I found some discussions about doing this using the inject method, like this one https://groups.google.com/forum/#!topic/paperjs/16ToDJquig8
But I cannot find this method in the official doc. So what is the officially recommended way to add custom properties to Paperjs objects?
If you just want to add properties to an Item, you can use Item.data.
From paper.js documentation:
Item.data: A plain javascript object which can be used to store arbitrary data on the item.
Example:
var path = new Path();
path.data.remember = 'milk';
Related
TL;DR
Is PinView.prototype = _.extend(PinView.prototype, google.maps.OverlayView.prototype) the "proper" way to have a Backbone View inherit from another "class"?
Long read
We're redoing our site using Backbone and are working on including some mapping functionality.
I've got a Backbone view that handles placing <div>s onto specific points within the browser window; this seems like a natural thing to extend in order have Google's Map API place them on geographical coordinates.
According to the Google API, in order to generate a custom overlay you create a new object and set the prototype for that object to a new instance of google.maps.OverlayView. You then implement three functions on top of that object so that the object responds to:
onAdd
draw
onRemove
Where onAdd is responsible for generating the HTML and then applying it on top of the Map. This subsequently calls draw which positions the element correctly according to the LatLng pairs and bounds you've provided. onRemove gets called when you want to get rid of your layer.
So I've modified my View to include these three methods (which just call render and unrender and are bound to my collection). And then to make "the magic happen" I'm doing:
PinView.prototype = _.extend(PinView.prototype, google.maps.OverlayView.prototype)
Does this look right? I can post the code for the View and the Model on which it's based, but honestly, they're irrelevant to this example -- the code works and I'm able to place custom divs generated through Backbone model, view and controller components on the map without a issue, what I'm asking I guess (and maybe this question is more apropos for programmers.se, so let me know and I'll move it).
This seems to be the easiest way to make my PinView both a Backbone View and a Google Maps OverlayView, but I'm not 100% comfortable with prototypal inheritance to know if I'm doing something "wrong" or breaking something somewhere down the road.
Nice idea! I'm usually a bit sceptical about weather or not you're 'correct' when things work so if you haven't run into a showstopper and the overlays shows up and does what the're supposed to do I'd say you are.
One thing to check out closer, though:
This isn't (and can't) be "real" multiple inheritance - that concept isn't really relevant in a prototype based language: one implementation of a method will inevitable "win" and overwrite the other implementation, at least when using _.extend()
This means that if there are members or methods with the same names in Backbone.View and google.maps.OverlayView the one last in your _.extend() call will be the one that takes over. But when I inspect them using Chrome's Developer Tools I didn't see any obvious collision of this kind.
So my recommendation: continue using this, just test a lot. I'd love to see an example of this technique some time.
Ah! So I've been doing the above, but it's never felt right.
Then I found this discussion on a Backbone group which leads me to the following:
var MyView = (function(){
var view = function(){
Backbone.View.apply(this, arguments);
};
view.extend = Backbone.View.extend;
_.extend(view.prototype, Backbone.View.prototype, google.maps.OverlayView.prototype, [other prototypes...], { [VIEW DEFINITION] });
return view;
}());
This way if we need to override any of the definitions in a class we're extending from, we can since it's earlier in the _.extend chain (later definitions overwrite earlier definitions).
I'm working on 'extending' extend to keep track of the "parent" object's references that would be overridden and providing a method to call them still (like Python's super call). I haven't decided if this should be done through monkey-patching, an intercepter pattern (via underscore's _.tap() method or something else, but I think it'll add a lot of flexibility.
This would allow you to define an initialize view in your "parent" class which could be called by doing something like _.super('ParentClass', 'initialize'); at the end of the "child" class's initialize routine...
I have to change the data set displayed on a map according to selections on the page and I would like to do this by creating several marker layers then switching between them based on user input.
For some reason I cannot add a layer after the map has been rendered on the page, seems like it shouldn't be that hard I think I may have the syntax wrong since the way Drupal sets up the map is different from straight forward openlayers.
Can I not get the map object like
var map = Drupal.settings.openlayers.maps["openlayers-map-auto-id-0"];
then add and remove marker layers from it? maybe there's another way of getting it?
Any help appreciated,
- Chris
The Drupal OpenLayers module only stores settings in Drupal.settings.openlayers.maps.
What you need is something like this:
var ol = $('#openlayers-map-auto-id-0').data('openlayers');
var max_extent = ol.openlayers.getMaxExtent(); // Or some other OpenLayers method...
...
The actual OpenLayers instance (as well as a copy of the map-specific settings) are stored with jQuery's .data() method. When you call $('#map-id').data('openlayers') you'll get back an object with map and openlayers members that correspond to the map settings and the actual OL object instance, respectively.
You might want to consider writing an OL behavior to handle your use case -- check out the default behaviors provided by the Drupal OpenLayers module to get a sense of how this works.
I have a dropfilter defined using some bindable variables as parameters.
<mx:filters>
<mx:DropShadowFilter id="torinofilter" distance="0" color="{dropShadowColor}"
blurX="{dropBlur}" blurY="{dropBlur}" strength="8" quality="2"
alpha="{dropAlpha}"/>
</mx:filters>
I would like to update the filter in a method call like this:
this.dropShadowColor = <new color>
this.dropBlur = 15.0;
this.dropAlpha = 0.8;
Upon tracing both this.dropShadowColor and torinofilter.color, I see they have updated to the new color, but the color of the dropfilter doesnt change.
I would prefer not to create a new filter because then I get issues with swapChildren.
Properties of filters cannot be modified like this.
