Background color on rotate always black

is_numeric() returns true for all number literals as strings in php. That is, it will return true for all these cases:

• '123' (decimal)
• '0x123' (hex)
• '0123' (oct)
• '123e4' (123*10^4)
• '1.23' (float)

This means that the test is_numeric() also accept colors specified as hex string ('0xRRGGBB'). Now, casting this value (same as intval()) will return 0 (This is what PHP does internally with the argument to dechex()). Assuming you know it's a hex string, you can run hexdec(), but there is no point in that, as you want a hex representation of the color as a string.

I'd like to think that if you get a color, and it already is an integer, it's because it has been specified as PHP hex literals or that it already has been run through hexdec(). Is it a string, well, then it's in hex of some sort ('#RGB', '0xRRGGBB', 'RGB').

Now, as the comment in imageapi_image_rotate() says, the color parameter should be a hex integer. If it's a string, everything is ok, just strip the '0x' or '#' part in the beginning. If it's a hex literal as integer, test whether it's an integer and run dechex() and everything is ok.