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File: APNG_Creator.php

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  Classes of Dzsoni Voker  >  Animated PNG Creator  >  APNG_Creator.php  >  Download  
File: APNG_Creator.php
Role: Class source
Content type: text/plain
Description: Animated PNG Creator class
Class: Animated PNG Creator
Create PNG format animations from a list of images
Author: By
Last change: Changelog:

Version 1.6:
- $transparent_color property introduced (see the documentation)

Version 1.6.2:
- The "Creation Time" tEXt chunk is used to write creation time to the file instead of the tIME chunk
Date: 5 years ago
Size: 9,718 bytes
 

Contents

Class file image Download
<?php
/*
Animated PNG Creator
Version: 1.6.2
Licence: GNU Lesser General Public License
http://www.gnu.org/licenses/lgpl.html

Feedback, bug report, feature request: apng@zoznam.sk
*/

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);
    public
$transparent_color = false;
   
   
// 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 = "1.6.2";
   
    function
APNG_Creator() {
       
$this->gd_data = gd_info();
    }
   
   
/*
    Returns IDAT chunk's data fields.
    */
   
protected function get_png_idat_data($img) {
       
ob_start();
       
imagepng($img, null);
       
$data = ob_get_contents();
       
$idat_data = "";
       
$chunk_data = "";
       
$idat_offset = 0;
       
ob_end_clean();
       
// There can be more IDAT chunks!!!
       
do {
           
$idat_offset = strpos($data, "IDAT", $idat_offset);
            if (
$idat_offset === false) return $idat_data;
           
$chunk_data = substr($data, $idat_offset - 4);
           
$chunk = unpack("Nlength", $chunk_data);
           
$chunk_data = substr($chunk_data, 8, $chunk['length']);
           
$idat_data .= $chunk_data;
           
$idat_offset += 4;
        } while (
$idat_offset !== false);
        return
$idat_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 (!isset(
$this->image_data['WIDTH']) || $width > $this->image_data['WIDTH']) $this->image_data['WIDTH'] = $width;
        if (!isset(
$this->image_data['HEIGHT']) || $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 false;
       
$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) {
           
$out .= $this->complete_chunk("tEXt", "Creation Time" . chr(0) . date("D, d M Y H:i:s O"));
        }
       
// tRNS - transparent color
       
if ($this->transparent_color && !($this->save_alpha)) {
           
$out .= $this->complete_chunk("tRNS", pack("nnn", $this->transparent_color[0], $this->transparent_color[1], $this->transparent_color[2]));
        }
       
// 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->complete_chunk("IDAT", $this->get_png_idat_data($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);
    }
}
?>