以不同格式保存图像

Question

根据用户使用GD选择的图像，我想以不同的格式保存图像。对于PNG，JPG和GIF图像，具有将图像保存为该格式的功能。

如何将图像另存为TIFF，BMP或PSD？这些格式有可用的功能吗？

Answer 1

您无法使用GD执行此操作，您需要使用ImageMagick。我假设您已经有png格式的图片，并且图片网址为$imageUrl。

$imageFormat = $_POST["format"];
$imageFormats = array("tiff", "bmp");
if (in_array($imageFormat, $imageFormats)) {
    $handle = fopen($imageUrl, 'rb');
    $imageMagick = new Imagick();
    $imageMagick->readImageFile($handle);
    $imageMagick->setImageFormat($imageFormat);
    $imageMagick->setImageColorSpace(5);
    $imageMagick->writeImage("path_to_tiff_image." . $imageFormat);
    fclose($handle);
    $imageMagick->destroy();    
} else {
    die("Invalid format!");
}
对于PSD部分，为什么要将其另存为psd？没有办法做到这一点。如果您说另存为psd的原因，我可以为您提供帮助。

Answer 2

<?php
    if(!function_exists('image_type_to_extension')){       

        $extension;

        function image_type_or_mime_type_to_extension($image_type, $include_dot) {
            define ("INVALID_IMAGETYPE", '');

            $extension = INVALID_IMAGETYPE;            /// Default return value for invalid input

            $image_type_identifiers = array (                                                                ### These values correspond to the IMAGETYPE constants
                    array (IMAGETYPE_GIF         => 'gif',     "mime_type" => 'image/gif'),                        ###  1 = GIF
                    array (IMAGETYPE_JPEG        => 'jpg',     "mime_type" => 'image/jpeg'),                        ###  2 = JPG
                    array (IMAGETYPE_PNG        => 'png',     "mime_type" => 'image/png'),                        ###  3 = PNG
                    array (IMAGETYPE_SWF        => 'swf',     "mime_type" => 'application/x-shockwave-flash'),    ###  4 = SWF  // A. Duplicated MIME type
                    array (IMAGETYPE_PSD        => 'psd',     "mime_type" => 'image/psd'),                        ###  5 = PSD
                    array (IMAGETYPE_BMP        => 'bmp',     "mime_type" => 'image/bmp'),                        ###  6 = BMP
                    array (IMAGETYPE_TIFF_II    => 'tiff',     "mime_type" => 'image/tiff'),                        ###  7 = TIFF (intel byte order)
                    array (IMAGETYPE_TIFF_MM    => 'tiff',     "mime_type" => 'image/tiff'),                        ###  8 = TIFF (motorola byte order)
                    array (IMAGETYPE_JPC        => 'jpc',     "mime_type" => 'application/octet-stream'),            ###  9 = JPC  // B. Duplicated MIME type
                    array (IMAGETYPE_JP2        => 'jp2',     "mime_type" => 'image/jp2'),                        ### 10 = JP2
                    array (IMAGETYPE_JPX        => 'jpf',     "mime_type" => 'application/octet-stream'),            ### 11 = JPX  // B. Duplicated MIME type
                    array (IMAGETYPE_JB2        => 'jb2',     "mime_type" => 'application/octet-stream'),            ### 12 = JB2  // B. Duplicated MIME type            
                    array (IMAGETYPE_SWC        => 'swc',     "mime_type" => 'application/x-shockwave-flash'),    ### 13 = SWC  // A. Duplicated MIME type
                    array (IMAGETYPE_IFF        => 'aiff',     "mime_type" => 'image/iff'),                        ### 14 = IFF
                    array (IMAGETYPE_WBMP        => 'wbmp',     "mime_type" => 'image/vnd.wap.wbmp'),                ### 15 = WBMP
                    array (IMAGETYPE_XBM        => 'xbm',     "mime_type" => 'image/xbm')                            ### 16 = XBM
            );                                                                                    

            if((is_int($image_type)) AND (IMAGETYPE_GIF <= $image_type) AND (IMAGETYPE_XBM >= $image_type)){
                $extension = $image_type_identifiers[$image_type-1]; // -1 because $image_type_identifiers array starts at [0]
                $extension = $extension[$image_type];
            }
            elseif(is_string($image_type) AND (($image_type != 'application/x-shockwave-flash') OR ($image_type != 'application/octet-stream'))){                

                $extension =  match_mime_type_to_extension($image_type, $image_type_identifiers);
            }
            else
            {
                $extension = INVALID_IMAGETYPE;
            }

               if(is_bool($include_dot)){

                   if((false != $include_dot) AND (INVALID_IMAGETYPE != $extension)){
                       $extension = '.' . $extension;
                   }
               }
               else
               {
                   $extension = INVALID_IMAGETYPE;
               }                  

           return $extension;

           }
    }    

    function match_mime_type_to_extension($image_type, $image_type_identifiers){
        // Return from loop on a match
        foreach($image_type_identifiers as $_key_outer_loop => $_val_outer_loop){            
            foreach($_val_outer_loop as $_key => $_val){
                if(is_int ($_key)){             // Keep record of extension for mime check
                    $extension = $_val;
                } 
                if($_key == 'mime_type'){    
                    if($_val === $image_type){    // Found match no need to continue looping
                        return $extension;        ### Return
                    }                     
                }
            }
        }
        // Compared all values without match
        return $extension = INVALID_IMAGETYPE;    
    } 

    $extension = image_type_or_mime_type_to_extension($image_type, $include_dot);
     return $extension;
}
?>

Answer 3

您可以使用GD库的内置图像类型和mime类型。例如：