All Classes, Interfaces, Objects and Records
| Name | Unit | Description |
|---|---|---|
| ELQTException | uLazQuadTree |
|
| ELQTGException | uLazQuadTreeGeometry | Used for the smallest possible increment of an Double value |
| ELQTStreamException | uLazQuadTree |
|
| TLazQuadTree | uLazQuadTree | TLazQuadTree A QuadTree for Lazarus. Organizes arbitrary Items who are ordered on a plane by X and Y coordinates for a fast access for a given Rect. The TLazQuadTree could be used to store tenthousands of items and access them very fast, because items that are not within the desired Rect are sorted out quickly. To allow the processing of any kind of objects or data, an event is used where the user has to provide the location or Rect of a specific item in the tree. The tree could be used for a flat world with borders on all four edges or a cylindric world, where the right and left edge are connected. Additionally the orientation of the Y-Axis could be adjusted, to cover cartesian-coordinate-systems (like Maps or mathematical function diagrams, where the Y value increases when going upwards) or computer-coordinate-system (like Bitmaps or Editors, where the Y increases when going downwards). To aggregate data on smaller magnification (e.g. showing bigger parts of the plane) a sum of TotalItems in the (Sub-)Nodes is maintained. This allowes, instead of a search of a bunch of unusefull Items, the display of a Placeholder/Sum of the items which are hidden. |
| TLQTAgglomerationRec | uLazQuadTree | TLQTAgglomerationRec is used by the Agglomeration method Point contains the center coordinate of the agglomeration (= center of the node rectangle) Count the estimated number of items within the agglomeration. |
| TLQTNode | uLazQuadTree | TLQTNode A node in the Tree. The node is assumed to be the root node, if the ParentNode is not assigned. The node can contain data items. These data items are generic TObjects. There actual Coordinates are fetched via an Event in the Tree |
| TLQTNodeItemsRec | uLazQuadTree | TLQTNodeItemsRec is used by the Node to store the Items and chache there positions |
| TLQTPoint | uLazQuadTreeGeometry | TLQTPoint describes the a single point in the QuadTree-World |
| TLQTRect | uLazQuadTreeGeometry | TLQTRect describes an area in the QuadTree-World Details to the rectangles are described above. The TLQTRect could be used in two ways. One forming a world description, the other by forming a rectangle within the world. If defining a world, the sign of the axis are taken from the values Top vs Bottom or Left vs Right. To define a world map one would set Left = -180 and Right = 180 Top = 90 and Bottom = -90 This means that X increases while traveling from left to right and Y increases from top to bottom. This is different from the default definition (e.g. on TCanvas). A rectangle on the world could be defined by Left = -100 and Right = 100 Top = 45 and Bottom = -45 |
| TLQTStreamWriteHelper | uLazQuadTree | TLQTStreamWriteHelper an internal helper for the writing of the LengthField |
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