Function of Tick or Ticker - html5-canvas

What is the use of tick function in easeljs. When to use it? What exactly does it do to a stage? What is the exact format? I see different ways in which it has been called in different tutorials.
What is difference between tick and ticker?

The tick function on the Stage (and other display objects) advances all the child animations. Things like MovieClip and Sprite have frame-based animation, which are advanced the the next frame whenever they are ticked. You can turn off updateOnTick on the stage to prevent this.
The Ticker is a utility class that manages an actual heartbeat. It is a totally optional utility, but it creates an interval (using timeouts or requestAnimationFrame), and then dispatches events at a ~constant rate (the rate will be dependant on the performance on the device).
You can set the stage as a listener to the Ticker (instead of a custom handler function), and it will automatically call update() (and hence tick()) on the stage. This is the easiest usage. You can also manually call stage.update() in your own function to tick and redraw the stage. Note that using the stage as a listener guarantees that the stage will constantly update - so if you want to control it, then listen to the Ticker yourself, and manually call stage.update().

Related

How to stop slick-carousel in cypress

I need to stop this carousel in order to perform validation on it
Tried to set autoplay=false
The autoplay function is based on setInterval() which is able to be controlled by Cypress.
See the Cypress documentation for clock
cy.clock() overrides native global functions related to time allowing them to be controlled synchronously via cy.tick() or the yielded clock object. This includes controlling:
setTimeout
clearTimeout
setInterval
clearInterval
Date Objects
So you should be able to freeze the carousel by putting the cy.clock() command at the top of your test, or before the cy.visit() page load.
In case you want to test the second slide and the third slide, etc, you can issue a cy.tick(5000) to move the autoplay on for one slide each time, since you configured autoplaySpeed: 5000.

Redux/Flux (with ReactJS) and animation

I'm learning React+Redux and I don't understand the proper way of doing the animations. Lets speak by example:
For instance, I have a list and I would like to remove items on click. That's super easy if I have no animation effects there: dispatch REMOVE_ITEM action on click, reducer removes the item from the store and react re-renders html.
Let's add an animation of deleting the line item on click. So, when user clicks on an item I want to run a fancy effect of line item removal and... how? I can think of several ways how to do it:
1) On click I dispatch REMOVE_ITEM action, then reducer mark an item as goingToBeDeleted in Store, then react renders that element with a class of .fancy-dissolve-animation and I run a timer to dispatch the second action REMOVE_ITEM_COMPLETED. I don't like this idea, because it's still unclear how to add JS animations here (for example, with TweenMax) and I run a JS timer to re-render when CSS animation ends. Doesn't sound good.
2) I dispatch ITEM_REMOVE_PROGRESS actions with an interval of ~30ms, and store holds some "value" which represents the current state of animation. I don't like it too, as it would require me to copy the store ~120 times for ~2 seconds of animation (say, I want smooth 60 fps animation) and that's simply a waste of memory.
3) Make an animation and dispatch REMOVE_ITEM only after animation finishes. That's the most appropriate way I can think of, but still I'd like to have things changed in store right after user makes the action. For example, animation may take longer than few seconds and REMOVE_ITEM might sync with a backend – there's no reason to wait animation finish to make a backend API call.
Thanks for reading – any suggestions?
React has a great solution to this problem in the ReactCSSTransitionGroup helper class (see https://facebook.github.io/react/docs/animation.html). With this option, React takes care of it for you, by keeping the DOM state for the child as it was at the last render. You simply wrap your items in a ReactCSSTransitionGroup object. This keeps track of its children, and when it is rendered with a child removed, instead of rendering without the child, it renders with the child, but adds a CSS class to the child (which you can use to trigger a CSS animation, or you can just use CSS transitions for simplicity). Then, after a timeout (configured as a prop passed to ReactCSSTransitionGroup), it will re-render again, with the child removed from the DOM.
To use ReactCSSTransitionGroup, you'll need to npm install react-addons-css-transition-group, and then require/import 'react-addons-css-transition-group'. The animation docs give more detailed information.
One thing to remember - make sure the children have unique, unchanging keys. Just using the index as the key will make it behave incorrectly.
Instant actions are problematic in redux which saves state, so if we send action and it will change store then this change in store is available in next states, so We can have situation where animation is showing over and over because in store such parameter was set.
My solution for redux instant actions is to add some id like ( Action example code ):
{
type:"SOME_ANIMATION",
id: new Date().getTime() //we get timestamp of animation init
}
Next in component which runs animations save last animation id and if its match don't do animation. I use component state so for example ( Component code):
componentDidUpdate (){
if (this.lastAnimationId===this.props.animation.id)
return; //the same animation id so do not do anything
//here setState or do animation because it is new one
this.lastAnimationId=this.props.animation.id; //here set new id of last abnimation
}
Thanks id we can have only one action without actions which are reversing the state. Reversing actions after timeout can cause problems because if other action ( which is connected with component ) will be send before reverse action then animation can start again.
Minuses of proposed by me approach are that animation data exists in state, but exists also animation id which give us information about it. So we can say that store saves last dispatched animation.

