View source for LibreOffice-Technical Comparison

=Technical comparison: LibreOffice vs Microsoft Office=
For those users familiar with Microsoft Office and its automation API, this page holds some comparisons between the two suites' APIs and internal behaviour.

==COM vs UNO==
''Microsoft Office'' uses the COM (Component Object Model) model for Automation and Inter-Process Communication (IPC).<p>
''LibreOffice'' has inherited from OpenOffice.org a very similar model called UNO (Universal Network Object). <br>
While ''LibreOffice'' uses UNO, for automation on Windows using AutoIt, the COM model is still used externally and all communication is then passed through a bridge to interact with UNO internally. <br>
A few reasons why UNO was created are as follows: 
* Platform Independence (works on Windows, Linux, Mac),
* Exception Handling, which is not natively supported by COM, and 
* the large code generation needed, e.g., in COM etc., "results in huge libraries if there are many types. For each new bridge, new generated glue code would be necessary, which becomes too difficult to handle". 

But if you would like further information, you can begin at the following websites: 
* [https://www.openoffice.org/udk/common/man/uno_the_idea.html UNO the idea]
* [https://www.openoffice.org/udk/common/man/uno.html UNO]
* [https://en.wikipedia.org/wiki/Universal_Network_Objects Universal_Network_Objects]
* [https://chris-sherlock.gitbook.io/inside-libreoffice/universal-network-objects inside-libreoffice - universal-network-objects]


==Applications vs ServiceManager==
In ''Microsoft Office'', you always begin with a Microsoft Word, Excel or Powerpoint Application object, which is an instance of the respective component without a Document, Book, or presentation opened in it yet. The application instance is then used to create, connect or open Documents, Books or Presentations, or to set global settings. The Application instance when created can be either visible or invisible.<p>
In ''LibreOffice'' you always begin with what is called a “ServiceManager”, this is essentially the equivalent of the Word, Excel or Powerpoint application Object, and is used to open, create or connect to Documents, Sheets or Presentations as needed. <br>
The ServiceManager, when created, has '''no visible UI'''.<p> 
The UDFs included with AutoIt for ''MS Word'' and ''MS Excel'' include separate functions for creating an instance of the corresponding Application Object, _Word_Create and _Excel_Open, because the Application objects are unique for each component, e.g., an Excel Application is used solely for working with Excel files and settings, etc.<p>
In the ''LibreOffice'' UDF, the user is saved steps of initializing the ServiceManager, as the ServiceManager is used alike for all the different components of LibreOffice (Base, Calc, Writer, etc.). The ServiceManager is “aware” of all opened Documents in the several LibreOffice Components, and can create instances of any component type, as needed.<br>
It can also open any appropriate Document in the correct component as needed. When the user calls for the first time *_DocCreate, or *_DocConnect, or *_DocOpen, or any similar functions, the ServiceManager is initialized in the background, and stored as a static variable for use in the UDF when needed. 

==Selections and Cursors==
===Word vs Writer===
''MS Word'' uses two types of data selections, the first is called a “''Selection''”, which is the visible selection you create in the Word application using your keyboard or mouse (or also using the API). The second type is called a “''Range''”, and is an invisible or background selection of data, created solely using the API. Both support similar methods for extending or collapsing the selection, and have similar properties. A Range is able to be extended, or the beginning and ending position is able to be moved nearly the same as a Selection is, except a Range cannot be extended or moved by visual or on-screen lines, only structural units (paragraphs, sentences, etc.). There can be only one instance of a Selection at once, but you can have multiple Ranges at one time.<p>
In ''LO Writer'' you also have two primary types of data selections. The first type of selection or “''cursor''” as it is generally known, is internally known as a “''ViewCursor''”, which is visible to the user. The second type of selection or “cursor” is called a "''TextCursor''", and is invisible to the user.<p> 
A ''ViewCursor'' is what you see when you select some data in the document, and is also located wherever the caret is placed in the document. A ''ViewCursor'' is “aware” of characters, lines (where you see a line breaks to go to the next line to fit the Document width), pages and screens (your current view), as well as the start and end of the Document, it is "View dependent" for its usefulness. There can only be one ''ViewCursor'' existing in a document at one time. A ''ViewCursor'' can be used very similarly to a ''TextCursor'' for the purpose of inserting or retrieve text, inserting shapes or tables etc., as well as getting and setting properties.<p>
The ''TextCursor'' on the other hand is always invisible to the user whether or not data is selected. The ''TextCursor'' is “blind” to lines, pages and screens. A ''TextCursor'' can, like a ''ViewCursor'' “see” characters, but it is also aware of the start and ending of words, sentences and paragraphs, it is more "document dependent" for its usefulness. Unlike a ''ViewCursor'', you can have as many ''TextCursors'' as needed in one document.<p>
There is a third type of Cursor that I will mention here briefly, it is called a "''Table Cursor''". It is, as you may have guessed, only used for manipulating Tables, whether for joining cells, coloring, or sizing rows and columns etc. A Table Cursor is only aware of the Table and its cells. It cannot transverse outside of the Table. It is aware of cells, and the beginning and ending of the Table. It can go be moved to a specific cell by name, and merge and split cells. It cannot insert or retrieve text, nor edit text attributes.<p>
When retrieving the current selection(s) made by the user, i.e. a selected string of text, the resulting object is essentially identical to a TextCursor, and in this UDF a TextCursor is created matching the selection to be returned to lessen the number of cursor types to account for in other functions. If the selection is not just text, another type of Object will be returned, as described in the selection function.

