<?php
/**
 * Image manipulation support. Allows images to be resized, cropped, etc.
 *
 * @package    Kohana/Image
 * @category   Base
 * @author     Kohana Team
 * @copyright  (c) 2008-2009 Kohana Team
 * @license    http://kohanaphp.com/license.html
 */
class Image
{

	// Resizing constraints
	const NONE = 0x01;
	const WIDTH = 0x02;
	const HEIGHT = 0x03;
	const AUTO = 0x04;
	const INVERSE = 0x05;
	const PRECISE = 0x06;

	// Flipping directions
	const HORIZONTAL = 0x11;
	const VERTICAL = 0x12;

	/**
	 * @var  string  default driver: GD, ImageMagick, etc
	 */
	public static $default_driver = 'GD';

	// Status of the driver check
	protected static $_checked = FALSE;

	/**
	 * Loads an image and prepares it for manipulation.
	 *
	 *     $image = Image::factory('upload/test.jpg');
	 *
	 * @param   string   $file    image file path
	 * @param   string   $driver  driver type: GD, ImageMagick, etc
	 * @return  Image
	 * @uses    Image::$default_driver
	 */
	public static function factory($file, $driver = NULL)
	{
		if ($driver === NULL) {
			// Use the default driver
			$driver = Image::$default_driver;
		}

		// Set the class name
		$class = 'Image_' . $driver;
		return new $class($file);
	}

	/**
	 * @var  string  image file path
	 */
	public $file;

	/**
	 * @var  integer  image width
	 */
	public $width;

	/**
	 * @var  integer  image height
	 */
	public $height;

	/**
	 * @var  integer  one of the IMAGETYPE_* constants
	 */
	public $type;

	/**
	 * @var  string  mime type of the image
	 */
	public $mime;

	/**
	 * Loads information about the image. Will throw an exception if the image
	 * does not exist or is not an image.
	 *
	 * @param   string  $file  image file path
	 * @return  void
	 * @throws  CException
	 */
	public function __construct($file)
	{
		try {
			// Get the real path to the file
			$file = realpath($file);

			// Get the image information
			$info = getimagesize($file);
		} catch (Exception $e) {
			// Ignore all errors while reading the image
		}

		if (empty($file) OR empty($info)) {
			throw new CException('Not an image or invalid image: ' . $file);
		}

		// Store the image information
		$this->file = $file;
		$this->width = $info[0];
		$this->height = $info[1];
		$this->type = $info[2];
		$this->mime = image_type_to_mime_type($this->type);
	}

	/**
	 * Render the current image.
	 *
	 *     echo $image;
	 *
	 * [!!] The output of this function is binary and must be rendered with the
	 * appropriate Content-Type header or it will not be displayed correctly!
	 *
	 * @return  string
	 */
	public function __toString()
	{
		try {
			// Render the current image
			return $this->render();
		} catch (CException $e) {
			// Showing any kind of error will be "inside" image data
			return '';
		}
	}

	/**
	 * Resize the image to the given size. Either the width or the height can
	 * be omitted and the image will be resized proportionally.
	 *
	 *     // Resize to 200 pixels on the shortest side
	 *     $image->resize(200, 200);
	 *
	 *     // Resize to 200x200 pixels, keeping aspect ratio
	 *     $image->resize(200, 200, Image::INVERSE);
	 *
	 *     // Resize to 500 pixel width, keeping aspect ratio
	 *     $image->resize(500, NULL);
	 *
	 *     // Resize to 500 pixel height, keeping aspect ratio
	 *     $image->resize(NULL, 500);
	 *
	 *     // Resize to 200x500 pixels, ignoring aspect ratio
	 *     $image->resize(200, 500, Image::NONE);
	 *
	 * @param   integer  $width   new width
	 * @param   integer  $height  new height
	 * @param   integer  $master  master dimension
	 * @return  $this
	 * @uses    Image::_do_resize
	 */
	public function resize($width = NULL, $height = NULL, $master = NULL)
	{
		if ($master === NULL) {
			// Choose the master dimension automatically
			$master = Image::AUTO;
		} // Image::WIDTH and Image::HEIGHT deprecated. You can use it in old projects,
		// but in new you must pass empty value for non-master dimension
		elseif ($master == Image::WIDTH AND !empty($width)) {
			$master = Image::AUTO;

