Taking a snapshot of a movieclip (to jpg)? is this possible?

[azukizero]

Hi all,

I'm trying to figure out if it's possible to have Flash take a snapshot (like a screenshot) of a movieclip then make it available as a jpg. Basically, here's what I'm trying to do:

I have an Ad Libs type of form where users type in answers in text fields. When they've filled them all out, a dynamically generated image pops in below (as if their answers generated a unique result). I want the user to be able to email this result, design and all, not just the information.

Any ideas on a good way to accomplish this?

thanks!

[Gundark]

You'll need the help of server-side scripting language such as PHP to accomplish this.

I believe this is basically done by getting the bitmap data from your movieclip, sending it to PHP and then having PHP return the jpg file created.

[wvxvw]

You can encode bitmapdata into JPEG format using JPEGEncoder class from as3corelib (http://code.google.com/p/as3corelib/) (it is available in mx framework too).

[Gundark]

^ Cool, I wasn't aware those included JPG and PNG encoders. Of course that still leaves you with a byte stream. Wouldn't you need to use either AIR or a server-side language to allow the user to download the JPG?

And if you do choose to use a server-side language wouldn't it be faster to encode the JPG on the server? Unless of course you wanted to reduce server CPU load.

[wvxvw]

Sure, you have to have some script on the server to store the file, and, technically, you can write an encoder, or use GD library with PHP or something like it. But encoded JPEG may be 4+ times smaller than raw bitmapdata, so I'd encode on the client, if possible.

[sanjit_rane1]

Hi,
I had the same requirement in my project. I found a site which had a function which solved my problem. Sorry for forgetting the name of the person who wrote the function. It was done in AS2. Hope you can convert it in AS3.

Flash:
import flash.display.BitmapData;
import flash.geom.*;
import com.quasimondo.display.BitmapExporter;
// This is the bitmap that we draw() the camera picture in
// and which will be saved: the dimensions can be changed (W,H)
var snapshot:BitmapData = new BitmapData(278,204,false);
// You will have to change the gatewayURL to your server
// except if you are testing this locally:
BitmapExporter.gatewayURL = "http://localhost/BitmapExporter.php";
// It is a good idea to listen to the various events that
// BitmapExporter provides:
BitmapExporter.addEventListener( "progress", this);
BitmapExporter.addEventListener( "status", this);
BitmapExporter.addEventListener( "error", this);
//BitmapExporter.addEventListener( "complete", this);
function save():Void
{
// Check if there is still an export going on:
if (BitmapExporter.getStatus() == "idle") {

// update the bitmap with the latest camera image:
//Take the snapshot in a dummy mc.
dummy_mc.attachBitmap(takeSnapshot(movieClip), 1);
snapshot.draw(dummy_mc);


progress_back._visible = progressbar._visible=true;

// this is only to compare the different speeds
timer = getTimer();
onEnterFrame = updateTimer;

// Since the webcam image is very small we can get away with turboscan here:
BitmapExporter.saveBitmap(snapshot, "snapshot.png", "turboscan", 0 );

// Usually it is receommended to use one of the other modes:
// BitmapExporter.saveBitmap(snapshot, "snapshot.jpg", "fastscan", 0, 70);
// BitmapExporter.saveBitmap(snapshot, "snapshot.jpg", "default", 0, 70);
// BitmapExporter.saveBitmap(snapshot, "snapshot.jpg", "palette", 0, 70);
// BitmapExporter.saveBitmap(snapshot, "snapshot.jpg", "rgb_rle", 0, 70);


