Timelines, Events, and Triggers

We can animate process through a timeline, using seconds or frames to detect positions along a sequence. When we meet a keyframe, the programmed action occurs, and runs until another event or trigger.

The Trigger is similar to an event, such as the event of reaching a certain x/y. however a user can actuate a trigger. It would be prudent to ensure the trigger end is a range, ensuring a value and nearly hit for an event to occur.

a.x = 0
a.x += 100
    a.x == 99:
        event(a, 'x')
            b.x = a.x
            b.y += 100
                b.y == 99:
                    event(a, 'y')
                        ...

This can occur in two forms. An enforced procedure, or event-like.

The enforced changes a value at a specific time. Such as x must be 100 at 2 seconds - performed with timers.

An event-like is more nuance - upon each iteration we test to see if a value meets a condition. Such as "if x ~= 100" (regardless of time taken.) - performed with a tick test.

The event-like example is useful for trigger interaction, such as a user has moved a point to a certain position. The enforced method is good for explicit states such as canned animations.

t = new Timeline(stage)

p = new Point(20,20)

// 1 second
t.at(1, ()={
    p.x = 100
})

// 3 seconds
t.at(3, ()={
    p.x = 400
})

t.play()
/* Run (20 => 100) 1 second, (100 => 400) 2 seconds */

Info