Main Features |
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To manage large amounts of data TGlobe 4 has implemented an object data caching mechanism. This is used to control the maximum amount of memory used by the TGeoDataObjects. When the memory in use reaches the cache maximum, the least recently used objects are removed from memory and new object loaded in their place. This can have an impact on performance but if only a subset of the data is displayed at one time then this leads to a dramatic improvement in performance for large data sets. TGlobe now stores some meta data about the data file. This meta data contains the bounding rectangle for the objects plus information used to quickly locate and load the object from the source data file. The meta data is created automatically for the data file and once created can dramatically improve the performance of loading and using the data file. Also new with TGlobe 4 is the ability for the Layer data to be shared between two or more TGlobe objects. This means that data only needs to be loaded once if multiple Globe components are displaying the same information. TGlobe now saves its settings to a new environment file based on the XML syntax. This environment file stores most of the properties of the component plus its associated layers. Using this environment file it is possible to save and restore the component to a specific projection, orientation and set of layers. TGlobe does not directly have the capability to print itself. Instead printing is performed using the Globe.RenderToCanvas method. This method can also be used to render the globe image to any canvas desired including bitmaps and other components. The following code shows how to print a 3 x 3 inch image of the Globe onto a 600 dpi printer. Printer.BeginDoc; Globe.RenderToCanvas( Printer.Canvas, Rect( 600, 600, 2400, 2400 ); Printer.EndDoc; TGlobe also supports a texture mapped surface. The surface of the globe can be overlaid with a bitmap image. The image is rendered very quickly as it is loaded into memory. The size of the image can effect performance when it gets large enough to exceed available memory and the operating system starts to swap. |
Email: tglobe@iname.com |