}
}
function takeSnapshot(mc:MovieClip):BitmapData {
var sp:BitmapData = new BitmapData(300, 300, false);
var myMatrix:Matrix = new Matrix()
myMatrix.tx =150
myMatrix.ty =50
trace(myMatrix)
sp.draw(mc, myMatrix, new ColorTransform(), "normal");
return sp;
}
function updateTimer(){
time.text = getTimer() - timer;
}
function cancel():Void {
cancel_btn.enabled = false;
cancel_btn._visible = false;
BitmapExporter.cancel();
}
function progress(evt:Object):Void {
progressbar.setProgress(evt.current, evt.total);
progressbar.label = evt.message+" (%3%%)";
}
function error(evt:Object):Void {
errormsg.text += evt.message+"\n"+" .............."+ evt;
delete onEnterFrame;
trace( evt.message )
}
function status(evt:Object):Void {
trace( evt.status );

switch (evt.status) {

case "contacting server" :
save_btn._visible = false;
save_btn.enabled = false;
cancel_btn._visible = true;
cancel_btn.enabled = true;
break;

case "idle" :
progress_back._visible = progressbar._visible=false;
save_btn.enabled = true;
save_btn._visible = true;
cancel_btn.enabled = false;
cancel_btn._visible = false;
onEnterFrame = null;
break;

case "retrieving":
onEnterFrame = null;
break;
}
}

cancel_btn.onPress = function() {
this._parent.cancel();
};
save_btn.onPress = function() {
this._parent.save();
};

progress_back._visible = progressbar._visible=false;
cancel_btn._visible = false;
save_btn._visible = true;
progressbar.minimum = 0;
cancel_btn.enabled = false;
var timer:Number
var errormsg:TextField;
//================================================== ==
PHP:
Thanxs to Author: Mario Klingemann
<?php
$RELATIVE_SAVEPATH = "BitmapExporter_Tempfiles/";


// $DOWNLOADURL contains the url to the script that returns the final image as seen from the Flash file.
// By default this is the url of BitmapExporter.php itself and you have to adjust the path if you copy it to
// a subfolder.
$DOWNLOADURL = "http://".$_SERVER['SERVER_NAME']."/BitmapExporter.php?mode=download&name (http://&quot;.$_SERVER['SERVER_NAME'].&quot;/BitmapExporter.php?mode=download&name)=";

//Alternatively you can also return the direct link tothe image - but then you'llhave to take care
//yourself about cleaning up afterwards:
//$DOWNLOADURL = "http://localhost/BitmapExporter_Tempfiles/";

// The maximum allowed time in seconds the script is allowed to calculate - if you deal with big bitmaps
// and lzw compression you might have to increase this value. A value of 0 removes any time limit.
// Depending on your servers PHP configuration this value might be ignored and there is a fixed time limit.
// In that case you will have to contact your administrator if you experience timeout errors.

$MAX_CALCULATION_TIME = 0;


// if you happen to get "error [unefined]" messages PHP probably does not have enough memory
// to process the bitmap. Uncomment the following lines to give PHP 32MB.
/*
if( ini_get('safe_mode') ){
if ($LOGGING) error_log( "WARNING: php safe mode is activated on this server, thus the memory limit can not be overridden. This might cause the script to quit prematurely on big images\n",3,$RELATIVE_SAVEPATH."be_log");
}else{
ini_set ( "memory_limit", "32M");
}
*/

// if you are experiences errors, try to set $LOGGING to true.
// All errors/messages will be stored in $RELATIVE_SAVEPATH."be_log" in the same directory
// as this file
$LOGGING = false;

// for debugging purposes only - if KEEP_TEMP_FILES=true temporary files will not be deleted
$KEEP_TEMP_FILES = false;

error_reporting(E_ALL);
set_error_handler("errorHandler");
// If you use a https:// connection to save the bitmaps you will have to uncomment two of the header commands
// in order to ensure that the script works in IE:

header("Expires: Mon, 25 Jan 1970 05:00:00 GMT"); // comment this line out in https
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache"); // and comment this line out in https

if( ini_get('safe_mode') ){
if ($LOGGING) error_log( "WARNING: php safe mode is activated on this server, thus the script time limit can not be overridden. This might cause the script to quit prematurely on big images\n",3,$RELATIVE_SAVEPATH."be_log");
}else{
set_time_limit ( $MAX_CALCULATION_TIME );
}


$postsize=0;

if ( isset( $_POST ) )
{
foreach ($_POST as $key => $value)
{
$postsize += strlen($value);
}
}

