使用PHP缩放图像并保持宽高比

Question

基本上，我想上传图像（已排序）并将其按比例缩小到某些限制，例如最大宽度和高度，但要保持原始图像的纵横比。

我没有在服务器上安装Imagick-否则这很容易。

一如既往地提供任何帮助。谢谢。

编辑：我不需要整个代码或任何东西，只是朝着正确的方向推进将是很棒的。

Answer 1

我为完成的另一个项目编写了这样的代码。我已在下面复制了它，可能需要修补一下！（它确实需要GD库）

这些是它需要的参数：

$image_name - Name of the image which is uploaded
$new_width - Width of the resized photo (maximum)
$new_height - Height of the resized photo (maximum)
$uploadDir - Directory of the original image
$moveToDir - Directory to save the resized image

它将按比例缩小或放大图像到最大宽度或高度

function createThumbnail($image_name,$new_width,$new_height,$uploadDir,$moveToDir)
{
    $path = $uploadDir . '/' . $image_name;

    $mime = getimagesize($path);

    if($mime['mime']=='image/png') { 
        $src_img = imagecreatefrompng($path);
    }
    if($mime['mime']=='image/jpg' || $mime['mime']=='image/jpeg' || $mime['mime']=='image/pjpeg') {
        $src_img = imagecreatefromjpeg($path);
    }

    $old_x          =   imageSX($src_img);
    $old_y          =   imageSY($src_img);

    if($old_x > $old_y) 
    {
        $thumb_w    =   $new_width;
        $thumb_h    =   $old_y*($new_height/$old_x);
    }

    if($old_x < $old_y) 
    {
        $thumb_w    =   $old_x*($new_width/$old_y);
        $thumb_h    =   $new_height;
    }

    if($old_x == $old_y) 
    {
        $thumb_w    =   $new_width;
        $thumb_h    =   $new_height;
    }

    $dst_img        =   ImageCreateTrueColor($thumb_w,$thumb_h);

    imagecopyresampled($dst_img,$src_img,0,0,0,0,$thumb_w,$thumb_h,$old_x,$old_y);


    // New save location
    $new_thumb_loc = $moveToDir . $image_name;

    if($mime['mime']=='image/png') {
        $result = imagepng($dst_img,$new_thumb_loc,8);
    }
    if($mime['mime']=='image/jpg' || $mime['mime']=='image/jpeg' || $mime['mime']=='image/pjpeg') {
        $result = imagejpeg($dst_img,$new_thumb_loc,80);
    }

    imagedestroy($dst_img); 
    imagedestroy($src_img);

    return $result;
}