php生成水印函数

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/*

 * 图片加水印

 * $source  string  图片资源

 * $target  string  添加水印后的名字

 * $w_pos   int     水印位置 具体看代码

 * $w_img   string  水印图片路径

 * $w_text  string  显示的文字

 * $w_font  int     字体大小

 * $w_color string  字体颜色

 */

function watermark($source, $target = ‘’, $w_pos = ‘’, $w_img = ‘’, $w_text = ‘80shihua.com’, $w_font = 10, $w_color = ‘#CC0000’)

{

   if (!$target) {

        $target = $source;

    }

    $w_minwidth = 200;

    $w_minheight = 200;

    $w_quality =90;//图像质量

    $w_pct = 85; //透明度

    $source_info = getimagesize($source); //图片信息

    $source_w = $source_info[0]; //图片宽度

    $source_h = $source_info[1]; //图片高度

    if ($source_w < $w_minwidth || $source_h < $w_minheight) {
        return false;
    }

    switch ($source_info[2]) {
        //图片类型
        case 1: //GIF格式
            $source_img = imagecreatefromgif($source);
            break;
        case 2: //JPG格式
            $source_img = imagecreatefromjpeg($source);
            break;
        case 3: //PNG格式
            $source_img = imagecreatefrompng($source);
            //imagealphablending($source_img,false); //关闭混色模式
            imagesavealpha($source_img, true); //设置标记以在保存 PNG 图像时保存完整的 alpha 通道信息（与单一透明色相反）
            break;
        default:
            return false;
    }

    if (!empty($w_img) && file_exists($w_img)) {
        //水印图片有效
        $ifwaterimage = 1; //标记
        $water_info = getimagesize($w_img);
        $width = $water_info[0];
        $height = $water_info[1];

        switch ($water_info[2]) {
            case 1:
                $water_img = imagecreatefromgif($w_img);
                break;
            case 2:
                $water_img = imagecreatefromjpeg($w_img);
                break;
            case 3:
                $water_img = imagecreatefrompng($w_img);
                //imagealphablending($w_img, false);
                //imagesavealpha($w_img, true);
                break;
            default:
                return;
        }
    } else {
       
        $path = '/80shihua.ttf';
        $ifwaterimage = 0;
        $temp = imagettfbbox(ceil($w_font * 2.5), 0, $path, $w_text); //imagettfbbox返回一个含有 8 个单元的数组表示了文本外框的四个角
        $width = $temp[2] - $temp[6];
        $height = $temp[3] - $temp[7];
        unset($temp);
    }

    switch ($w_pos) {
        case 1:
            $wx = 5;
            $wy = 5;
            break;
        case 2:
            $wx = ($source_w - $width) / 2;
            $wy = 0;
            break;
        case 3:
            $wx = $source_w - $width;
            $wy = 0;
            break;
        case 4:
            $wx = 0;
            $wy = ($source_h - $height) / 2;
            break;
        case 5:
            $wx = ($source_w - $width) / 2;
            $wy = ($source_h - $height) / 2;
            break;
        case 6:
            $wx = $source_w - $width;
            $wy = ($source_h - $height) / 2;
            break;
        case 7:
            $wx = 0;
            $wy = $source_h - $height;
            break;
        case 8:
            $wx = ($source_w - $width) / 2;
            $wy = $source_h - $height;
            break;
        case 9:
            $wx = $source_w - ($width + 5);
            $wy = $source_h - ($height + 5);
            break;
        case 10:
            $wx = rand(0, ($source_w - $width));
            $wy = rand(0, ($source_h - $height));
            break;
        default:
            $wx = rand(0, ($source_w - $width));
            $wy = rand(0, ($source_h - $height));
            break;
    }
    if ($ifwaterimage) {
        if ($water_info[2] == 3) {
            imagecopy($source_img, $water_img, $wx, $wy, 0, 0, $width, $height);
        } else {
            imagecopymerge($source_img, $water_img, $wx, $wy, 0, 0, $width, $height, $this->w_pct);

        }

    } else {

        if (!empty($w_color) && (strlen($w_color) == 7)) {

            $r = hexdec(substr($w_color, 1, 2));

            $g = hexdec(substr($w_color, 3, 2));

            $b = hexdec(substr($w_color, 5));

        } else {

            return;

        }

imagestring($source_img, $w_font, $wx, $wy, $w_text, imagecolorallocate($source_img, $r, $g, $b));

    }

switch ($source_info[2]) {

        case 1:

            imagegif($source_img, $target);

            //GIF 格式将图像输出到浏览器或文件(欲输出的图像资源, 指定输出图像的文件名)

            break;

        case 2:

            imagejpeg($source_img, $target, $this->w_quality);

            break;

        case 3:

            imagepng($source_img, $target);

            break;

        default:

            return;

    }

    if (isset($water_info)) {

        unset($water_info);

    }

    if (isset($water_img)) {

        imagedestroy($water_img);

    }

    unset($source_info);

    imagedestroy($source_img);

    return true;

}

`

存在水印图片则根据图片生成水印，否则调用80shihua.ttf字体文件生成水印，水印文字可以自己指定.