$mode = "";

if ( isset( $_REQUEST["mode"] ) ) {
$mode = $_REQUEST["mode"];
if ($LOGGING) error_log( "mode: ".$mode."\n",3,$RELATIVE_SAVEPATH."be_log");
}

switch ($mode)
{
case "getImageHandle":

$uniqueID = md5( microtime() . rand() );
sendResult( "success=1&uniqueID=$uniqueID" );
break;

case "turboscan":

$uniqueID = $_POST["uniqueID"];
$bitmapString = $_POST["bitmapString"];
$data = explode( ",", $bitmapString );

$l = count($data);
$bitmapData = "";

for ($i=0; $i<$l; $i++ )
{
$d = $data[$i];
$bitmapData .= pack("nC", ($d >> 8) & 0xffff, $d & 0xff );
}

appendToTempFile( $uniqueID, $bitmapData );

sendResult( "success=1&sentBytes=".$postsize );

break;

case "fastscan":

$uniqueID = $_POST["uniqueID"];
$bitmapString = $_POST["bitmapString"];

$data = explode( ",", $bitmapString );
$l = count($data);
$bitmapData = "";

for ($i=0; $i<$l; $i++ )
{
$d = base_convert( $data[$i], 36, 10 );
$bitmapData .= pack("nC", ($d >> 8) & 0xffff, $d & 0xff );
}

appendToTempFile( $uniqueID, $bitmapData );
sendResult( "success=1&sentBytes=".$postsize );

break;

case "default":

appendToTempFile( $_POST["uniqueID"], base64_decode( $_POST["bitmapString"] ) );
sendResult( "success=1&sentBytes=".$postsize );

break;

case "palette":


$uniqueID = $_POST["uniqueID"];
$paletteString = $_POST["paletteString"];
$bitmapString = $_POST["bitmapString"];

$bitmapString= base64_decode( $bitmapString );
$l = strlen($bitmapString);
$bitmapData = array();

for ($i=0; $i<$l; $i++){
$bitmapData[$i] = ord($bitmapString{$i});
}

$paletteString = base64_decode( $paletteString );
$paletteData = array();
$l = strlen($paletteString);
$idx = 0;

for ($i=0; $i<$l; $i+=3)
{
$paletteData[$idx++] = $paletteString{$i}.$paletteString{$i+1}.$paletteSt ring{$i+2};
}

$idx = 0;
$paletteIdx = 0;
$decodedBitmap = "";

while ( $idx < count( $bitmapData ) )
{
$repeat = 2;
if ( $bitmapData[$idx]==0x80 && $bitmapData[$idx+1]==0)
{
$repeat = 2 * ( ($bitmapData[$idx+2]<<8) + $bitmapData[$idx+3]);
$idx+=4;
}

$pointer = 0;
while ($repeat>0)
{
$offset = ( ( $bitmapData[$idx + $pointer] << 8 ) + $bitmapData[ $idx+1+$pointer]);
if ( $offset > 0x7fff ) $offset -= 0x10000;
$paletteIdx += $offset;

$decodedBitmap .= $paletteData[$paletteIdx];
$repeat--;
$pointer = 2 - $pointer;
}
$idx+=4;
}
appendToTempFile( $uniqueID, $decodedBitmap );
sendResult( "success=1&sentBytes=".$postsize );
break;

case "rgb_rle":
$uniqueID = $_POST["uniqueID"];
$rString = $_POST["red"];
$gString = $_POST["green"];
$bString = $_POST["blue"];

$rString= base64_decode( $rString );
$l = strlen($rString);
$rData = array();
for ($i=0; $i<$l; $i++){
$rData[$i] = ord($rString{$i});
}

$gString= base64_decode( $gString );
$l = strlen($gString);
$gData = array();
for ($i=0; $i<$l; $i++){
$gData[$i] = ord($gString{$i});
}

$bString= base64_decode( $bString );
$l = strlen($bString);
$bData = array();
for ($i=0; $i<$l; $i++){
$bData[$i] = ord($bString{$i});
}

