Location: PHPKode > scripts > GIF images into animated GIF with native PHP class > gif-images-into-animated-gif-with-native-php-class/GifMerge.class.php
<?php
/*
+-------------------------------------------------+
+                                                 +
+   GifMaerge.class.php ver. 1.1 by László Zsidi  +
+     examples and support on http://gifs.hu      +
+                                                 +
+    This class can be used and distributed       +
+    free of charge, but cannot be modified       +
+        without permission of author.            +
+                                                 +
+-------------------------------------------------+
*/
class GifMerge
{
	/*
	:::::::::::::::::::::::::::::::::::::::::::::::
	::                                           ::
	::        Class variables - constans         ::
	::                                           ::
	:::::::::::::::::::::::::::::::::::::::::::::::
	*/
	var $ver							= '1.1';
	var $dly							= 50;
	var $mod							= 'C_FILE';
	/*
	:::::::::::::::::::::::::::::::::::::::::::::::
	::                                           ::
	::         Class variables - booleans        ::
	::                                           ::
	:::::::::::::::::::::::::::::::::::::::::::::::
	*/
	var $first							= true;
	var $debug 							= false;
	var $use_loop						= false;
	var $transparent					= false;
	var $use_global_in					= false;
	/*
	:::::::::::::::::::::::::::::::::::::::::::::::
	::                                           ::
	::         Class variables - integers        ::
	::                                           ::
	:::::::::::::::::::::::::::::::::::::::::::::::
	*/
	var $x								= 0;
	var $y								= 0;
	var $ch								= 0;
	var $fin							= 0;
	var $fout							= '';
	var $loop							= 0;
	var $delay							= 0;
	var $width							= 0;
	var $height							= 0;
	var $trans1 						= 255;
	var $trans2 						= 255;
	var $trans3 						= 255;
	var $disposal						= 2;
	var $out_color_table_size			= 0;
	var $local_color_table_flag			= 0;
	var $global_color_table_size		= 0;
	var $out_color_table_sizecode		= 0;
	var $global_color_table_sizecode	= 0;
	/*
	:::::::::::::::::::::::::::::::::::::::::::::::
	::                                           ::
	::         Class variables - arrays          ::
	::                                           ::
	:::::::::::::::::::::::::::::::::::::::::::::::
	*/
	var $gif							= array(0x47, 0x49, 0x46);
	var $buffer							= array();
	var $local_in						= array();
	var $global_in						= array();
	var $global_out						= array();
	var $logical_screen_descriptor		= array();
	/*
	:::::::::::::::::::::::::::::::::::::::::::::::
	::                                           ::
	::            Class entry point              ::
	::                                           ::
	:::::::::::::::::::::::::::::::::::::::::::::::