			// Set empty height for backward compatibility
			$height = NULL;
		} elseif ($master == Image::HEIGHT AND !empty($height)) {
			$master = Image::AUTO;

			// Set empty width for backward compatibility
			$width = NULL;
		}

		if (empty($width)) {
			if ($master === Image::NONE) {
				// Use the current width
				$width = $this->width;
			} else {
				// If width not set, master will be height
				$master = Image::HEIGHT;
			}
		}

		if (empty($height)) {
			if ($master === Image::NONE) {
				// Use the current height
				$height = $this->height;
			} else {
				// If height not set, master will be width
				$master = Image::WIDTH;
			}
		}

		switch ($master) {
			case Image::AUTO:
				// Choose direction with the greatest reduction ratio
				$master = ($this->width / $width) > ($this->height / $height) ? Image::WIDTH : Image::HEIGHT;
				break;
			case Image::INVERSE:
				// Choose direction with the minimum reduction ratio
				$master = ($this->width / $width) > ($this->height / $height) ? Image::HEIGHT : Image::WIDTH;
				break;
		}

		switch ($master) {
			case Image::WIDTH:
				// Recalculate the height based on the width proportions
				$height = $this->height * $width / $this->width;
				break;
			case Image::HEIGHT:
				// Recalculate the width based on the height proportions
				$width = $this->width * $height / $this->height;
				break;
			case Image::PRECISE:
				// Resize to precise size
				$ratio = $this->width / $this->height;

				if ($width / $height > $ratio) {
					$height = $this->height * $width / $this->width;
				} else {
					$width = $this->width * $height / $this->height;
				}
				break;
		}

		// Convert the width and height to integers, minimum value is 1px
		$width = max(round($width), 1);
		$height = max(round($height), 1);

		$this->_do_resize($width, $height);

		return $this;
	}

	/**
	 * Crop an image to the given size. Either the width or the height can be
	 * omitted and the current width or height will be used.
	 *
	 * If no offset is specified, the center of the axis will be used.
	 * If an offset of TRUE is specified, the bottom of the axis will be used.
	 *
	 *     // Crop the image to 200x200 pixels, from the center
	 *     $image->crop(200, 200);
	 *
	 * @param   integer  $width     new width
	 * @param   integer  $height    new height
	 * @param   mixed    $offset_x  offset from the left
	 * @param   mixed    $offset_y  offset from the top
	 * @return  $this
	 * @uses    Image::_do_crop
	 */
	public function crop($width, $height, $offset_x = NULL, $offset_y = NULL)
	{
		if ($width > $this->width) {
			// Use the current width
			$width = $this->width;
		}

		if ($height > $this->height) {
			// Use the current height
			$height = $this->height;
		}

		if ($offset_x === NULL) {
			// Center the X offset
			$offset_x = round(($this->width - $width) / 2);
		} elseif ($offset_x === TRUE) {
			// Bottom the X offset
			$offset_x = $this->width - $width;
		} elseif ($offset_x < 0) {
			// Set the X offset from the right
			$offset_x = $this->width - $width + $offset_x;
		}

		if ($offset_y === NULL) {
			// Center the Y offset
			$offset_y = round(($this->height - $height) / 2);
		} elseif ($offset_y === TRUE) {
			// Bottom the Y offset
			$offset_y = $this->height - $height;
		} elseif ($offset_y < 0) {
			// Set the Y offset from the bottom
			$offset_y = $this->height - $height + $offset_y;
		}

		// Determine the maximum possible width and height
		$max_width = $this->width - $offset_x;
		$max_height = $this->height - $offset_y;

		if ($width > $max_width) {
			// Use the maximum available width
			$width = $max_width;
		}

		if ($height > $max_height) {
			// Use the maximum available height
			$height = $max_height;
		}