$pixels = array();
$i_in = 0;
$i_out = 0;
$r = $rData[$i_in++];
$pixels[$i_out++] = $r << 16;
while ($i_in < count($rData))
{
if ( $rData[$i_in] == 0 )
{
if ( $rData[++$i_in] == 0 )
{
$count = $rData[++$i_in] | ( $rData[++$i_in] << 8 );
$i_in++;
} else {
$count = $rData[$i_in++];
}
$p = $rData[$i_in++];
for ( $i=0; $i < $count; $i++ )
{
$r = ( $r + $p ) & 0xff;
$pixels[$i_out++] = $r << 16;
}
} else {
$r = ( $r + $rData[$i_in++] ) & 0xff;
$pixels[$i_out++] = $r << 16;
}
}

$i_in = 0;
$i_out = 0;
$g = $gData[$i_in++];
$pixels[$i_out++] |= $g << 8;
while ($i_in < count($gData))
{
if ($gData[$i_in]==0)
{
if ( $gData[++$i_in]==0)
{
$count = $gData[++$i_in] | ( $gData[++$i_in] << 8 );
$i_in++;
} else {
$count = $gData[$i_in++];
}
$p = $gData[$i_in++];
for ($i=0;$i<$count;$i++)
{
$g = ( $g + $p ) & 0xff;

$pixels[$i_out] |= $g << 8;
$i_out++;
}
} else {
$g = ( $g + $gData[$i_in++] ) & 0xff;
$pixels[$i_out] |= $g << 8;
$i_out++;
}
}

$i_in = 0;
$i_out = 0;
$b = $bData[$i_in++];
$d = $pixels[$i_out++];
$bitmapData = pack("nC", ($d >> 8) & 0xffff, $b );

while ($i_in < count($bData))
{
if ($bData[$i_in]==0)
{
if ( $bData[++$i_in]==0)
{
$count = $bData[++$i_in] | ( $bData[++$i_in] << 8);
$i_in++;
} else {
$count = $bData[$i_in++];
}
$p = $bData[$i_in++];
for ( $i=0; $i<$count; $i++ )
{
$b = ( $b + $p ) & 0xff;
$d = $pixels[$i_out++];
$bitmapData .= pack("nC", ($d >> 8) & 0xffff,$b );
}
} else {
$b = ( $b + $bData[$i_in++] ) & 0xff;
$d = $pixels[$i_out++] | $b;
$bitmapData .= pack("nC", ($d >> 8) & 0xffff, $b );
}
}

appendToTempFile( $uniqueID, $bitmapData );
sendResult( "success=1&sentBytes=".$postsize );

break;

case "save":

$width = $_POST["width"];
$height = $_POST["height"];
$uniqueID = $_POST["uniqueID"];
$filename = $_POST["filename"];
$quality = $_POST["quality"];

if ( $width <= 0 || $height <= 0 )
{
if ($LOGGING) error_log("Wrong width or height data submitted\n",3,$RELATIVE_SAVEPATH."be_log");
sendResult( "success=0&error=".urlencode("Wrong width or height data submitted") );
}

$tempImagePath = $RELATIVE_SAVEPATH.$uniqueID.".tmp";
checkTempImage();

echo "keepalive&";
flush();

$_format = explode( ".", $filename);
$format = strtolower( $_format[1] );

$tempFileName = $uniqueID.".".$format;

switch ( $format )
{
case "bmp":
$fp = fopen( $RELATIVE_SAVEPATH.$tempFileName, "w" );
fputs( $fp, stringToBmp( file_get_contents( $tempImagePath ), $width, $height ) );
fclose ( $fp );
if (!$KEEP_TEMP_FILES) @unlink( $tempImagePath );
break;

case "png":
case "jpg":
case "jpeg":
$fp = fopen( $RELATIVE_SAVEPATH.$tempFileName, "w" );
fputs( $fp, stringToPNG( file_get_contents( $tempImagePath ), $width, $height ) );
fclose ( $fp );
if (!$KEEP_TEMP_FILES) @unlink( $tempImagePath );

echo "keepalive&";
flush();

if ( $format != "png")
{
if ( !function_exists("imagecreatefrompng") )
{
if ($LOGGING) error_log("No GD installed on Server\n",3,$RELATIVE_SAVEPATH."be_log");
sendResult( "success=0&error=".urlencode("No GD installed on Server"), false );
}

