Created
March 8, 2019 05:11
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Class to generate animated Gif
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<?php | |
/* | |
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: | |
:: Formerly known as::: | |
:: GIFEncoder Version 2.0 by László Zsidi, http://gifs.hu | |
:: | |
:: This class is a rewritten 'GifMerge.class.php' version. | |
:: | |
:: Modification: | |
:: - Simplified and easy code, | |
:: - Ultra fast encoding, | |
:: - Built-in errors, | |
:: - Stable working | |
:: | |
:: | |
:: Updated at 2007. 02. 13. '00.05.AM' | |
:: | |
:: | |
:: | |
:: Try on-line GIFBuilder Form demo based on GIFEncoder. | |
:: | |
:: http://gifs.hu/phpclasses/demos/GifBuilder/ | |
:: | |
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: | |
*/ | |
/* | |
08 Mar 2019 | |
Lightly modernised by phena109 | |
*/ | |
/** | |
* Encode animated gifs | |
*/ | |
class AnimatedGif | |
{ | |
/** | |
* The built gif image | |
* @var resource | |
*/ | |
private $image = ''; | |
/** | |
* The array of images to stack | |
* @var array | |
*/ | |
private $buffer = []; | |
/** | |
* How many times to loop? 0 = infinite | |
* @var int | |
*/ | |
private $number_of_loops = 0; | |
/** | |
* | |
* @var int | |
*/ | |
private $DIS = 2; | |
/** | |
* Which colour is transparent | |
* @var int | |
*/ | |
private $transparent_colour = -1; | |
/** | |
* Is this the first frame | |
* @var int | |
*/ | |
private $first_frame = true; | |
/** | |
* Encode an animated gif | |
* @param array $source_images An array of binary source images | |
* @param array $image_delays The delays associated with the source images | |
* @param int $number_of_loops The number of times to loop | |
* @param int $transparent_colour_red | |
* @param int $transparent_colour_green | |
* @param int $transparent_colour_blue | |
*/ | |
function __construct( | |
array $source_images, | |
array $image_delays, | |
$number_of_loops, | |
$transparent_colour_red = -1, | |
$transparent_colour_green = -1, | |
$transparent_colour_blue = -1 | |
) { | |
/** | |
* I have no idea what these even do, they appear to do nothing to the image so far | |
*/ | |
$transparent_colour_red = 0; | |
$transparent_colour_green = 0; | |
$transparent_colour_blue = 0; | |
$this->number_of_loops = ($number_of_loops > -1) ? $number_of_loops : 0; | |
$this->set_transparent_colour($transparent_colour_red, | |
$transparent_colour_green, $transparent_colour_blue); | |
$this->buffer_images($source_images); | |
$this->addHeader(); | |
for ($i = 0; $i < count($this->buffer); $i++) { | |
$this->addFrame($i, $image_delays [$i]); | |
} | |
} | |
/** | |
* Set the transparent colour | |
* @param int $red | |
* @param int $green | |
* @param int $blue | |
*/ | |
private function set_transparent_colour($red, $green, $blue) | |
{ | |
$this->transparent_colour = ($red > -1 && $green > -1 && $blue > -1) ? | |
($red | ($green << 8) | ($blue << 16)) : -1; | |
} | |
/** | |
* Buffer the images and check to make sure they are vaild | |
* @param array $source_images the array of source images | |
* @throws Exception | |
*/ | |
private function buffer_images($source_images) | |
{ | |
for ($i = 0; $i < count($source_images); $i++) { | |
$this->buffer [] = $source_images [$i]; | |
if (substr($this->buffer [$i], 0, | |
6) != "GIF87a" && substr($this->buffer [$i], 0, | |
6) != "GIF89a") { | |
throw new \Exception('Image at position ' . $i . ' is not a gif'); | |
} | |
for ($j = (13 + 3 * (2 << (ord($this->buffer [$i]{10}) & 0x07))), $k = true; $k; $j++) { | |
switch ($this->buffer [$i]{$j}) { | |
case "!": | |
if ((substr($this->buffer [$i], ($j + 3), | |
8)) == "NETSCAPE") { | |
throw new \Exception('You cannot make an animation from an animated gif.'); | |
} | |
break; | |
case ";": | |
$k = false; | |
break; | |
} | |
} | |
} | |
} | |
/** | |
* Add the gif header to the image | |
*/ | |
private function addHeader() | |
{ | |
$cmap = 0; | |
$this->image = 'GIF89a'; | |
if (ord($this->buffer [0]{10}) & 0x80) { | |
$cmap = 3 * (2 << (ord($this->buffer [0]{10}) & 0x07)); | |