		$this->_do_crop($width, $height, $offset_x, $offset_y);

		return $this;
	}

	/**
	 * Rotate the image by a given amount.
	 *
	 *     // Rotate 45 degrees clockwise
	 *     $image->rotate(45);
	 *
	 *     // Rotate 90% counter-clockwise
	 *     $image->rotate(-90);
	 *
	 * @param   integer  $degrees  degrees to rotate: -360-360
	 * @return  $this
	 * @uses    Image::_do_rotate
	 */
	public function rotate($degrees)
	{
		// Make the degrees an integer
		$degrees = (int)$degrees;

		if ($degrees > 180) {
			do {
				// Keep subtracting full circles until the degrees have normalized
				$degrees -= 360;
			} while ($degrees > 180);
		}

		if ($degrees < -180) {
			do {
				// Keep adding full circles until the degrees have normalized
				$degrees += 360;
			} while ($degrees < -180);
		}

		if($degrees != 0) {
			$this->_do_rotate($degrees);
		}

		return $this;
	}

	/**
	 * Flip the image along the horizontal or vertical axis.
	 *
	 *     // Flip the image from top to bottom
	 *     $image->flip(Image::HORIZONTAL);
	 *
	 *     // Flip the image from left to right
	 *     $image->flip(Image::VERTICAL);
	 *
	 * @param   integer  $direction  direction: Image::HORIZONTAL, Image::VERTICAL
	 * @return  $this
	 * @uses    Image::_do_flip
	 */
	public function flip($direction)
	{
		if ($direction !== Image::HORIZONTAL) {
			// Flip vertically
			$direction = Image::VERTICAL;
		}

		$this->_do_flip($direction);

		return $this;
	}

	/**
	 * Sharpen the image by a given amount.
	 *
	 *     // Sharpen the image by 20%
	 *     $image->sharpen(20);
	 *
	 * @param   integer  $amount  amount to sharpen: 1-100
	 * @return  $this
	 * @uses    Image::_do_sharpen
	 */
	public function sharpen($amount)
	{
		// The amount must be in the range of 1 to 100
		$amount = min(max($amount, 1), 100);

		$this->_do_sharpen($amount);

		return $this;
	}

	/**
	 * Add a reflection to an image. The most opaque part of the reflection
	 * will be equal to the opacity setting and fade out to full transparent.
	 * Alpha transparency is preserved.
	 *
	 *     // Create a 50 pixel reflection that fades from 0-100% opacity
	 *     $image->reflection(50);
	 *
	 *     // Create a 50 pixel reflection that fades from 100-0% opacity
	 *     $image->reflection(50, 100, TRUE);
	 *
	 *     // Create a 50 pixel reflection that fades from 0-60% opacity
	 *     $image->reflection(50, 60, TRUE);
	 *
	 * [!!] By default, the reflection will be go from transparent at the top
	 * to opaque at the bottom.
	 *
	 * @param   integer   $height   reflection height
	 * @param   integer   $opacity  reflection opacity: 0-100
	 * @param   boolean   $fade_in  TRUE to fade in, FALSE to fade out
	 * @return  $this
	 * @uses    Image::_do_reflection
	 */
	public function reflection($height = NULL, $opacity = 100, $fade_in = FALSE)
	{
		if ($height === NULL OR $height > $this->height) {
			// Use the current height
			$height = $this->height;
		}

		// The opacity must be in the range of 0 to 100
		$opacity = min(max($opacity, 0), 100);

		$this->_do_reflection($height, $opacity, $fade_in);

		return $this;
	}

	/**
	 * Add a watermark to an image with a specified opacity. Alpha transparency
	 * will be preserved.
	 *
	 * If no offset is specified, the center of the axis will be used.
	 * If an offset of TRUE is specified, the bottom of the axis will be used.
	 *
	 *     // Add a watermark to the bottom right of the image
	 *     $mark = Image::factory('upload/watermark.png');
	 *     $image->watermark($mark, TRUE, TRUE);
	 *
	 * @param   Image    $watermark  watermark Image instance
	 * @param   integer  $offset_x   offset from the left
	 * @param   integer  $offset_y   offset from the top
	 * @param   integer  $opacity    opacity of watermark: 1-100
	 * @return  $this
	 * @uses    Image::_do_watermark
	 */
	public function watermark($watermark, $offset_x = NULL, $offset_y = NULL, $opacity = 100)
	{
		if ($offset_x === NULL) {
			// Center the X offset
			$offset_x = round(($this->width - $watermark->width) / 2);
		} elseif ($offset_x === TRUE) {
			// Bottom the X offset
			$offset_x = $this->width - $watermark->width;
		} elseif ($offset_x < 0) {
			// Set the X offset from the right
			$offset_x = $this->width - $watermark->width + $offset_x;
		}

