FocusEngine Framer Module
The FocusEngine module allows you to simulate the grid focus behavior seen on streaming media players like Apple TV and Roku. Use the keyboard, RemoteLayer, or another mechanism to direct focus around your prototype’s canvas.
Once initialized, any visible layer can be brought into focus, even if it’s off screen. This permits the activation of off-screen menus. Visual appearance of focused elements can be customized.
$ cd /your/framer/project $ npm i @blackpixel/framer-focusengine
Copy or save the
FocusEngine.coffee file into your project's
Adding It to Your Project
In your Framer project add the following:
# If you manually installed fe = require "FocusEngine" # else fe = require "@blackpixel/framer-focusengine"
Customize focused and unfocused states
fe.focusStyle.scale = <number> fe.focusStyle.shadowX = <number> fe.focusStyle.shadowY = <number> fe.focusStyle.shadowColor = <string> (hex or rgba) fe.focusStyle.shadowBlur = <number> fe.focusStyle.shadowSpread = <number> fe.unfocusStyle.shadowX = <number> fe.unfocusStyle.shadowY = <number> fe.unfocusStyle.shadowColor = <string> (hex or rgba) fe.unfocusStyle.shadowBlur = <number> fe.unfocusStyle.shadowSpread = <number>
(Unfocused scale is always assumed to be the layer’s original scale. This need not be 1. You may get better visual results by drawing your layer slightly larger than needed and setting its initial scale to something less than 1.)
Customize state switch duration
fe.time = <number>
Collect layers that will participate into an array
myFocusableLayers = [layerA, layerB, layerC]
Initialize the engine with your array
Add a layer created post-initialization
Optionally attach changeFocus() to keyboard events
document.addEventListener "keydown", (event) -> keyCode = event.which switch keyCode when 13 then fe.changeFocus("select") when 37 then fe.changeFocus("left") when 38 then fe.changeFocus("up") when 39 then fe.changeFocus("right") when 40 then fe.changeFocus("down") else null
Place initial focus
focusPrevious() is available to use in conjunction with FlowComponent's showPrevious()
(Note that focus cannot be placed on a layer whose visibility, or whose ancestor’s visibility, is false. You may need to delay calling
focusPrevious() until the FlowComponent’s transition is ended, perhaps by using
Layers can trigger behavior upon receiving or losing focus, or being selected
layerA.on "focus", -> layerA.on "unfocus", -> layerA.on "selected", ->
Shortcuts are also available:
layerA.onFocus -> layerA.onUnfocus -> layerA.onSelected ->
Integration with RemoteLayer
RemoteLayer = require "RemoteLayer" myRemote = new RemoteLayer clickAction: -> fe.changeFocus("select") swipeUpAction: -> fe.changeFocus("up") swipeDownAction: -> fe.changeFocus("down") swipeLeftAction: -> fe.changeFocus("left") swipeRightAction: -> fe.changeFocus("right")
Check the currently focused layer
Check whether a layer has focus
Overriding focus logic
Sometimes you will want to change focus in a way that doesn't make exact geometric sense. For example, when switching from a large header row to a smaller secondary row, you may prefer the first cell in the secondary row receive focus. Or, you may want to provide a way for focus to "loop around" at a row's end. These kinds of functions are possible through overrides.
Set a layer's overrides using the
layerA.overrides = up: <layer> down: <layer> left: <layer> right: <layer>
It is not necessary to set all four overrides; but only for those directions which require custom behavior. Now, shifting focus from
layerA will always land on the direction-specified target -- no matter what FocusEngine thinks should happen.
Obviously, you can create very counterintuitive behaviors this way. Use with care!
If a layer has custom overrides, or has been initialized with FocusEngine, you may check any of its current overrides:
? permits the check to fail gracefully on layers which have no overrides.
Enable debug mode to log focus changes
fe.debug = true
Download the example to try it for yourself.
Attempting to perform a
placeFocus() call as FocusEngine is changing its own focus will fail. (The call is discarded.) If you need to override FocusEngine's logic, use the
overrides feature or add a slight delay to ensure the call is respected.
layerA.on "unfocus", -> Utils.delay 0.1, -> fe.placeFocus(layerB)