	:::::::::::::::::::::::::::::::::::::::::::::::
	::                                           ::
	::            Class constructor              ::
	::                                           ::
	:::::::::::::::::::::::::::::::::::::::::::::::
	*/
	function GifMerge($images, $t1, $t2, $t3, $loop, $dl, $xpos, $ypos, $model, $debug = false)
	{
		$debug ? $this->debug = true : $this->debug = false;
		if($this->debug) print "<b>GifMerge $this->ver debugger:</b><br>\n";
		if($model)
			$this->mod = $model;
		if($loop > -1)
		{
			$this->loop = floor($loop - 1);
			$this->use_loop = true;
		}
		if($t1 > -1 && $t2 > -1 && $t3 > -1)
		{
			$this->trans1 = $t1;
			$this->trans2 = $t2;
			$this->trans3 = $t3;
			$this->transparent = true;
		}
		for($i = 0; $i < count($images); $i++)
		{
			$dl[$i]		? $this->delay	= $dl[$i]	: $this->delay = $this->dly;
			$xpos[$i] 	? $this->x		= $xpos[$i] : $this->x = 0;
			$ypos[$i] 	? $this->y		= $ypos[$i] : $this->y = 0;
			$this->start_gifmerge_process($images[$i]);
		}
		$this->fout .= "\x3b";
	}
	/*
	:::::::::::::::::::::::::::::::::::::::::::::::
	::                                           ::
	::             Gifmerge processor            ::
	::                                           ::
	:::::::::::::::::::::::::::::::::::::::::::::::
	*/	function start_gifmerge_process($fp)
	{
		if($this->mod == 'C_FILE')
		{
			if(!$this->fin = fopen($fp, 'rb'))
			{
				if($this->debug) print "Error file open: $fp\<br>";
				return;
			}
		}
		else if($this->mod == 'C_MEMORY')
		{
			$this->ch  = 0;
			$this->fin = $fp;
		}
		$this->getbytes (6);
		if(!$this->arrcmp($this->buffer, $this->gif, 3))
		{
			if($this->debug) print "Isn't GIF file!\n<br>";
			return;
		}
		$this->getbytes (7);
		if($this->first) $this->logical_screen_descriptor = $this->buffer;
		$this->global_color_table_sizecode = $this->buffer[4] & 0x07;
		$this->global_color_table_size = 2 << $this->global_color_table_sizecode;
		if($this->buffer[4] & 0x80)
		{
			$this->getbytes((3 * $this->global_color_table_size));
			for($i = 0; $i < ((3 * $this->global_color_table_size)); $i++)
			{
				$this->global_in[$i] = $this->buffer[$i];
			}
			if($this->out_color_table_size == 0)
			{
				$this->out_color_table_size = $this->global_color_table_size;
				$out_color_table_sizecode = $this->global_color_table_sizecode;
				$this->global_out = $this->global_in;
			}
			if($this->global_color_table_size != $this->out_color_table_size || $this->arrcmp($this->global_out, $this->global_in, (3 * $this->global_color_table_size)))
			{
				$this->use_global_in = true;
			}
		}
		for($loop = true; $loop;)
		{
			$this->getbytes(1);
			switch ($this->buffer[0])
			{
				case 0x21:
					$this->read_extension();
					break;
				case 0x2c:
					$this->read_image_descriptor();
					break;
				case 0x3b:
					$loop = false;
				break;
				default:
            		if($this->debug) printf("Unrecognized byte code 0x%x, truncating file!\n<br>", $this->buffer[0]);
						$loop = false;
			}
		}
		if($this->mod == 'C_FILE')
			fclose($this->fin);
	}
	/*
	:::::::::::::::::::::::::::::::::::::::::::::::
	::                                           ::
	::          Image descriptor block           ::
	::                                           ::
	:::::::::::::::::::::::::::::::::::::::::::::::
	*/
	function read_image_descriptor()
	{
		$this->getbytes(9);
		$head = $this->buffer;
    	$this->local_color_table_flag = ($this->buffer[8] & 0x80) ? true : false;
    	if($this->local_color_table_flag)
    	{
        	$sizecode = $this->buffer[8] & 0x07;
			$size = 2 << $sizecode;
			$this->getbytes(3 * $size);
			for($i = 0; $i < (3 * $size); $i++)
			{
        		$this->local_in[$i] = $this->buffer[$i];
        	}
        	if($this->out_color_table_size == 0)
        	{
        		$this->out_color_table_size = $size;
        		$out_color_table_sizecode = $sizecode;
				for($i = 0; $i < (3 * $size); $i++)
				{
					$this->global_out[$i] = $this->local_in[$i];
				}
        	}
    	}
    	if($this->first)
    	{
			$this->first = false;
			$this->fout .= "\x47\x49\x46\x38\x39\x61"; // <= 'GIF89a'
			if($this->width && $this->height)
			{
				$this->logical_screen_descriptor[0] = $this->width & 0xFF;
				$this->logical_screen_descriptor[1] = ($this->width & 0xFF00) >> 8;
				$this->logical_screen_descriptor[2] = $this->height & 0xFF;
				$this->logical_screen_descriptor[3] = ($this->height & 0xFF00) >> 8;
			}
			$this->logical_screen_descriptor[4] |= 0x80;
			$this->logical_screen_descriptor[5] &= 0xF0;
			$this->logical_screen_descriptor[6] |= $this->out_color_table_sizecode;
			$this->putbytes($this->logical_screen_descriptor, 7);
        	$this->putbytes($this->global_out, ($this->out_color_table_size * 3));
			if($this->use_loop)
			{
				$ns[0] = 0x21;
				$ns[1] = 0xFF;
				$ns[2] = 0x0B;
				$ns[3] = 0x4e;  // N
				$ns[4] = 0x45;  // E
				$ns[5] = 0x54;  // T
				$ns[6] = 0x53;  // S
				$ns[7] = 0x43;  // C
				$ns[8] = 0x41;  // A
				$ns[9] = 0x50;  // P
