PHP implements Watermarking Based on the image color field in different locations

This article mainly introduces how to add watermarks to different positions in the image color field in PHP. it involves some techniques related to using the MagickWand module in php to add watermarks to images, which is of great practical value, for more information about how to add watermarks to different positions in the image color field, see the example in this article. Share it with you for your reference. The details are as follows:

When using php programming, you often need to add a watermark to the uploaded image to determine the copyright and source of the image. however, the position of the watermark is usually in the lower-right corner of the image. However, different images have different levels of color. sometimes, when the watermark of our image is the same as that of the image itself, the watermark will not be obvious.

The following code automatically identifies the color order of the image and adds the watermark to the image based on the color difference. This avoids the disadvantages of the watermark and the image's color level.

<? Php function add_wm ($ nmw_water, $ src_file, $ output_file, $ x, $ y) {if (file_exists ($ output_file) return; $ w1 = MagickGetImageWidth ($ nmw_water ); $ h1 = MagickGetImageHeight ($ nmw_water); $ nmw = NewMagickWand (); MagickReadImage ($ nmw, $ src_file); // Adjust the default Watermark Position $ lt_w = 50; $ lt_h = 50; if ($ x = 0) {$ w = MagickGetImageWidth ($ nmw); $ h = MagickGetImageHeight ($ nmw); $ x = $ w; $ y = $ h;} else {// Adjust $ lt_w = according to the actual situation 30; $ lt_h = 40;} MagickCompositeImage ($ nmw, $ nmw_water, MW_OverCompositeOp, $ x-$ w1-$ lt_w, $ y-$ h1-$ lt_h ); magickWriteImage ($ nmw, $ output_file); DestroyMagickWand ($ nmw);} // function compute ($ nmw_water, $ to_dir, $ output_dir, $ arr) {$ dp = dir ($ to_dir); while ($ file = $ dp-> read () {if ($ file! = '.' & $ File! = '.. ') {If (is_dir ($ to_dir. '/'. $ file) {mkdir ($ output_dir. '/'. $ file); add_wm_recurse ($ nmw_water, $ to_dir. '/'. $ file, $ output_dir. '/'. $ file, $ arr);} else {if (! Array_key_exists ($ to_dir. '/'. $ file, $ arr) {continue;} $ sub_arr = $ arr [$ to_dir. '/'. $ file]; if ($ sub_arr) {$ x = intval ($ sub_arr [0]); $ y = intval ($ sub_arr [1]); add_wm ($ nmw_water, $ to_dir. '/'. $ file, $ output_dir. '/'. $ file, $ x, $ y) ;}}}$ dp-> close () ;}$ to_dir = '. /resized '; $ output_dir = '. /output'; // This is the coordinate array (posX, posY) $ arr = array (50, 5 0); $ water = '. /water.png '; $ nmw_water = NewMagickWand (); MagickReadImage ($ nmw_water, $ water); add_wm_recurse ($ nmw_water, $ to_dir, $ output_dir, $ arr ); destroyMagickWand ($ nmw_water);?>

Supplement:

PHP image processing module MagickWand usage

MagickWand is a PHP module used to access the image processing library of ImageMagick. The following is a code snippet using MagicWand:

$magick_wand=NewMagickWand();MagickReadImage($magick_wand,'rose.jpg');$drawing_wand=NewDrawingWand();DrawSetFont($drawing_wand,"/usr/share/fonts/bitstream-vera/Vera.ttf");DrawSetFontSize($drawing_wand,20);DrawSetGravity($drawing_wand,MW_CenterGravity);$pixel_wand=NewPixelWand();PixelSetColor($pixel_wand,"white");DrawSetFillColor($drawing_wand,$pixel_wand);if (MagickAnnotateImage($magick_wand,$drawing_wand,0,0,0,"Rose") != 0){ MagickEchoImageBlob( $magick_wand );}else{ echo MagickGetExceptionString($magick_wand);}?>

Installation method:

1. download php_magickwand_q16_st.dll for 5.2.x
2. place it in the extension directory of PHP
3. add extension = php_magickwand_q16_st.dll to the php. ini file.
4. restart apache

I hope this article will help you with php programming.