Unity global mouse events

Most Unity tutorials suggest using Mouse events within the Update function, like this:
function Update () {
if (UnityEngine.Input.GetMouseButton(1)) {
}
}
This strikes me as really inefficient though, similar to using onEnterFrame in AS or setInterval in JS to power the whole application - I'd really prefer to use an events based system.
the OnMouseDown() method is useful, but is only fired when the MouseDown is on the object, not anywhere in the scene.
So here's the question: Is there a MouseEvent in Unity for detecting if the mouse button is down globally, or is the Update solution the recommended option?
This strikes me as really inefficient though, similar to using
onEnterFrame in AS or setInterval in JS to power the whole application
- I'd really prefer to use an events based system.
As already pointed out in comments, this isn't necessary less efficient. Every event based system is probably using a polling routine like that behind the scenes, updated at a given frequency.
In many game engines/frameworks you are going to find a polling based approach for input handling. I think this is related to the fact that input update frequency is directly correlated to the frame rate/update loop frequency. In fact it doesn't make much sense to listen for input at higher or lower frequency than your game loop.
So here's the question: Is there a MouseEvent in Unity for detecting
if the mouse button is down globally, or is the Update solution the
recommended option?
No there isn't. Btw if you want you can wrap mouse input detection inside a single class, and expose events from there where other classes can register to.
Something like:
public class MouseInputHandler : MonoBehavior
{
public event Action<Vector2> MousePressed;
public event Action<Vector2> MouseMoved;
...
void Update()
{
if (Input.GetMouseButton(0))
{
MousePressed(Input.mousePosition);
...
}
}
}
Like stated, you can use it without major concerns, Unity will 'make its magic' internally as to set processing power sensitive code execution for you in terms of polling events. That's the beauty of a modern game engine after all. You normally shouldn't have to be hacking your way around a common feature such a mouse click detection.
However if you don't want to go using the main Update() you can make a CoRoutine if you feel more comfortable with that, just bear in mind that Unity coroutines are not multi-threaded neither, so at the end everything needs to wait anyway.

Core Data: trigger a long-running operation on change of an attribute

I have in my model an object, that when modified requires a large number of other objects to recompute values based on those changes.
The way this is currently set up, is that this one object can only be modified in one place. This is a sheet with a Cancel and an OK button. Once the user commits the change, the sheet shows a progress bar and starts processing the objects affected by the change. The presentation and dismissal of the sheet are wrapped in a NSUndoManager group. The user may undo all changes in one pass after dismissing the sheet.
What bothers me is that I keep thinking that all this should happen at the business level. Rather than at the controller level. I.e. I should be able to modify my business object any place in the UI and code and have it trigger the necessary computations.
So I would set up KVO to watch my object and trigger the long running operation when needed. Once I go down that path, I start hitting walls.
How do I coalesce changes? My object has several attributes. I don't want to start a computation when the first attribute is changed and the second is likely to change next. Basically I need an edit sheet and some control point to commit all changes at once.
How do I add a UI to this long running operation? I could have an NSOperationQueue attached to the NSManagedObjectContext and have my window controller observe that. When the queue is not empty, I would pop up a sheet with a progress bar monitoring the current operation.
How can I implement Undo/Redo support? If I delay recomputation to an operation running after the fact, I cannot imagine how to undo the initial change and the propagated once at the same time. I can only imagine undoing the original change and having that trigger another reevaluation of all other object.
In short:
What is the best practice for such dependancies?
Is the propagation a job for the model layer or the control layer?
I believe I came up with a solution:
the center-piece model object watches itself for changes
on change, it creates or amends a ToDo object
the controller watches for new ToDo objects
the controller dequeues the ToDo, presents a progress-bar and performs the operation

How can I refresh core plot without returning from a method?

I have a cocoa interface that uses core plot. When I press a button in the interface, a plot is drawn. I wanted to create a sequence of graphs by calling the plotting method multiple times along with calls to sleep() in between. But it seems that even though the call to reload data is made that nothing happens until the function exits(only showing last graph as well). Now I know that CPAnimation exists but before I start using it I was wondering what it is that happens when the function exits that makes the graph refresh. Would I have to yield to the thread that takes care of the refreshing instead of using sleep?
Ok I figured out how. I called the reloadData method from a method in a separate thread (which always returns). This boiled down to calling reloadData from an IBAction and also with an NSTimer. Finally instead of using sleep I will use NSConditionLock coordinate the processing and the refreshing
Presumably, Core Plot (or your code) sets the view as needing display. That doesn't happen immediately; it happens when you return to the event loop.
Whenever you use sleep in a Mac OS X application, you kill a puppy. Use NSTimer instead. Have your timer callback method do the work required for one graph, and set whatever instance variables are necessary for your the method to know which graph it should draw, so that the method draws each graph in turn until it runs out of them.
Or, better yet, present a list of graphs that the user can choose from, instead of making the user watch all the graphs as a slide-show. (Unless an explicitly-labeled slide-show is what you're implementing.)
Core Plot, like most Cocoa drawing frameworks, is lazy: it draws at the end of the run loop iteration. This is to ensure that things aren't drawn too often.
Rather than drawing immediately, the layers are marked as needing drawing.
As was pointed out by others, a better approach to sleeping is to use NSTimer to avoid blocking the run loop, or to use NSObject methods like performSelector:withObject:afterDelay:
Peter has it right—the reload data method doesn't actually draw anything. The plot is marked as needing display and refreshed the next time the layers are drawn to the screen. If you use sleep, it never gets a chance to draw.
Also note that Core Plot is a fairly young project; CPAnimation and the related classes are stubs. They don't really do anything yet. :-)

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