===Excel vs Calc===
In ''MS Excel'' there are two types of data selections. One is called a "''Selection''", which represents what the user has currently selected with the cursor, be it a single cell or a range of cells.<br>The second is known as "''Range''", a Range is a group of cells, such as A2 to C4, or even a single cell. Excel treats these two very similarly, a selection is essentially the same as a Range, but is visually selected.<p>
Similarly, in ''LO Calc'' there are two types of data selections. There are "''Selections''", which is whatever the user has selected with the cursor, this can be text within a cell, a single cell, a range of cells (e.g. A1 to B3) or several ranges of cells (e.g. A1:C3 and D3:F5). <br>
The second type is also called a "''Range''"", this can be either a single cell, a group of cells, or even the entire sheet is considered a Range.

==Newlines==
Another difference to briefly touch upon, is the different line endings used between Microsoft Office and LibreOffice. <p>
''Microsoft Office'', of course, uses the standard '''Windows''' '''CRLF''' (Carriage Return, Line Feed) hard newline sequence (when you push Enter while editing a document). And a '''LF''' (LineFeed) for a soft newline (when you push Shift+Enter in a document).<p>
''LibreOffice'' on the other hand uses the '''Unix''' style newline sequences, either '''CR''' (Carriage Return) or '''LF''' (Line Feed). The '''CR''' sequence is used for hard newlines, and the '''LF''' sequence is used for soft newlines. <p>
This generally won't be encountered nor cause much issue for the majority of tasks while automating LibreOffice. However it may become an issue when getting or inserting strings, particularly in Writer. <br>
For example, if I select several paragraphs and retrieve the text of those paragraphs for processing in AutoIt, and then replace those selected paragraphs with the text I processed in AutoIt, the resulting text will most likely not have the same amount of newlines, there would be a mixture of hard and soft newlines in the paragraph, where before there maybe was only hard newlines.<br> 
The root cause for this seems to be due to the way strings are handled when retrieving them from LibreOffice, newlines use the platform default newline sequence when retrieving the string, instead of maintaining the current newline sequence used by LibreOffice, so when working on Windows, the '''CRLF''' is used for all hard newlines. This is generally only true if inserting and retrieving strings directly in the document, or any frames, textboxes, or table cells in Writer. Caution should be exercised when inserting a string, to manually use the '''CR''' or '''LF''' sequences as needed when wanting to insert a hard or soft newline respectively.<p>
Presently this UDF attempts to perform a find and replace operation for '''CRLF''' newlines to convert them to '''CR''' whenever strings are being set that allow newlines, and that may be affected by this issue. It is still recommended that the user does this themselves to ensure they obtain expected results.<p>
Calc does not seem to be affected by this issue, as it appears to convert any '''CR''' or '''CRLF''' to '''LF'''.

==Formatting==
One more less important difference between ''Microsoft Office'' and LibreOffice is formatting. When formatting text in Microsoft Office, usually the user uses what is called “Direct Formatting”, i.e., selecting some text and selecting Bold, to bolden the text, or italic, etc. Not that you can't and don't create and apply formatting styles, but primarily this is how Microsoft Office intends the user to apply formatting and styling.<p>
In ''LibreOffice'' however, the way the user applies formatting is intended to be slightly different. This is not to say that the user cannot use “Direct Formatting”, but it sometimes does not produce desirable results when attempts are made later on to change this or that styling, often unsightly text ends up being produced, perhaps wrong text sizing when the font was made bigger, or words still in an old font style etc.<br>
The way ''LibreOffice'' intends the user to apply formatting and styling is by the use of Paragraph and Character styles. Paragraph styles, would be used to apply, for example, a certain font to an entire paragraph. They modify and apply their affects to the whole paragraph where they are applied, except when overridden by direct formatting. Character styles on the other hand apply the styling only to selected character(s), except where direct formatting is applied already.<p>
Given the fact that ''LibreOffice'' also supports direct formatting as ''Microsoft Office'' does, this difference isn't necessarily important. But for the best experience, both manually working with LibreOffice, and while automating it with this UDF, it is recommended to use the styling approach instead, or at least keep these facts in mind to you know what to expect.