(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
Eine von den verschiedenen Erzeugungsfunktionen wie imagecreatetruecolor() gelieferte Grafikressource.
redWert der Rotkomponente.
greenWert der Grünkomponente.
blueWert der Blaukomponente.
alphaA value between 0 and 127. 0 indicates completely opaque while 127 indicates completely transparent.
Returns the index of the closest color in the palette.
Beispiel #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);
?>
Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:
#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).
Hinweis: Diese Funktion setzt die GD-Bibliothek in der Version 2.0.1 oder höher (empfohlen wird mindestens 2.0.28) voraus.