				$ns[10] = 0x45; // E
				$ns[11] = 0x32; // 2
				$ns[12] = 0x2e; // .
				$ns[13] = 0x30; // 0
				$ns[14] = 0x03;
				$ns[15] = 0x01;
				$ns[16] = $this->loop & 255;
    			$ns[17] = $this->loop >> 8;
				$ns[18] = 0x00;
				$this->putbytes($ns, 19);
			}
    	}
  		if($this->use_global_in)
		{
			$outtable = $this->global_in;
			$outsize = $this->global_color_table_size;
			$outsizecode = $this->global_color_table_sizecode;
		}
		else
		{
			$outtable = $this->global_out;
			$outsize = $this->out_color_table_size;
		}
		if ($this->local_color_table_flag)
		{
			if ($size == $this->out_color_table_size && !$this->arrcmp($this->local_in, $this->global_out, $size))
			{
				$outtable = $global_out;
				$outsize = $this->out_color_table_size;
			}
			else
			{
				$outtable = $this->local_in;
				$outsize = $size;
				$outsizecode = $sizecode;
			}
		}
		$use_trans = false;
		if($this->transparent)
		{
			for ($i = 0; $i < $outsize; $i++)
				if (   $outtable [3 * $i	] == $this->trans1
					&& $outtable [3 * $i + 1] == $this->trans2
					&& $outtable [3 * $i + 2] == $this->trans3
				)
					break;
			if ($i < $outsize)
			{
				$transindex = $i;
				$use_trans = true;
			}
			else
			{
				if($this->debug) print "Transparent color not found!\n<br>";
			}
		}
		if($this->delay || $use_trans)
		{
			$this->buffer[0] = 0x21;
			$this->buffer[1] = 0xf9;
			$this->buffer[2] = 0x04;
			$this->buffer[3] = ($this->disposal << 2) + ($use_trans ? 1 : 0);
			$this->buffer[4] = $this->delay & 0xff;
			$this->buffer[5] = ($this->delay & 0xff00) >> 8;
			$this->buffer[6] = $use_trans ? $transindex : 0;
			$this->buffer[7] = 0x00;
			$this->putbytes($this->buffer,8);
		}
		$this->buffer[0] = 0x2c;
		$this->putbytes($this->buffer,1);
		$head[0] = $this->x & 0xff;
		$head[1] = ($this->x & 0xff00) >> 8;
		$head[2] = $this->y & 0xff;
		$head[3] = ($this->y & 0xff00) >> 8;
		$head[8] &= 0x40;
		if($outtable != $this->global_out)
		{
			$head[8] |= 0x80;
			$head[8] |= $outsizecode;
		}
		$this->putbytes($head,9);
		if($outtable != $this->global_out)
		{
			if($this->debug) print "Using local color table.\n<br>";
			$this->putbytes($outtable, (3 * $outsize));
		}
		$this->getbytes(1);
		$this->putbytes($this->buffer,1);
		for (;;)
		{
			$this->getbytes(1);
			$this->putbytes($this->buffer,1);
			if(($u = $this->buffer[0]) == 0)
			{
				break;
			}
			$this->getbytes($u);
			$this->putbytes($this->buffer, $u);
    	}
	}
	/*
	:::::::::::::::::::::::::::::::::::::::::::::::
	::                                           ::
	::           Image extension block           ::
	::                                           ::
	:::::::::::::::::::::::::::::::::::::::::::::::
	*/
	function read_extension()
	{
    	$this->getbytes(1);
    	switch($this->buffer[0])
    	{
			case 0xf9:
				if($this->debug) print "Skipping Graphic Control Extension.\n<br>";
	    		$this->getbytes(6);
	   			break;
			case 0xfe:
				if($this->debug) print "Skipping Comment Extension.\n<br>";
	    		for (;;)
	    		{
					$this->getbytes(1);
                	if (($u = $this->buffer[0]) == 0)
		    			break;
					$this->getbytes($u);
	    		}
	    		break;
			case 0x01:
				if($this->debug) print "Skipping Plain Text Extension.\n<br>";
	    		$this->getbytes(13);
	    		for (;;)
	    		{
					$this->getbytes(0);
                	if (($u = $this->buffer[0]) == 0)
		    			break;
					$this->getbytes($u);
	    		}
				break;
       		case 0xff:
				if($this->debug) print "Skipping Application Extension.\n<br>";
	    		$this->getbytes(9);
	    		$this->getbytes(3);
	    		for (;;)
	    		{
					$this->getbytes(1);
                	if (!$this->buffer[0])
                		break;
                	$this->getbytes($this->buffer[0]);
            	}
				break;
			default:
				if($this->debug) print "Skipping unrecognized extension.\n<br>";
	    		for (;;)
	    		{
					$this->getbytes(1);
        			if(!$this->buffer[0])
        				break;
					$this->getbytes($this->buffer[0]);
				}
    	}
	}

	/*::::::::::::::::::::::::::::::::::::::::::*/

	function arrcmp($b, $s, $l)
	{
		for($i = 0; $i < $l; $i++)
		{
			if($s{$i} != $b{$i}) return false;
		}
		return true;
	}

	/*::::::::::::::::::::::::::::::::::::::::::*/

	function getbytes($l)
	{
		for($i = 0; $i < $l; $i++)
		{
			if($this->mod == 'C_FILE')
			{
        		$bin = unpack('C*', fread($this->fin, 1));
        		$this->buffer[$i] = $bin[1];
        	}
        	else if($this->mod == 'C_MEMORY')
        	{
                $bin = unpack('C*', substr($this->fin, $this->ch, 1));
                $this->buffer[$i] = $bin[1];
                $this->ch++;
        	}
		}
		return $this->buffer;
	}

	/*::::::::::::::::::::::::::::::::::::::::::*/

	function putbytes($s, $l)
	{
		for($i = 0; $i < $l; $i++)
		{
			$this->fout .= pack('C*', $s[$i]);
		}
	}

	/*::::::::::::::::::::::::::::::::::::::::::*/

	function getAnimation()
	{
		return $this->fout;
	}
}
?>
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