thinkphp image类添加png图片水印不投明问题

1、添加水印可以参照手册，直接引入image类，使用water方法即可

2、在导入类后，我们发现如果使用png图片作为水印背景，会出现添加水印时原来应该是透明的部分变成了黑色

3、在网上找了一番之后，对image类的water方法做下述修改

大约在82行

//生成混合图像
// imagecopymerge($sImage, $wImage, $posX, $posY, 0, 0, $wInfo['width'], $wInfo['height'], $alpha);
imagecopy($sImage, $wImage, $posX, $posY, 0, 0, $wInfo['width'], $wInfo['height']);

对，你没有看错，把他原来的注释掉，改成下面的就好了。

下面放上整个image类的代码，便于以后查看下载

<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2009 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

/**
* 图像操作类库
* @category   ORG
* @package  ORG
* @subpackage  Util
* @author    liu21st <liu21st@gmail.com>
*/
class Image {

/**
* 取得图像信息
* @static
* @access public
* @param string $image 图像文件名
* @return mixed
*/

static function getImageInfo($img) {
$imageInfo = getimagesize($img);
if ($imageInfo !== false) {
$imageType = strtolower(substr(image_type_to_extension($imageInfo[2]), 1));
$imageSize = filesize($img);
$info = array(
"width" => $imageInfo[0],
"height" => $imageInfo[1],
"type" => $imageType,
"size" => $imageSize,
"mime" => $imageInfo['mime']
);
return $info;
} else {
return false;
}
}

/**
* 为图片添加水印
* @static public
* @param string $source 原文件名
* @param string $water  水印图片
* @param string $$savename  添加水印后的图片名
* @param string $alpha  水印的透明度
* @return void
*/
static public function water($source, $water, $savename=null, $alpha=80) {
//检查文件是否存在
if (!file_exists($source) || !file_exists($water))
return false;

//图片信息
$sInfo = self::getImageInfo($source);
$wInfo = self::getImageInfo($water);

//如果图片小于水印图片，不生成图片
if ($sInfo["width"] < $wInfo["width"] || $sInfo['height'] < $wInfo['height'])
return false;

//建立图像
$sCreateFun = "imagecreatefrom" . $sInfo['type'];
$sImage = $sCreateFun($source);
$wCreateFun = "imagecreatefrom" . $wInfo['type'];
$wImage = $wCreateFun($water);

//设定图像的混色模式
imagealphablending($wImage, true);

//图像位置,默认为右下角右对齐
$posY = $sInfo["height"] - $wInfo["height"];
$posX = $sInfo["width"] - $wInfo["width"];

//生成混合图像
// imagecopymerge($sImage, $wImage, $posX, $posY, 0, 0, $wInfo['width'], $wInfo['height'], $alpha);
imagecopy($sImage, $wImage, $posX, $posY, 0, 0, $wInfo['width'], $wInfo['height']);

//输出图像
$ImageFun = 'Image' . $sInfo['type'];
//如果没有给出保存文件名，默认为原图像名
if (!$savename) {
$savename = $source;
@unlink($source);
}
//保存图像
$ImageFun($sImage, $savename);
imagedestroy($sImage);
}

function showImg($imgFile, $text='', $x='10', $y='10', $alpha='50') {
//获取图像文件信息
//2007/6/26 增加图片水印输出，$text为图片的完整路径即可
$info = Image::getImageInfo($imgFile);
if ($info !== false) {
$createFun = str_replace('/', 'createfrom', $info['mime']);
$im = $createFun($imgFile);
if ($im) {
$ImageFun = str_replace('/', '', $info['mime']);
//水印开始
if (!empty($text)) {
$tc = imagecolorallocate($im, 0, 0, 0);
if (is_file($text) && file_exists($text)) {//判断$text是否是图片路径
// 取得水印信息
$textInfo = Image::getImageInfo($text);
$createFun2 = str_replace('/', 'createfrom', $textInfo['mime']);
$waterMark = $createFun2($text);
//$waterMark=imagecolorallocatealpha($text,255,255,0,50);
$imgW = $info["width"];
$imgH = $info["width"] * $textInfo["height"] / $textInfo["width"];
//$y	=	($info["height"]-$textInfo["height"])/2;
//设置水印的显示位置和透明度支持各种图片格式
imagecopymerge($im, $waterMark, $x, $y, 0, 0, $textInfo['width'], $textInfo['height'], $alpha);
} else {
imagestring($im, 80, $x, $y, $text, $tc);
}
//ImageDestroy($tc);
}
//水印结束
if ($info['type'] == 'png' || $info['type'] == 'gif') {
imagealphablending($im, FALSE); //取消默认的混色模式
imagesavealpha($im, TRUE); //设定保存完整的 alpha 通道信息
}
Header("Content-type: " . $info['mime']);
$ImageFun($im);
@ImageDestroy($im);
return;
}

