The most flexible way to animate modifier properties is by creating a Transitionable object on the scope and binding the property in the html. Any changes to the Transitionable object on the scope will be reflected in the view immediately via Angular's two-way data binding.
var Transitionable = $famous['famous/transitions/Transitionable'];
var Easing = $famous['famous/transitions/Easing'];
$scope.boxTransitionable = new Transitionable([0, 0, 0]);
$scope.animate = function() {
$scope.boxTransitionable.set([200, 300, 0], {duration: 2000, curve: Easing.inOutBack});
};<fa-modifier fa-size="[100, 100]" fa-translate="boxTransitionable.get()">
<fa-surface fa-background-color="'red'" fa-click="animate()">
</fa-surface>
</fa-modifier>In the html, fa-translate is passed boxTransitionable.get(), a function expression that will return a value of [0,0,0] initially.
All transitionables have a .get() method that returns the interpolated state of the transition at the current time of invocation, returning either a number/array or an object.
This means that during this transition, calls to .get() provide the interpolated state along the way, perhaps [100, 150], [150, 185], and so on, until it reaches [200, 300].
When the user clicks the fa-surface, it will trigger the animate() function defined on the scope. In turn, this calls the .set() method on the boxTransitionable,
which is passed the end state and a transition.
One may also choose to pass an array, with one or more of its values a function expression or a number.
<fa-modifier fa-size="[100, 100]" fa-translate="[yTrans.get(), 0, 0]" fa-touchstart="animate()">
<fa-surface fa-background-color="'red'" fa-click="animateY()">
</fa-surface>
</fa-modifier>$scope.yTrans = new Transitionable(0);
$scope.animateY = function() {
$scope.yTrans.set(200, {duration: 2000, curve: 'easeInOut'})
};In this example, fa-translate is passed an array, with the x value bound to a function expression that will return 0, and y & z values as 0's.
When animateY() is called, yTrans begins its transition, and its values are interpolated, updated on the view through Angular's two-way data binding.
A point of possible confusion is the fact that some modifier properties (faOpacity, faSize, faOrigin, faAlign) can be bound to a Transitionable object directly, without needing to be passed a .get() function expression, unlike the example above.
In the example below, we create transitionable objects that will perform transitions on opacity (which accepts a Transitionable object directly) and translate (which does not accept a transitionable object directly).
The value of fa-opacity is bound to a Transitionable directly, box.opacity.
Whereas fa-translate is bound to a method of a Transitionable, box.translate.get(), that returns an interpolated value.
Clicking the fa-surface invokes animateBox() on the scope, in turn, executing the .set() methods of each prospective Transitionable from initial state to end state.
<fa-modifier fa-translate="box.translate.get()" fa-opacity="box.opacity" fa-size="[100, 100]">
<fa-surface fa-click="animateBox()" fa-background-color="'red'"></fa-surface>
</fa-modifier>var Transitionable = $famous['famous/transitions/Transitionable'];
$scope.box = {
translate: new Transitionable([200,200,0]),
opacity: new Transitionable(.3)
};
$scope.animateBox = function() {
$scope.box.translate.set([0, 100, 0], {duration: 500, curve: 'easeInOut'});
$scope.box.opacity.set(1, {duration: 500, curve: 'easeInOut'});
};FaTranslate (along with faRotate, faTranslate, faScale, faSkew, & more) pass through a Famous Transform function (Transform.translate()), whereas faOpacity, faSize, faOrigin, and faAlign are passed through a Famous Modifier.
A Famous Transform.translate() function does not accept a Transitionable object, but only an array.
A .get() function of a Transitionable returns an interpolated value of a current transition, therefore in the case of a faTranslate, it can return an array that a Transform.translate() can accept.
faOpacity passes through a Famous Modifier, which has an .opacityFrom() method that can accept a Transitionable object directly.
As a design principle, Famous-Angular attempts to pass values directly to Famous as much as possible, and these differences are due to the core Famous library.
The .set() method of a Transitionable can accept 3 arguments: an endState, a transition, and an optional callback to be called upon observed completion of the transition.
In the example below, when the first transition completes, with the element translated to [200, 300, 0], the callback function is called, and the element begins the transition to [100, 100, 0].
var Transitionable = $famous['famous/transitions/Transitionable'];
$scope.boxTrans = new Transitionable([0, 0, 0]);
$scope.animateWithCallback = function() {
$scope.boxTrans.set([200, 300, 0], {duration: 1000, curve: 'easeInOut'},
function() {
$scope.boxTrans.set([100, 100, 0], {duration: 1000, curve: 'easeInOut'});
}
);
};<fa-modifier fa-size="[100, 100]" fa-translate="boxTrans.get()">
<fa-surface fa-background-color="'red'" fa-click="animateWithCallback()">
</fa-surface>
</fa-modifier>Famous Modifiers affect all renderable child nodes (Modifiers & Surfaces) below them on the Render Tree.
In this example, two properties will be animated: the outermost Modifier's fa-scale property and innermost Modifier's fa-rotate-Z property.
