Symbol size and masked object

[sPretzel]

Hi,

Say I create a square of size 1 in = 72pt (with a stroke size of 1pt) then mask it with the same square. When I select the resulting object, its size is  w=h=72pt. If I make that a symbol and place the symbol on the artboard, the size of the object is now 73pt (72pt + 0.5pt on each side of the object). Why is the symbol size taking into account the masked part of the stroke?

This is for CS4.

Thanks.

[c.pfaffenbichler]

Because the Stroke is there. 

In this case I wonder, though, why you don’t just apply a 0,5pt Stroke that’s aligned inside. 

[Jacob Bugge · Accepted solution]

sPretzel,

Another way of expressing it is: Because the size of a symbol is determined by the outer bounds.

For a normal stroked square, the size is determined by the spine of the stroke regardless of the stroke alignment, with the default centred half the stroke is outside, so when you mask it by itself only the inner half is masked = visible and the outer half is outside the mask and invisible.

For a symbol, the size is the same as the outer bounds, in other words includes the outer half of the stroke so everything will be masked = visible.

And (also) the second thing c said.

[sPretzel]

Hi c.pfaffenbichler. Setting the stroke to inside creates outlines for the stroke, believe it or not (although this may apply to stroked text only, I would have to check). I had inquired about that here some time ago.

Hi Jacob. I realise that the symbol took the half of the stroke that sits outside the mask into account. Selecting the masked square when it's not a symbol does not take that outer part of the stroke into account for the size, so why would the symbol do? Can you point me to Adobe Illustrator documentation that says symbols takes outer bounds into account?

[Jacob Bugge]

sPretzel,

"Can you point me to Adobe Illustrator documentation that says symbols takes outer bounds into account?"

I am afraid I have never seen it.

In a funny way you may say that symbols act as if Use Previews Bounds is switched on in the preferences just for them.

You can try this for amusement or abhorrence:

1) Create a square with a thick centre aligned stroke, thenClickDrag it to the Symbols palette, then ClickDrag the square symbol out to the right of the square and align them vertically;

2) Select both, then Click the square, then in Align>Distribute Spacing set Spacing to 0 and distribute horizontally;

3) Select the square symbol and ClickDrag a copy straight downwards, then ClickDrag the copy straight to the left, then select both, then click the first copy square symbol, then distribute horizontally;

4) Select the square and ClickDrag a copy straight upwards, then ClickDrag the copy straight to the right, then click the first copy square, then distribute horizontally;

5) Select both copies from 4) and ClickDrag a copy set straight upwards, then click the first copy square, then tick Use Preview Bounds, then distribute horizontally.

Remember to untick Use Preview Bounds.

[sPretzel]

Hi Jacob,

My head is spinning just reading your exercise! 😉

I wonder if there is a reason why AI is handling the size of regular objects and symbols differently. As it is, I find it to be a misleading implementation.

[Jacob Bugge]

sPretzel,

I hope you will still give the excercise a spin (too).

Also without any basis in what I have never seen about it, I believe you may say that symbols are pulled out of the general overall way objects are treated, to be treated somewhat like tiny linked files, which speeds up everything because it requires less memory and (thereby) time to refresh/show the document, in addition to the reduction of file size which (more or less) corresponds to that obtained with multiple copies as effect.

Or said in another way with no more basis, I believe you may say that both symbols and linked files are treated like black boxes, only with visible contents, simply represented by the outer bounds (copies as effects are not treated as anything, they just appear as ghosts following the original).

By the way, as you may know (by now), to position a symbol relative to normal objects you often/(almost)  always need to base the positioning on its centre.

[sPretzel]

By the way, as you may know (by now), to position a symbol relative to normal objects you often/(almost)  always need to base the positioning on its centre.

By @Jacob Bugge

That's a good point. I was going to mention that symbol registration point never seemed to work for me. No matter what registration point I select, it's always the same (centre). In fact, in CS4, I don't have "Use Registration Point for Symbol". https://helpx.adobe.com/sea/illustrator/using/symbols.html#symbol_registration_point