本文实例讲述了PHP实现根据图片色界在不同位置加水印的方法。分享给大家供大家参考。具体如下:
在使用php编程的时候, 很多时候需要对上传的图片加水印,来确定图片版权和出处. 但是,一般情况下加水印的位置是图片的右下角, 但是,不同图片的色阶不同,有时候我们 图片的水印和图片本身色阶相同,就会造成水印不明显.
下面这段代码可以实现自动识别图片的色阶,更加色阶差来添加图片的水印,这样可以避免水印和图片色阶一样的弊端.
<?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); // 默认的加水印位置调整 $lt_w = 50; $lt_h = 50; if($x == 0){ $w = MagickGetImageWidth($nmw); $h = MagickGetImageHeight($nmw); $x = $w; $y = $h; }else{ // 根据具体情况调整 $lt_w = 30; $lt_h = 40; } MagickCompositeImage($nmw, $nmw_water, MW_OverCompositeOp, $x - $w1 - $lt_w, $y - $h1 - $lt_h); MagickWriteImage($nmw, $output_file); DestroyMagickWand($nmw); } // 还是groovy的eachFileRecurse好用啊 function add_wm_recurse($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'; // 这个是我用java的ImageIO遍历图片像素获取的符合裤子颜色的区域的坐标array(posX, posY) $arr = array( array(50, 50) ); $water = './water.png'; $nmw_water =NewMagickWand(); MagickReadImage($nmw_water, $water); add_wm_recurse($nmw_water, $to_dir, $output_dir, $arr); DestroyMagickWand($nmw_water); ?>
补充:
PHP图像处理模块 MagickWand用法
MagickWand 是一个PHP的模块,用来访问 ImageMagick 的图像处理库。下面是一个使用 MagicWand 的代码片段:
$magick_wand=NewMagickWand(); MagickReadImage($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); } ?>
安装方法:
1. 下载 php_magickwand_q16_st.dll for 5.2.x
2. 将其放在PHP的扩展目录
3. 在php.ini文件总增加 extension=php_magickwand_q16_st.dll
4. 重新启动apache
希望本文所述对大家的php程序设计有所帮助。

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