oxigdal-mobile 0.1.3

Mobile FFI bindings for OxiGDAL - iOS and Android support for Pure Rust geospatial library
Documentation

OxiGDAL Mobile SDK

Mobile FFI bindings for OxiGDAL - bringing Pure Rust geospatial capabilities to iOS and Android.

Overview

OxiGDAL Mobile provides C-compatible FFI bindings that enable OxiGDAL to be used from native iOS (Swift/Objective-C) and Android (Kotlin/Java) applications. This allows mobile developers to leverage OxiGDAL's powerful geospatial capabilities with:

  • Zero-copy operations for maximum performance
  • Offline-first COG (Cloud Optimized GeoTIFF) support
  • Pure Rust implementation - no C/C++ dependencies
  • Memory efficient design for mobile devices
  • Battery conscious algorithms
  • Platform-native APIs (Swift for iOS, Kotlin for Android)

Features

  • ✅ Raster dataset reading (GeoTIFF, COG, PNG, JPEG)
  • ✅ Vector dataset reading (GeoJSON, Shapefile, GeoPackage)
  • ✅ Map tile generation (XYZ scheme)
  • ✅ Image enhancement (brightness, contrast, saturation, gamma)
  • ✅ Coordinate transformations
  • ✅ Spatial filtering
  • ✅ Statistics computation
  • ✅ iOS UIImage integration
  • ✅ Android Bitmap integration
  • ✅ Memory-safe FFI layer
  • ✅ Comprehensive error handling

Architecture

┌─────────────────────────────────────────┐
│         Mobile Applications             │
│  ┌──────────────┐  ┌──────────────┐    │
│  │ Swift (iOS)  │  │Kotlin(Android)│    │
│  └──────────────┘  └──────────────┘    │
└─────────────────────────────────────────┘
           │                  │
           ▼                  ▼
┌─────────────────────────────────────────┐
│        Language Bindings                │
│  ┌──────────────┐  ┌──────────────┐    │
│  │OxiGDAL.swift │  │ OxiGDAL.kt   │    │
│  └──────────────┘  └──────────────┘    │
└─────────────────────────────────────────┘
                    │
                    ▼
┌─────────────────────────────────────────┐
│         C FFI Layer (Rust)              │
│  ┌───────────────────────────────────┐  │
│  │ • Error handling                  │  │
│  │ • Type conversions                │  │
│  │ • Memory management               │  │
│  │ • Platform-specific utilities     │  │
│  └───────────────────────────────────┘  │
└─────────────────────────────────────────┘
                    │
                    ▼
┌─────────────────────────────────────────┐
│          OxiGDAL Core                   │
│         (Pure Rust)                     │
└─────────────────────────────────────────┘

Platform Support

iOS

  • Minimum: iOS 13.0+
  • Architectures: arm64 (device), x86_64 (simulator)
  • Integration: Swift Package Manager, CocoaPods
  • Language: Swift 5.9+

Android

  • Minimum: Android 7.0 (API 24)+
  • Architectures: arm64-v8a, armeabi-v7a, x86_64
  • Integration: Gradle, AAR library
  • Language: Kotlin 1.9+

Quick Start

iOS (Swift)

import OxiGDAL

// Initialize
OxiGDAL.initialize()

// Open dataset
let dataset = try OxiGDAL.open("map.tif")

// Read as UIImage
let image = try dataset.toImage()
imageView.image = image

// Clean up
dataset.close()

Android (Kotlin)

import com.cooljapan.oxigdal.OxiGDAL

// Initialize
OxiGDAL.initialize()

// Open dataset
val dataset = OxiGDAL.open("map.tif")

// Read as Bitmap
val bitmap = dataset.toBitmap()
imageView.setImageBitmap(bitmap)

// Clean up
dataset.close()

Installation

See platform-specific guides:

