imagecolorexact

    (PHP 4, PHP 5, PHP 7, PHP 8)

    imagecolorexact — Get the index of the specified color

    Descrizione

    imagecolorexact(
        GdImage $image,
        int $red,
        int $green,
        int $blue
    ): int

    Returns the index of the specified color in the palette of the image.

    Se l'immagine è stata creata da un file, solo i colori usati nell'immagine sono risolti. I colori presenti solo nella palette non sono risolti.

    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.

    Valori restituiti

    Returns the index of the specified color in the palette, or -1 if the color does not exist.

    Log delle modifiche

    Versione Descrizione
    8.0.0 image expects a GdImage instance now; previously, a valid gd resource was expected.

    Esempi

    Example #1 Get colors from the GD logo

    <?php
    // Setup an image
    $im = imagecreatefrompng('./gdlogo.png');

    $colors = Array();
    $colors[] = imagecolorexact($im, 255, 0, 0);
    $colors[] = imagecolorexact($im, 0, 0, 0);
    $colors[] = imagecolorexact($im, 255, 255, 255);
    $colors[] = imagecolorexact($im, 100, 255, 52);

    print_r($colors);

    // Free from memory
    imagedestroy($im);
    ?>

    Il precedente esempio visualizzerà qualcosa simile a:

    Array
(
    [0] => 16711680
    [1] => 0
    [2] => 16777215
    [3] => 6618932
)

    Vedere anche:

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    User Contributed Notes 3 notes

    up
    2
    jbr at ya-right dot com
    18 years ago
    A few notes about this function...

    This function will only work on images where the palette is 256 colors or less. You also can not use imagetruecolortopalette() to reduce the palette on a true color PNG image that has greater than 256 colors in it's palette, then call this function. If you try to do this imagecolorexact() will report colors not being in the image when they are in the image!

    1. works on png(s) 8bit/256 colors or less.
    2. works on all gif(s)
    3. does not work on any type of jpg/jpeg image.
    up
    0
    samtobia at geemail dot com
    13 years ago
    A script that changes colors depending on get variable
    important to note: I had little success with pngs and getting true red
    gifs work much better

    <?php
    //0 is yellow, 1 is red, 2 is blue
    $y = 1 - ceil($_GET["c"]/2);
    $r = 1 - floor($_GET["c"]/2);
    $b = floor($_GET["c"]/2);

    $gd = imagecreatefromgif("example.gif");
    imagecolorset($gd, imagecolorexact($gd, 255, 0, 0), $r*255, $y*255, $b*255);
    imagecolorset($gd, imagecolorexact($gd, 191, 0, 0), $r*191, $y*191, $b*191);
    imagecolorset($gd, imagecolorexact($gd, 128, 0, 0), $r*128, $y*128, $b*128);
    imagecolorset($gd, imagecolorexact($gd, 255, 0, 0), $r*64, $y*64, $b*64);

    header('Content-Type: image/gif');
    imagegif($gd);

    ?>
    up
    -2
    info at educar dot pro dot br
    19 years ago
    <?php

    $src     = "../images/pic.gif";

    $red = 9;
    $green = 9;
    $blue = 4;

    $pic0026 = imagecreatefromgif ( $src );

    $ind = imagecolorexact ( $pic, $red, $green, $blue );

    echo     '<img src="../images/pic.gif" border="0" alt="pic" title="View pic" /><br /><br />';

    echo     "RED ( " . $red . " ) GREEN ( " . $green . " ) BLUE ( " . $blue . " )<br />-> Palette Index = " . $ind;

    if (     $ind != -1 )
    {
    echo     "<br />[ The color exists! ]";
    }
    else
    {
    echo     "<br />[ The color does not exist! ]";
    }

    imagedestroy ( $pic );

    ?>
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