//保存图像
$ImageFun($sImage, $savename);
imagedestroy($sImage);
//获取或者创建图像文件失败则生成空白PNG图片
$im = imagecreatetruecolor(80, 30);
$bgc = imagecolorallocate($im, 255, 255, 255);
$tc = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 150, 30, $bgc);
imagestring($im, 4, 5, 5, "no pic", $tc);
Image::output($im);
return;
}
}

/**
* 生成缩略图
* @static
* @access public
* @param string $image  原图
* @param string $type 图像格式
* @param string $thumbname 缩略图文件名
* @param string $maxWidth  宽度
* @param string $maxHeight  高度
* @param string $position 缩略图保存目录
* @param boolean $interlace 启用隔行扫描
* @return void
*/
static function thumb($image, $thumbname, $type='', $maxWidth=200, $maxHeight=50, $interlace=true) {
// 获取原图信息
$info = Image::getImageInfo($image);
if ($info !== false) {
$srcWidth = $info['width'];
$srcHeight = $info['height'];
$type = empty($type) ? $info['type'] : $type;
$type = strtolower($type);
$interlace = $interlace ? 1 : 0;
unset($info);
$scale = min($maxWidth / $srcWidth, $maxHeight / $srcHeight); // 计算缩放比例
if ($scale >= 1) {
// 超过原图大小不再缩略
$width = $srcWidth;
$height = $srcHeight;
} else {
// 缩略图尺寸
$width = (int) ($srcWidth * $scale);
$height = (int) ($srcHeight * $scale);
}

// 载入原图
$createFun = 'ImageCreateFrom' . ($type == 'jpg' ? 'jpeg' : $type);
if(!function_exists($createFun)) {
return false;
}
$srcImg = $createFun($image);

//创建缩略图
if ($type != 'gif' && function_exists('imagecreatetruecolor'))
$thumbImg = imagecreatetruecolor($width, $height);
else
$thumbImg = imagecreate($width, $height);
//png和gif的透明处理 by luofei614
if('png'==$type){
imagealphablending($thumbImg, false);//取消默认的混色模式（为解决阴影为绿色的问题）
imagesavealpha($thumbImg,true);//设定保存完整的 alpha 通道信息（为解决阴影为绿色的问题）
}elseif('gif'==$type){
$trnprt_indx = imagecolortransparent($srcImg);
if ($trnprt_indx >= 0) {
//its transparent
$trnprt_color = imagecolorsforindex($srcImg , $trnprt_indx);
$trnprt_indx = imagecolorallocate($thumbImg, $trnprt_color['red'], $trnprt_color['green'], $trnprt_color['blue']);
imagefill($thumbImg, 0, 0, $trnprt_indx);
imagecolortransparent($thumbImg, $trnprt_indx);
}
}
// 复制图片
if (function_exists("ImageCopyResampled"))
imagecopyresampled($thumbImg, $srcImg, 0, 0, 0, 0, $width, $height, $srcWidth, $srcHeight);
else
imagecopyresized($thumbImg, $srcImg, 0, 0, 0, 0, $width, $height, $srcWidth, $srcHeight);

// 对jpeg图形设置隔行扫描
if ('jpg' == $type || 'jpeg' == $type)
imageinterlace($thumbImg, $interlace);

// 生成图片
$imageFun = 'image' . ($type == 'jpg' ? 'jpeg' : $type);
$imageFun($thumbImg, $thumbname);
imagedestroy($thumbImg);
imagedestroy($srcImg);
return $thumbname;
}
return false;
}

/**
* 根据给定的字符串生成图像
* @static
* @access public
* @param string $string  字符串
* @param string $size  图像大小 width,height 或者 array(width,height)
* @param string $font  字体信息 fontface,fontsize 或者 array(fontface,fontsize)
* @param string $type 图像格式 默认PNG
* @param integer $disturb 是否干扰 1 点干扰 2 线干扰 3 复合干扰 0 无干扰
* @param bool $border  是否加边框 array(color)
* @return string
*/
static function buildString($string, $rgb=array(), $filename='', $type='png', $disturb=1, $border=true) {
if (is_string($size))
$size = explode(',', $size);
$width = $size[0];
$height = $size[1];
if (is_string($font))
$font = explode(',', $font);
$fontface = $font[0];
$fontsize = $font[1];
$length = strlen($string);
$width = ($length * 9 + 10) > $width ? $length * 9 + 10 : $width;
$height = 22;
if ($type != 'gif' && function_exists('imagecreatetruecolor')) {
$im = @imagecreatetruecolor($width, $height);
} else {
$im = @imagecreate($width, $height);
}
if (empty($rgb)) {
$color = imagecolorallocate($im, 102, 104, 104);
} else {
$color = imagecolorallocate($im, $rgb[0], $rgb[1], $rgb[2]);
}
$backColor = imagecolorallocate($im, 255, 255, 255);    //背景色（随机）
$borderColor = imagecolorallocate($im, 100, 100, 100);                    //边框色
$pointColor = imagecolorallocate($im, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));                 //点颜色

