Proposal to add/adopt adaptive sync throttling method

[fuweichin]

An alternate 'throttleAdaptiveSync' method based on requestAnimationFrame, used to throttle user input event in order to achive more fluent redraw for Canvas / WebGL applications.

Background
Consider the following case:

An interactive webpage contains a range <input> and a 2D <canvas>, when the range slider input event gets triggered, the canvas will be redrawed.

Problem

Since the range input may be triggered frequently (8ms ~ 12 ms interval on my computer), Sometimes it causes laggy if canvas redraw takes long time.

Alternative

• Fixed-delay throttling can basically solve the problem, but that is not perfect for different computers, different screens or different canvas states (normal and fullscreen).
• Dynamic-delay throttling can be very complex, as complex as TCP congestion control, such it can be heavy-weight, more overhead.

Solution
I worked out a simple method, as a reference implemention, to achive adaptive sync throttling. see online demo and source code.