javascript 将 RGB 颜色值转换为 0.75 alpha 的 RGBA
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Convert RGB color value to RGBA at 0.75 alpha
提问by Tom
I have the following code to get the background color of an element.
我有以下代码来获取元素的背景颜色。
var currentColor = $(this).css('background-color');
which returns something like rgb(123,123,123)
它返回类似的东西 rgb(123,123,123)
What I now want to do convert this to rgba and show it at 0.75 alpha
我现在想做的是将其转换为 rgba 并以 0.75 alpha 显示
So returning something like rgba(123,123,123,0.75)
所以返回类似的东西 rgba(123,123,123,0.75)
Any ideas?
有任何想法吗？
回答by Cerbrus
Since jQuery always seems to return the color like rgb(r, g, b)for elements that have no alpha, you could simply use:
由于 jQuery 似乎总是rgb(r, g, b)为没有 alpha 的元素返回颜色，因此您可以简单地使用：
$(this).css('background-color').replace(')', ', 0.75)').replace('rgb', 'rgba');
Just make sure the background color isn't rgba already:
只需确保背景颜色不是 rgba：
var bg = $(this).css('background-color');
if(bg.indexOf('a') == -1){
var result = bg.replace(')', ', 0.75)').replace('rgb', 'rgba');
}
回答by Henrik Peinar
var re = /(rgb)\(([0-9]+),\s+([0-9]+),\s+([0-9]+)/;
var currentColor = $(this).css('background-color');
var subst = 'rgba(,,,0.75';
$(this).css('background-color', currentColor.replace(re, subst));
Another solution using regex. But as Cerbrusmentioned, using regex for something this simple is overkill.
使用正则表达式的另一种解决方案。但正如Cerbrus 所提到的，将正则表达式用于如此简单的事情是过度的。
回答by nicolallias
Another regex try http://jsfiddle.net/hc3BA/
另一个正则表达式尝试http://jsfiddle.net/hc3BA/
var colour = 'rgb(123,123,123)',
new_col = colour.replace(/rgb/i, "rgba");
new_col = new_col.replace(/\)/i,',0.75)');
