CropCenter
The CropCenter class implements the simplest and fastest cropping strategy by centering the crop area on the image.
Class Overview
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| class drzippie\crop\CropCenter extends drzippie\crop\Crop
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This class provides basic center-based cropping functionality. It’s the fastest option and ideal for:
- Thumbnail generation
- Batch processing
- Cases where simple center cropping is sufficient
Algorithm
The CropCenter algorithm works as follows:
- Find the center of the original image
- Calculate crop area centered on the image center
- Trim edges that exceed the target dimensions
- Resize to final dimensions
This approach is:
- ✅ Fast - Minimal computation required
- ✅ Predictable - Always crops from center
- ✅ Memory efficient - No image analysis needed
- ❌ Basic - Doesn’t consider image content
Constructor
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| public function __construct(string|Imagick|null $image = null)
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Creates a new CropCenter instance.
Parameters:
$image - File path, Imagick object, or null
Examples:
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| // From file path
$crop = new CropCenter('photo.jpg');
// From Imagick object
$imagick = new Imagick('photo.jpg');
$crop = new CropCenter($imagick);
// Empty instance
$crop = new CropCenter();
$crop->setImage(new Imagick('photo.jpg'));
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Basic Usage
Simple Center Crop
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| use drzippie\crop\CropCenter;
$crop = new CropCenter('landscape.jpg');
$result = $crop->resizeAndCrop(300, 200);
$result->writeImage('thumbnail.jpg');
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Multiple Sizes
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| use drzippie\crop\CropCenter;
$crop = new CropCenter('photo.jpg');
// Generate different sizes
$sizes = [
'thumb' => [100, 100],
'small' => [200, 150],
'medium' => [400, 300],
'large' => [800, 600]
];
foreach ($sizes as $name => [$width, $height]) {
$result = $crop->resizeAndCrop($width, $height);
$result->writeImage("output_{$name}.jpg");
}
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Advanced Configuration
Custom Filter Settings
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| use drzippie\crop\CropCenter;
$crop = new CropCenter('image.jpg');
// High quality (slower)
$crop->setFilter(Imagick::FILTER_LANCZOS);
// Default quality
$crop->setFilter(Imagick::FILTER_CUBIC);
// Fast processing
$crop->setFilter(Imagick::FILTER_POINT);
$result = $crop->resizeAndCrop(300, 200);
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Blur Adjustment
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| use drzippie\crop\CropCenter;
$crop = new CropCenter('image.jpg');
// Sharper result
$crop->setBlur(0.2);
// Softer result
$crop->setBlur(1.0);
$result = $crop->resizeAndCrop(300, 200);
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Auto-Orientation
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| use drzippie\crop\CropCenter;
$crop = new CropCenter('photo_with_exif.jpg');
// Enable auto-orientation (default)
$crop->setAutoOrient(true);
// Disable to preserve original orientation
$crop->setAutoOrient(false);
$result = $crop->resizeAndCrop(300, 200);
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Method Chaining
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| use drzippie\crop\CropCenter;
$result = (new CropCenter('image.jpg'))
->setFilter(Imagick::FILTER_LANCZOS)
->setBlur(0.8)
->setAutoOrient(true)
->resizeAndCrop(400, 300);
$result->writeImage('output.jpg');
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Speed
- Fastest of all cropping strategies
- Minimal computation overhead
- Suitable for batch processing
Memory Usage
- Lowest memory footprint
- No image analysis required
- Efficient for large images
Quality Trade-offs
- Simple but effective for many use cases
- May not preserve important image content
- Best for images where center contains main subject
Use Cases
Ideal For:
- Profile pictures - Faces often centered
- Product thumbnails - Products usually centered
- Batch processing - Speed is priority
- Simple galleries - Basic thumbnail generation
- Avatar generation - Quick square crops
Not Ideal For:
- Landscape photos - Important content may be off-center
- Artistic images - May crop out focal points
- Complex compositions - Content-aware cropping preferred
For a 1920x1080 image:
- CropCenter: ~10ms
- CropBalanced: ~50ms
- CropEntropy: ~100ms
Error Handling
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| use drzippie\crop\CropCenter;
try {
$crop = new CropCenter('image.jpg');
$result = $crop->resizeAndCrop(300, 200);
$result->writeImage('output.jpg');
} catch (RuntimeException $e) {
echo "Error: " . $e->getMessage();
} catch (ImagickException $e) {
echo "ImageMagick error: " . $e->getMessage();
}
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Examples
Thumbnail Generation
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| use drzippie\crop\CropCenter;
function generateThumbnail($inputPath, $outputPath, $size = 150) {
$crop = new CropCenter($inputPath);
$result = $crop->resizeAndCrop($size, $size);
$result->writeImage($outputPath);
return $outputPath;
}
// Usage
$thumb = generateThumbnail('photo.jpg', 'thumb.jpg', 200);
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Batch Processing
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| use drzippie\crop\CropCenter;
function processBatch($inputDir, $outputDir, $width, $height) {
$files = glob($inputDir . '/*.jpg');
foreach ($files as $file) {
$crop = new CropCenter($file);
$result = $crop->resizeAndCrop($width, $height);
$filename = basename($file);
$result->writeImage($outputDir . '/' . $filename);
}
}
// Process all images in directory
processBatch('input/', 'output/', 300, 200);
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Implementation Details
The getSpecialOffset() method simply returns the center coordinates:
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| protected function getSpecialOffset(
Imagick $original,
int $targetWidth,
int $targetHeight
): array {
$geometry = $original->getImageGeometry();
return [
($geometry['width'] - $targetWidth) / 2,
($geometry['height'] - $targetHeight) / 2
];
}
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See Also