JPEG resize on BLOBs

[Anon]

Hello

I have a problem with doing resize of JPEG file if i keep it in DB as BLOB. I know how to do resize on files ( using imagecopyresized with imagejpeg ), but don't know how to work with that functions on data from database. Any1 could give me some tips about it ?

PS: I don't want to use any temporary file ... i need to do it directly on data returned as blob.

[yesurbius]

I am showing some code below - I hope it will show up ... If it doesn't I can email it to you..
I've set up a database in PostgreSQL and I've imported all of my images from a directory into the database, and filled in descriptions. I wanted to extract the picture from the database along with information about the picture (Photographer, date added, number of times viewed, etc)

My database is in the format:

ID,Description,Photographer,Date Taken,data

data is a large object identifier (BLO😎

I've looked up all the code in this last snippet, but problems with my php have prevented me from testing it further... but I hope it helps..

<code>
<?php
dl("pgsql.so");

Which record we want to see

$id = 1;

pg_connect(host, port, options, tty, dbname);

$database = pg_Connect("localhost","5432","","","photoalbum");

if (!$database)
{
echo "Connection to database failed.";
exit;
}

$imagedata = pg_Exec($database,
"SELECT photo.data " .
"FROM photo " .
"WHERE photo.id = " . $id . ";");

if ($imagedata)
{

Apparently BEGIN / COMMIT required

for a pg_loopen command

pg_Exec($database, "BEGIN");

get the BLOB identifier (OID)

$imageoid = pg_Result($imagedata,0,0);

get a file descriptor for the BLOB

at BLOB identifier $imageoid

$fd = pg_loopen($database,$imageoid,"r");

read in the data (I've put a max on mine)

$imagedata = pg_loread( $fd, 500000 );

required for pg_loopen()

pg_Exec($database,"COMMIT");

Create an image from extracted data

$theimage = ImageCreateFromString( $imagedata );

display it in the browser

ImageJPEG( $theimage );
Header( "Content-type: image/jpeg" );
} else {
echo "Image Retrieval Failed!" . chr(13);
}

?>
</code>

[Anon]

i can not see where you resize jpg here ?

[yesurbius]

I didn't put the code in there, the hardest part was simply getting the image from the database and into an image variable that you can work with.. a call to ImageCopyResized is all you needed. I got everything figured out with my system and tested .. so here's the source:

<?php

Load our extensions

dl("pgsql.so");
dl("gd.so");

# # # # # # # # # # # # # # # # # # # # #

Load the image from the database

# # # # # # # # # # # # # # # # # # # # #

pg_connect(host, port, options, tty, dbname);

$database = pg_Connect("localhost","5432","","","photoalbum");

if ($database == False)
{
echo "Connection to database failed.";
exit;
}

$imagedata = pg_Exec($database,
"SELECT photo.data " .
"FROM photo " .
"WHERE photo.photo_id = " . $id . ";");

if ($imagedata == False)
{
header( "Content-type: text/html" );
echo "Image retrieval failed on query execution!";
exit;
}

Required for accessing large objects

pg_Exec($database, "BEGIN");

Get the OID from row_number 0 and fieldname 0 (using index value)

$imageoid = pg_Result($imagedata,0,0);
if ($imageoid == NULL) {
exit;
}

Get a file descriptor for the large object

$fd = pg_loopen($database,$imageoid,"r");

Read the large object data (image data) and store it in a string. We've assigned a limit to stop buffer overruns

$imagedata = pg_loread( $fd, 1000000 );

close the large object descriptor

pg_loclose( $fd );

Required for accessing large objects

pg_Exec($database,"COMMIT");

load the image from the database, into a string

$theimage = ImageCreateFromString( $imagedata );

Close the database

pg_close( $database );

# # # # # # # # # # # # # # # # # # # # #

Process the Image

# # # # # # # # # # # # # # # # # # # # #

Next, we need to determine what we are supposed to do here:

