50 lines
2.1 KiB
Text
50 lines
2.1 KiB
Text
Contains non-graphical helper code for office applications.
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Specifically this module does not depend on or use includes from module
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vcl. Originally all code in svtools that did not depend on vcl was split
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off into this svl ("svtools light") module.
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In particular the SfxItemSet is a property-bag like container that
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stores arbitrary sets of properties for everything from text run
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formats, to Chart regression line properties.
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There are lots of other useful helpers in here for various office
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tasks; much of this code was originally moved from svx/sfx2.
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== Items, Pools and Sets ==
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=== SfxPoolItem ===
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A small reference counted piece of data. Many subclasses, each with a
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unique integer to identify its type (WhichId). Can be compared for equality
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(operator==), Clone()d, and converted to/from uno::Any (QueryValue/PutValue).
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A pool item may have value semantics (SFX_ITEM_POOLABLE), meaning that
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there will generally be only one instance that compares equal per item pool,
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or not, in which case the item will be Clone()d quite a bit.
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=== SfxItemPool ===
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Usually there is one item pool per document, with a range of valid WhichIds
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that is specific to the type of document.
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The item pool owns all instances of SfxPoolItem or its subclasses that have
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ever been added to an item set. It also contains a default item for
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every WhichId, which will be (depending on parameters) returned from item
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sets if the set does not contain an item at this WhichId.
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=== SfxItemSet ===
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The item set can be created with a user-supplied range of WhichIds; it
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will accept SfxPoolItems with matching WhichIds and ignore attempts to
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insert items with non-matching WhichIds.
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Items that are successfully inserted into the set will be stored in the
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set's SfxItemPool, and for poolable items only a single instance that
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compares equal under the predicate operator== will be stored in the pool,
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regardless of how many sets contain it, thus conserving memory.
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There are members _pWhichRanges for the valid ranges (as pairs of WhichIds),
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_nCount for the number of items contained, and _aItems for the pointers to
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the actual items.
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