php resizing image from image stream - php

Question

Basically an Image is created on a canvas html5 element and saved as image on server using the following code
<?php
$upload_dir = "uploads/";
$img = $_POST['hidden_data'];
$imageID = $_POST['imageID'];
$img = str_replace('data:image/png;base64,', '', $img);
$img = str_replace(' ', '+', $img);
$data = base64_decode($img);
$file = $upload_dir . "gillette_" . $imageID . ".png";
$success = file_put_contents($file, $data);
print $success ? $file : 'Unable to save the file.';
?>
I want to save a thumbnail version 100X100 px but prefer to do it straight from the stream. Any help would be greatly appreciated
the following code for resizing and saving image did not work trying to use imagecreatefromstring
<?php
############ Configuration ##############
$thumb_square_size = 100; //Thumbnails will be cropped to 200x200 pixels
$max_image_size = 520; //Maximum image size (height and width)
$thumb_prefix = "small_"; //Normal thumb Prefix
$destination_folder = 'uploads/'; //upload directory ends with / (slash)
$jpeg_quality = 90; //jpeg quality
##########################################
$upload_dir = "uploads/";
$img = $_POST['hidden_data'];
$imageID = $_POST['imageID'];
$img = str_replace('data:image/png;base64,', '', $img);
$img = str_replace(' ', '+', $img);
$data = base64_decode($img);
$file = $upload_dir . "gillette_" . $imageID . ".png";
$success = file_put_contents($file, $data);
print $success ? $file : 'Unable to save the file.';
$im = imagecreatefromstring($data);
if($im){
$new_file_name = $imageID . ".png";
$thumb_save_folder = $destination_folder . $thumb_prefix . $new_file_name;
//call crop_image_square() function to create square thumbnails
if(!crop_image_square($im, $thumb_save_folder, "png", $thumb_square_size, 520, 382, $jpeg_quality))
{
die('Error Creating thumbnail');
}
imagedestroy($im); //freeup memory
}
##### This function corps image to create exact square, no matter what its original size! ######
function crop_image_square($source, $destination, $image_type, $square_size, $image_width, $image_height, $quality){
if($image_width <= 0 || $image_height <= 0){return false;} //return false if nothing to resize
if( $image_width > $image_height )
{
$y_offset = 0;
$x_offset = ($image_width - $image_height) / 2;
$s_size = $image_width - ($x_offset * 2);
}else{
$x_offset = 0;
$y_offset = ($image_height - $image_width) / 2;
$s_size = $image_height - ($y_offset * 2);
}
$new_canvas = imagecreatetruecolor( $square_size, $square_size); //Create a new true color image
//Copy and resize part of an image with resampling
if(imagecopyresampled($new_canvas, $source, 0, 0, $x_offset, $y_offset, $square_size, $square_size, $s_size, $s_size)){
save_image($new_canvas, $destination, $image_type, $quality);
}
return true;
}
##### Saves image resource to file #####
function save_image($source, $destination, $image_type, $quality){
switch(strtolower($image_type)){//determine mime type
case 'image/png':
imagepng($source, $destination); return true; //save png file
break;
case 'image/gif':
imagegif($source, $destination); return true; //save gif file
break;
case 'image/jpeg': case 'image/pjpeg':
imagejpeg($source, $destination, $quality); return true; //save jpeg file
break;
default: return false;
}
}
?>

Answer 1

problem solved:
code works now. image type was supposed to be the whole mime type - image/png and not just png
this is the fixed code, hope it helps someone:
<?php
############ Configuration ##############
$thumb_square_size = 100; //Thumbnails will be cropped to 200x200 pixels
$max_image_size = 520; //Maximum image size (height and width)
$thumb_prefix = "small_"; //Normal thumb Prefix
$destination_folder = 'uploads/'; //upload directory ends with / (slash)
$jpeg_quality = 90; //jpeg quality
##########################################
$upload_dir = "uploads/";
$img = $_POST['hidden_data'];
$imageID = $_POST['imageID'];
$img = str_replace('data:image/png;base64,', '', $img);
$img = str_replace(' ', '+', $img);
$data = base64_decode($img);
$file = $upload_dir . "gillette_" . $imageID . ".png";
$success = file_put_contents($file, $data);
print $success ? $file : 'Unable to save the file.';
$im = imagecreatefromstring($data);
if($im){
$new_file_name = $imageID . ".png";
$thumb_save_folder = $destination_folder . $thumb_prefix . $new_file_name;
//call crop_image_square() function to create square thumbnails
if(!crop_image_square($im, $thumb_save_folder, "image/png", $thumb_square_size, 520, 382, $jpeg_quality))
{
die('Error Creating thumbnail');
}
imagedestroy($im); //freeup memory
}
##### This function corps image to create exact square, no matter what its original size! ######
function crop_image_square($source, $destination, $image_type, $square_size, $image_width, $image_height, $quality){
if($image_width <= 0 || $image_height <= 0){return false;} //return false if nothing to resize
if( $image_width > $image_height )
{
$y_offset = 0;
$x_offset = ($image_width - $image_height) / 2;
$s_size = $image_width - ($x_offset * 2);
}else{
$x_offset = 0;
$y_offset = ($image_height - $image_width) / 2;
$s_size = $image_height - ($y_offset * 2);
}
$new_canvas = imagecreatetruecolor( $square_size, $square_size); //Create a new true color image
//Copy and resize part of an image with resampling
if(imagecopyresampled($new_canvas, $source, 0, 0, $x_offset, $y_offset, $square_size, $square_size, $s_size, $s_size)){
save_image($new_canvas, $destination, $image_type, $quality);
}
return true;
}
##### Saves image resource to file #####
function save_image($source, $destination, $image_type, $quality){
switch(strtolower($image_type)){//determine mime type
case 'image/png':
imagepng($source, $destination); return true; //save png file
break;
case 'image/gif':
imagegif($source, $destination); return true; //save gif file
break;
case 'image/jpeg': case 'image/pjpeg':
imagejpeg($source, $destination, $quality); return true; //save jpeg file
break;
default: return false;
}
}
?>