PHP: Function to change text to PNG image with transparency - php

Question

I am trying to change a section of text into an image. I can't figure out what is wrong with my code and also how to make it transparent. Here is what I have so far:
<?PHP
function fsrep_imageaddress($address, $listingid) {
$font_size = 4;
$width = imagefontwidth($font_size)*strlen($address);
$height = imagefontheight($font_size);
$img = imagecreate($width,$height);
$bg = imagecolorallocate($img, 25, 25, 25);
$color = imagecolorallocate($img, 255, 255, 255);
$len = strlen($address);
$ypos = 0;
for($i=0;$i<$len;$i++){
$xpos = $i * imagefontwidth($font_size);
imagechar($img, $font_size, $xpos, $ypos, $address, $color);
$address = substr($address, 1);
}
imagepng($img, ABSPATH.'wp-content/uploads/fsrep/houses/address-'.$listingid.'.png',100);
imagedestroy($img);
}
fsrep_imageaddress(Just Testing, 12)
?>

Answer 1

Why is it not working?
If you look in the error log, you'll see you need to put "Just Testing" in quotes (thanks #scrowler!) in the function call. Then you'll get an error that imagepng takes a quality level of 0 (no compression) to 9 (max). You have 100! Here, I set it to 5 (medium compression).
imagepng($img, ABSPATH.'wp-content/uploads/fsrep/houses/address-'.$listingid.'.png',5);
How do I set a transparent background?
There's a weird thing with palette images (ie those created with imagecreate). The first colour allocated is set as the background, and can't be transparent - so you need to create a dummy color and then convert it to transparent.
// after this line
$bg = imagecolorallocate($img, 25, 25, 25);
// add this
imagecolortransparent($img, $bg);
Result
I made these changes and changed the text to red (255,0,0) for readability and got this: