(PHP 4 >= 4.0.6, PHP 5, PHP 7, PHP 8)
imagecolorclosestalpha — Get the index of the closest color to the specified color + alpha
Returns the index of the color in the palette of the image which
is "closest" to the specified RGB value and
alpha
level.
image
A GdImage object, returned by one of the image creation functions, such as imagecreatetruecolor().
red
Value of red component.
green
Value of green component.
blue
Value of blue component.
alpha
A value between 0
and 127
.
0
indicates completely opaque while
127
indicates completely transparent.
Returns the index of the closest color in the palette.
Example #1 Search for a set of colors in an image
<?php// Start with an image and convert it to a palette-based image$im = imagecreatefrompng('figures/imagecolorclosest.png');imagetruecolortopalette($im, false, 255);// Search colors (RGB)$colors = array( array(254, 145, 154, 50), array(153, 145, 188, 127), array(153, 90, 145, 0), array(255, 137, 92, 84));// Loop through each search and find the closest color in the palette.// Return the search number, the search RGB and the converted RGB matchforeach($colors as $id => $rgb){ $result = imagecolorclosestalpha($im, $rgb[0], $rgb[1], $rgb[2], $rgb[3]); $result = imagecolorsforindex($im, $result); $result = "({$result['red']}, {$result['green']}, {$result['blue']}, {$result['alpha']})"; echo "#$id: Search ($rgb[0], $rgb[1], $rgb[2], $rgb[3]); Closest match: $result.\n";}imagedestroy($im);?>
The above example will output something similar to:
#0: Search (254, 145, 154, 50); Closest match: (252, 150, 148, 0). #1: Search (153, 145, 188, 127); Closest match: (148, 150, 196, 0). #2: Search (153, 90, 145, 0); Closest match: (148, 90, 156, 0). #3: Search (255, 137, 92, 84); Closest match: (252, 150, 92, 0).