PHP Imagick black areas after converting PDF to JPG - php

Question

I'm using Imagick to generate JPG thumbnails for PDFs files but some of them generate with black areas (http://i.imgur.com/fKBncKw.jpg) – I'm assuming it's caused by transparency in the PDFs but can anything be done about it?
Code I'm using to generate these:
$imagick = new Imagick($filename);
$imagick->setIteratorIndex(0);
$imagick->setImageFormat('jpg');
return $imagick->getImageBlob();
Is there a way to flatten the PDF and/or add a white background so that the black areas don't appear?

Answer 1

Here is a solution which will only work for PNG to JPG.
This code adds a white background to the transparent areas in PNG and converts it to JPG.
What it does?
This code takes all PNG images from a folder, converts them to JPG's with white backgrounds and saves them in another folder.
<?php
ini_set('max_execution_time', 3000);
$dir = 'transparent/';
$arr = scandir($dir);
for($i=0;$i<count($arr);$i++)
{
if($i==0 || $i==1)
{
}
else{
$input_file = "transparent/".$arr[$i];
$output_file = "White/".str_replace('.png','.jpg',$arr[$i]);
$input = imagecreatefrompng($input_file);
list($width, $height) = getimagesize($input_file);
$output = imagecreatetruecolor($width, $height);
$white = imagecolorallocate($output, 255, 255, 255);
imagefilledrectangle($output, 0, 0, $width, $height, $white);
imagecopy($output, $input, 0, 0, 0, 0, $width, $height);
imagejpeg($output, $output_file);
}
}
?>
Its Image Processing and GD in PHP.
PHP Manual
Hope it helps, you can change it as you want.

Answer 2

Try this code: Imagick::setCompressionQuality
$im = new imagick(realpath($file).'[0]');
$im->setCompression(Imagick::COMPRESSION_JPEG);
$im->setCompressionQuality(100);
$im->setImageFormat("jpeg");
$im->writeImage("imagename.jpg");
Alternative solution: this may help:
<?php
//Note that the function returns an Imagick object and does not modify the existing object. Below is my code for converting a PNG with transparency into a JPG with a background color. This code illustrates the difference.
$im = new Imagick($filename);
$im->setImageBackgroundColor('white');
$im->flattenImages(); // This does not do anything.
$im = $im->flattenImages(); // Use this instead.
$im->setImageFormat('jpg');
$im->writeImage('image.jpg');
?>

Answer 3

use like this
class ImageConvertorLib{
private $CI;
/**
* loading codeIgniter instance
*/
public function __construct(){
$this->CI =& get_instance();
}
public function pdfToJpg($param){
$filename = $param['filename'];
$image_name = $param['image_name'];
$path = $param['path'];
$db_path = $param['db_path'];
$im = new Imagick();
$im->setResolution(220,220);
$im->readimage($filename."[0]");
$im->setImageFormat('jpeg');
$im->setImageBackgroundColor('#ffffff');
$im->flattenImages();
$image_name = $image_name.".jpg";//"save_as_name.jpg";
$imageprops = $im->getImageGeometry();
/*if ($imageprops['width'] <= 175 && $imageprops['height'] <= 300) {
// don't upscale
} else {
$im->resizeImage(175,300, imagick::FILTER_LANCZOS, 0.9, true);
}*/
$im->writeImage($path.$image_name);
if($im){
$Img = array();
$Img['status'] = 1;
$Img['image'] = ($db_path.$image_name);
return $Img;
}
$im->clear();
$im->destroy();
}
}

Answer 4

After endless attempts to append a pdf file with a jpeg image without getting black areas, I found the solution: the function transformImageColorspace
Used in this order works perfectly:
$im = new Imagick();
$im->readImage("file.pdf");
$im->transformImageColorspace(Imagick::COLORSPACE_SRGB);
$im->setImageFormat('jpeg');
$im->writeImage('image.jpg');