Question

我在网上发现了一个PHP脚本帮助我创建上传图像的缩略图，只有一个问题：我不知道如何更改缩略图的结果大小。我找到了教程：http://www.w3schools.in/php/image-upload-and-generate-thumbnail-using-ajax-in-php/

有人可以帮我改变缩略图的结果大小吗？

到目前为止，这是我的代码：

<?php
function createDir($path){      
    if (!file_exists($path)) {
        $old_mask = umask(0);
        mkdir($path, 0777, TRUE);
        umask($old_mask);
    }
}

function createThumb($path1, $path2, $file_type, $new_w, $new_h, $squareSize = ''){
    /* read the source image */
    $source_image = FALSE;

    if (preg_match("/jpg|JPG|jpeg|JPEG/", $file_type)) {
        $source_image = imagecreatefromjpeg($path1);
    }
    elseif (preg_match("/png|PNG/", $file_type)) {

        if (!$source_image = @imagecreatefrompng($path1)) {
            $source_image = imagecreatefromjpeg($path1);
        }
    }
    elseif (preg_match("/gif|GIF/", $file_type)) {
        $source_image = imagecreatefromgif($path1);
    }       
    if ($source_image == FALSE) {
        $source_image = imagecreatefromjpeg($path1);
    }

    $orig_w = imageSX($source_image);
    $orig_h = imageSY($source_image);

    if ($orig_w < $new_w && $orig_h < $new_h) {
        $desired_width = $orig_w;
        $desired_height = $orig_h;
    } else {
        $scale = min($new_w / $orig_w, $new_h / $orig_h);
        $desired_width = ceil($scale * $orig_w);
        $desired_height = ceil($scale * $orig_h);
    }

    if ($squareSize != '') {
        $desired_width = $desired_height = $squareSize;
    }

    /* create a new, "virtual" image */
    $virtual_image = imagecreatetruecolor($desired_width, $desired_height);
    // for PNG background white----------->
    $kek = imagecolorallocate($virtual_image, 255, 255, 255);
    imagefill($virtual_image, 0, 0, $kek);

    if ($squareSize == '') {
        /* copy source image at a resized size */
        imagecopyresampled($virtual_image, $source_image, 0, 0, 0, 0, $desired_width, $desired_height, $orig_w, $orig_h);
    } else {
        $wm = $orig_w / $squareSize;
        $hm = $orig_h / $squareSize;
        $h_height = $squareSize / 2;
        $w_height = $squareSize / 2;

        if ($orig_w > $orig_h) {
            $adjusted_width = $orig_w / $hm;
            $half_width = $adjusted_width / 2;
            $int_width = $half_width - $w_height;
            imagecopyresampled($virtual_image, $source_image, -$int_width, 0, 0, 0, $adjusted_width, $squareSize, $orig_w, $orig_h);
        }

        elseif (($orig_w <= $orig_h)) {
            $adjusted_height = $orig_h / $wm;
            $half_height = $adjusted_height / 2;
            imagecopyresampled($virtual_image, $source_image, 0,0, 0, 0, $squareSize, $adjusted_height, $orig_w, $orig_h);
        } else {
            imagecopyresampled($virtual_image, $source_image, 0, 0, 0, 0, $squareSize, $squareSize, $orig_w, $orig_h);
        }
    }

    if (@imagejpeg($virtual_image, $path2, 90)) {
        imagedestroy($virtual_image);
        imagedestroy($source_image);
        return TRUE;
    } else {
        return FALSE;
    }
}   
?>

该函数由以下代码行调用：

<?php
include('./functions.php');
/*defined settings - start*/
ini_set("memory_limit", "99M");
ini_set('post_max_size', '20M');
ini_set('max_execution_time', 600);
define('IMAGE_SMALL_DIR', './uploades/small/');
define('IMAGE_SMALL_SIZE', 50);
define('IMAGE_MEDIUM_DIR', './uploades/medium/');
define('IMAGE_MEDIUM_SIZE', 250);
/*defined settings - end*/

if(isset($_FILES['image_upload_file'])){
    $output['status']=FALSE;
    set_time_limit(0);
    $allowedImageType = array("image/gif",   "image/jpeg",   "image/pjpeg",   "image/png",   "image/x-png"  );

    if ($_FILES['image_upload_file']["error"] > 0) {
        $output['error']= "Error in File";
    }
    elseif (!in_array($_FILES['image_upload_file']["type"], $allowedImageType)) {
        $output['error']= "You can only upload JPG, PNG and GIF file";
    }
    elseif (round($_FILES['image_upload_file']["size"] / 1024) > 4096) {
        $output['error']= "You can upload file size up to 4 MB";
    } else {
        /*create directory with 777 permission if not exist - start*/
        createDir(IMAGE_SMALL_DIR);
        createDir(IMAGE_MEDIUM_DIR);
        /*create directory with 777 permission if not exist - end*/
        $path[0] = $_FILES['image_upload_file']['tmp_name'];
        $file = pathinfo($_FILES['image_upload_file']['name']);
        $fileType = $file["extension"];
        $desiredExt='jpg';
        $fileNameNew = rand(333, 999) . time() . ".$desiredExt";
        $path[1] = IMAGE_MEDIUM_DIR . $fileNameNew;
        $path[2] = IMAGE_SMALL_DIR . $fileNameNew;

        if (createThumb($path[0], $path[1], $fileType, IMAGE_MEDIUM_SIZE, IMAGE_MEDIUM_SIZE,IMAGE_MEDIUM_SIZE)) {

            if (createThumb($path[1], $path[2],"$desiredExt", IMAGE_SMALL_SIZE, IMAGE_SMALL_SIZE,IMAGE_SMALL_SIZE)) {
                $output['status']=TRUE;
                $output['image_medium']= $path[1];
                $output['image_small']= $path[2];
            }
        }
    }
    echo json_encode($output);
}
?>

Answer 1

我看到你找到了自己问题的答案。我想补充一些额外的见解。

正确的方式

理想情况下，您应该将param传递给方法，因为您可以根据需要重置它：

$imageSize = 100; // size

createThumb($path[0], $path[1], $fileType, $imageSize, $imageSize, $imageSize);

错误的方式

上面的脚本使用常量。它们使用define方法概述。 IE。

define('IMAGE_SMALL_SIZE', 50);
define('IMAGE_MEDIUM_SIZE', 250);

将数字更改为所需的大小。即

define('IMAGE_SMALL_SIZE', 150);

在这个特定的用例中，常量仍然被传递给函数，这就不需要常量。

如何更改PHP缩略图图像大小？

1 个答案: