imagecolorclosestalpha

(PHP 4 >= 4.0.6, PHP 5, PHP 7, PHP 8)

imagecolorclosestalphaGet the index of the closest color to the specified color + alpha

Description

imagecolorclosestalpha(
    GdImage $image,
    int $red,
    int $green,
    int $blue,
    int $alpha
): int

Returns the index of the color in the palette of the image which is "closest" to the specified RGB value and alpha level.

Parameters

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.

The colors parameters are integers between 0 and 255 or hexadecimals between 0x00 and 0xFF.

Return Values

Returns the index of the closest color in the palette.

Examples

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).

See Also