Because Famous Modifiers affect all child nodes nested within them, when the outermost Modifier's scale property changes, it affects the scale of every modifier and surface below it.
The innermost Modifier with the fa-rotate-Z property affects the innermost surface only.
<fa-modifier fa-scale="boxes.outer.scale.get()">
<fa-modifier fa-size="[100, 100]">
<fa-surface fa-background-color="'red'"></fa-surface>
<fa-modifier fa-size="[50, 50]" fa-origin="[.5, .5]" fa-rotate-z="boxes.inner.rotateZ.get()">
<fa-surface fa-background-color="'blue'" fa-click="animateBoxes()"></fa-surface>
</fa-modifier>
</fa-modifier>
</fa-modifier>var Transitionable = $famous['famous/transitions/Transitionable'];
$scope.boxes = {
outer: {
scale: new Transitionable([2, 2])
},
inner: {
rotateZ: new Transitionable(0)
}
};
$scope.animateBoxes = function() {
$scope.boxes.outer.scale.set([1, 1], {duration: 2000, curve: 'easeInOut'});
$scope.boxes.inner.rotateZ.set(.8, {duration: 1000, curve: 'easeInOut'});
};$famous.find() is a method that can be used to perform a DOM look-up to retrieve the Famous isolate (node) of the appropriate object.
It accepts one argument, a string css selector (e.g. an #id or a .class,) and returns an array of elements matching the query.
It is useful for manipulation of Famous objects after they have been declared in the DOM. With Angular, it is best to do DOM manipulation (including look-ups) in a directive's post-link function; Famous-Angular is no exception.
<fa-modifier id="myBox">
<fa-surface></fa-surface>
</fa-modifier>var myBox = $famous.find('#myBox'); // [Object]
// myBox[0] is the isolate object belonging to the modifier of id 'myBox' in the DOM.
// myBox[0].modifier is a reference to the Famo.us modifier corresponding to that element.If this is done outside of a directive's post-link function, there is no guarantee that $famous.find() will return anything, because the element may not have compiled yet.
Below is an example of a custom directive called fade-in used to animate an element by transitioning its opacity from the values of fa-opacity to opacity-end, with the duration of duration. Note: opacity-end and duration are NOT Famous-Angular attributes; they are custom to this particular example.
<fa-modifier fade-in fa-opacity="0.2" opacity-end="1" duration="500">
<fa-surface fa-background-color="'red'"></fa-surface>
</fa-modifier>.directive('fadeIn',
['$famous', '$famousDecorator', '$timeout',
function ($famous, $famousDecorator, $timeout) {
return {
restrict: 'A',
scope: false,
priority: 16,
compile: function(tElement, tAttrs, transclude) {
var Transitionable = $famous['famous/transitions/Transitionable'];
return {
pre: function(scope, element, attrs) {
},
post: function(scope, element, attrs) {
$famousDecorator.ensureIsolate(scope)
$timeout(function() {
var opacityStartValue = attrs.faOpacity;
var opacityEndValue = attrs.opacityEnd;
var duration = attrs.duration;
var opacityTransitionable = new Transitionable(opacityStartValue);
scope.isolate[scope.$id].modifier.opacityFrom(function() {
return opacityTransitionable.get();
});
opacityTransitionable.set(opacityEndValue, {duration: duration, curve: 'easeInOut'});
});
}
}
}
}
}]);In the compile function, load up the AMD module for a Famous Transitionable, which will be used for the animation.
The fade-in directive's priority is 16, higher than the priority of an fa-modifier (4) to ensure that the fa-modifier will be compiled first. Therefore the post-link function of fade-in allows access to the scope of fa-modifier.
$famousDecorator.ensureIsolate(scope) checks the passed in scope for an existing isolate; if scope.isolate does not exist, it creates one.
Below, the rest of the directive is wrapped in a $timeout function to ensure that the animation will call on the next Famous engine tick.
opacityStartValue, opacityEndValue, and duration are convenience variables that access the fa-opacity, opacity-end, and duration attributes from the html.
A transitionable called OpacityTransitionable is instantiated with startOpacity (value of 0.2 in this example).
scope.isolate is a reference to the Famous-Angular isolate object that stores properties available to each particular Famous-Angular element. The isolate object may look like this: {004: {Context Object} 005: {Modifier Object} 006: {Surface Object}}.
A particular element's "isolate" is accessed from the isolate object by key, with the unique $id property of the element, like so: scope.isolate[scope.$id]. (The fa-modifier's unique $id property might be 005, for example)
Accessing the reference of the Famous Modifier that corresponds to the element, (scope.isolate[scope.$id].modifier), use the .opacityFrom() method (available to Famous Modifiers), and pass it a callback function that will return opacityTransitionable.get(). In this particular example, we passed the value of opacityStartValue (0.2) into the constructor of opacityTransitionable earlier. Therefore, at this point, opacityTransitionable.get() will return 0.2.
The transition begins when opacityTransitionable.set() is called, which passes in the opacityEndValue and a transition object.