Warry

How to make faster scroll effects?

• Avoid too many reflows (the browser to recalculate everything)
• Use advanced CSS3 for graphic card rendering
• Precalculate sizes and positions

Beware of reflows

The reflow appens as many times as there are frames per seconds. It recalculate all positions that change in order to diplay them. Basically, when you scroll you execute a function where you move things between two reflows. But there are functions that triggers reflows such as jQuery offset, scroll... So there are two things to take care about when you dynamically change objects in javascript to avoid too many reflows:

codeinthehole

#!/usr/bin/env bash
# 
# Bootstrap script for setting up a new OSX machine
# 
# This should be idempotent so it can be run multiple times.
#
# Some apps don't have a cask and so still need to be installed by hand. These
# include:
#
# - Twitter (app store)

paulirish

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent