How can PHP developers utilize PNG format and transparency to improve the quality of resized images with white backgrounds in web applications?

When resizing images with white backgrounds in web applications, the white background can appear jagged or pixelated after resizing. To improve the quality of resized images with white backgrounds, PHP developers can utilize the PNG format and transparency. By setting the background of the PNG image to transparent instead of white, the resized image will have smoother edges and a more professional appearance. 

// Load the original image
$original_image = imagecreatefrompng('original_image.png');

// Create a new truecolor image with transparency
$resized_image = imagecreatetruecolor($new_width, $new_height);
imagesavealpha($resized_image, true);
$trans_colour = imagecolorallocatealpha($resized_image, 0, 0, 0, 127);
imagefill($resized_image, 0, 0, $trans_colour);

// Resize the original image onto the transparent background
imagecopyresampled($resized_image, $original_image, 0, 0, 0, 0, $new_width, $new_height, imagesx($original_image), imagesy($original_image));

// Output the resized image with transparent background
header('Content-Type: image/png');
imagepng($resized_image);

// Free up memory
imagedestroy($original_image);
imagedestroy($resized_image);

Keywords

PHP PNG format transparency resized images white backgrounds

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