诸位:
我将一幅JPG图像,通过setWater函数嵌入水印后(图片),像素数没变,但是总大小变小了很多(从1.4M变为350k左右)!!应该是某个函数影响了图像每个像素的丰富度或色彩变化度。。是imagecopy吗?还是imagecreatetruecolor?
请高人指点!!!!下边贴出嵌入水印函数:
//嵌入水印程序, 文字水印和图片水印请分别添加!!!
function setWater($imgSrc,$markImg,$markText,$TextColor,$markPos,$fontType,$markType,$fontSize)
{
/*
参数说明:
$imgSrc:目标图片,可带相对目录地址,
$markImg:水印图片,可带相对目录地址,支持PNG和GIF两种格式,如水印图片在执行文件mark目录下,可写成:mark/mark.gif
$markText:给图片添加的水印文字
$TextColor:水印文字的字体颜色
$markPos:图片水印添加的位置,取值范围:0~9
0:随机位置,在1~8之间随机选取一个位置
1:顶部居左 2:顶部居中 3:顶部居右 4:左边居中
5:图片中心 6:右边居中 7:底部居左 8:底部居中 9:底部居右
$fontType:具体的字体库,可带相对目录地址
$markType:图片添加水印的方式,img代表以图片方式,text代表以文字方式添加水印
*/
$srcInfo = @getimagesize($imgSrc);
$srcImg_w = $srcInfo[0];
$srcImg_h = $srcInfo[1];
switch ($srcInfo[2])
{
case 1:
$srcim =@imagecreatefromgif($imgSrc);
if($srcim==false)
echo "打开失败!";
break;
case 2:
$srcim =@imagecreatefromjpeg($imgSrc);
if($srcim==false)
echo "打开失败!";
break;
case 3:
$srcim =@imagecreatefrompng($imgSrc);
if($srcim==false)
echo "打开失败!";
break;
default:
die("不支持的图片文件类型");
exit;
}
if(!strcmp($markType,"img"))
{
//print_r(" hello ! img");
if(!file_exists($markImg) || empty($markImg))
{
return;
}
$markImgInfo = @getimagesize($markImg);
$markImg_w = $markImgInfo[0];
$markImg_h = $markImgInfo[1];
if($srcImg_w {
return;
}
switch ($markImgInfo[2])
{
case 1:
$markim =@imagecreatefromgif($markImg);
if($markim==false)
echo "打开失败!";
break;
case 2:
$markim =@imagecreatefromjpeg($markImg);
if($markim==false)
echo "打开失败!";
break;
case 3:
$markim =@imagecreatefrompng($markImg);
if($markim==false)
echo "打开失败!";
break;
default:
die("不支持的水印图片文件类型");
exit;
}
$logow = $markImg_w;
$logoh = $markImg_h;
}
if(!strcmp($markType,"text"))
{
if(!empty($markText))
{
if(!file_exists($fontType))
{
//print_r(" hello ! no fonttype");
return;
}
}
else
{
//print_r(" hello ! no marktext");
return;
}
$box = imagettfbbox($fontSize, 0, $fontType,$markText);
$logow = max($box[2], $box[4]) - min($box[0], $box[6]);
$logoh = max($box[1], $box[3]) - min($box[5], $box[7]);
}
if($markPos == 0)
{
$markPos = rand(1, 9);
}
switch($markPos)
{
case 1:
$x = +25;
$y = +95;
break;
case 2:
$x = ($srcImg_w - $logow) / 2;
$y = +5;
break;
case 3:
$x = $srcImg_w - $logow - 105;
$y = +85;
break;
case 4:
$x = +5;
$y = ($srcImg_h - $logoh) / 2;
break;
case 5:
$x = ($srcImg_w - $logow) / 2;
$y = ($srcImg_h - $logoh) / 2;
break;
case 6:
$x = $srcImg_w - $logow - 5;
$y = ($srcImg_h - $logoh) / 2;
break;
case 7:
$x = +5;
$y = $srcImg_h - $logoh - 5;
break;
case 8:
$x = ($srcImg_w - $logow) / 2;
$y = $srcImg_h - $logoh - 5;
break;
case 9:
$x = $srcImg_w - $logow - 5;
$y = $srcImg_h - $logoh -5;
break;
default:
die("此位置不支持");
exit;
}
$dst_img=imagecreatetruecolor($srcImg_w, $srcImg_h); //建立空白背景,真彩色图片
imagecopy ( $dst_img, $srcim, 0, 0, 0, 0, $srcImg_w, $srcImg_h);
if(!strcmp($markType,"img"))
{
imagecopy($dst_img, $markim, $x, $y, 0, 0, $logow, $logoh);
imagedestroy($markim);
}
if(!strcmp($markType,"text"))
{
//print_r(" hello ! text2");
$rgb = explode(',', $TextColor);
$color = imagecolorallocate($dst_img, $rgb[0], $rgb[1], $rgb[2]);
imagettftext($dst_img, $fontSize, 0, $x, $y, $color, $fontType,$markText);
}
switch ($srcInfo[2])
{
case 1:
imagegif($dst_img, $imgSrc);
break;
case 2:
//print_r("hello!");
imagejpeg($dst_img, $imgSrc);
break;
case 3:
imagepng($dst_img, $imgSrc);
break;
default:
die("不支持的水印图片文件类型");
exit;
}
imagedestroy($dst_img);
imagedestroy($srcim);
}
回复讨论(解决方案)
imagejpeg
第三个参数设置的图片的质量,默认不是最佳。是不是这个原因导致的呢?
是的,多谢指教!网上找的函数,没有逐个函数推敲,只管能用就可以了。多谢多谢!

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