Create an image to specific size and fill any space with black infill in PHP

General
1

Looking to resize images to set dimensions of (1080x1350) without cropping, just fill the dead space with black boarders/buffers.

As we can’t control what size and aspect ratios users uploads images. Im looking to create a php function that creates a ‘canvas’ that has set dimensions of 1080x1350.

I then place the users image in the middle this ‘canvas’ (without cropping) and fill any dead space with black boards.

Here’s what I’ve developed so far:

// orignal image size
$width = imageSX($image);
$height = imageSY($image);


// canvas size
$thumb_width = 1080;
$thumb_height = 1350;


$original_aspect = $width / $height;
$thumb_aspect = $thumb_width / $thumb_height;
        
if ( $original_aspect >= $thumb_aspect ) {
    $new_height = $thumb_height;
    $new_width = $width / ($height / $thumb_height);
} else {
    $new_width = $thumb_width;
    $new_height = $height / ($width / $thumb_width);
}
        
$tmp = imagecreatetruecolor( $thumb_width, $thumb_height );
imagealphablending($tmp, false);
imagesavealpha($tmp, true);
        
$transparent = imagecolorallocatealpha($tmp, 255, 255, 255, 127);
imagefilledrectangle($tmp, 0, 0, round($new_width), round($new_height), $transparent);
        
                
// Resize and crop
imagecopyresampled($tmp, $image, round(0 - ($new_width - $thumb_width) / 2), round(0 - ($new_height - $thumb_height) / 2), 0, 0, round($new_width), round($new_height), round($width), round($height));

what changes would I need to achieve the expected results. I think i’m close, but just would like to bounce some ideas around. Thank you.

2

You’re almost there with your approach! To create a black-bordered canvas for any image, you just need to make a couple of adjustments:

Changes to Make:

  1. Create a Black Background: Instead of using a transparent background, allocate a solid black color to fill the canvas.
  2. Image Filling Logic: Make sure you correctly center the image on the canvas.

Here’s an updated version of your code to achieve that:

php

Copy code

// original image size
$width = imagesx($image);
$height = imagesy($image);

// canvas size
$thumb_width = 1080;
$thumb_height = 1350;

$original_aspect = $width / $height;
$thumb_aspect = $thumb_width / $thumb_height;

if ($original_aspect >= $thumb_aspect) {
    // Fit to height
    $new_height = $thumb_height;
    $new_width = $width / ($height / $thumb_height);
} else {
    // Fit to width
    $new_width = $thumb_width;
    $new_height = $height / ($width / $thumb_width);
}

// Create canvas
$tmp = imagecreatetruecolor($thumb_width, $thumb_height);

// Fill with black background
$black = imagecolorallocate($tmp, 0, 0, 0);
imagefill($tmp, 0, 0, $black);

// Center the resized image
$x_offset = round(($thumb_width - $new_width) / 2);
$y_offset = round(($thumb_height - $new_height) / 2);

// Resize and place the image in the middle
imagecopyresampled($tmp, $image, $x_offset, $y_offset, 0, 0, round($new_width), round($new_height), round($width), round($height));

// Save or output the image
imagejpeg($tmp, 'output_image.jpg'); // Or any other preferred format

// Clean up
imagedestroy($tmp);
imagedestroy($image);

Key Adjustments:

  1. Black background: $black = imagecolorallocate($tmp, 0, 0, 0); ensures the dead space is filled with black instead of transparent.
  2. Centering the image: $x_offset and $y_offset are calculated to properly position the image in the middle of the canvas.

This should achieve the result you’re aiming for: an image placed in the middle of a black 1080x1350 canvas without cropping, with the extra space filled in with black borders.