PHP shares two methods of adding watermark to images

<?<span style="color: #000000;">php
</span><span style="color: #008000;">//</span><span style="color: #008000;"> http://www.manongjc.com</span>
<span style="color: #800080;">$img</span> = imagecreatefromjpeg(<span style="color: #800080;">$filename</span><span style="color: #000000;">);
</span><span style="color: #800080;">$logo</span> = imagecreatefromjpeg(<span style="color: #800080;">$filename</span><span style="color: #000000;">);
</span><span style="color: #008000;">/*</span><span style="color: #008000;">imagecraetefromjpeg-由文件或URL创建一个新图像
imagecreatefromjpeg(string $filename)
如果启用了fopen包装器，URL可以作为文件名</span><span style="color: #008000;">*/</span><span style="color: #000000;">
imagecopy(</span><span style="color: #800080;">$img</span>,<span style="color: #800080;">$logo</span>,15,15,0,0,<span style="color: #800080;">$width</span>,<span style="color: #800080;">$height</span><span style="color: #000000;">);
</span><span style="color: #008000;">/*</span><span style="color: #008000;">imagecopy($dst_im,$src_im,$dst_x,$dst_y,$src_x,$src_y,$src_w,$src_h)
$dst_im是背景图像，就是需要添加水印的图片
$src_im是水印图片；$dst_x,#dst_y需要把水印放到背景图片的(x,y)坐标;
$src_x,$src_y是截取水印的图片的开始坐标
$width，$height是截取的图片的就是水印的长度和宽度</span><span style="color: #008000;">*/</span>
<span style="color: #800080;">$url</span> = 'http://www.stchat.cn/data/attachment/forum/201506/12/100759pidbdaydh8dy7iby.jpg'<span style="color: #000000;">;
</span><span style="color: #800080;">$content</span> = <span style="color: #008080;">file_get_contents</span>(<span style="color: #800080;">$url</span>);<span style="color: #008000;">//</span><span style="color: #008000;">把url写入到content这个变量里面</span><span style="color: #008000;">
/*</span><span style="color: #008000;">file_get_contents--将整个文件读入到一个字符串</span><span style="color: #008000;">*/</span>
<span style="color: #800080;">$filename</span> = 'tmp.jpg'<span style="color: #000000;">;
</span><span style="color: #008080;">file_put_contents</span>(<span style="color: #800080;">$filename</span>,<span style="color: #800080;">$content</span><span style="color: #000000;">);
</span><span style="color: #008000;">//</span><span style="color: #008000;">把所有内容放到filename这个变量里面，第一个存放的是背景图片</span><span style="color: #008000;">
/*</span><span style="color: #008000;">file_put_contents(string $filename,mixed $data)将一个字符串写入一个文件
filename要被写入数据的文件名
data要写入的数据，类型可以是string,array或者是stream资源</span><span style="color: #008000;">*/</span>
<span style="color: #800080;">$url</span> = ''<span style="color: #000000;">;
</span><span style="color: #008080;">file_put_contents</span>('logo.png',<span style="color: #008080;">file_get_contents</span>(<span style="color: #800080;">$url</span><span style="color: #000000;">));
</span><span style="color: #008000;">//</span><span style="color: #008000;">第二个是水印的图片</span>
<span style="color: #800080;">$img</span> = imagecreatefromjpeg(<span style="color: #800080;">$filename</span><span style="color: #000000;">);
</span><span style="color: #800080;">$logo</span> = imagecreatefrompng('logo.png'<span style="color: #000000;">);
</span><span style="color: #800080;">$size</span> = <span style="color: #008080;">getimagesize</span>('logo.png'<span style="color: #000000;">);
</span><span style="color: #008000;">/*</span><span style="color: #008000;">getimagesize()获得图像大小</span><span style="color: #008000;">*/</span><span style="color: #000000;">
imagecopy(</span><span style="color: #800080;">$img</span>,<span style="color: #800080;">$logo</span>,15,15,0,0,<span style="color: #800080;">$size</span>[0],<span style="color: #800080;">$size</span>[1<span style="color: #000000;">]);
</span><span style="color: #008080;">header</span>("centent-type:image/jpeg"<span style="color: #000000;">);
imagejpeg(img);
</span>?>