Building

Prerequisites

  • Rust 1.85+
  • For iOS: Xcode 15.0+
  • For Android: Android NDK 26+

iOS Targets

# Add targets
rustup target add aarch64-apple-ios x86_64-apple-ios

# Build
cargo build --release --target aarch64-apple-ios --features ios
cargo build --release --target x86_64-apple-ios --features ios

Android Targets

# Add targets
rustup target add aarch64-linux-android armv7-linux-androideabi x86_64-linux-android

# Build
cargo build --release --target aarch64-linux-android --features android
cargo build --release --target armv7-linux-androideabi --features android
cargo build --release --target x86_64-linux-android --features android

API Overview

Core Types

  • OxiGdalDataset - Opaque handle to a dataset
  • OxiGdalBand - Opaque handle to a raster band
  • OxiGdalLayer - Opaque handle to a vector layer
  • OxiGdalFeature - Opaque handle to a feature
  • OxiGdalBuffer - Image buffer with pixel data
  • OxiGdalMetadata - Dataset metadata (size, bands, CRS, etc.)

Error Handling

All FFI functions return OxiGdalErrorCode:

typedef enum {
    Success = 0,
    NullPointer = 1,
    InvalidArgument = 2,
    FileNotFound = 3,
    IoError = 4,
    UnsupportedFormat = 5,
    OutOfBounds = 6,
    AllocationFailed = 7,
    InvalidUtf8 = 8,
    DriverError = 9,
    ProjectionError = 10,
    Unknown = 99
} OxiGdalErrorCode;

Detailed error messages are available via oxigdal_get_last_error().

Memory Management

  • Handles: Created by *_open/*_create, freed by *_close/*_free
  • Strings: Returned strings must be freed with oxigdal_string_free()
  • Buffers: Caller-allocated, OxiGDAL writes to them
  • Opaque Types: Never dereference on FFI side

Thread Safety

  • Error messages are thread-local
  • Handles can be used from different threads (with external synchronization)
  • No global mutable state

Features

  • std (default) - Standard library support
  • ios - iOS-specific bindings and utilities
  • android - Android JNI bindings and utilities
  • offline - Offline COG reading support
  • filters - Image enhancement filters
  • tiles - Map tile generation

Examples

Reading a Region

// C API
OxiGdalDataset* dataset;
oxigdal_dataset_open("/path/to/map.tif", &dataset);

OxiGdalBuffer* buffer = oxigdal_buffer_alloc(512, 512, 3);
oxigdal_dataset_read_region(dataset, 0, 0, 512, 512, 1, buffer);

// Use buffer...

oxigdal_buffer_free(buffer);
oxigdal_dataset_close(dataset);

Map Tiles

OxiGdalTileCoord coord = { .z = 10, .x = 512, .y = 341 };
OxiGdalTile* tile;
oxigdal_dataset_read_tile(dataset, &coord, 256, &tile);

Metadata

OxiGdalMetadata metadata;
oxigdal_dataset_get_metadata(dataset, &metadata);

printf("Size: %dx%d\n", metadata.width, metadata.height);
printf("Bands: %d\n", metadata.band_count);
printf("EPSG: %d\n", metadata.epsg_code);

Testing

# Run tests
cargo test --features std

# Run iOS tests
cargo test --target aarch64-apple-ios --features ios

# Run Android tests
cargo test --target aarch64-linux-android --features android

Performance

The mobile SDK is optimized for:

  • Low memory footprint - Streaming operations, no large allocations
  • Battery efficiency - Minimal CPU usage, efficient algorithms
  • Fast startup - Lazy initialization, minimal setup
  • Offline performance - Local file operations, no network required

Limitations

  • Maximum dataset size depends on available device memory
  • Some operations may be slower on older devices
  • Mobile-native exposure of all 11 format drivers still expanding (v0.2.0)

Roadmap

Release Feature
v0.1.0 (released) GeoTIFF/COG, GeoJSON, Shapefile, PROJ, raster algorithms, offline sync
v0.2.0 (Q2 2026) HDF5, NetCDF, Zarr mobile bindings; write support expansion; 3D terrain
v0.3.0 (Q3 2026) