哪种方式调整图像大小更好？
现在我正在使用缩略图类，它工作正常，但它大大降低了图像的质量。
我想要大小 = 32 x 32 的拇指形式的个人资料图像。
我现在使用的代码是：
$cimg = $_FILES["image_src"]["name"];
move_uploaded_file($_FILES["image_src"]["tmp_name"],"uploads/profile_images/".$cimg);
$thumb=new thumbnail("uploads/profile_images/".$cimg);
$thumb->size_width(32);
$thumb->save("uploads/profile_images/".$cimg);
$thumb=new thumbnail("uploads/profile_images/".$cimg);
$thumb->size_width(32);
$thumb->save("uploads/profile_images/thumbs/".$cimg);
请建议我一些更好的方法。我的图像现在太拉伸和低质量。
我的缩略图类：
class thumbnail
{
var $img;
function thumbnail($imgfile)
{
//detect image format
$this->img["format"]=ereg_replace(".*'.(.*)$","''1",$imgfile);
$this->img["format"]=strtoupper($this->img["format"]);
if ($this->img["format"]=="JPG" || $this->img["format"]=="JPEG") {
//JPEG
$this->img["format"]="JPEG";
$this->img["src"] = ImageCreateFromJPEG ($imgfile);
} elseif ($this->img["format"]=="PNG") {
//PNG
$this->img["format"]="PNG";
$this->img["src"] = ImageCreateFromPNG ($imgfile);
} elseif ($this->img["format"]=="GIF") {
//GIF
$this->img["format"]="GIF";
$this->img["src"] = ImageCreateFromGIF ($imgfile);
} elseif ($this->img["format"]=="WBMP") {
//WBMP
$this->img["format"]="WBMP";
$this->img["src"] = ImageCreateFromWBMP ($imgfile);
} else {
//DEFAULT
echo "Not Supported File";
exit();
}
@$this->img["lebar"] = imagesx($this->img["src"]);
@$this->img["tinggi"] = imagesy($this->img["src"]);
//default quality jpeg
$this->img["quality"]=75;
}
function size_height($size=100)
{
//height
$this->img["tinggi_thumb"]=$size;
@$this->img["lebar_thumb"] = ($this->img["tinggi_thumb"]/$this->img["tinggi"])*$this->img["lebar"];
}
function size_width($size=100)
{
//width
$this->img["lebar_thumb"]=$size;
@$this->img["tinggi_thumb"] = ($this->img["lebar_thumb"]/$this->img["lebar"])*$this->img["tinggi"];
}
function size_auto($size=100)
{
//size
if ($this->img["lebar"]>=$this->img["tinggi"]) {
$this->img["lebar_thumb"]=$size;
@$this->img["tinggi_thumb"] = ($this->img["lebar_thumb"]/$this->img["lebar"])*$this->img["tinggi"];
} else {
$this->img["tinggi_thumb"]=$size;
@$this->img["lebar_thumb"] = ($this->img["tinggi_thumb"]/$this->img["tinggi"])*$this->img["lebar"];
}
}
function jpeg_quality($quality=75)
{
//jpeg quality
$this->img["quality"]=$quality;
}
function show()
{
//show thumb
@Header("Content-Type: image/".$this->img["format"]);
/* change ImageCreateTrueColor to ImageCreate if your GD not supported ImageCreateTrueColor function*/
$this->img["des"] = ImageCreateTrueColor($this->img["lebar_thumb"],$this->img["tinggi_thumb"]);
@imagecopyresized ($this->img["des"], $this->img["src"], 0, 0, 0, 0, $this->img["lebar_thumb"], $this->img["tinggi_thumb"], $this->img["lebar"], $this->img["tinggi"]);
if ($this->img["format"]=="JPG" || $this->img["format"]=="JPEG") {
//JPEG
imageJPEG($this->img["des"],"",$this->img["quality"]);
} elseif ($this->img["format"]=="PNG") {
//PNG
imagePNG($this->img["des"]);
} elseif ($this->img["format"]=="GIF") {
//GIF
imageGIF($this->img["des"]);
} elseif ($this->img["format"]=="WBMP") {
//WBMP
imageWBMP($this->img["des"]);
}
}
function save($save="")
{
//save thumb
if (empty($save)) $save=strtolower("./thumb.".$this->img["format"]);
/* change ImageCreateTrueColor to ImageCreate if your GD not supported ImageCreateTrueColor function*/
$this->img["des"] = ImageCreateTrueColor($this->img["lebar_thumb"],$this->img["tinggi_thumb"]);
@imagecopyresized ($this->img["des"], $this->img["src"], 0, 0, 0, 0, $this->img["lebar_thumb"], $this->img["tinggi_thumb"], $this->img["lebar"], $this->img["tinggi"]);
if ($this->img["format"]=="JPG" || $this->img["format"]=="JPEG") {
//JPEG
imageJPEG($this->img["des"],"$save",$this->img["quality"]);
} elseif ($this->img["format"]=="PNG") {
//PNG
imagePNG($this->img["des"],"$save");
} elseif ($this->img["format"]=="GIF") {
//GIF
imageGIF($this->img["des"],"$save");
} elseif ($this->img["format"]=="WBMP") {
//WBMP
imageWBMP($this->img["des"],"$save");
}
}
}
?>
这
使用imagecopyresampled对我有用（请注意，图像将始终使用.png格式和保持纵横比保存）：
// thumbnail size
$thumb_width = 32; $thumb_height = 32;
// get image from post from
$img = $_FILES['image_src']['tmp_name'];
// thumbnail filename
$dst = 'uploads/profile_images/thumbs/image_name.png';
// check valid image
if (($img_info = getimagesize($img)) === FALSE) { die("Image not found or not an image"); }
// check source image format and check valid image. get image in $src variable if valid image
switch ($img_info[2]) {
case IMAGETYPE_GIF : $src = imagecreatefromgif($img); break;
case IMAGETYPE_JPEG : $src = imagecreatefromjpeg($img); break;
case IMAGETYPE_PNG : $src = imagecreatefrompng($img); break;
default : $src = false;
}
if(!$src) { die("Image not found or not an image"); }
// get metrics to resize image to fit to thumbnail size
$width = $img_info[0]; $height = $img_info[1];
$original_aspect = $width / $height;
$thumb_aspect = $thumb_width / $thumb_height;
if ( $original_aspect >= $thumb_aspect ) {
$new_height = $thumb_height;
$new_width = $width / ($height / $thumb_height);
}
else {
$new_width = $thumb_width;
$new_height = $height / ($width / $thumb_width);
}
// create thumbnail
$tmp = imagecreatetruecolor($thumb_width, $thumb_height);
imagecopyresampled($tmp, $src, 0 - ($new_width - $thumb_width) / 2, 0 - ($new_height - $thumb_height) / 2, 0, 0, $new_width, $new_height, $width, $height);
imagepng($tmp, $dst);