CodeIgniter图像水印在使用动态输出时返回空白图像 - CodeIgniter image watermark returns blank image when using dynamic output

我使用jquery将数据发布到一个控制器函数，该函数为服务器上的图像添加水印并动态发布。当我不使用动态输出时，水印功能可以工作，但当我使用时，它只返回一个周围有1像素灰色边界的空白图像。

返回的图像名称正确，并应用了正确的图像类型标题。这是网络检查器中返回的第一行：

ÿØÿàJFIFÿþ;CREATOR: gd-jpeg v1.0 (using IJG JPEG v90), quality = 90

任何实现这一目标的替代方法都将受到赞赏，我们已经为此花费了数天时间，但收效甚微。如果可能的话，我宁愿不动服务器上的图像。

Java：

$('#body').on('click', '#get_file', function(ev)
{
    ev.preventDefault();
    var type = 'file';
    var uid = $('#file_select').val();
    var v1 = retD['res'][0].v1;
    var v2 = retD['res'][0].v2;
    var v3 = retD['res'][0].v3;
    var v4 = retD['res'][0].v4;
    $.ajax({
        type: 'POST',
        url: '<?php echo site_url("Home_controller/drawInfo") ?>',
        data: {v1:v1, v2:v2, v3:v3, v4:v4},
        dataType: 'html',
        success: function(img)
        {
            $("#i").attr("src", img);
        }
    }); 
});

控制器：

function drawInfo()
{
    $v1 = $_POST['v1'];
    $v2 = $_POST['v2'];
    $v3 = $_POST['v3'];
    $v4 = $_POST['v4'];
    $config['image_library'] = 'gd2';
    $config['source_image'] = './img/Test_image.jpg';
    $config['wm_text'] = 'v1: ' . $v1 . ' v2: ' . $v2 . ' v3: ' . $v3 . ' v4: ' . $v4;
    $config['wm_type'] = 'text';
    $config['dynamic_output'] = true;
    $config['wm_font_color'] = 'ff0000';
    $config['wm_font_path'] = './system/fonts/texb.ttf';
    $config['wm_vrt_alignment'] = 'bottom';
    $config['wm_hor_alignment'] = 'center';
    $config['wm_padding'] = '20';
    $this->image_lib->initialize($config); 
    if(!$this->image_lib->watermark())
    {
        echo $this->image_lib->display_errors();
    }
}

从控制器返回图像二进制数据，但在Javascript中，您希望将其用作img元素的"src"属性。

在控制器中，您应该返回新生成的图像的src
当您设置路径并为将要生成图像的文件夹设置正确的权限时，请小心（它应该可由apache写入）。

控制器：

function drawInfo()
{
    $return = array(
        'src'   => '',
        'error' => '',
    );
    $v1 = $_POST['v1'];
    $v2 = $_POST['v2'];
    $v3 = $_POST['v3'];
    $v4 = $_POST['v4'];
    $config['image_library'] = 'gd2';
    // set image path
    $config['source_image'] = FCPATH . 'img/Test_image.jpg';
    // this image will be watermarked (path should be writable by apache!!!)
    $config['new_image'] = FCPATH . 'img/Test_image_new.jpg';
    $config['wm_text'] = 'v1: ' . $v1 . ' v2: ' . $v2 . ' v3: ' . $v3 . ' v4: ' . $v4;
    $config['wm_type'] = 'text';
    // to false to save image to file instead of print it (you can leave this setting because the false is the default value)
    $config['dynamic_output'] = false;
    $config['wm_font_color'] = 'ff0000';
    // set the proper path!!
    $config['wm_font_path'] = FCPATH . 'system/fonts/texb.ttf';
    $config['wm_vrt_alignment'] = 'bottom';
    $config['wm_hor_alignment'] = 'center';
    $config['wm_padding'] = '20';
    $this->image_lib->initialize($config);
    if(!$this->image_lib->watermark())
    {
        $return['error'] = $this->image_lib->display_errors();
    }
    else 
    {
        // generate the URL of the new watermarked image (modify to your needs)
        $return['src'] = base_url() .'/'. $config['new_image'];
    }
    echo json_encode($return);
}

JavaScript:

    $.ajax({
        type: 'POST',
        url: '<?php echo site_url("Home_controller/drawInfo") ?>',
        data: {v1:v1, v2:v2, v3:v3, v4:v4},
        dataType: 'html',
        success: function(response)
        {
            if(response.error) 
            {
                alert(response.error);
            }
            else 
            {
                $("#i").attr("src", response.src);    
            }
        }
    });