<?php

function imageWaterMark($groundImage,$waterPos=0,$waterImage="",$waterText="",$textFont=5,$textColor="#FF0000",$transparent=100,$quality=100) {
	if(substr($waterImage,0,1) == '/'){
		$waterImage = substr($waterImage,1);
	}
    $isWaterImage = FALSE;
    $formatMsg = "暂不支持该文件格式，请用图片处理软件将图片转换为GIF、JPG、PNG格式。";
    if(!empty($waterImage) &&file_exists($waterImage)) {
        $isWaterImage = TRUE;
        $water_info = getimagesize($waterImage);
        $water_w = $water_info[0];
        $water_h = $water_info[1];
        switch($water_info[2]) {
            case 1:
            	$water_im = imagecreatefromgif($waterImage);
                break;
            case 2:
            	$water_im = imagecreatefromjpeg($waterImage);
                break;
            case 3:
            	$water_im = imagecreatefrompng($waterImage);
                break;
            default:die($formatMsg);
        }
    }
    if(!empty($groundImage) &&file_exists($groundImage)) {
        $ground_info = getimagesize($groundImage);
        $ground_w = $ground_info[0];
        $ground_h = $ground_info[1];
        switch($ground_info[2]) {
            case 1:
            	$ground_im = imagecreatefromgif($groundImage);
                break;
            case 2:
            	$ground_im = imagecreatefromjpeg($groundImage);
                break;
            case 3:
            	$ground_im = imagecreatefrompng($groundImage);
                break;
            default:die($formatMsg);
        }
    }else {
        return;
    }
    if($isWaterImage) {
        $w = $water_w;
        $h = $water_h;
        $label = "图片的";
    }else {
        $temp = @imagettfbbox(ceil($textFont*2.5),0,"./cour.ttf",$waterText);
        $w = $temp[2] -$temp[6];
        $h = $temp[3] -$temp[7];
        unset($temp);
        $label = "文字区域";
    }
    if( ($ground_w<=$w) ||($ground_h<=$h) ) {
        return;
    }
    switch($waterPos) {
        case 0:
            $posX = rand(0,($ground_w -$w));
            $posY = rand(0,($ground_h -$h));
            break;
        case 1:
            $posX = 0;
            $posY = 0;
            break;
        case 2:
            $posX = ($ground_w -$w) / 2;
            $posY = 0;
            break;
        case 3:
            $posX = $ground_w -$w;
            $posY = 0;
            break;
        case 4:
            $posX = 0;
            $posY = ($ground_h -$h) / 2;
            break;
        case 5:
            $posX = ($ground_w -$w) / 2;
            $posY = ($ground_h -$h) / 2;
            break;
        case 6:
            $posX = $ground_w -$w;
            $posY = ($ground_h -$h) / 2;
            break;
        case 7:
            $posX = 0;
            $posY = $ground_h -$h;
            break;
        case 8:
            $posX = ($ground_w -$w) / 2;
            $posY = $ground_h -$h;
            break;
        case 9:
            $posX = $ground_w -$w;
            $posY = $ground_h -$h;
            break;
        default:
            $posX = rand(0,($ground_w -$w));
            $posY = rand(0,($ground_h -$h));
            break;
    }
    if($posX<20) $posX=20;
    if($posY<20) $posY=20;
    if($posX>$ground_w -$w-20) $posX=$ground_w -$w-20;
    if($posY>$ground_h -$h-20) $posY=$ground_h -$h-20;
    imagesavealpha($ground_im,true);
    imagealphablending($ground_im,false);
    imagesavealpha($water_im,true);
    imagealphablending($water_im,false);
    if($isWaterImage) {
        imagecopymerge_alpha($ground_im,$water_im,$posX,$posY,0,0,$water_w,$water_h,$transparent);
    }else {
        if( !empty($textColor) &&(strlen($textColor)==7) ) {
            $R = hexdec(substr($textColor,1,2));
            $G = hexdec(substr($textColor,3,2));
            $B = hexdec(substr($textColor,5));
        }else {
            die("水印文字颜色格式不正确！");
        }
        imagestring ( $ground_im,$textFont,$posX,$posY,$waterText,imagecolorallocate($ground_im,$R,$G,$B));
    }
    @unlink($groundImage);
    switch($ground_info[2]) {
        case 1:
        	imagegif($ground_im,$groundImage);
            break;
        case 2:
        	imagejpeg($ground_im,$groundImage,$quality);
            break;
        case 3:
        	imagepng($ground_im,$groundImage);
            break;
        default:die('未知格式');
    }
    if(isset($water_info)) unset($water_info);
    if(isset($water_im)) imagedestroy($water_im);
    unset($ground_info);
    imagedestroy($ground_im);
}

function imagecopymerge_alpha($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h, $pct){
	// getting the watermark width
	$w = imagesx($src_im);
	// getting the watermark height
	$h = imagesy($src_im);
	 
	// creating a cut resource
	$cut = imagecreatetruecolor($src_w, $src_h);
	// copying that section of the background to the cut
	imagecopy($cut, $dst_im, 0, 0, $dst_x, $dst_y, $src_w, $src_h);
	// inverting the opacity
	//$opacity = 100 - $opacity;
	 
	// placing the watermark now
	imagecopy($cut, $src_im, 0, 0, $src_x, $src_y, $src_w, $src_h);
	imagecopymerge($dst_im, $cut, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h, $pct);
}