@imagefilledrectangle($im, 0, 0, $width - 1, $height - 1, $backColor);
@imagerectangle($im, 0, 0, $width - 1, $height - 1, $borderColor);
@imagestring($im, 5, 5, 3, $string, $color);
if (!empty($disturb)) {
// 添加干扰
if ($disturb = 1 || $disturb = 3) {
for ($i = 0; $i < 25; $i++) {
imagesetpixel($im, mt_rand(0, $width), mt_rand(0, $height), $pointColor);
}
} elseif ($disturb = 2 || $disturb = 3) {
for ($i = 0; $i < 10; $i++) {
imagearc($im, mt_rand(-10, $width), mt_rand(-10, $height), mt_rand(30, 300), mt_rand(20, 200), 55, 44, $pointColor);
}
}
}
Image::output($im, $type, $filename);
}

/**
* 生成图像验证码
* @static
* @access public
* @param string $length  位数
* @param string $mode  类型
* @param string $type 图像格式
* @param string $width  宽度
* @param string $height  高度
* @return string
*/
static function buildImageVerify($length=4, $mode=1, $type='png', $width=48, $height=22, $verifyName='verify') {
import('ORG.Util.String');
$randval = String::randString($length, $mode);
session($verifyName, md5($randval));
$width = ($length * 10 + 10) > $width ? $length * 10 + 10 : $width;
if ($type != 'gif' && function_exists('imagecreatetruecolor')) {
$im = imagecreatetruecolor($width, $height);
} else {
$im = imagecreate($width, $height);
}
$r = Array(225, 255, 255, 223);
$g = Array(225, 236, 237, 255);
$b = Array(225, 236, 166, 125);
$key = mt_rand(0, 3);

$backColor = imagecolorallocate($im, $r[$key], $g[$key], $b[$key]);    //背景色（随机）
$borderColor = imagecolorallocate($im, 100, 100, 100);                    //边框色
imagefilledrectangle($im, 0, 0, $width - 1, $height - 1, $backColor);
imagerectangle($im, 0, 0, $width - 1, $height - 1, $borderColor);
$stringColor = imagecolorallocate($im, mt_rand(0, 200), mt_rand(0, 120), mt_rand(0, 120));
// 干扰
for ($i = 0; $i < 10; $i++) {
imagearc($im, mt_rand(-10, $width), mt_rand(-10, $height), mt_rand(30, 300), mt_rand(20, 200), 55, 44, $stringColor);
}
for ($i = 0; $i < 25; $i++) {
imagesetpixel($im, mt_rand(0, $width), mt_rand(0, $height), $stringColor);
}
for ($i = 0; $i < $length; $i++) {
imagestring($im, 5, $i * 10 + 5, mt_rand(1, 8), $randval{$i}, $stringColor);
}
Image::output($im, $type);
}

// 中文验证码
static function GBVerify($length=4, $type='png', $width=180, $height=50, $fontface='simhei.ttf', $verifyName='verify') {
import('ORG.Util.String');
$code = String::randString($length, 4);
$width = ($length * 45) > $width ? $length * 45 : $width;
session($verifyName, md5($code));
$im = imagecreatetruecolor($width, $height);
$borderColor = imagecolorallocate($im, 100, 100, 100);                    //边框色
$bkcolor = imagecolorallocate($im, 250, 250, 250);
imagefill($im, 0, 0, $bkcolor);
@imagerectangle($im, 0, 0, $width - 1, $height - 1, $borderColor);
// 干扰
for ($i = 0; $i < 15; $i++) {
$fontcolor = imagecolorallocate($im, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
imagearc($im, mt_rand(-10, $width), mt_rand(-10, $height), mt_rand(30, 300), mt_rand(20, 200), 55, 44, $fontcolor);
}
for ($i = 0; $i < 255; $i++) {
$fontcolor = imagecolorallocate($im, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
imagesetpixel($im, mt_rand(0, $width), mt_rand(0, $height), $fontcolor);
}
if (!is_file($fontface)) {
$fontface = dirname(__FILE__) . "/" . $fontface;
}
for ($i = 0; $i < $length; $i++) {
$fontcolor = imagecolorallocate($im, mt_rand(0, 120), mt_rand(0, 120), mt_rand(0, 120)); //这样保证随机出来的颜色较深。
$codex = String::msubstr($code, $i, 1);
imagettftext($im, mt_rand(16, 20), mt_rand(-60, 60), 40 * $i + 20, mt_rand(30, 35), $fontcolor, $fontface, $codex);
}
Image::output($im, $type);
}

