Redimensionner image en gardant les proportions

                               

                            
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/*
 Titre : Redimensionner image en gardant les proportions                                                                  
                                                                                                                          
 Auteur           : sitexw                                                                                                
 Date édition     : 06 Juil 2010                                                                                         
*/
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$chemin  = "http://www.google.fr/logos/classicplus.png"; // Adresse complete
$x_c     = 640; // Taille de l'image
$y_c     = 480;
$qualite = 80; // Qualite de l'image (0=pourrit/100=super)
$color   = "000000"; // Couleur de fond

$size = getimagesize($chemin);

if($size[0] >= $x_c AND $size[1] >= $y_c) {
    if(($size[0]/$x_c) > ($size[1]/$y_c)) {
        $x_t = $x_c;
        $y_t = floor(($size[1]*$x_c)/$size[0]);
        $x_p = 0;
        $y_p = ($y_c/2)-($y_t/2);
    } else {
        $x_t = floor(($size[0]*$y_c)/$size[1]);
        $y_t = $y_c;
        $x_p = ($x_c/2)-($x_t/2);
        $y_p = 0;
    }
} else {
    $x_t = $size[0];
    $y_t = $size[1];
    $x_p = ($x_c/2)-($x_t/2);
    $y_p = ($y_c/2)-($y_t/2);
}

$extension = strrchr($chemin,'.');
$extension = strtolower(substr($extension,1));

if($extension == 'jpg' OR $extension == 'jpeg') {
    $image_new = imagecreatefromjpeg($chemin);
} elseif($extension == 'gif') {
    $image_new = imagecreatefromgif($chemin);
} elseif($extension == 'png') {
    $image_new = imagecreatefrompng($chemin);
} elseif($extension == 'bmp') {
    $image_new = imagecreatefromwbmp($chemin);
} else {
    echo "Erreur !";
    exit;
}

Header("Content-type: image/jpeg");

$image = imagecreatetruecolor($x_c, $y_c);
$color = imagecolorallocate($image, hexdec($color[0].$color[1]), hexdec($color[2
].$color[3]), hexdec($color[4].$color[5]));
imagefilledrectangle($image,0,0,$x_c,$y_c,$color);
imagecopyresampled($image,$image_new,$x_p,$y_p,0,0,$x_t,$y_t,$size[0],$size[1]);
imagejpeg($image,NULL,$qualite);

?>