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KB10934 - Progressive background rendering basemap layers.

As of the DK11, any layer (or set of layers) can now be marked as basemap. Then, upon map zooming or panning operations, such basemap layer(s) is progressively rendered in the background. This feature works with any layer type, e.g., vector, raster, tiles.

How to enable this feature:

  1. Ensure the GIS.IncrementalPaint property is set to True,
  2. Set for the bottommost layer(s) the property Basemap to True

Once enabled, you should see the progressive rendering behavior upon mouse operations.

Progressive basemap rendering is available on all platforms except FMX Mobile. Implementation on FMX Mobile is not possible due to technical limitations with threaded based canvas drawing. Progressive basemap rendering feature is, therefore, enabled for VCL, Desktop FMX, WinForms, WPF, ActiveX, and Java Swing.

A few hints:

  • Any continuous number of bottommost layers can be marked as basemap. However, the first layer (from the bottom) with Basemap=False turns progressive rendering off from that layer up.
  • Technically any layer can be used as a basemap. It is best, however, to use layers for which rendering times are not too long. Therefore, web tiles and PixelStore are great candidates for basemap layer(s), as are vector maps with not too many features.
  • Labels on vector basemaps will be drawn before the rest of the map.
  • When using basemap layers, try to avoid selecting, editing, etc., on the basemap layers.

The progressive basemap rendering feature is much like the obsolete DK10 IncrementalPaint feature, but better implemented and in a way that is compatible with any layer type.

Created: March 08, 2018, Modified: March 13, 2018