$im = @imagecreatefrompng ( $RELATIVE_SAVEPATH.$tempFileName );

if (!$im)
{
if ($LOGGING) error_log("Could not create GD-image: ".$php_errormsg."\n",3,$RELATIVE_SAVEPATH."be_log");
sendResult( "success=0&error=".urlencode("Could not create GD-image (".$php_errormsg.")"), false );
}

if (!@imagejpeg ( $im , $RELATIVE_SAVEPATH.$tempFileName, $quality )){
sendResult( "success=0&error=".urlencode("Could not generate JPEG file"), false );
}

}
break;

default:

if ( $format != "jpg" && $format != "jpeg" && $format != "png" ){
sendResult( "success=0&error=".urlencode("Desired file-format is not available (".$format.")"), false);
}
break;
}

$size = filesize( $RELATIVE_SAVEPATH.$tempFileName );
if ($LOGGING) error_log("File ".$RELATIVE_SAVEPATH.$tempFileName." (".$size." Bytes) created\n",3,$RELATIVE_SAVEPATH."be_log");

sendResult( "success=1&url=".urlencode( $DOWNLOADURL.$tempFileName )."&filename=".urlencode($tempFileName)."&size=".$size, false );

break;


case "dropImageHandle":

$uniqueID = $_POST["uniqueID"];

$imageFilePath = $RELATIVE_SAVEPATH.$uniqueID.".tmp";

if ( !$KEEP_TEMP_FILES && file_exists( $imageFilePath ) )
{
unlink( $imageFilePath );
}

sendResult( "success=1" );

break;

case "":
sendResult( "success=1" );
break;

case "download":
$file = $RELATIVE_SAVEPATH.basename($_GET["name"]);
if (isset($_GET["delete"]))
{
$deleteFile = ($_GET["delete"] == "1");
}
if (file_exists($file))
{
$_format = explode( ".", $file);
$format = strtolower( $_format[1] );

switch ( $format )
{
case "png":
header ("Content-type: image/png");
break;

case "jpg":
case "jpeg":
header ("Content-type: image/jpeg");
break;

case "bmp":
header ("Content-type: image/bmp");
break;

default:
if ($LOGGING) error_log("Unknown filetype: ".$format, 3, $RELATIVE_SAVEPATH."be_log" );
exit();
break;
}
header("Content-Length: ".(string)(filesize($file)));

readfile( $file );
if ($deleteFile) while(!unlink( $file ));
} else {
if ($LOGGING) error_log($file." does not exist", 3, $RELATIVE_SAVEPATH."be_log" );
exit();
}

cleanUpTempFolder();
break;



default:
sendResult( "success=0&error=Unknown Command: ".$mode );
break;

}

function sendResult( $data, $sendHeader=true, $exit = true )
{
if ($sendHeader) header( "content-length: ".strlen($data) );
echo $data;
if ($exit) exit();
}
function checkTempImage()
{
global $tempImagePath;

if ( !file_exists( $tempImagePath ) )
{
sendResult( "success=0&error=".urlencode("No temporary image with provided uniqueID found: ".$tempImagePath) );
}
}

function appendToTempFile( $uniqueID, $bitmapString )
{
global $RELATIVE_SAVEPATH, $LOGGING;

if ( $LOGGING ) error_log( "appendToTempFile: ".$uniqueID." ".strlen( $bitmapString )." Bytes\n",3,$RELATIVE_SAVEPATH."be_log");

if ( strlen( $bitmapString ) ==0 ) return;

$tempImagePath = $RELATIVE_SAVEPATH.$uniqueID.".tmp";

