Layer Management for TUniMap

[Kattes]

Overview

I would like to request an enhancement to the TUniMap component that introduces advanced layer management capabilities, allowing for more flexible and dynamic map presentations in UniGUI applications. The proposed extension would facilitate the handling of various map layers, including bitmap and vector layers, with features such as custom Z-indexing and transparency control.

Proposed Features

Layer Type Enumeration: Introduce TMapLayerType to distinguish between different types of map layers (e.g., bitmap, vector).

Base Map Layer Class: Implement a TMapLayer base class with properties like ID, LayerType, and ZIndex, and methods for adding to the map, removing from the map, and updating the Z-index.

Bitmap and Vector Layer Classes: Create TBitmapLayer and TVectorLayer subclasses to manage specific layer types, including functionalities for setting transparency (for bitmap layers) and handling vector data.

Extended UniMap Component: Develop TExtendedUniMap, an enhanced version of TUniMap, with capabilities to add, remove, update, and reorder layers dynamically. This component should manage a collection of TMapLayer objects, offering a unified interface for layer manipulation.

Justification

In many mapping applications, the need to dynamically adjust the visibility and order of layers is crucial for providing users with a clear and informative view of the data. The ability to change the transparency of layers, apply blending modes, and manipulate the stacking order (Z-index) of both bitmap and vector layers would greatly enhance the flexibility and utility of the TUniMap component.

Example Use Cases

Environmental Monitoring: Displaying real-time data overlays (e.g., weather, pollution) on top of a base map, with user-controlled transparency for comparative analysis.

Geospatial Analysis: Layering thematic maps in a specific order, adjusting visibility and order to highlight spatial relationships or patterns.

Urban Planning: Overlaying architectural plans or development proposals on existing city maps, allowing for interactive exploration of future changes.