/**
* 把图像转换成字符显示
* @static
* @access public
* @param string $image  要显示的图像
* @param string $type  图像类型，默认自动获取
* @return string
*/
static function showASCIIImg($image, $string='', $type='') {
$info = Image::getImageInfo($image);
if ($info !== false) {
$type = empty($type) ? $info['type'] : $type;
unset($info);
// 载入原图
$createFun = 'ImageCreateFrom' . ($type == 'jpg' ? 'jpeg' : $type);
$im = $createFun($image);
$dx = imagesx($im);
$dy = imagesy($im);
$i = 0;
$out = '<span style="padding:0px;margin:0;line-height:100%;font-size:1px;">';
set_time_limit(0);
for ($y = 0; $y < $dy; $y++) {
for ($x = 0; $x < $dx; $x++) {
$col = imagecolorat($im, $x, $y);
$rgb = imagecolorsforindex($im, $col);
$str = empty($string) ? '*' : $string[$i++];
$out .= sprintf('<span style="margin:0px;color:#%02x%02x%02x">' . $str . '</span>', $rgb['red'], $rgb['green'], $rgb['blue']);
}
$out .= "<br>\n";
}
$out .= '</span>';
imagedestroy($im);
return $out;
}
return false;
}

/**
* 生成UPC-A条形码
* @static
* @param string $type 图像格式
* @param string $type 图像格式
* @param string $lw  单元宽度
* @param string $hi   条码高度
* @return string
*/
static function UPCA($code, $type='png', $lw=2, $hi=100) {
static $Lencode = array('0001101', '0011001', '0010011', '0111101', '0100011',
'0110001', '0101111', '0111011', '0110111', '0001011');
static $Rencode = array('1110010', '1100110', '1101100', '1000010', '1011100',
'1001110', '1010000', '1000100', '1001000', '1110100');
$ends = '101';
$center = '01010';
/* UPC-A Must be 11 digits, we compute the checksum. */
if (strlen($code) != 11) {
die("UPC-A Must be 11 digits.");
}
/* Compute the EAN-13 Checksum digit */
$ncode = '0' . $code;
$even = 0;
$odd = 0;
for ($x = 0; $x < 12; $x++) {
if ($x % 2) {
$odd += $ncode[$x];
} else {
$even += $ncode[$x];
}
}
$code.= ( 10 - (($odd * 3 + $even) % 10)) % 10;
/* Create the bar encoding using a binary string */
$bars = $ends;
$bars.=$Lencode[$code[0]];
for ($x = 1; $x < 6; $x++) {
$bars.=$Lencode[$code[$x]];
}
$bars.=$center;
for ($x = 6; $x < 12; $x++) {
$bars.=$Rencode[$code[$x]];
}
$bars.=$ends;
/* Generate the Barcode Image */
if ($type != 'gif' && function_exists('imagecreatetruecolor')) {
$im = imagecreatetruecolor($lw * 95 + 30, $hi + 30);
} else {
$im = imagecreate($lw * 95 + 30, $hi + 30);
}
$fg = ImageColorAllocate($im, 0, 0, 0);
$bg = ImageColorAllocate($im, 255, 255, 255);
ImageFilledRectangle($im, 0, 0, $lw * 95 + 30, $hi + 30, $bg);
$shift = 10;
for ($x = 0; $x < strlen($bars); $x++) {
if (($x < 10) || ($x >= 45 && $x < 50) || ($x >= 85)) {
$sh = 10;
} else {
$sh = 0;
}
if ($bars[$x] == '1') {
$color = $fg;
} else {
$color = $bg;
}
ImageFilledRectangle($im, ($x * $lw) + 15, 5, ($x + 1) * $lw + 14, $hi + 5 + $sh, $color);
}
/* Add the Human Readable Label */
ImageString($im, 4, 5, $hi - 5, $code[0], $fg);
for ($x = 0; $x < 5; $x++) {
ImageString($im, 5, $lw * (13 + $x * 6) + 15, $hi + 5, $code[$x + 1], $fg);
ImageString($im, 5, $lw * (53 + $x * 6) + 15, $hi + 5, $code[$x + 6], $fg);
}
ImageString($im, 4, $lw * 95 + 17, $hi - 5, $code[11], $fg);
/* Output the Header and Content. */
Image::output($im, $type);
}

static function output($im, $type='png', $filename='') {
header("Content-type: image/" . $type);
$ImageFun = 'image' . $type;
if (empty($filename)) {
$ImageFun($im);
} else {
$ImageFun($im, $filename);
}
imagedestroy($im);
}

}