		if ($offset_y === NULL) {
			// Center the Y offset
			$offset_y = round(($this->height - $watermark->height) / 2);
		} elseif ($offset_y === TRUE) {
			// Bottom the Y offset
			$offset_y = $this->height - $watermark->height;
		} elseif ($offset_y < 0) {
			// Set the Y offset from the bottom
			$offset_y = $this->height - $watermark->height + $offset_y;
		}

		// The opacity must be in the range of 1 to 100
		$opacity = min(max($opacity, 1), 100);

		$this->_do_watermark($watermark, $offset_x, $offset_y, $opacity);

		return $this;
	}

	/**
	 * Set the background color of an image. This is only useful for images
	 * with alpha transparency.
	 *
	 *     // Make the image background black
	 *     $image->background('#000');
	 *
	 *     // Make the image background black with 50% opacity
	 *     $image->background('#000', 50);
	 *
	 * @param   string   $color    hexadecimal color value
	 * @param   integer  $opacity  background opacity: 0-100
	 * @return  $this
	 * @uses    Image::_do_background
	 */
	public function background($color, $opacity = 100)
	{
		if ($color[0] === '#') {
			// Remove the pound
			$color = substr($color, 1);
		}

		if (strlen($color) === 3) {
			// Convert shorthand into longhand hex notation
			$color = preg_replace('/./', '$0$0', $color);
		}

		// Convert the hex into RGB values
		list ($r, $g, $b) = array_map('hexdec', str_split($color, 2));

		// The opacity must be in the range of 0 to 100
		$opacity = min(max($opacity, 0), 100);

		$this->_do_background($r, $g, $b, $opacity);

		return $this;
	}

	/**
	 * Save the image. If the filename is omitted, the original image will
	 * be overwritten.
	 *
	 *     // Save the image as a PNG
	 *     $image->save('saved/cool.png');
	 *
	 *     // Overwrite the original image
	 *     $image->save();
	 *
	 * [!!] If the file exists, but is not writable, an exception will be thrown.
	 *
	 * [!!] If the file does not exist, and the directory is not writable, an
	 * exception will be thrown.
	 *
	 * @param   string   $file     new image path
	 * @param   integer  $quality  quality of image: 1-100
	 * @return  boolean
	 * @uses    Image::_save
	 * @throws  CException
	 */
	public function save($file = NULL, $quality = 100)
	{
		if ($file === NULL) {
			// Overwrite the file
			$file = $this->file;
		}

		if (is_file($file)) {
			if (!is_writable($file)) {
				throw new CException('File must be writable: ' . $file);
			}
		} else {
			// Get the directory of the file
			$directory = realpath(pathinfo($file, PATHINFO_DIRNAME));

			if (!is_dir($directory) OR !is_writable($directory)) {
				throw new CException('Directory must be writable: ' . $directory);
			}
		}

		// The quality must be in the range of 1 to 100
		$quality = min(max($quality, 1), 100);

		return $this->_do_save($file, $quality);
	}

	/**
	 * Render the image and return the binary string.
	 *
	 *     // Render the image at 50% quality
	 *     $data = $image->render(NULL, 50);
	 *
	 *     // Render the image as a PNG
	 *     $data = $image->render('png');
	 *
	 * @param   string   $type     image type to return: png, jpg, gif, etc
	 * @param   integer  $quality  quality of image: 1-100
	 * @return  string
	 * @uses    Image::_do_render
	 */
	public function render($type = NULL, $quality = 100)
	{
		if ($type === NULL) {
			// Use the current image type
			$type = image_type_to_extension($this->type, FALSE);
		}

		return $this->_do_render($type, $quality);
	}

} // End Image
