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    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

    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 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);
    ?>

    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

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