为什么浏览器在OSX上呈现rgba的方式不同？ [英] Why do browsers render rgba differently on OSX?

问题描述

我试图编写一些颜色处理代码，并在alpha上停留了很长时间，然后（两个小时后）我意识到浏览器呈现rgba的方式有所不同。

I was trying to code up some color manipulation code and was stuck for a long time with alpha, then I (2 hours later) realized browsers render rgba differently.

我创建了此测试： http://jsbin.com/adekez/2/
添加/ edit来查看代码

I created this test: http://jsbin.com/adekez/2/ add /edit to look at the code

以下是OSX Lion中4种浏览器的结果： http://imgur.com/g2iqu

Here are the results in 4 browsers in OSX Lion: http://imgur.com/g2iqu

该元素的背景为rgba（0,0,0,0.5

That is an element with a background of rgba(0,0,0,0.5) on top of white.

我的十六进制计算器说：FF÷2 = 7F.8这意味着

My hex calculator says: FF÷2 = 7F.8 which means

＃808080上的Safari是正确的
＃7F7F7F上的Firefox关闭了1
＃7E7E7E上的Opera关闭了2
Chrome在＃929292上的Chrome浏览器已关闭

Safari at #808080 is correct Firefox at #7F7F7F is off by 1 Opera at #7E7E7E is off by 2 Chrome at #929292 is way off

这是怎么回事，这是Chrome中的bug还是我只是不了解颜色（true）？

What's going here, is this a bug in Chrome or do I just not know about colors (true)?

推荐答案

先行

嗯，实际上是Safari 和 Firefox a都正确：
0xFF = 255 ， 255/2 = 127.5 。因此 128 可能是正确的（ 0x80 ），但 127 （ 0x7F ）-取决于浏览器的四舍五入约定。

First off

Well, actually Safari and Firefox are both correct: 0xFF = 255, 255 / 2 = 127.5. So 128 may be correct (0x80), but also 127 (0x7F) - depending on the rounding convention of the browser.

这些都是四舍五入的问题。我不太明白为什么会有舍入问题，因为0.5可以用二进制数表示而没有精度损失，但是实际上存在舍入问题：

These are rounding issues. I don't quite get why there are rounding issues, since 0.5 is representable in binary numbers without precision loss, but there are, in fact rounding issues:

Opera：

Opera:

Chrome浏览器：

Chrome:

这篇关于为什么浏览器在OSX上呈现rgba的方式不同？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！