digit hex color code
I've been using 3-digit hex color values in CSS for a long time: #fff , #999 , #069 , etc. I can see how the repeating letters/numbers are merged to create a 3-digit hex color code, but I don't fully understand the pattern to be able to write a converter in PHP. Is there documentation for this?
Edit: Oh, perhaps my question wasn't clear. I need to know how some of the 6-digit hex color values are converted to 3-digits. xxxxxx ( ffffff ) and xxyyzz ( 006699 ) – these are the only two patterns, correct?
To convert a 3-character hex code into a 6 character one, you need to repeat each character:
$hex = '#fff';
$hex6 = '#' . $hex[1] . $hex[1] . $hex[2] . $hex[2] . $hex[3] . $hex[3];
If you want to convert it to decimal you can use the hexdec function
3 digit CSS code is short for 6 digits": #06a; is #0066aa;
Each two digits represent a number from 0 to 255.
Converting these values to hex and back is all you need.
#f0f is expanded to #ff00ff so basically you just need to calculate the value and the value times 16 for each character, eg:
#f98 : f = 15 => red = 15 + 15*16 = 255 etc.
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