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# Complementary Color Calculator Free tool | Plus Source Code

As a web designer, I always found myself lurking to find complementary color for a given color code.

I came across a complicated PHP script that claims to calculate the complementary color using
hue, saturation and lightness parameters – but found several errors with its output.

So i decided to write my own code. The code is simple and has nothing to do hue, saturation and lightness.
I simple uses the hexadecimal color code to derive the color codes and it is accurate.

So without much ado, here is the conversion tool.

[complementary-color-calculator]

Update:
While this code works great and gives the complementary color, this is an old code.
I have made a much more detailed color calculator to replace this code.
Check it out at:
http://knowpapa.com/color-combo/

I have tested this using random samples and this conforms with photoshop results.
However if you come across a bug or some discrepancy, please post it here as a comment.

And should you need the actual code behind this, here it goes

```sorry you entered an invalid color code,
\$hexcode = mysql_real_escape_string(\$hexcode);
\$hexcode = htmlentities(\$hexcode);
\$complementarycolor = "Tit for Tat ! invalid color yields invalid results.
}
// do all the routine form sanitization and validation
// i have excluded my actual validation code for security reasons
but it should work even without validation.
else {
//NOW the actual conversion begins

// \$hexcode is the six digit hex colour code we want to convert
// \$hexcode is the six digit hex colour code we want to convert

\$redhex1  = substr(\$hexcode,0,1);
\$redhex2  = substr(\$hexcode,1,1);
\$greenhex1 = substr(\$hexcode,2,1);
\$greenhex2 = substr(\$hexcode,3,1);
\$bluehex1 = substr(\$hexcode,4,1);
\$bluehex2 = substr(\$hexcode,5,1);

\$var_r1 = dechex((15-(hexdec(\$redhex1)))) ;
\$var_r2 = dechex((15- (hexdec(\$redhex2)))) ;
\$var_g1 = dechex((15-(hexdec(\$greenhex1)))) ;
\$var_g2 = dechex((15-(hexdec(\$greenhex2)))) ;
\$var_b1 = dechex((15-(hexdec(\$bluehex1))));
\$var_b2 = dechex((15-(hexdec(\$bluehex2))));

\$complementarycolor = \$var_r1.\$var_r2.\$var_g1.\$var_g2.\$var_b1.\$var_b2;

}
}

?>

Enter Your Hexacolor code (excluding #)

#

```

My name is Bhaskar. I am a CTO and a startup techno guy with 10+ years of experience startups.
Full-time coding in Python, React. Part-time coding in Haskell, Java, C.
Scientifically interested in Music, BioInformatics, Linear Algebra, Category theory, Graph theory.

What excites me: anything that has the potential to disrupt the status quo.

Looking for technical support on a startup idea ?
write at : bhaskar {-at-} knowpapa.com