Paper.js中的事件处理程序 [英] Event handlers in Paper.js
问题描述
我是Paper.js的新手,在阅读教程时,我对事件系统感到惊奇。
这就是教程中描述的事件处理:
var path;
函数onMouseDown(event){
//创建路径:
path = new Path();
path.strokeColor ='black';
//添加鼠标位置:
path.add(event.point);
function onMouseUp(event){
//增加鼠标位置:
path.add(event.point);
$ b $ p
$ b $ p所以,它在全局名字空间中的作用...
最终我有几个关于它的问题,并且我没有在互联网上发现任何东西:
- 如何将事件处理程序绑定到特定画布?
- 如何绑定如何将多个事件处理程序绑定到某个东西?
解决方案您可以使用attach()方法(或其在jQuery风格的别名on())上绑定多个事件处理程序。您可以使用detach()或off()来删除它们。这里有一个来自事件处理文档< a>:
//在视图中心创建一个圆形路径:
var path = new Path .Circle({
center:view.center,
radius:25,
fillColor:'black'
});
var shiftPath = function(){
this.position + = new Point(15,15);
};
//当鼠标进入该项目时,将其填充颜色设置为红色:
path.attach('mouseenter',function(){
this.fillColor ='red ';
});
path.on('mouseenter',shiftPath);
//当鼠标离开物品时,将其填充颜色设置为黑色
//并移除移动器功能:
path.on('mouseleave',function() {
this.fillColor ='black';
path.detach('mouseenter',shiftPath);
});
如果您想为某类对象的所有实例设置事件处理函数,最好创建一个工厂函数,按照这个答案 。
I am new to Paper.js, and I was wondered by the event system, while reading tutorial.
Thats how event hanling described in tutorial:
var path;
function onMouseDown(event) {
// Create a path:
path = new Path();
path.strokeColor = 'black';
// Add the mouse down position:
path.add(event.point);
}
function onMouseUp(event) {
// Add the mouse up position:
path.add(event.point);
}
So, its just functions in global namespace...
Eventually I have a few questions about it, and I didnt found anything on the internet on this:
- How to bind event handler to particular canvas?
- How to bind event handler to particular "object" (raster image, rectangle, etc)?
- How to bind multiple event handlers to something?
解决方案 You can bind multiple event handlers using the attach() method (or its jQuery-style alias, on()). You can remove them with detach() or off(). Here's a modified example from the event handling documentation:
// Create a circle shaped path at the center of the view:
var path = new Path.Circle({
center: view.center,
radius: 25,
fillColor: 'black'
});
var shiftPath = function() {
this.position += new Point(15,15);
};
// When the mouse enters the item, set its fill color to red:
path.attach('mouseenter', function() {
this.fillColor = 'red';
});
path.on('mouseenter', shiftPath);
// When the mouse leaves the item, set its fill color to black
// and remove the mover function:
path.on('mouseleave', function() {
this.fillColor = 'black';
path.detach('mouseenter', shiftPath);
});
If you want to set an event handler for all instances of a type of object, it's best to create a factory function, as per this answer.
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