$fp = fopen( $tempImagePath, "ab+" );

if ( !$fp )
{
sendResult( "success=0&error=".urlencode("Could not write to temporary file ".$tempImagePath ) );
}

fputs( $fp, $bitmapString );

fclose ( $fp );

}


// stringToBmp function with kind permission
// by Patrick Mineault, http://www.5etdemi.com/
// adapted to BitmapExporter data stream format

function stringToBmp($stream, $width, $height)
{
//Bitmap header
$bmpHeader = "BM";

//Length is number of bytes + header size (54 bytes)
$len = $width*$height*3;
//write as little endian
$bmpHeader .= pack("V", $len + 54);

//Four empty bytes
$bmpHeader .= "\0\0\0\0";
//Offset to beginning of data
$bmpHeader .= chr(54) . "\0\0\0";

//Size of the bmpinfo header
$bmpHeader .= chr(40) . "\0\0\0";
//width
$bmpHeader .= pack("V", $width);
//height
$bmpHeader .= pack("V", $height);
//Number of biplanes
$bmpHeader .= chr(1) . "\0";
//Bits per pixel
$bmpHeader .= chr(24) . "\0\0\0";
//Compression type (0 = none)
$bmpHeader .= "\0\0";
//Image data size
$bmpHeader .= pack("V", $len);
//BiXPelsPerMeter & BiYPelsPerMeter (this is the value Fireworks writes)
$bmpHeader .= pack("V", 2834) . pack("V", 2834);
//Extra useless bytes
$bmpHeader .= "\0\0\0\0\0\0\0\0";

//Normalize the string so it's the right length, fill with white
//pixels if necesary

$idx = $width * $height + 1 ;

$slicedStream = str_pad(strrev($stream), $len, str_repeat(chr(255), 1024));

//And we're done
return $bmpHeader . $slicedStream;
}

function stringToPNG($stream, $width, $height)
{
$png = pack("V",0x474e5089);
$png .= pack("V",0x0a1a0a0d);

$IHDR = pack("N", $width);
$IHDR .= pack("N", $height);
$IHDR .= pack("C",8);
$IHDR .= pack("C",2);
$IHDR .= pack("C",0);
$IHDR .= pack("C",0);
$IHDR .= pack("C",0);

$png .= pack("N", strlen($IHDR) );
$png .= "IHDR";
$png .= $IHDR;
$png .= pack("N", crc32("IHDR".$IHDR));

$img = "";
for ($i=0;$i<$height;$i++)
{
$img .= "\0".substr($stream,$i * $width*3,$width*3);
}

$img = gzcompress($img);
$png .= pack("N", strlen($img) );
$png .= "IDAT";
$png .= $img;
$png .= pack("N", crc32("IDAT".$img));

$png .= pack("N",0 );
$png .= "IEND";
$png .= pack("N", crc32("IEND"));

return $png;
}

function cleanUpTempFolder()
{
$days = 1;

$dir = opendir( $RELATIVE_SAVEPATH );
while( false !== ( $file = readdir( $dir ) ) )
{
$tsuffix = explode(".",$file);
$suffix = $suffix[count($tsuffix)-1];
if ( $suffix=="tmp" || $suffix=="png" || $suffix=="jpg" || $suffix=="jpeg" || $suffix=="bmp" )
{
$find_date = ( time() - filemtime($file) )/60/60/24;
if( $find_date > $days )
{
while( !unlink($file) );
}
}
}
closedir($dir);

}

function errorHandler($errno, $errstr, $errfile, $errline)
{

switch ($errno) {

case E_ERROR:
case E_USER_ERROR:
$message = "ERROR [$errno] $errstr ";
$message .= "in line $errline of file $errfile";
$message .= ", PHP " . PHP_VERSION . " (" . PHP_OS . ")";
break;

case E_WARNING:
case E_USER_WARNING:
$message = "WARNING [$errno] $errstr";
break;

case E_NOTICE:
case E_USER_NOTICE:
$message = "NOTICE [$errno] $errstr";
break;

default:
$message = "Unkown error type: [$errno] $errstr";
break;
}

sendResult( "success=0&error=".urlencode($message) );

}

?>