note 79337 added to function.imagefilter

Note: applying IMG_FILTER_EMBOSS to text and using in a customization to the CAPTCHA image script in phpBB or a project of your own is a very good way to stop OCR-ing bots from getting through. Embossed serif fonts are fairly easy for the human eye to understand but to an OCR script it is extremely difficult because it seems to give it the illusion of 3D. If you only allocate 2 or 3 colours in the image, it uses the background colour alot in the embossed text, which greatly contributes to this. I made my own custom CAPTCHA script to stop phpBB post spam for a client site I was developing and I have gone from getting 2-3 new spam users created every day to zero. Anything with the source code freely available out there right now is possible to be defeated by spammers once one of them stars sharing code with the other spammers, but if you run something at least someone custom, their bots will pass you over. ---- Server IP: 66.207.199.35 Probable Submitter: 209.115.237.124 ---- Manual Page -- http://www.php.net/manual/en/function.imagefilter.php Edit -- https://master.php.net/note/edit/79337 Del: integrated -- https://master.php.net/note/delete/79337/integrated Del: useless -- https://master.php.net/note/delete/79337/useless Del: bad code -- https://master.php.net/note/delete/79337/bad+code Del: spam -- https://master.php.net/note/delete/79337/spam Del: non-english -- https://master.php.net/note/delete/79337/non-english Del: in docs -- https://master.php.net/note/delete/79337/in+docs Del: other reasons-- https://master.php.net/note/delete/79337 Reject -- https://master.php.net/note/reject/79337 Search -- https://master.php.net/manage/user-notes.php