SilverStripe Balanced Image

BalancedImageExtension.php

<?php

class BalancedImageExtension extends DataExtension {
	
	/**
	 * Creates a scaled image that fits within a given container and does not exceed a specified area (square space).
	 * Useful for ensuring a series of images of various dimensions (especially logos) have approximately the same visual weight.
	 * Use in templates with $BalancedImage
	 * 
	 * @param integer $containerWidth Max width of image
	 * @param integer $containerHeight Max height of image
	 * @param integer $multiplier Maximum portion of container space image can take up (max 1)
	 * @param integer $margin Min space between frame edge and image
	 * @return Image
	 */
	public function BalancedImage($containerW, $containerH, $multiplier = 0.5, $padX = false, $padY = false, $margin = 0) {
		// ToDo - Trim any white space included around image before adjusting.
		
		$frameW = $containerW;
		$frameH = $containerH;
		
		if ($margin) {
			//reduce container size to accommodate margin
			$containerW = $containerW - $margin*2;
			$containerH = $containerH - $margin*2;
		}
		
		$w = $this->owner->width;
		$h = $this->owner->height;
		
		if (!($w && $h)) return false;
		
		$iWHRatio = $w/$h;
		$cWHRatio = $containerW/$containerH;
		
		// Default to 50% of available space		
		$maxPixels = round($containerW*$containerH*$multiplier);
		
		// Scale to fill container
		if ($iWHRatio >= $cWHRatio) {
			$w = $containerW;
			$h = round($w/$iWHRatio);
		}
		else {
			$h = $containerH;
			$w = round($h*$iWHRatio);
		}
		
		// Scale down further if exceeds max space
		if ($w*$h > $maxPixels) {
			$w = round(sqrt($maxPixels * $iWHRatio));
			$h = round($w / $iWHRatio);
		}
		
		if ($padX && $padY) return $this->owner->getFormattedImage('FramedImage', $w, $h, $frameW, $frameH);
		if ($padX) return $this->owner->getFormattedImage('FramedImage', $w, $h, $frameW, $h);
		if ($padY) return $this->owner->getFormattedImage('FramedImage', $w, $h, $w, $frameH);
		
		return $this->owner->isSize($w, $h)
			? $this->owner
			: $this->owner->ResizedImage($w, $h);
	}
	
	/**
	 * // ToDo Description
	 * Use in templates with $
	 * 
	 * @param Image_Backend $backend
	 * @param integer $
	 * @param integer $
	 * @return Image_Backend
	 */
	public function generateFramedImage(Image_Backend $backend, $imageW, $imageH, $frameW, $frameH, $backgroundColor = "FFFFFF"){
		
		// Pad on both sides
		return $backend->resize($imageW, $imageH)->paddedResize($frameW, $imageH, $backgroundColor)->paddedResize($frameW, $frameH, $backgroundColor);
	}
}