<?<span style="color: #000000;">php
</span><span style="color: #008000;">//</span><span style="color: #008000;"> http://www.manongjc.com/article/593.html</span><span style="color: #008000;">
/*</span><span style="color: #008000;">给图片加文字水印的方法</span><span style="color: #008000;">*/</span>
<span style="color: #800080;">$dst_path</span> = 'http://f4.topitme.com/4/15/11/1166351597fe111154l.jpg'<span style="color: #000000;">;
</span><span style="color: #800080;">$dst</span> = imagecreatefromstring(<span style="color: #008080;">file_get_contents</span>(<span style="color: #800080;">$dst_path</span><span style="color: #000000;">));
</span><span style="color: #008000;">/*</span><span style="color: #008000;">imagecreatefromstring()--从字符串中的图像流新建一个图像，返回一个图像标示符，其表达了从给定字符串得来的图像
图像格式将自动监测，只要php支持jpeg,png,gif,wbmp,gd2.</span><span style="color: #008000;">*/</span>
  
<span style="color: #800080;">$font</span> = './t1.ttf'<span style="color: #000000;">;
</span><span style="color: #800080;">$black</span> = imagecolorallocate(<span style="color: #800080;">$dst</span>, 0, 0, 0<span style="color: #000000;">);
imagefttext(</span><span style="color: #800080;">$dst</span>, 20, 0, 10, 30, <span style="color: #800080;">$black</span>, <span style="color: #800080;">$font</span>, 'Hello world!'<span style="color: #000000;">);
</span><span style="color: #008000;">/*</span><span style="color: #008000;">imagefttext($img,$size,$angle,$x,$y,$color,$fontfile,$text)
$img由图像创建函数返回的图像资源
size要使用的水印的字体大小
angle（角度）文字的倾斜角度，如果是0度代表文字从左往右，如果是90度代表从上往下
x,y水印文字的第一个文字的起始位置
color是水印文字的颜色
fontfile，你希望使用truetype字体的路径
http://www.manongjc.com/article/1302.html </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">list</span>(<span style="color: #800080;">$dst_w</span>,<span style="color: #800080;">$dst_h</span>,<span style="color: #800080;">$dst_type</span>) = <span style="color: #008080;">getimagesize</span>(<span style="color: #800080;">$dst_path</span><span style="color: #000000;">);
</span><span style="color: #008000;">/*</span><span style="color: #008000;">list(mixed $varname[,mixed $......])--把数组中的值赋给一些变量
像array()一样，这不是真正的函数，而是语言结构，List()用一步操作给一组变量进行赋值</span><span style="color: #008000;">*/</span>
<span style="color: #008000;">/*</span><span style="color: #008000;">getimagesize()能获取到什么信息？
getimagesize函数会返回图像的所有信息，包括大小，类型等等</span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">switch</span>(<span style="color: #800080;">$dst_type</span><span style="color: #000000;">){
  </span><span style="color: #0000ff;">case</span> 1:<span style="color: #008000;">//</span><span style="color: #008000;">GIF</span>
    <span style="color: #008080;">header</span>("content-type:image/gif"<span style="color: #000000;">);
    imagegif(</span><span style="color: #800080;">$dst</span><span style="color: #000000;">);
    </span><span style="color: #0000ff;">break</span><span style="color: #000000;">;
  </span><span style="color: #0000ff;">case</span> 2:<span style="color: #008000;">//</span><span style="color: #008000;">JPG</span>
    <span style="color: #008080;">header</span>("content-type:image/jpeg"<span style="color: #000000;">);
    imagejpeg(</span><span style="color: #800080;">$dst</span><span style="color: #000000;">);
    </span><span style="color: #0000ff;">break</span><span style="color: #000000;">;
  </span><span style="color: #0000ff;">case</span> 3:<span style="color: #008000;">//</span><span style="color: #008000;">PNG</span>
    <span style="color: #008080;">header</span>("content-type:image/png"<span style="color: #000000;">);
    imagepng(</span><span style="color: #800080;">$dst</span><span style="color: #000000;">);
    </span><span style="color: #0000ff;">break</span><span style="color: #000000;">;
  </span><span style="color: #0000ff;">default</span>:
    <span style="color: #0000ff;">break</span><span style="color: #000000;">;
  </span><span style="color: #008000;">/*</span><span style="color: #008000;">imagepng--以PNG格式将图像输出到浏览器或文件
  imagepng()将GD图像流(image)以png格式输出到标注输出（通常为浏览器），或者如果用filename给出了文件名则将其输出到文件</span><span style="color: #008000;">*/</span><span style="color: #000000;">
}
imagedestroy(</span><span style="color: #800080;">$dst</span><span style="color: #000000;">);
</span>?>