Cropping an image in PHP - php

Question

I am doing PNG image cropping using this function. Everything is working fine, but whenever I upload the .png, the image background color is changed to black. Here is the code.
$bgimage_attribs = getimagesize($bgim_file_name);
if($filetype3=='image/gif')
{
$bgim_old = imagecreatefromgif($bgim_file_name);
}
else if(($filetype3=='image/pjpeg') || ($filetype3=='image/jpeg'))
{
$bgim_old = imagecreatefromjpeg($bgim_file_name);
}
else if(($filetype3=='image/png') || ($filetype3=='image/x-png'))
{
$bgim_old = imagecreatefrompng($bgim_file_name);
}
$bgth_max_width =265; //for Album image
$bgth_max_height =150;
$bgratio = ($bgwidth > $bgheight) ? $bgth_max_width/$bgimage_attribs[0] : $bgth_max_height/$bgimage_attribs[1];
$bgth_width =265;//$image_attribs[0] * $ratio;
$bgth_height =150;//$image_attribs[1] * $ratio;
$bgim_new = imagecreatetruecolor($bgth_width,$bgth_height);
imageantialias($bgim_new,true);
$bgth_file_name = "partners_logs/250x150/$Attachments3";
imagecopyresampled($bgim_new,$bgim_old,0,0,0,0,$bgth_width,$bgth_height, $bgimage_attribs[0], $bgimage_attribs[1]);
if($filetype3=='image/gif')
{
imagegif($bgim_new,$bgth_file_name,100);
//$bgim_old = imagegif($bgim_file_name);
}
else if(($filetype3=='image/pjpeg') || ($filetype3=='image/jpeg'))
{
imagejpeg($bgim_new,$bgth_file_name,100);
}
else if(($filetype3=='image/png') || ($filetype3=='image/x-png'))
{
imagepng($bgim_new,$bgth_file_name,9);
} `
even i tried like this also
/************************************Resizing the image 80*60****************/
$path3="partners_logs";
$filetype3=$_FILES["pimage"]["type"];
$bgim_file_name = $path3."/".$Attachments2;
$bgimage_attribs = getimagesize($bgim_file_name);
if($filetype3=='image/gif')
{
$bgim_old = imagecreatefromgif($bgim_file_name);
}
else if(($filetype3=='image/pjpeg') || ($filetype3=='image/jpeg'))
{
$bgim_old = imagecreatefromjpeg($bgim_file_name);
}
else if(($filetype3=='image/png') || ($filetype3=='image/x-png'))
{
$bgim_old = imagecreatefrompng($bgim_file_name);
imageAlphaBlending($bgim_old, true);
imageSaveAlpha($bgim_old, true);
}
$bgth_max_width =265; //for Album image
$bgth_max_height =150;
$bgratio = ($bgwidth > $bgheight) ? $bgth_max_width/$bgimage_attribs[0] : $bgth_max_height/$bgimage_attribs[1];
$bgth_width =265;//$image_attribs[0] * $ratio;
$bgth_height =150;//$image_attribs[1] * $ratio;
$bgim_new = imagecreatetruecolor($bgth_width,$bgth_height);
imageantialias($bgim_new,true);
$bgth_file_name = "partners_logs/250x150/$Attachments2";
imagecopyresampled($bgim_new,$bgim_old,0,0,0,0,$bgth_width,$bgth_height, $bgimage_attribs[0], $bgimage_attribs[1]);
if($filetype3=='image/gif')
{
imagegif($bgim_new,$bgth_file_name,100);
//$bgim_old = imagegif($bgim_file_name);
}
else if(($filetype3=='image/pjpeg') || ($filetype3=='image/jpeg'))
{
imagejpeg($bgim_new,$bgth_file_name,100);
}
else if(($filetype3=='image/png') || ($filetype3=='image/x-png'))
{
imagepng($bgim_new,$bgth_file_name,9);
//set the background color to your choice, paramters are int values of red,green and blue
imagecolorallocate($bgim_new,0xFF,0xFF,0xFF);
}
/************End Resize of 80*60*******************/

Answer 1

maybe this helps
Don't forget about
imagealphablending() and
imagesavealpha() if you're working
with [semi]transparent png.
<?php
$file = 'semitransparent.png'; // path to png image
$img = imagecreatefrompng($file); // open image
imagealphablending($img, true); // setting alpha blending on
imagesavealpha($img, true); // save alphablending setting (important)
found at php.net - imagecreatefrompng under User Contributed Notes
NOT tested
edit see comment
<?php
$bgim_new = imagecreatetruecolor($bgth_width,$bgth_height);
imageantialias($bgim_new,true);
imageAlphaBlending($bgim_new, true);
imageSaveAlpha($bgim_new, true);
?>
After some testing and reading througt several pnp.net comments i've got a working script
<?php
$newImageName = "PNG_transparency_copy.png";
$newWidth = 265;
$newHeight = 150;
$orgAttribs = getimagesize("PNG_transparency_demonstration_1.png");
$orginal = imagecreatefrompng("PNG_transparency_demonstration_1.png");
imagesavealpha($orginal, true);
$newPng = imagecreatetruecolor($newWidth,$newHeight);
imagealphablending($newPng, false);
$color = imagecolortransparent($newPng, imagecolorallocatealpha($newPng, 0, 0, 0, 127));
imagefill($newPng, 0, 0, $color);
imagesavealpha($newPng, true);
imagecopyresampled($newPng,$orginal,0,0,0,0,$newWidth,$newHeight, $orgAttribs[0], $orgAttribs[1]);
header("Content-type: image/png");
imagepng($newPng,$newImageName);
PNG taken from Wikipedia

Answer 2

Try This Function....
<?php
function CropImg($img_dst, $img_src, $dst_width = 300, $dst_height = 180){
$ext = pathinfo($img_src, PATHINFO_EXTENSION);
if($ext != 'jpg' and $ext != 'jpeg'){
$image = imagecreatefrompng($img_src);
}else{
$image = imagecreatefromjpeg($img_src);
}
$filename = $img_dst;
$thumb_width = $dst_width;
$thumb_height = $dst_height;
$width = imagesx($image);
$height = imagesy($image);
$original_aspect = $width / $height;
$thumb_aspect = $thumb_width / $thumb_height;
if ( $original_aspect >= $thumb_aspect )
{
// If image is wider than thumbnail (in aspect ratio sense)
$new_height = $thumb_height;
$new_width = $width / ($height / $thumb_height);
}
else
{
// If the thumbnail is wider than the image
$new_width = $thumb_width;
$new_height = $height / ($width / $thumb_width);
}
$thumb = imagecreatetruecolor( $thumb_width, $thumb_height );
if($ext == 'png'){
imagealphablending($thumb, false);
$white = imagecolorallocatealpha($thumb, 0, 0, 0, 127); //FOR WHITE BACKGROUND
imagefilledrectangle($thumb,0,0,$thumb_width,$thumb_height,$white);
imagesavealpha($thumb, true);
}
// Resize and crop
imagecopyresampled($thumb,
$image,
0 - ($new_width - $thumb_width) / 2, // Center the image horizontally
0 - ($new_height - $thumb_height) / 2, // Center the image vertically
0, 0,
$new_width, $new_height,
$width, $height);
if($ext == 'png'){
imagepng($thumb, $filename);
}else{
imagejpeg($thumb, $filename, 80);
}
return true;
}
CropImg("photo.png", "result.png", 300, 180);
?>