我正在使用Adobe Flex 3构建图表工具。我即将实现连接线，我有一个问题。
想象一下，我在画布上的随机位置有2个正方形。我需要在它们之间画一条箭头连接线。我需要它倾向于目标广场的中心，但结束于它的边界。 alt text http://i44.tinypic.com/25tw4n4.jpg
如何找出画线之间的确切点？
谢谢
答案 0 :(得分：5)
这是一个做你想做的事的例子。
package
{
import flash.display.Shape;
import flash.display.Sprite;
import flash.events.Event;
import flash.geom.Matrix;
import flash.geom.Point;
import flash.ui.Mouse;
/**
* Sample class to draw squares and arrows between them.
*/
public class SquareArrows extends Sprite
{
/**
* Initialize the scene as soon as we can.
*/
public function SquareArrows()
{
if(stage) {
init();
}
else {
addEventListener(Event.ADDED_TO_STAGE, init);
}
}
/**
* Draw two squares and an arrow between them.
*/
private function init(e : Event = null) : void
{
if(hasEventListener(Event.ADDED_TO_STAGE)) {
removeEventListener(Event.ADDED_TO_STAGE, init);
}
// Drawing random-sized squares.
var squareOne : Shape =
getSquareShape((Math.random() * 50) + 20, 0xBBBBBB);
var squareTwo : Shape =
getSquareShape((Math.random() * 50) + 20, 0xDDDDDD);
addChild(squareOne);
addChild(squareTwo);
// Draw the connector.
var connector : Shape = getConnectorShape(squareOne, squareTwo);
addChild(connector);
}
/**
* Draw a connector arrow between two square shapes.
*/
private function getConnectorShape(connectFrom : Shape, connectTo : Shape) : Shape
{
// Getting the center of the first square.
var centerFrom : Point = new Point();
centerFrom.x = connectFrom.x + (connectFrom.width / 2);
centerFrom.y = connectFrom.y + (connectFrom.height / 2);
// Getting the center of the second square.
var centerTo : Point = new Point();
centerTo.x = connectTo.x + (connectTo.width / 2);
centerTo.y = connectTo.y + (connectTo.height / 2);
// Getting the angle between those two.
var angleTo : Number =
Math.atan2(centerTo.x - centerFrom.x, centerTo.y - centerFrom.y);
var angleFrom : Number =
Math.atan2(centerFrom.x - centerTo.x, centerFrom.y - centerTo.y);
// Getting the points on both borders.
var pointFrom : Point = getSquareBorderPointAtAngle(connectFrom, angleTo);
var pointTo : Point = getSquareBorderPointAtAngle(connectTo, angleFrom);
// Calculating arrow edges.
var arrowSlope : Number = 30;
var arrowHeadLength : Number = 10;
var vector : Point =
new Point(-(pointTo.x - pointFrom.x), -(pointTo.y - pointFrom.y));
// First edge of the head...
var edgeOneMatrix : Matrix = new Matrix();
edgeOneMatrix.rotate(arrowSlope * Math.PI / 180);
var edgeOneVector : Point = edgeOneMatrix.transformPoint(vector);
edgeOneVector.normalize(arrowHeadLength);
var edgeOne : Point = new Point();
edgeOne.x = pointTo.x + edgeOneVector.x;
edgeOne.y = pointTo.y + edgeOneVector.y;
// And second edge of the head.
var edgeTwoMatrix : Matrix = new Matrix();
edgeTwoMatrix.rotate((0 - arrowSlope) * Math.PI / 180);
var edgeTwoVector : Point = edgeTwoMatrix.transformPoint(vector);
edgeTwoVector.normalize(arrowHeadLength);
var edgeTwo : Point = new Point();
edgeTwo.x = pointTo.x + edgeTwoVector.x;
edgeTwo.y = pointTo.y + edgeTwoVector.y;
// Drawing the arrow.
var arrow : Shape = new Shape();
with(arrow.graphics) {
lineStyle(2);
// Drawing the line.
moveTo(pointFrom.x, pointFrom.y);
lineTo(pointTo.x, pointTo.y);
// Drawing the arrow head.
lineTo(edgeOne.x, edgeOne.y);
moveTo(pointTo.x, pointTo.y);
lineTo(edgeTwo.x, edgeTwo.y);
}
return arrow;
}
/**
* Utility method to get a point on a square border at a certain angle.
*/
private function getSquareBorderPointAtAngle(square : Shape, angle : Number) : Point
{
// Calculating rays of inner and outer circles.
var minRay : Number = Math.SQRT2 * square.width / 2;
var maxRay : Number = square.width / 2;
// Calculating the weight of each rays depending on the angle.
var rayAtAngle : Number = ((maxRay - minRay) * Math.abs(Math.cos(angle * 2))) + minRay;
// We have our point.
var point : Point = new Point();
point.x = rayAtAngle * Math.sin(angle) + square.x + (square.width / 2);
point.y = rayAtAngle * Math.cos(angle) + square.y + (square.height / 2);
return point;
}
/**
* Utility method to draw a square of a given size in a new shape.
*/
private function getSquareShape(edgeSize : Number, fillColor : Number) : Shape
{
// Draw the square.
var square : Shape = new Shape();
with(square.graphics) {
lineStyle(1);
beginFill(fillColor);
drawRect(0, 0, edgeSize, edgeSize);
endFill();
}
// Set a random position.
square.x = Math.random() * (stage.stageWidth - square.width);
square.y = Math.random() * (stage.stageHeight - square.height);
return square;
}
}
}
此代码未完全优化。这个想法更多的是解释它是如何工作的。基本上，我们定义了两个（随机）方块，并在它们之间描绘了一条线。为了跟踪线，我们计算从第一个方格的中心到第二个方格的中心的角度，我们使用特殊方法（getSquareBorderPointAtAngle）在方向边框上向右方向提取一个点。
此方法是此代码段的第一个关键点。我们使用简单的圆几何计算，稍微复杂化我们如何使点匹配边框而不是匹配方形周围或内部的圆。
然后，我们画一个箭头。为此，我们正在使用Flash Matrix类，因为这样做比从头开始计算要容易得多。
我们已经完成了。
答案 1 :(得分：4)
我一个月前在这里阅读答案，因为我需要同样的东西。在此期间找到此连接器绘图示例，并认为我将共享链接。
该示例绘制uicomponents之间的连接线，并在拖动连接器时更新线。好的！
alt text http://sammyjoeosborne.com/Images/connectorImage.jpg
http://sammyjoeosborne.com/Examples/Connector/ConnectorExample.html
答案 2 :(得分：-1)
最简单的事情可能是使用flash.geom.Point。取两个中心c1和c2。采取它们不同的向量d。根据其角度（315至45,45至135,135至225,225至315），您将知道涉及哪些侧面（分别为：左右，顶部和底部，左侧和右侧，底部和顶部）。
然后计算每一侧与连接中心的线之间的交叉点。
连接中心的线可以表示为p=t*v+c1（以向量说话）。将边表示为一条线然后计算t，使得两个方程产生相同的点p，这是您正在寻找的交点。
