Flex坐标系统及转换

这些天简单重新玩了一下Flex，感受觉坐标这块挺有意思，下面译一下关于坐标的文档

????????flash和flex针对不同的目的，提供了3种不同的坐标系

????????? 全局的就是(stage级别的)

????????? 本地坐标系（组件级别的）

????????? 内容坐标系（相对于本地坐标系说的）

????这些坐标系的点是可以转换的，并且有相应的方法，看来adobe想得挺周到。我们一个一个的说一下

???

????全局

?????????? 这个坐标系的原点在整个flash舞台的左上角，MouseEvent实例的stageX,stageY就是这个坐标系中的值，

??? 本地

????????坐标原点是相对的组件的左上角，MouseEvent中的localX,localY就是相对这个坐标系说的，

????内容

????????这个东西比较抽象了UIComponent类实例的contentMouseX?和?contentMouseY?就是了，这个主要针对有滚动条的组件说的，有滚动条了，内容肯定不少，内容所占的区域的坐标就是这个坐标系了。

下面有个官方的图说明了三个坐标系的关系及位置：

坐标转换还有现成的方法

?

下面是一个小例子

<?xml version="1.0"?>
<!-- containers/intro/MousePosition.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
??? backgroundColor="white">
????
??? <mx:Script>
??????? <![CDATA[
????????? import mx.controls.Alert;

????????? // Handle the mouseDown event generated?
????????? // by clicking in the application.
????????? private function handleMouseDown(event:MouseEvent):void {
????????????????
??????????? // Convert the mouse position to global?coordinates.
??????????? // The localX and localY properties of the mouse event contain
??????????? // the?coordinates at which the event occurred relative to the
??????????? // event target,typically one of the?
??????????? // colored internal Canvas controls.
??????????? // A production version of this example could use the stageX?
??????????? // and stageY properties,which use the global?coordinates,?
??????????? // and avoid this step.
??????????? // This example uses the localX and localY properties only to
??????????? // illustrate conversion between different frames of reference.
??????????? var pt:Point = new Point(event.localX,event.localY);
??????????? pt = event.target.localToGlobal(pt);
????????????????
??????????? // Convert the global?coordinates to the content?coordinates?
??????????? // inside the outer c1 Canvas control.
??????????? pt = c1.globalToContent(pt);
???????????????
??????????? // Figure out which quadrant was clicked.
??????????? var whichColor:String = "border area";
??????????????
??????????? if (pt.x < 150) {
??????????????? if (pt.y < 150)
??????????????????? whichColor = "red";
??????????????? else
??????????????????? whichColor = "blue";
??????????? }
??????????? else {
??????????????? if (pt.y < 150)
??????????????????? whichColor = "green";
??????????????? else
??????????????????? whichColor = "magenta";
??????????? }
????????????????
??????????? Alert.show("You clicked on the " + whichColor);
????????? }
??????? ]]>
??? </mx:Script>

??? <!-- Canvas container with four child Canvas containers -->
??? <mx:Canvas id="c1"?
??????? borderStyle="none"?
??????? width="300" height="300"?
??????? mouseDown="handleMouseDown(event);">
????????
??????? <mx:Canvas?
??????????? width="150" height="150"?
??????????? x="0" y="0"?
??????????? backgroundColor="red">
??????????? <mx:Button label="I'm in Red"/>
??????? </mx:Canvas>
??????? <mx:Canvas?
??????????? width="150" height="150"?
??????????? x="150" y="0"
??????????? backgroundColor="green">
??????????? <mx:Button label="I'm in Green"/>
??????? </mx:Canvas>
??????? <mx:Canvas?
??????????? width="150" height="150"?
??????????? x="0" y="150"
??????????? backgroundColor="blue">
??????????? <mx:Button label="I'm in Blue"/>
??????? </mx:Canvas>
??????? <mx:Canvas?
??????????? width="150" height="150"?
??????????? x="150" y="150"
??????????? backgroundColor="magenta">
??????????? <mx:Button label="I'm in Magenta"/>
??????? </mx:Canvas>
??? </mx:Canvas>
</mx:Application>

我想大概就这些了，有兴趣的大家再研究研究，一起学哦

转载：http://blog.csdn.net/JavaTiger1/article/details/3289947