How far does intellectual property extend?

If you don't want to read this whole thing, there's a TLDR version of this at the bottom.

I have several questions about intellectual property and how far it extends so that I can get a better idea of what is and what isn't intellectual property:
(note, when I say "intellectual property" I'm referring to the intellectual property of the company you are working for)

1.) Where is the line drawn between trivial/public knowledge and private/protected "property"?

2.) Is it considered theft of intellectual property if, for example, I learn how to create better microprocessors for my one job, and then apply this knowledge to my other job?

4.) What if I design an iPhone app, and I figure out a way to display a video with rounded corners, or a way to flip through video files (a functionality that isn't provided, but isn't extremely hard for anyone to implement). Would I be able to reuse this code at another company or on my own, since I wrote it and figured it out myself, and it's not the main idea of the app?

5.) Similar to question 4, what if the thing that I create is conceptually trivial and the idea isn't really patentable, for example lets say I created a photo album for an app I made when working for a company. Would this photo album be considered intellectual property? Would I be able to reuse this code? Photo albums aren't a "new idea" however I wrote this code for this company is unique, so does this have any effect?

6.) Is intellectual property only considered to be the proprietary information your company tells you that isn't trivial? Is it the "main idea of the app and how things function together" or do each of the separate individual components that make it work (no matter how simple they are) count as intellectual property?

7.) Similar to question 6, is everything you figure out on your own when working for the company yours or theirs? How can it be theirs if its trivial?

TLDR:
I guess what this boils down to is:
- If the idea of something you create (which is a part of a larger project) is trivial, but you do it your unique way that you made up, is this considered intellectual property of the company?

I'd hate to create something simple for a company such as a photo album as part of an iPhone app, and not be able to reuse it in any of my other apps. In this event, when working on a second app, I would have to make up a new photo album, and there are only so many ways you can make a photo album on an iPhone, that it's almost impossible to patent / be considered "intellectual property." I just don't see how it can be counted as intellectual property, since if anyone else created a photo album, they would most likely do it the same way I did it. Would it be considered a company's "intellectual property" if I created it when working for a company or no?

This is why all good software companies have lawyer son retainer and extensive contracts detailing intellectual property rights.

The problem here is you're looking for a rule of thumb, when you need to be looking at your specific contract.

If you use someone else's intellectual property (IP) without their permission you may be infringing their IP rights and they may be able take legal action against you. There are also a number of exceptions in copyright law which allow limited use of copyright works without the permission of the copyright owner.

Patent infringement
If you make, use, sell or import something protected by a patent, without permission, you may be infringing the owner's rights.

Design infringement
If you use, sell or import something that is identical or similar to a design registration, without permission, you may be infringing the owner's rights.

SEE A LAWYER AND THEY WILL CHECK OUT YOUR RIGHTS WITH YOUR EMPLOYER.

An intellectual property infringement is the infringement or violation of an intellectual property right. There are several types of intellectual property rights, such as copyrights, patents, and trademarks. Therefore, an intellectual property infringement may for instance be a

Copyright infringement
Patent infringement
Trademark infringement
Techniques to detect (or deter) intellectual property infringement include:

Fictitious entry, such as:
Fictitious dictionary entry. An example is Esquivalience included in the New Oxford American Dictionary (NOAD)
Trap street, a fictitious street included on a map for the purpose of "trapping" potential copyright violators of the map
Watermarking

Unless you have a prior written contract that says otherwise, anything you produce on the job belongs to the employer.

For details concerning your particular situation, you should speak with a patent attorney.