果图: 前面那条线是选中增加的handle 不会使创建handle逻辑复杂化