<?php
// 圖片添加水印的方法  
// 參數(shù)：source-主圖极祸、water-水印圖、position-水印的位置（將圖片分為九宮格）、alpha-透明度济瓢、type-輸出圖片格式、path-輸出路徑护侮、isRandName-圖片文件名是否隨機(jī)
function watermark($source, $water, $position = 9, $alpha = 100, $type = 'jpeg', $path = 'test', $isRandName = true)
{
    // 打開圖片
    $sourceRes = open($source);
    $waterRes = open($water);

    // 獲取圖片大小畜隶，算出水印放置的位置
    $sourceInfo = getimagesize($source);
    $waterInfo = getimagesize($water);

    switch ($position) { //算出位置
        case 1:
            $x = 0;
            $y = 0;
            break;
        case 2:
            $x = ($sourceInfo[0] - $waterInfo[0]) / 2;
            $y = 0;
            break;
        case 3:
            $x = $sourceInfo[0] - $waterInfo[0];
            $y = 0;
            break;
        case 4:
            $x = 0;
            $y = ($sourceInfo[1] - $waterInfo[1]) / 2;
            break;
        case 5:
            $x = ($sourceInfo[0] - $waterInfo[0]) / 2;
            $y = ($sourceInfo[1] - $waterInfo[1]) / 2;
            break;
        case 6:
            $x = $sourceInfo[0] - $waterInfo[0];
            $y = ($sourceInfo[1] - $waterInfo[1]) / 2;
            break;
        case 7:
            $x = 0;
            $y = $sourceInfo[1] - $waterInfo[1];
            break;
        case 8:
            $x = ($sourceInfo[0] - $waterInfo[0]) / 2;
            $y = $sourceInfo[1] - $waterInfo[1];
            break;
        case 9:
            $x = $sourceInfo[0] - $waterInfo[0];
            $y = $sourceInfo[1] - $waterInfo[1];
            break;
        default: //如果沒有傳1-9的數(shù)字就默認(rèn)隨機(jī)放
            $x = mt_rand(0, $sourceInfo[0] - $waterInfo[0]);
            $y = mt_rand(0, $sourceInfo[1] - $waterInfo[1]);
            break;
    }

    // 使用剛求出的$x,$y合并兩張圖片
    imagecopymerge($sourceRes, $waterRes, $x, $y, 0, 0, $waterInfo[0], $waterInfo[1], $alpha);

    // 處理路徑與文件名
    $func = 'image' . $type;
    /* 
    imagepng();
    imagejpeg();
    imagewbmp();
    */
    if ($isRandName) {
        $name = uniqid() . '.' . $type;
    } else {
        $pathInfo = pathinfo($source);
        $name = $pathInfo['filename'] . '.' . $type;
    }

    $path = rtrim($path, '/') . '/' . $name;
    $func($sourceRes, $path);
    imagedestroy($sourceRes);
    imagedestroy($waterRes);
}

// 打開圖片的函數(shù)
function open($path)
{
    // 判斷是否存在
    if (!file_exists($path)) {
        exit('文件不存在');
    }

    $info = getimagesize($path);
    switch ($info['mime']) {
        case 'image/jpeg':
        case 'image/jpg':
        case 'image/pjpeg':
            $res = imagecreatefromjpeg($path);
            break;
        case 'image/png':
            $res = imagecreatefrompng($path);
            break;
        case 'image/gif':
            $res = imagecreatefromgif($path);
            break;
        case 'image/wbmp':
        case 'image/bmp':
            $res = imagecreatefromwebp($path);
            break;
    }
    return $res;
}

// watermark('E:\phpstudy_pro\WWW\test.png', 'E:\phpstudy_pro\WWW\watermark.png', 1.2);