To modify an existing filter object, you must use the technique of modifying a copy of the filters array:
Assign the value of the filters array to a temporary array, such as one named myFilters.
Modify the property by using the temporary array, myFilters. For example, to set the quality property of the first filter in the array, you could use the following code: myFilters[0].quality = 1;
Assign the value of the temporary array to the filters array.
Basically when you read filters array of a DisplayObject, flash returns a copy of the array, not the live filters array. Pushing a new filter or updating existing filters will only modify the copy, not the original; you have to assign it back to the array to reflect the changes.
Do this from actionscript instead of mxml.
I would prefer not to create a new filter because then I get issues with swapChildren.
swapChildren applies only to display objects (UIComponents in case of flex containers).
I have a Flex application which references a separate MXML file as a template for a custom component. I create instances of the component dynamically several times in my program, but I need to get a handle that will allow me to modify that instance of the component as desired.
I pass specific information to this component on instantiation using bindable public variables in the component's MXML file. I add it to my main program using addChild().
I want to update the component's progressbar as necessary and I want to remove it from the box to which I addChild'd it.
What's the easiest/best way to get a variable that will give me predictable access to each component so I can easily manipulate the components as necessary? Some research suggests creationComplete, but I decided it was faster to just ask than to go through lots of different experiments and come up blank.
Thanks for all the help. : )
Can you not just keep a list of your components in an array? Presumably you have an object reference when you create them and call addChild() on their parent. Why not just put them in an array at the same time?
var list_of_controls:Array = new Array();
var new_Object:<yourType>;
new_Object = new <yourType>();
parent.addChild(new_Object);
list_of_controls.push(new_Object);
then you can get at them...
var my_Object:<yourType>;
for each (my_Object in list_of_controls)
{
// do something
}
You would have to make sure you dispose of them properly when you re done because the reference in your array would keep them in existence until cleared.
If you decide that you want to use getChildren() instead - which you could - take the time to read the documentation because I think it returns a new array with each call.
I hope that helps.
I'm re-writing an MXML item renderer in pure AS. A problem I can't seem to get past is how to have each item renderer react to a change on a static property on the item renderer class. In the MXML version, I have the following binding set up on the item renderer:
instanceProperty={callInstanceFunction(ItemRenderer.staticProperty)}
What would be the equivalent way of setting this up in AS (using BindingUtils, I assume)?
UPDATE:
So I thought the following wasn't working, but it appears as if Flex is suppressing errors thrown in the instanceFunction, making it appear as if the binding itself is bad.
BindingUtils.bindSetter(instanceFunction, ItemRenderer, "staticProperty");
However, when instanceFunction is called, already initialized variables on the given instance are all null, which was the cause of the errors referenced above. Any ideas why this is?
You have 2 options that I am aware of:
Option 1
You can dig into the code that the flex compiler builds based on your MXML to see how it handles binding to static properties. There is a compiler directive called -keep-generated-actionscript that will cause generated files to stick around. Sleuthing through these can give you an idea what happens. This option will involve instantiating Binding objects and StaticPropertyWatcher objects.
Option 2
There is staticEventDispatcher object that gets added at build time to classes containing static variables see this post http://thecomcor.blogspot.com/2008/07/adobe-flex-undocumented-buildin.html. According to the post, this object only gets added based on the presence of static variables and not getter functions.
Example of Option 2
Say we have a class named MyClassContainingStaticVariable with a static variable named MyStaticVariable and another variable someobject.somearrayproperty that we want to get updated whenever MyStaticVariable changes.
Class(MyClassContainingStaticVariable).staticEventDispatcher.addEventListener(
PropertyChangeEvent.PROPERTY_CHANGE,
function(event:PropertyChangeEvent):void
{
if(event.property == "MyStaticVariable")
{
someobject.somearrayproperty = event.newValue as Array;
}
});
I think you need to respond to the "PropertyChanged" event.
If you're going to do that, use a singleton instead of static. I don't think it will work on a static. (If you have to do it that way at all, there are probably a couple ways you could reapproach this that would be better).
var instance:ItemRenderer = ItemRenderer.getInstance();
BindingUtils.bindProperty(this, "myProperty", instance, "theirProperty");
After fiddling with this for a while, I have concluded that this currently isn't possible in ActionScript, not even with bindSetter. It seems there are some MXML-only features of data bindings judging by the following excerpt from the Adobe docs (though isn't it all compiled to AS code anyways)?
You cannot include functions or array
elements in property chains in a data
binding expression defined by the
bindProperty() or bindSetter() method.
For more information on property
chains, see Working with bindable
property chains.
Source: http://livedocs.adobe.com/flex/3/html/help.html?content=databinding_7.html
You can create a HostProxy class to stand in for the funciton call. Sort of like a HostFunctionProxy class which extends from proxy, and has a getProperty("functionInvokeStringWithParameters") which will invoke the function remotely from the host, and dispatch a "change" event to trigger the binding in typical [Bindable("change")] Proxy class.
You than let the HostProxy class act as the host, and use the property to remotely trigger the function call. Of course, it'd be cooler to have some TypeHelperUtil to allow converting raw string values to serialized type values at runtime for method parameters (splitted by commas usually).
Example:
eg.
var standInHost:Object = new HostFunctionProxy(someModelClassWithMethod, "theMethodToCall(20,11)");
// With BindingUtils.....
// bind host: standInHost
// bind property: "theMethodToCall(20,11)"
Of course, you nee to create such a utlity to help support such functionality beyond the basic Flex prescription. It seems many of such (more advanced) Flex bindings are usually done at compile time, but now you have to create code to do this at runtime in a completely cross-platform Actionscript manner without relying on the Flex framework.