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Imagick Image Processor

addWatermark()

Adds a watermark to an image with flexible positioning and diagonal-based scaling.

Signature

Section titled “Signature”
public function addWatermark(
    string $inputImagePath,
    string $outputImagePath,
    string $watermarkImagePath,
    string $position = 'center',
    int $scalePercent = 10
): void

Parameters

Section titled “Parameters”

$inputImagePath (string, required)

Section titled “$inputImagePath (string, required)”

Path to the input image file.

$outputImagePath (string, required)

Section titled “$outputImagePath (string, required)”

Path where the watermarked image will be saved.

$watermarkImagePath (string, required)

Section titled “$watermarkImagePath (string, required)”

Path to the watermark image file. PNG with transparency recommended.

$position (string, optional)

Section titled “$position (string, optional)”

Watermark position. Default: 'center'

Valid values:

  • 'center' - Center of image
  • 'top' - Top center
  • 'bottom' - Bottom center
  • 'left' - Left center
  • 'right' - Right center
  • 'top-left' - Top left corner
  • 'top-right' - Top right corner
  • 'bottom-left' - Bottom left corner
  • 'bottom-right' - Bottom right corner

$scalePercent (int, optional)

Section titled “$scalePercent (int, optional)”

Watermark size as percentage of image diagonal. Default: 10

  • Recommended: 5-30
  • Smaller values = subtle watermark
  • Larger values = prominent watermark

Return Value

Section titled “Return Value”

Returns void. Creates the output file with watermark.

Behavior

Section titled “Behavior”

Scaling Algorithm

Section titled “Scaling Algorithm”

Watermark size is calculated based on the image’s diagonal length:

diagonal = √(width² + height²)
watermark_width = (scalePercent / 100) × diagonal
watermark_height = watermark_width × (original_watermark_height / original_watermark_width)

This ensures consistent appearance across different image sizes and orientations.

Aspect Ratio

Section titled “Aspect Ratio”

Watermark aspect ratio is always preserved.

Examples

Section titled “Examples”

Basic Watermark

Section titled “Basic Watermark”
use Kenura\Imagick\ImageProcessor;


$processor = new ImageProcessor();


$processor->addWatermark(
    'photo.jpg',
    'watermarked.jpg',
    'logo.png',
    'bottom-right',
    10
);

All Positions

Section titled “All Positions”
$positions = [
    'center', 'top', 'bottom', 'left', 'right',
    'top-left', 'top-right', 'bottom-left', 'bottom-right'
];


foreach ($positions as $position) {
    $processor->addWatermark(
        'photo.jpg',
        "watermarked-{$position}.jpg",
        'logo.png',
        $position,
        10
    );
}

Different Sizes

Section titled “Different Sizes”
// Small, subtle watermark
$processor->addWatermark('photo.jpg', 'small.jpg', 'logo.png', 'bottom-right', 5);


// Medium watermark
$processor->addWatermark('photo.jpg', 'medium.jpg', 'logo.png', 'bottom-right', 10);


// Large, prominent watermark
$processor->addWatermark('photo.jpg', 'large.jpg', 'logo.png', 'center', 25);

Batch Watermarking

Section titled “Batch Watermarking”
$images = glob('photos/*.jpg');
$watermark = 'assets/watermark.png';


foreach ($images as $image) {
    $filename = basename($image);
    $processor->addWatermark(
        $image,
        "watermarked/{$filename}",
        $watermark,
        'bottom-right',
        10
    );
}

Position Visual Guide

Section titled “Position Visual Guide”
┌─────────────────────────────────┐
│ top-left      top      top-right│
│                                  │
│                                  │
│ left         center        right│
│                                  │
│                                  │
│bottom-left  bottom  bottom-right│
└─────────────────────────────────┘

Best Practices

Section titled “Best Practices”

1. Use PNG Watermarks

Section titled “1. Use PNG Watermarks”
// ✅ Good: PNG with transparency
$processor->addWatermark('photo.jpg', 'out.jpg', 'logo.png', 'bottom-right', 10);


// ⚠️ OK: JPEG watermark (no transparency)
$processor->addWatermark('photo.jpg', 'out.jpg', 'logo.jpg', 'bottom-right', 10);

2. Create Semi-Transparent Watermarks

Section titled “2. Create Semi-Transparent Watermarks”
// Create transparent watermark first
$processor->addOpacity('logo.png', 'watermark.png', 50);


// Then apply
$processor->addWatermark('photo.jpg', 'out.jpg', 'watermark.png', 'bottom-right', 10);

3. Choose Appropriate Size

Section titled “3. Choose Appropriate Size”
Use CaseScale %Description
Copyright protection5-8Small, corner placement
Branding10-15Medium, visible but not intrusive
Preview watermark20-30Large, center placement

Common Issues

Section titled “Common Issues”

Issue: Watermark too small/large

Section titled “Issue: Watermark too small/large”

Solution: Adjust $scalePercent parameter

// Too small? Increase scale
$processor->addWatermark('photo.jpg', 'out.jpg', 'logo.png', 'center', 20);


// Too large? Decrease scale
$processor->addWatermark('photo.jpg', 'out.jpg', 'logo.png', 'corner', 5);

Issue: Watermark not visible

Section titled “Issue: Watermark not visible”

Cause: Watermark color blends with image

Solution: Use contrasting colors or add opacity

Section titled “Related Methods”

See Also

Section titled “See Also”