Beginner PHP Tutorial - 165 - Creating Captcha Image Security Part 2 Video Lecture | PHP for Absolute Beginners: From Novice to PHP Master - Web Development

okay so we do need to bring in if
statement here not just yet but soon and
this will ensure that we maintain the
same value after we've submitted our
form
but once we've included our form then we
won't need to worry about it so we've
got our text what do we need to do next
well we need to create a variable with
our font size so and their mind this is
experimental so the font size depends on
obviously what font you're using so for
now I'm going to set this to a 30 and
but we might want to change it later on
what we also want to do is set the the
width of the height and the image so
we'll pull out here and we'll come down
a couple more say let's call the
variable image height and image width
we'll start with width image width let's
say we'll give it a width of 200 and
image height oops sorry
let's say 40 for now but obviously we're
going to change this around depending on
how our text is output and just so we
can get a feel of everything the way it
works and how it looks so the next thing
is to create the image itself so let's
create a variable called image and we're
going to be using the image create
function as part of the GD library and
the image create function takes two
parameters this is going to be the width
and the height so obviously we've
already defined this up here so we just
put image width and image height in okay
so now we've generated the image and the
the width and the height of that we need
to allocate a background color and a
foreground color now my background color
is going to be white even though we even
though we are working the white
background anyway we still need to
define this just so it we ensure that it
stays white so we use the image color
allocate function here and we use this
on our own we don't set it to any
variable and this ensures it just
applies it to the background backdrop of
our document
or our image rather so let's go ahead
and say image color allocate and we're
allocating this to the image so we've
already opened this image here we've
already created this image so we're
applying it to image and we specify this
in an RGB value so we've got three
integers and this is for white this is
obviously going to be 255 255 and 255 if
you already know how to work with RGB
values that's great you'll know that
white is 255 255 255 and black is zero
zero zero which is what we're going to
be doing for our foreground color or our
text color but if you not sure about
these look them up try convertor if
you're used to hexadecimal color values
etc etc okay so now with regards to the
text color we need to look at setting
this into a variable because what we
want to do is when we use this image
TTFN text function we need to supply a
text color whereas we don't need to
supply the background color that's why
we've done it without a variable
declaration so let's create a new
variable called text underscore color
and we're going to use the image color
allocate function once again and we're
applying this to image but this time
we're using zero zero zero so our text
color is going to be zero zero zero
which is black okay so the next thing to
do is we want to use our image TTFN text
function to ensure that we are
outputting the the secure session
properly and we're going to preview this
from index dot PHP we're not going to
preview it from generator PHP so let's
start with the image TTFN text function
now it takes a number of parameters so
as we go along I'll explain each one
more or less each one the ones that are
relevant to us the first one's easy it's
just the image that we're working with
at the moment as we've specified here
here
and that's it so we're just supplying
the image that we're working with now we
want the font size which we predefined
up there so we can just pop that
straight in this is the reason we've
predefined our variables so they can
change dynamically as well
next is the angle which we don't need to
worry about in this case and now is the
positioning so I'm going to say 15 from
the from X sorry and v and 30 from Y we
can play around with these values we're
going to play around with the font size
the width and the height of the document
and these as well just so we can get in
the middle of the of the little area
that we've created okay so the next is
the text color so we've already supplied
that in a variable just a moment ago so
we can say text underscore color there
okay and now what we want to do is the
the font file itself
now I've already created the font file
or rather copied it over from my windows
fonts folder and I've just I've just
called it font
TTFN so make sure you do this copy over
the font that you want to use and this
one's Cali hand
so when copy this over from your fonts
folder and just put it in the same
directory or in another directory and
you're going to specify it in this next
parameter so I'm just going to type in
font TTFN simple
okay the next is the text itself because
you can probably see we haven't actually
defined what text so we've got the text
in a variable up here called text so we
simply just put that in there and that's
done we've only got one more thing to do
and that is use the image JPEG function
and what this is going to do is going to
finalize everything and it's going to
write out our image onto this page so it
can be displayed as an image so image
JPEG image this function can also be
used to save the file but in this case
we're just outputting it to the page
so let's go to index dot PHP and let's
come under here and create an image an
image property or element if you like
and we're going to reference this to
generate PHP and the reason we can do
this is remember generate PHP is now
even though it has its PHP extension
it's now an image file so hopefully
what's going to happen now considering
everything in here works or if it does
work we're going to view something out
on our page because we're setting the
session here and in the generator PHP
file we're reading it in here so let's
start open up our browser and see if
this works let's go over to index.php
okay so it hasn't worked so we need to
work out exactly why it hasn't worked so
let's have a look inside I'll generate a
PHP file I know what we haven't done is
even though we're declaring our session
up here we're starting our session
rather if you like in our generator PHP
file we still need to start our session
and the reason for this is that were
accessing the session data here as well
and although we're including it in here
as an image is still regarded as its own
file so remember to include sessions
start at the end of it at the start of
this let's go back and refresh