imagecolorclosestalpha

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

imagecolorclosestalpha — Get the index of the closest color to the specified color + alpha

Descrizione

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.

Elenco dei parametri

image: Una risorsa immagine, restituita da una delle funzioni di creazione immagine, come imagecreatetruecolor().
red: Valore della componente rossa.
green: Valore della componente verde.
blue: Valore della componente blu.
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.

Valori restituiti

Returns the index of the closest color in the palette.

Esempi

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);
?>

Il precedente esempio visualizzerà qualcosa simile a:

#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).

Vedere anche:

imagecolorexactalpha() - Get the index of the specified color + alpha
imagecolorclosest() - Get the index of the closest color to the specified color
imagecolorclosesthwb() - Get the index of the color which has the hue, white and blackness

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