Clarify Select All

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RunDontStop
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Joined: Mon Apr 05, 2021 8:03 pm

Clarify Select All

Post by RunDontStop » Wed Jan 19, 2022 5:08 pm

I am trying to understand something very simple – forgive my lack of knowledge. I make action lists fairly often. To select certain items, I usually just use Select All, then follow that up with the selection that I want. With the understanding that this selects everything, then out of that makes the target selection and in effect deselects anything else.

This has seemed to work. But as I go through and analyze some of the Action Lists in the Standard category, made by the experts at Enfocus, they use a different approach. They do line item selections of text, line art, images and shadings, using the OR operators, then follow that up with the target selection, with the AND operator. I follow the logic. For example, you want everything outside the media box selected. You select anything that is either text, or line art, or images, or shadings. Then out of that, the additional condition of being outside the media box.

My question is: what is the difference between this approach and Select All? With these various selections listed one by one, it seems like every possible category of artwork is included, which makes me wonder how this is different from just selecting everything. You can refer to the screen shots to see what I mean. Thanks in advance.
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Select various items.png
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Select all.png
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bens
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Joined: Thu Mar 03, 2011 10:13 am

Re: Clarify Select All

Post by bens » Thu Jan 20, 2022 9:35 am

This question touches on some technical details of how PitStop works. Specifically it is important to know that "Select all" selects all objects. So what is an object? Basically anything you can think of in a PDF. That includes text, images, line art, and shadings of course. But it also includes less obvious things like: clipping paths and clipping text, soft masks, annotations (comments), form XObjects etc. And even more: also things you might not think of as an "object" at all: a colour space resource, the page object, the document object, layers, etc. And perhaps even things you've never heard of like marks (not printer marks, content marks) or a PostScript XObject.

Now most actions will ignore objects they don't care about. This is for example why it's safe to do "Select all + Change line weight". Even though Select all has selected images - and the document, pages, marks, etc. - none of these have a line weight so only the line art and perhaps text will be changed. Some other actions however do check (some of) these unexpected objects. For example the action "Paste objects from clipboard" will only paste on selected page objects.

bens
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Posts: 223
Joined: Thu Mar 03, 2011 10:13 am

Re: Clarify Select All

Post by bens » Thu Jan 20, 2022 9:39 am

Oh and something else: there is normally just one "active" selection. You can think of this like a stack of plates. When you need a new plate you pick the top one, no matter how many are on the stack. So if you have "Select all + Select images + Change color" then the "Change color" only works on the top of the selection stack - that is, the selected images. That "Select all" is completely superfluous. Things like "AND", "OR" and some others use two selections - i.e. they use the top two plates from the stack.

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