PHP怎么处理图片水印 PHP添加水印的完整实现教程

<?php
// 使用GD库添加水印示例
function addWatermarkGD($source, $watermark, $output) {
    $sourceImage = imagecreatefromjpeg($source); // 支持jpeg，根据图片类型修改
    $watermarkImage = imagecreatefrompng($watermark); // 水印一般用png，支持透明

    $sourceWidth = imagesx($sourceImage);
    $sourceHeight = imagesy($sourceImage);
    $watermarkWidth = imagesx($watermarkImage);
    $watermarkHeight = imagesy($watermarkImage);

    // 水印位置，这里放在右下角
    $destX = $sourceWidth - $watermarkWidth - 10;
    $destY = $sourceHeight - $watermarkHeight - 10;

    // 合并水印
    imagecopy($sourceImage, $watermarkImage, $destX, $destY, 0, 0, $watermarkWidth, $watermarkHeight);

    // 输出图片
    imagejpeg($sourceImage, $output, 80); // 80是图片质量

    // 释放资源
    imagedestroy($sourceImage);
    imagedestroy($watermarkImage);
}

// 调用示例
addWatermarkGD('source.jpg', 'watermark.png', 'output.jpg');
?>

<?php
// 使用imagecopymerge添加透明水印
function addWatermarkGDTransparent($source, $watermark, $output, $opacity) {
    $sourceImage = imagecreatefromjpeg($source);
    $watermarkImage = imagecreatefrompng($watermark);

    $sourceWidth = imagesx($sourceImage);
    $sourceHeight = imagesy($sourceImage);
    $watermarkWidth = imagesx($watermarkImage);
    $watermarkHeight = imagesy($watermarkImage);

    $destX = $sourceWidth - $watermarkWidth - 10;
    $destY = $sourceHeight - $watermarkHeight - 10;

    // 使用imagecopymerge，最后一个参数是透明度，范围是0-100，0完全透明，100不透明
    imagecopymerge($sourceImage, $watermarkImage, $destX, $destY, 0, 0, $watermarkWidth, $watermarkHeight, $opacity);

    imagejpeg($sourceImage, $output, 80);

    imagedestroy($sourceImage);
    imagedestroy($watermarkImage);
}

// 调用示例，透明度50
addWatermarkGDTransparent('source.jpg', 'watermark.png', 'output.jpg', 50);
?>

<?php
function addWatermarkAuto($source, $watermark, $output, $opacity) {
    $imageInfo = getimagesize($source);
    $imageType = $imageInfo[2];

    switch ($imageType) {
        case IMAGETYPE_JPEG:
            $sourceImage = imagecreatefromjpeg($source);
            break;
        case IMAGETYPE_PNG:
            $sourceImage = imagecreatefrompng($source);
            break;
        case IMAGETYPE_GIF:
            $sourceImage = imagecreatefromgif($source);
            break;
        default:
            die("不支持的图片类型");
    }

    $watermarkImage = imagecreatefrompng($watermark);

    $sourceWidth = imagesx($sourceImage);
    $sourceHeight = imagesy($sourceImage);
    $watermarkWidth = imagesx($watermarkImage);
    $watermarkHeight = imagesy($watermarkImage);

    $destX = $sourceWidth - $watermarkWidth - 10;
    $destY = $sourceHeight - $watermarkHeight - 10;

    imagecopymerge($sourceImage, $watermarkImage, $destX, $destY, 0, 0, $watermarkWidth, $watermarkHeight, $opacity);

    // 根据原始图片类型输出
    switch ($imageType) {
        case IMAGETYPE_JPEG:
            imagejpeg($sourceImage, $output, 80);
            break;
        case IMAGETYPE_PNG:
            imagepng($sourceImage, $output);
            break;
        case IMAGETYPE_GIF:
            imagegif($sourceImage, $output);
            break;
    }


    imagedestroy($sourceImage);
    imagedestroy($watermarkImage);
}

// 调用示例
addWatermarkAuto('source.png', 'watermark.png', 'output.png', 50);
?>

<?php
// 使用ImageMagick添加水印示例
function addWatermarkIM($source, $watermark, $output) {
    $image = new Imagick($source);
    $watermarkImage = new Imagick($watermark);

    $sourceWidth = $image->getImageWidth();
    $sourceHeight = $image->getImageHeight();
    $watermarkWidth = $watermarkImage->getImageWidth();
    $watermarkHeight = $watermarkImage->getImageHeight();

    $destX = $sourceWidth - $watermarkWidth - 10;
    $destY = $sourceHeight - $watermarkHeight - 10;

    // 调整水印大小
    // $watermarkImage->scaleImage($sourceWidth * 0.2, $sourceHeight * 0.2);

    // 设置水印透明度
    $watermarkImage->setImageOpacity(0.5);

    // 合并水印
    $image->compositeImage($watermarkImage, Imagick::COMPOSITE_OVER, $destX, $destY);

    // 输出图片
    $image->writeImage($output);

    // 释放资源
    $image->destroy();
    $watermarkImage->destroy();
}

// 调用示例
addWatermarkIM('source.jpg', 'watermark.png', 'output.jpg');
?>

<?php
function addTextWatermark($source, $text, $output, $font, $color) {
    $sourceImage = imagecreatefromjpeg($source);
    $sourceWidth = imagesx($sourceImage);
    $sourceHeight = imagesy($sourceImage);

    // 设置字体颜色
    $textColor = imagecolorallocate($sourceImage, hexdec(substr($color, 1, 2)), hexdec(substr($color, 3, 2)), hexdec(substr($color, 5, 2)));

    // 设置字体大小
    $fontSize = 20;

    // 计算文字位置，这里放在右下角
    $textWidth = strlen($text) * 10; // 估算文字宽度
    $textHeight = $fontSize;
    $destX = $sourceWidth - $textWidth - 10;
    $destY = $sourceHeight - $textHeight - 10;

    // 添加文字
    imagestring($sourceImage, 5, $destX, $destY, $text, $textColor); // imagestring 字体较小，可以使用imagettftext

    // 输出图片
    imagejpeg($sourceImage, $output, 80);

    // 释放资源
    imagedestroy($sourceImage);
}

// 调用示例，字体颜色为白色，字体文件需要存在
addTextWatermark('source.jpg', 'My Watermark', 'output.jpg', 'arial.ttf', '#FFFFFF');
?>

<?php
// 批量添加水印
function batchAddWatermark($sourceDir, $watermark, $outputDir, $opacity) {
    $files = scandir($sourceDir);
    foreach ($files as $file) {
        if ($file == "." || $file == "..") {
            continue;
        }

        $source = $sourceDir . "/" . $file;
        $output = $outputDir . "/" . $file;

        // 检查是否是图片文件，简单判断后缀
        $ext = strtolower(pathinfo($file, PATHINFO_EXTENSION));
        if (in_array($ext, ['jpg', 'jpeg', 'png', 'gif'])) {
            addWatermarkAuto($source, $watermark, $output, $opacity);
            echo "已处理: " . $file . "<br>";
        }
    }
}

// 调用示例
batchAddWatermark('images', 'watermark.png', 'watermarked', 50);
?>