$this->image .= substr($this->buffer [0], 6, 7); | |
$this->image .= substr($this->buffer [0], 13, $cmap); | |
$this->image .= "!\377\13NETSCAPE2.0\3\1" . $this->word($this->number_of_loops) . "\0"; | |
} | |
} | |
/** | |
* Add a frame to the animation | |
* @param int $frame The frame to be added | |
* @param int $delay The delay associated with the frame | |
*/ | |
private function addFrame($frame, $delay) | |
{ | |
$Locals_str = 13 + 3 * (2 << (ord($this->buffer [$frame]{10}) & 0x07)); | |
$Locals_end = strlen($this->buffer [$frame]) - $Locals_str - 1; | |
$Locals_tmp = substr($this->buffer [$frame], $Locals_str, $Locals_end); | |
$Global_len = 2 << (ord($this->buffer [0]{10}) & 0x07); | |
$Locals_len = 2 << (ord($this->buffer [$frame]{10}) & 0x07); | |
$Global_rgb = substr($this->buffer [0], 13, | |
3 * (2 << (ord($this->buffer [0]{10}) & 0x07))); | |
$Locals_rgb = substr($this->buffer [$frame], 13, | |
3 * (2 << (ord($this->buffer [$frame]{10}) & 0x07))); | |
$Locals_ext = "!\xF9\x04" . chr(($this->DIS << 2) + 0) . | |
chr(($delay >> 0) & 0xFF) . chr(($delay >> 8) & 0xFF) . "\x0\x0"; | |
if ($this->transparent_colour > -1 && ord($this->buffer [$frame]{10}) & 0x80) { | |
for ($j = 0; $j < (2 << (ord($this->buffer [$frame]{10}) & 0x07)); $j++) { | |
if ( | |
ord($Locals_rgb{3 * $j + 0}) == (($this->transparent_colour >> 16) & 0xFF) && | |
ord($Locals_rgb{3 * $j + 1}) == (($this->transparent_colour >> 8) & 0xFF) && | |
ord($Locals_rgb{3 * $j + 2}) == (($this->transparent_colour >> 0) & 0xFF) | |
) { | |
$Locals_ext = "!\xF9\x04" . chr(($this->DIS << 2) + 1) . | |
chr(($delay >> 0) & 0xFF) . chr(($delay >> 8) & 0xFF) . chr($j) . "\x0"; | |
break; | |
} | |
} | |
} | |
switch ($Locals_tmp{0}) { | |
case "!": | |
$Locals_img = substr($Locals_tmp, 8, 10); | |
$Locals_tmp = substr($Locals_tmp, 18, strlen($Locals_tmp) - 18); | |
break; | |
case ",": | |
$Locals_img = substr($Locals_tmp, 0, 10); | |
$Locals_tmp = substr($Locals_tmp, 10, strlen($Locals_tmp) - 10); | |
break; | |
} | |
if (ord($this->buffer [$frame]{10}) & 0x80 && $this->first_frame === false) { | |
if ($Global_len == $Locals_len) { | |
if ($this->blockCompare($Global_rgb, $Locals_rgb, | |
$Global_len)) { | |
$this->image .= ($Locals_ext . $Locals_img . $Locals_tmp); | |
} else { | |
$byte = ord($Locals_img{9}); | |
$byte |= 0x80; | |
$byte &= 0xF8; | |
$byte |= (ord($this->buffer [0]{10}) & 0x07); | |
$Locals_img{9} = chr($byte); | |
$this->image .= ($Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp); | |
} | |
} else { | |
$byte = ord($Locals_img{9}); | |
$byte |= 0x80; | |
$byte &= 0xF8; | |
$byte |= (ord($this->buffer [$frame]{10}) & 0x07); | |
$Locals_img{9} = chr($byte); | |
$this->image .= ($Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp); | |
} | |
} else { | |
$this->image .= ($Locals_ext . $Locals_img . $Locals_tmp); | |
} | |
$this->first_frame = false; | |
} | |
/** | |
* Add the gif footer | |
*/ | |
private function addFooter() | |
{ | |
$this->image .= ";"; | |
} | |
/** | |
* Compare gif blocks? What is a block? | |
* @param type $GlobalBlock | |
* @param type $LocalBlock | |
* @param int $Len | |
* @return bool | |
*/ | |
private function blockCompare($GlobalBlock, $LocalBlock, $Len) | |
{ | |
for ($i = 0; $i < $Len; $i++) { | |
if ( | |
$GlobalBlock{3 * $i + 0} != $LocalBlock{3 * $i + 0} || | |
$GlobalBlock{3 * $i + 1} != $LocalBlock{3 * $i + 1} || | |
$GlobalBlock{3 * $i + 2} != $LocalBlock{3 * $i + 2} | |
) { | |
return false; | |
} | |
} | |
return true; | |
} | |
/** | |
* No clue | |
* @param int $int | |
* @return string the char you meant? | |
*/ | |
private function word($int) | |
{ | |
return (chr($int & 0xFF) . chr(($int >> 8) & 0xFF)); | |
} | |
/** | |
* Return the animated gif | |
* @return resource | |
*/ | |
function getAnimation() | |
{ | |
return $this->image; | |
} | |
/** | |
* Return the animated gif | |
* @return void | |
*/ | |
function display() | |
{ | |
//late footer add | |
$this->addFooter(); | |
header('Content-type:image/gif'); | |
echo $this->image; | |
} | |
} |
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