- In this movie we'll discuss how strokes align
to their path outlines.
Initially it's going to seem a little but obscure
but it goes to the heart of how strokes work
inside of Illustrator.
Notice the title of this document its '220 x 420 guides'.
What we have here are three rectangular guides,
each of which measures 220 points wide and 420 points tall.
What I'm going to do now is click and hold on a
rectangle tool in order to bring up the 'Shape' tool
fly out menu and I'll select the ellipse tool and then
I'm going to position my cursor right here at the center
of this rectangle and I'm going to press the 'Alt' key
or the 'Option' key on a Mac and click.
Then, inside the ellipse dialog box I'm going to
set the width value, not to 220 but rather to 200 points
and I'm going to set the height value not to 220 but
rather to 400 points.
In other words, both the width and height values are 20 less
than the the width and the height of the rectangles.
I'll click 'OK' to create that ellipse from the center out.
I'm going to go up to the line weight value,
click the down pointing arrowhead and change the line weight
to 20 points, just as we saw in the previous movie.
I'm also going to change the color of that stroke to that
same shade of purple, just for the sake of demonstration,
R 102, G 45, B 145.
I'm going to get rid of the fill, just so it doesn't
get in our way, by clicking on the first swatch
and selecting none.
Now let's duplicate the shape a couple of times
by first switching to the black arrow tool,
which of course you can get by pressing the V key
and then I'm going to drag the center of this ellipse
over to the right until it snaps into alignment with the
rectangular guide line.
Now I'll press the 'Alt' key or the 'Option' key on a Mac
and if you're doing things right you should see a
double white arrow head, which tells you that you're
snapping and that you're going to create a duplicate
of this ellipse.
Then go ahead and press Ctrl+D or Command+D on a Mac
in order to create another duplicate of that shape.
Now I'll go up to the 'Select' menu and choose the 'All'
command, or press Ctrl+A or Command+A on a Mac
to select all three of these shapes.
I'm going to zoom in as well and I want you to see
that they exactly fill their rectangles.
You might think, 'Well, gosh Deke, that's really
entertaining, but why is this important?'
What's happening here is that the stroke is exactly
centered on the path outline and so,
because it measures 20 points thick,
it extends 10 points (that's half of 20 points)
outside the ellipse, and the other 10 points
into the ellipse.
As a result we're filling that 20 point gap between
each one of these shapes and we're doing so exactly.
If I were to turn off the guides layer for a moment
and then I was to zoom in on the inner section
of these two ellipses you can see that they
exactly touch each other.
That's because there's a 20 point gap between
the two ellipses and in both cases we have 20 point strokes
which extend 10 points to the left from the right shape
and 10 points to the right from the left shape.
You can modify that if you like.
I'll go ahead and zoom out just a little bit by pressing
Ctrl + - a few times.
To modify the alignment you click on the word 'Stroke'
up here in the control panel to bring up the stroke panel
and you drop down to this 'Align Stroke' option.
Notice that by default it's set to 'Align Stroke to Center'.
You can, if you like, set it to 'Align Stroke to Inside',
in which case all 20 points of the strike is going to move
to the inside of that path outline and none of the shapes
will touch each other as we're seeing right here.
Or, you can set it to 'Align Stroke to Outside'
in which case the entire 20 points of that stroke is
going to go outside the path outline and in our case
because each one of the ellipses is 20 points away from
it's neighbor, the strokes are going to entirely overlap
at this location.
We'll end up, if I press the 'Escape' key and then press
Ctrl+0, Command+0 on a Mac, to zoom out,
we'll end up with this perfect overlapping effect
right here.
Notice, the reason I say it's so perfect, is because
the stroke that's associated with this path outline,
for example the center one, is not extending at all,
it's just touching the inside edge of both of it's neighbors
but it's not overlapping into the neighbors one whit.
One of the things you should know about aligning strokes
is that it only works with closed path outlines.
In other words, if I were to switch to the
white arrow tool here, which I can get by pressing the A key
and then I click on, let's say, this segment right here,
and were to select it independently of the others
and then I press the 'Backspace' key,
or the 'Delete' key on a Mac, that goes ahead and
opens up that path outline so that it begins at one point
and ends at another, at which point I lose that alignment.
Notice now that the stroke is once again centered
on the path outline?
That's just the way it is.
For example, if I were to switch back to my letters
right here, you can see that they're either
open path outlines, in the case of the C for example,
or they're compound paths.
Whenever you're working with open paths or compound paths
when you click on 'Stroke' you'll see that your
'Align Stroke' options are dimmed.
Whereas if I was to switch to the infinity symbol,
which is a closed path outline, notice that it has
complete and total continuity, there are no end points,
I'll go ahead and press the V key to switch to the
black arrow tool, I'll click on that path to select it
and then I'll grab my eye dropper near the bottom
of the tool box, which has a keyboard shortcut of I.
I'll go ahead and click on any one of these paths,
whether it's an open path or a compound path,
that'll go ahead and lift that purple 20 point stroke
at which point I'll go ahead and zoom in by
Ctrl+Spacebar clicking or Command+Spacebar clicking on a Mac
now if I click on the word 'Stroke' the 'Align Stroke'
option is once again active so that I can switch the stroke
to the inside or to the outside, like so,
or I can move it back so that it's centered
on the path outline.
This is going to be integral because most strokes
are centered on their path outline.
That''s because we have a lot of different kinds of
path outlines that are available to us in Illustrator.
You want to think in terms of half of that line weight.
It's not so much that we have a 20 point line weight
as we have a 10 point weight on the outside
and a 10 point weight on the inside.
I'll show you exactly why that matters
in the very next movie.