Create Histgram (without normalize)

hist.php

<?php
main();

// 終了
exit;

function zero_array() {
    $ret = array();
    for ($i = 0; $i < 255; $i++) {
        $ret[$i] = 0;
    }
    return $ret;
}

function main() {
    $im = imagecreatefrompng("Austria.png");
    $rgb = imagecolorat($im, 70, 42);
    $r = ($rgb >> 16) & 0xFF;
    $g = ($rgb >> 8) & 0xFF;
    $b = $rgb & 0xFF;

    $width = imagesx($im);
    $height = imagesy($im);

    $hist_r = zero_array();
    $hist_g = zero_array();
    $hist_b = zero_array();

    for ($i = 0; $i < $width; $i++) {
        for ($j = 0; $j < $height; $j++) {
            $rgb = imagecolorat($im, $i, $j);
            $r = ($rgb >> 16) & 0xFF;
            $g = ($rgb >> 8) & 0xFF;
            $b = $rgb & 0xFF;
            $hist_r[$r] += 1;
            $hist_g[$g] += 1;
            $hist_b[$b] += 1;
        }
    }

    echo "======= size =======\n";
    var_dump($width);
    var_dump($height);
    var_dump(json_encode(array(
        r => $hist_r,
        g => $hist_g,
        b => $hist_b
    )));

}

?>