(PHP 4 >= 4.0.6, PHP 5, PHP 7)
imagecolorclosestalpha — Get the index of the closest color to the specified color + alpha
$image
, int $red
, int $green
, int $blue
, int $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
imagecreatetruecolor() 등의 이미지 생성 함수에서 반환한 이미지 자원.
red
Red 컴포넌트 값.
green
Green 컴포넌트 값.
blue
Blue 컴포넌트 값.
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)
$colors = array(
array(254, 145, 154, 50),
array(153, 145, 188, 127),
array(153, 90, 145, 0),
array(255, 137, 92, 84)
);
// Loop through each search and find the closest color in the palette.
// Return the search number, the search RGB and the converted RGB match
foreach($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);
?>
위 예제의 출력 예시:
#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).