Here is a table that outlines the actions and parameters

Action || Parameters

==========||========

help || none

display || none

resize || destination_size_x, destination_size_y

zoom || source_x, source_y, source_size_x, source_size_y, destination_x, destination_y, destination_size_x, destination_size_y

if (!isset($action)) {
$action = "display";
}

switch( $action ) {
case "help":

display the help

echo "PHP Script Usage: <br>";
echo "<table><th>Action</th><th>Parameters</th>";
echo "<tr><td>help</td><td>none</td></tr>";
echo "<tr><td>display</td><td>none</td></tr>";
echo "<tr><td>resize</td><td>destination_size_x, destination_size_y</td></tr>";
echo "<tr><td>zoom</td><td>source_x, source_y, source_size_x, source_size_y, destination_x, destination_y, destination_size_x, destination_size_y</td></tr>";
echo "</table>";
header( "Content-Type: text/html" );
break;

case "display":
ImageJPEG( $theimage );
break;

case "resize":
{
$changed = true;
if (isset($destination_size_x)) {

check to see if value given in percentage or not

if (!strrpos($destination_size_x,"%") === false) {

Percentage given, use that

$destination_size_x = round(ImageSX($theimage) * ( $destination_size_x / 100 ));
}
} else {
$changed = false;

no size_x given, so use image's size

$destination_size_x = ImageSX($theimage);
}

  if (isset($destination_size_y)) {
    # check to see if value given in percentage or not
    if (!strrpos($destination_size_y,'%') === false) {
      # Percentage given, use that
      $destination_size_y = round(ImageSY($theimage) * ( $destination_size_y / 100 ));
    }
  } else {
    # check if we should just switch to display mode
    if ($changed == false) {
      ImageJPEG( $theimage );
      exit;
    }
# no size_y given, so use image's size
$destination_size_y = ImageSY($theimage);
  }
}
$newimage = ImageCreate($destination_size_x, $destination_size_y);
ImageCopyResized($newimage, $theimage,0,0,0,0,$destination_size_x,$destination_size_y,ImageSX($theimage),ImageSY($theimage));
ImageJPEG( $newimage );
header( "Content-type: image/jpeg" );
break;

case zoom:

not yet implemented

break;

} # switch

?>

[Anon]

I want to open jpeg imagedata ($data) stored as a blob in MySQL database to resize with the gd php lib. can anyone tell me how to open the file data for resizing. This is what i have now (not working)

(partly displayed)

else if($image == "full"){
$QUERY = "SELECT imageData FROM $CATALOG_TABLE WHERE recordID = '$recordID'";
$result = @($QUERY);
$data = @MYSQL_RESULT($result,0, "imageData");

//thumbnail max size
$size = 100;

//max additional size created by margin
$margin = 10;

//draw a border?
$border = false;

//draw a drop shadow?
$shadow = true;

$jpeg = ImageCreateFromString($data);

if($d=getimagesize($jpeg)){
$dim = ($d[1]>$d[0]) ? 1 : 0;
$mod = $size / $d[$dim];

$w = (int) ($d[0] * $mod);
$h = (int) ($d[1] * $mod);

$x = (int)(($size + $margin - $w) / 2);
$y = (int)(($size + $margin - $h) / 2);

//echo "<br>$w x $h";
//echo "<br>$x x $y";

header('Content-type: image/jpeg');

$src = imagecreatefromjpeg($jpeg);
$dst = imagecreate($size+($margin * 2), $size+($margin * 2));
$white = imagecolorallocate($dst,255,255,255);
imagefill($dst,0,0,$white);
if($border){
	$black = imagecolorallocate($dst,0,0,0);
	imagerectangle($dst,0,0,$size+$margin,$size+$margin,$black);
}
if($shadow){
	$lighter = imagecolorallocate($dst,220,220,220);
	imagefilledrectangle($dst,($x+3),($y+3),($w+$x+3),($h+$y+3),$lighter);
	$light = imagecolorallocate($dst,180,180,180);
	imagefilledrectangle($dst,($x+1),($y+1),($w+$x+1),($h+$y+1),$light);
	$dark = imagecolorallocate($dst,140,140,140);
	imagefilledrectangle($dst,($x),($y),($w+$x),($h+$y),$dark);
}
//imagecopyresampled($dst,$src,$x,$y,0,0,$w,$h,$d[0],$d[1]);
imagecopyresized($dst,$src,$x,$y,0,0,$w,$h,$d[0],$d[1]);
imagejpeg($dst);
imagedestroy($dst);
imagedestroy($src);

}