WCAG compliance level
Strictness
Failing Colors
Saved Color Schemes
Modify Saved Color Schemes
Input comma separated color hex codes, example: #eee, #123def
Minimum required color contrast: 4.5 : 1
I found several color contrast tools online, but I found none written in JavaScript and none that compared a plurality of colors. I tired of watching my coworkers endlessly comparing colors from a limited list of approved colors. There existed a need, so I built the tool.
The intention of this application is to create all contrast comparisons for a given set of colors once. Since all colors are visible in a pass or fail state it should be immediately clear what combinations will be allowed. There is no need to even know what the acceptable rules and limitations are if using a tool like this.
The following rules defined my approach:
The solution is achieved by computing the relative luminance for a given color and then comparing that color with the defined contrast ratio. The mathmatical definitions are available in the W3C links mentioned above. The JavaScript solution is available in the JavaScript function luminance of this page's source code.
The reason why I had trouble finding similar tools written in JavaScript is because JavaScript is bad at frational arithmetic. The solution to this problem is to proportionally multiply all values by a power of ten until you are far left of the decimal. A few extra digits is recommended for extra precision.
Copyright (c) 2015 Austin Cheney
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
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