Watermark PDF Issue

### Solution 1: Adjust the Watermark Layer
The `WooCommerce PDF Invoices` plugin allows you to set the layer where the watermark appears. You want the watermark to appear behind the content, not in front of it.

1. **Go to WordPress Dashboard**:
– Navigate to `WooCommerce` > `PDF Invoices`.

2. **Access the Plugin Settings**:
– Click on the **Settings** tab.

3. **Adjust the Watermark Settings**:
– Look for the **Watermark** section.
– Check for an option like "Watermark Layer" or "Watermark Position."
– Set it to `Behind` or `Background`.

4. **Save Changes**:
– Save the settings and generate a new PDF invoice to verify that the watermark appears correctly.

### Solution 2: Modify the Watermark Code (if using custom code)
If you are using custom code to add a watermark using `Dompdf`, you might need to adjust the `setWatermarkText()` or `setWatermarkImage()` function. Make sure the watermark is added before the main content to ensure it's placed in the background.

Here's an example of how to set the watermark in the background using `Dompdf`:

use DompdfDompdf;
use DompdfOptions;

$options = new Options();
$options->set('isHtml5ParserEnabled', true);
$options->set('isRemoteEnabled', true);

$dompdf = new Dompdf($options);
$dompdf->loadHtml($htmlContent);

// Set watermark text
$dompdf->getCanvas()->page_script(function ($canvas, $pageNumber, $pageCount) {
    $canvas->set_opacity(0.1); // Set opacity for the watermark
    $canvas->text(250, 400, 'WATERMARK', 'Helvetica', 50, [0.85, 0.85, 0.85], 0, 0, 45); // Adjust as needed
});

$dompdf->render();
$dompdf->stream("invoice.pdf", ["Attachment" => false]);

### Solution 3: Clear Caches
If you are using caching plugins or have server-side caching enabled, clear your cache:

1. Clear your WordPress cache if you're using a caching plugin.
2. Clear your browser cache.
3. Regenerate the invoice to see if the changes are applied.

### Solution 4: Check for Plugin Updates
Ensure that you are using the latest version of the `WooCommerce PDF Invoices` plugin:

1. **Update Plugin**:
– Go to `Plugins` > `Installed Plugins`.
– Look for **WooCommerce PDF Invoices**.
– Click **Update Now** if an update is available.

2. **Check Compatibility**:
– Verify that the plugin is compatible with your current version of WordPress and WooCommerce.

By trying these steps, you should be able to correct the issue with the watermark appearing above the text in your PDF invoices.

Here's a detailed troubleshooting guide to fix this issue:

### Step 1: Adjust Watermark Settings in the Plugin
Ensure that the watermark is set to appear behind the content:

1. **Go to PDF Invoices Settings**:
– Navigate to `WooCommerce` > `PDF Invoices`.

2. **Check the Watermark Settings**:
– Locate the **Watermark** section.
– Ensure that options like **Watermark Position** or **Watermark Layer** are set to appear **behind** the content (if available).

3. **Save Settings**:
– Save changes and regenerate a new PDF invoice.

### Step 2: Test with Default Theme
To rule out theme-related issues:

1. **Switch to a Default WordPress Theme** (e.g., Twenty Twenty-Four):
– Go to `Appearance` > `Themes`.
– Activate a default theme temporarily.

2. **Generate a New PDF Invoice**:
– Check if the watermark issue persists.
– If it works correctly, the issue could be related to your custom theme.

3. **Switch Back to Your Original Theme**:
– If switching themes resolves the issue, consider reaching out to your theme developer for a fix.

### Step 3: Disable Other Plugins
Conflicts with other plugins can cause issues with PDF generation:

1. **Deactivate All Other Plugins Except WooCommerce and PDF Invoices**:
– Go to `Plugins` > `Installed Plugins`.
– Deactivate plugins one by one, except WooCommerce and PDF Invoices.

2. **Check the PDF Invoice**:
– Regenerate an invoice and see if the watermark appears correctly.
– If the problem is resolved, reactivate your plugins one by one to identify the conflicting plugin.

### Step 4: Modify Dompdf Configuration (Custom Solution)
If you're using custom code with `Dompdf`, the watermark might be drawn after the main content due to the order of function calls. You can force the watermark to appear behind the content by using the `page_script` method or adjusting the canvas layer:

use DompdfDompdf;
use DompdfOptions;

$options = new Options();
$options->set('isHtml5ParserEnabled', true);
$options->set('isRemoteEnabled', true);

$dompdf = new Dompdf($options);
$dompdf->loadHtml($htmlContent);

// Render content first
$dompdf->render();

// Add watermark in the background after rendering the content
$canvas = $dompdf->getCanvas();
$canvas->set_opacity(0.1, "multiply"); // Apply opacity
$canvas->text(200, 500, 'WATERMARK', 'Helvetica', 70, [0.8, 0.8, 0.8], 45);

$dompdf->stream("invoice.pdf", ["Attachment" => false]);

### Step 5: Check for Template Overrides
If you've customized the PDF template:

1. **Check for Overridden Templates**:
– Go to `wp-content/themes/your-theme/woocommerce/pdf/`.
– Ensure your custom template files are not interfering with the watermark.

2. **Revert to Default Templates**:
– Try removing or renaming the custom template files to see if the default template resolves the issue.

### Step 6: Increase Memory Limit
If your PDF is complex, it may exceed the default memory limit:

1. **Edit `wp-config.php`**:

define('WP_MEMORY_LIMIT', '256M');

2. **Edit `.htaccess`** (if necessary):

php_value memory_limit 256M

By following these steps, you should be able to address the watermark issue with your WooCommerce PDF invoices. Let me know if you need further assistance!