Location: PHPKode > scripts > Animated PNG Creator > animated-png-creator/APNG_Creator.php
<?php
/*
Animated PNG Creator
Version: 1.2.1
Licence: GNU Lesser General Public License
http://www.gnu.org/licenses/lgpl.html

Feedback, bug report, feature request: hide@address.com
*/

class APNG_Creator {
	/*
	The array containing the animation frames and it's properties.
	Data structure:
	$images[i] : array(
		IMAGE => a GD resource of an image,
		DELAY => the delay fraction before displaying the frame (in seconds) : array(
			[0] => numerator,
			[1] => denominator
		),
		DISPOSE => specifies how the output buffer should be changed at the end of the delay (before rendering the next frame)
		BLEND => specifies whether the frame is to be alpha blended into the current output buffer content, or whether it should completely replace its region in the output buffer
	)
	*/
	protected $gd_data = null;
	protected $images = array();
	// Contains  the width and the height of the image, respectively the biggest dimensions in the animation.
	protected $image_data = array();
	public $save_alpha = true;
	public $save_time = false;
	// Defines the play count for the animation. Value 0 (zero) means infinite playing.
	public $play_count = 0;
	
	public $background_color = array(255, 255, 255, 127);
	
	// The PNG signature
	const SIGNATURE = "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A";
	// Format strings for the pack() and unpack() functions representing some APNG chunk datas.
	// To understant this formats please read the APNG specification.
	const IHDR_data = "NNCCCCC";
	const acTL_data = "NN";
	const fcTL_data = "NNNNNnncc";
	const tIME = "nccccc";
	
	// The version of the class.
	const VERSION = "1.2.1";
	
	function APNG_Creator() {
		$this->gd_data = gd_info();
	}
	
	/*
	Returns the IDAT chunk of the image saved in PNG format.
	*/
	protected function get_png_idat($img) {
		ob_start();
		imagepng($img, null);
		$data = ob_get_contents();
		ob_end_clean();
		$idat_offset = strpos($data, "IDAT") - 4;
		$data = substr($data, $idat_offset);
		$chunk = unpack("Nlength", $data);
		$data = substr($data, 0, $chunk['length'] + 12);
		return $data;
	}
	
	/*
	Returns IDAT chunk's data fields.
	*/
	protected function get_png_idat_data($img) {
		ob_start();
		imagepng($img, null);
		$data = ob_get_contents();
		ob_end_clean();
		$idat_offset = strpos($data, "IDAT") - 4;
		$data = substr($data, $idat_offset);
		$chunk = unpack("Nlength", $data);
		$data = substr($data, 8, $chunk['length']);
		return $data;
	}
	
	/*
	$name : the name of the chunk (for example IDAT, fdAT, tEXt, ...)
	$data : the data fields of the chunk
	Returns a complete chunk, in the standard format:
	Length (4 bytes) - Name (4 bytes) - Data (length bytes) - CRC (4 bytes)
	*/
	protected function complete_chunk($name, $data) {
		$name_data = $name . $data;
		return (pack("N", strlen($data)) . $name_data . pack("N", crc32($name_data)));
	}
	
	/*
	Calculates the x and y offsets of a frame regarding to the buffer (see documentation).
	The values are returned in an array.
	*/
	protected function calculate_position($image, $position = "MIDDLE_CENTER") {
		$x = imagesx($image);
		$y = imagesy($image);
		if (!(is_array($position))) {
			switch ($position) {
				case "TOP_LEFT":
					$position = array(0, 0);
					break;
				case "TOP_CENTER":
					$position = array(($this->image_data['WIDTH'] - $x) / 2, 0);
					break;
				case "TOP_RIGHT":
					$position = array($this->image_data['WIDTH'] - $x, 0);
					break;
				case "BOTTOM_LEFT":
					$position = array(0, $this->image_data['HEIGHT'] - $y);
					break;
				case "BOTTOM_CENTER":
					$position = array(($this->image_data['WIDTH'] - $x) / 2, $this->image_data['HEIGHT'] - $y);
					break;
				case "BOTTOM_RIGHT":
					$position = array($this->image_data['WIDTH'] - $x, $this->image_data['HEIGHT'] - $y);
					break;
				case "MIDDLE_LEFT":
					$position = array(0, ($this->image_data['HEIGHT'] - $y) / 2);
					break;
				case "MIDDLE_RIGHT":
					$position = array($this->image_data['WIDTH'] - $x, ($this->image_data['HEIGHT'] - $y) / 2);
					break;
				case "MIDDLE_CENTER":
				default:
					$position = array(($this->image_data['WIDTH'] - $x) / 2, ($this->image_data['HEIGHT'] - $y) / 2);
			}
		}
		if ($position[0] + $x > $this->image_data['WIDTH']) $position[0] = $this->image_data['WIDTH'] - $x;
		if ($position[0] < 0) $position[0] = 0;
		if ($position[1] + $y > $this->image_data['HEIGHT']) $position[1] = $this->image_data['HEIGHT'] - $y;
		if ($position[1] < 0) $position[1] = 0;
		$position[0] = intval($position[0]);
		$position[1] = intval($position[1]);
		return $position;
	}
	
	public function destroy_images() {
		foreach ($this->images as $frame) {
			imagedestroy($frame['IMAGE']);
		}
	}
	
