高畫質縮圖函式

<?php   
function ImageResize (&$src, $x, $y) {   
    $dst=imagecreatetruecolor($x, $y);   
    $pals=ImageColorsTotal ($src);    
    for ($i=0; $i<$pals; $i++) {   
    $colors=ImageColorsForIndex ($src, $i);   
    ImageColorAllocate ($dst, $colors['red'], $colors['green'], $colors['blue']);   
  
    }        
    $scX =(imagesx ($src)-1)/$x;   
    $scY =(imagesy ($src)-1)/$y;   
    $scX2 =intval($scX/2);   
    $scY2 =intval($scY/2);   
  
    for ($j = 0; $j < ($y); $j++) {   
    $sY = intval($j * $scY);   
    $y13 = $sY + $scY2;   
    for ($i = 0; $i < ($x); $i++) {   
        $sX = intval($i * $scX);   
        $x34 = $sX + $scX2;   
        $c1 = ImageColorsForIndex ($src, ImageColorAt ($src, $sX, $y13));   
        $c2 = ImageColorsForIndex ($src, ImageColorAt ($src, $sX, $sY));   
        $c3 = ImageColorsForIndex ($src, ImageColorAt ($src, $x34, $y13));   
        $c4 = ImageColorsForIndex ($src, ImageColorAt ($src, $x34, $sY));   
        $r = ($c1['red']+$c2['red']+$c3['red']+$c4['red'])/4;   
        $g = ($c1['green']+$c2['green']+$c3['green']+$c4['green'])/4;   
        $b = ($c1['blue']+$c2['blue']+$c3['blue']+$c4['blue'])/4;   
        ImageSetPixel ($dst, $i, $j, ImageColorClosest ($dst, $r, $g, $b));   
    }   
    }   
    return ($dst);   
}   
?>