如何在图像上添加水印？

Question

如何在图像上放置水印而不影响源图像。

$SourceFile = '/uploadedimage/gallery/thumble/'; 
$DestinationFile = '/uploadedimage/gallery/thumble/image-watermark.jpg'; 
$WaterMarkText = 'Copyright appsbee.com'; 
watermarkImage ($SourceFile, $WaterMarkText, $DestinationFile); 



function watermarkImage ($SourceFile, $WaterMarkText, $DestinationFile) { 
    list($width, $height) = getimagesize($SourceFile); 
    $image_p = imagecreatetruecolor($width, $height); 
    $image = imagecreatefromjpeg($SourceFile); 
    imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width, $height); 
    $black = imagecolorallocate($image_p, 0, 0, 0); 
    $font = 'arial.ttf'; 
    $font_size = 10; 
    imagettftext($image_p, $font_size, 0, 10, 20, $black, $font, $WaterMarkText); 
    if ($DestinationFile<>'') { 
     imagejpeg ($image_p, $DestinationFile, 100); 
    } else { 
     header('Content-Type: image/jpeg'); 
     imagejpeg($image_p, null, 100); 
    }; 
    imagedestroy($image); 
    imagedestroy($image_p); 
}; 

如果我这样做，在thumble文件夹上出现的图像会受到影响。

Answer 1

不影响源图像。

只有添加一个包含透明图像的HTML图层，才能做到这一点而不影响实际图像。尽管如此，作为一种保护手段，这是无用的，因为每个拥有一点技术知识的人都可以在几秒钟内获取原始图像。

Answer 2

使用GD图像库：http://php.net/manual/en/book.image.php

这样，我想创建图像的网页水印版本，还可以存储源图像。

除非你的意思是在飞行中添加水印，在这种情况下，我不确定你可以轻松地做到这一点。

Answer 3

如果你不想影响源图像，那么我建议把一个透明的图像放在HTML中图像的绝对定位div上。这意味着您不必在每个页面加载过程中处理图像（因为您想保留原始图像），并且不必担心存储额外的图像。

Answer 4

使用此类，在放置水印之前只需复制原始图像。

<?php 
class Watermark{ 
    # given two images, return a blended watermarked image 
    # given two images, return a blended watermarked image 
    function create_watermark($main_img_obj, $watermark_img_obj, $alpha_level = 100) { 
     $alpha_level /= 100; # convert 0-100 (%) alpha to decimal 
     # calculate our images dimensions 
     $main_img_obj_w = imagesx($main_img_obj); 
     $main_img_obj_h = imagesy($main_img_obj); 
     $watermark_img_obj_w = imagesx($watermark_img_obj); 
     $watermark_img_obj_h = imagesy($watermark_img_obj); 
     # determine center position coordinates 
     $main_img_obj_min_x = floor(($main_img_obj_w/2) - ($watermark_img_obj_w/2)); 
     $main_img_obj_max_x = ceil(($main_img_obj_w/2) + ($watermark_img_obj_w/2)); 
     $main_img_obj_min_y = floor(($main_img_obj_h/2) - ($watermark_img_obj_h/2)); 
     $main_img_obj_max_y = ceil(($main_img_obj_h/2) + ($watermark_img_obj_h/2)); 
     # create new image to hold merged changes 
     $return_img = imagecreatetruecolor($main_img_obj_w, $main_img_obj_h); 
     # walk through main image 
     for($y = 0; $y < $main_img_obj_h; $y++) { 
      for($x = 0; $x < $main_img_obj_w; $x++) { 
       $return_color  = NULL; 

       # determine the correct pixel location within our watermark 
       $watermark_x  = $x - $main_img_obj_min_x; 
       $watermark_y  = $y - $main_img_obj_min_y; 

       # fetch color information for both of our images 
       $main_rgb = imagecolorsforindex($main_img_obj, imagecolorat($main_img_obj, $x, $y)); 

       # if our watermark has a non-transparent value at this pixel intersection 
       # and we're still within the bounds of the watermark image 
       if ( $watermark_x >= 0 && $watermark_x < $watermark_img_obj_w && 
       $watermark_y >= 0 && $watermark_y < $watermark_img_obj_h) { 
        $watermark_rbg = imagecolorsforindex($watermark_img_obj, imagecolorat($watermark_img_obj, $watermark_x, $watermark_y)); 

        # using image alpha, and user specified alpha, calculate average 
        $watermark_alpha = round(((127 - $watermark_rbg['alpha'])/127), 2); 
        $watermark_alpha = $watermark_alpha * $alpha_level; 

        # calculate the color 'average' between the two - taking into account the specified alpha level 
        $avg_red   = $this->_get_ave_color($main_rgb['red'],   $watermark_rbg['red'],  $watermark_alpha); 
        $avg_green = $this->_get_ave_color($main_rgb['green'],  $watermark_rbg['green'],  $watermark_alpha); 
        $avg_blue   = $this->_get_ave_color($main_rgb['blue'],  $watermark_rbg['blue'],  $watermark_alpha); 

        # calculate a color index value using the average RGB values we've determined 
        $return_color  = $this->_get_image_color($return_img, $avg_red, $avg_green, $avg_blue); 

        # if we're not dealing with an average color here, then let's just copy over the main color 
       } else { 
        $return_color  = imagecolorat($main_img_obj, $x, $y); 

       } # END if watermark 

       # draw the appropriate color onto the return image 
       imagesetpixel($return_img, $x, $y, $return_color); 

      } # END for each X pixel 
     } # END for each Y pixel 
     # return the resulting, watermarked image for display 
     return $return_img; 
    } # END create_watermark() 

    # average two colors given an alpha 
    function _get_ave_color($color_a, $color_b, $alpha_level) { 
     return round((($color_a * (1 - $alpha_level)) + ($color_b * $alpha_level))); 
    } # END _get_ave_color() 

    # return closest pallette-color match for RGB values 
    function _get_image_color($im, $r, $g, $b) { 
     $c=imagecolorexact($im, $r, $g, $b); 
     if ($c!=-1) return $c; 
     $c=imagecolorallocate($im, $r, $g, $b); 
     if ($c!=-1) return $c; 
     return imagecolorclosest($im, $r, $g, $b); 
    } # EBD _get_image_color() 
} # END watermark API 
?> 

，这是如何使用它

$watermark = new Watermark(); 
     $actual_image = imagecreatefromjpeg("images/$image_file"); 
     $watermark_image = imagecreatefrompng("images/water_mark.png"); 
     //create water marked image with 66% transparency 
     $return_img_obj = $watermark->create_watermark($actual_image, $watermark_image, 66); 

     //now save the updated image 
     imagejpeg($return_img_obj,"images/$image_file1"); 

     //clear the memory 
     imagedestroy($actual_image); 
     imagedestroy($watermark_image); 
     imagedestroy($return_img_obj); 

Answer 5

从一见钟情，我觉得这个代码不会影响到源文件如果u没有提供目标文件名的功能。