	public function add_image($img, $position = "MIDDLE_CENTER", $delay = 1000, $dispose_op = 0, $blend_op = 0, $part_of_anim = true) {
		$width = imagesx($img);
		$height = imagesy($img);
		if (!($width > 0 && $height > 0)) return false;
		if (!(is_array($delay))) {
			$delay = array(
				intval($delay),
				1000
			);
		}
		$dispose_options = array("APNG_DISPOSE_OP_NONE", "APNG_DISPOSE_OP_BACKGROUND", "APNG_DISPOSE_OP_PREVIOUS");
		$blend_options = array("APNG_BLEND_OP_SOURCE", "APNG_BLEND_OP_OVER");
		if (is_string($dispose_op)) $dispose_op = array_search($dispose_op, $dispose_options);
		if (is_string($blend_op)) $blend_op = array_search($blend_op, $blend_options);
		$is_default_image = (count($this->images) === 0);
		$this->images[] = array(
			"IMAGE" => $img,
			"DELAY" => $delay,
			"DISPOSE" => intval($dispose_op) % 3,
			"BLEND" => intval($blend_op) % 2,
			"POSITION" => $position,
			"PART_OF_ANIM" => (!($is_default_image && (! $part_of_anim)))
		);
		if ($width > $this->image_data['WIDTH']) $this->image_data['WIDTH'] = $width;
		if ($height > $this->image_data['HEIGHT']) $this->image_data['HEIGHT'] = $height;
		return true;
	}
	
	/*
	$filename : the filename of the output file
	Saves the animation.
	*/
	public function save($filename = "") {
		$fp = fopen($filename, "w");
		if (! $fp) return;
		$out = "";
		$out .= self::SIGNATURE;
		// IHDR
		$out .= $this->complete_chunk("IHDR", pack(self::IHDR_data, $this->image_data['WIDTH'], $this->image_data['HEIGHT'], 8, ($this->save_alpha ? 6 : 2), 0, 0, 0));
		// Metadata (tEXt) - Please don't remove this sequence of the code! It is necessary for debugging!
		$out .= $this->complete_chunk("tEXt", "Software" . chr(0) . "Animated PNG Creator v" . self::VERSION . " (www.phpclasses.org)");
		$out .= $this->complete_chunk("tEXt", "Technical informations" . chr(0) . phpversion() . "; " . $this->gd_data['GD Version']);
		// Saving time data
		if ($this->save_time) {
			$date_time = getdate();
			$out .= $this->complete_chunk("tIME", pack(self::tIME, $date_time['year'], $date_time['mon'], $date_time['mday'], $date_time['hours'], $date_time['minutes'], $date_time['seconds']));
		}
		// acTL
		$out .= $this->complete_chunk("acTL", pack(self::acTL_data, count($this->images), abs(intval($this->play_count))));
		fwrite($fp, $out);
		$sequence_number = 0;
		$is_default_image = true;
		foreach ($this->images as $frame) {
			$image = $frame['IMAGE'];
			$x = imagesx($image);
			$y = imagesy($image);
			$position = $this->calculate_position($image, $frame['POSITION']);
			$destroy_image = false;
			$is_tc = imageistruecolor($image);
			/*
			According to the APNG specification the default image can't be positioned via the fcTL
			x_offset and y_offset properties. So the script in case of the default image
			creates a new resized frame, fills it with the specified background (default color is fully
			transparent - if the save_alpha option is set to true) and copyes the frame to it's position.
			*/
			$align_needed = ($is_default_image && ($x < $this->image_data['WIDTH'] || $y < $this->image_data['HEIGHT']));
			if ((! $is_tc) || $align_needed) {
				if ($align_needed) {
					$i2x = $this->image_data['WIDTH'];
					$i2y = $this->image_data['HEIGHT'];
					$i2_offsx = ($this->image_data['WIDTH'] - $x) / 2;
					$i2_offsy = ($this->image_data['HEIGHT'] - $y) / 2;
					$position = array(0, 0);
				} else {
					$i2x = $x;
					$i2y = $y;
					$i2_offsx = 0;
					$i2_offsy = 0;
				}
				$image2 = imagecreatetruecolor($i2x, $i2y);
				$bckg = imagecolorallocatealpha($image2, $this->background_color[0], $this->background_color[1], $this->background_color[2], $this->background_color[3]);
				imagefill($image2, 0, 0, $bckg);
				imagecopy($image2, $image, $i2_offsx, $i2_offsy, 0, 0, $x, $y);
				$image = $image2;
				$x = $i2x;
				$y = $i2y;
				$destroy_image = true;
			}
			imagesavealpha($image, !(!($this->save_alpha)));
			$out = "";
			// fcTL
			if ($frame['PART_OF_ANIM']) {
				$out .= $this->complete_chunk("fcTL", pack(self::fcTL_data, $sequence_number, $x, $y, $position[0], $position[1], $frame['DELAY'][0], $frame['DELAY'][1], $frame['DISPOSE'], $frame['BLEND']));
				$sequence_number++;
			}
			// IDAT, fdAT
			if ($is_default_image) {
				$out .= $this->get_png_idat($image);
			} else {
				$out .= $this->complete_chunk("fdAT", pack("N", $sequence_number) . $this->get_png_idat_data($image));
				$sequence_number++;
			}
			fwrite($fp, $out);
			if ($destroy_image) imagedestroy($image);
			$is_default_image = false;
		}
		$IEND = $this->complete_chunk("IEND", "");
		fwrite($fp, $IEND);
		fclose($fp);
	}
}
?>
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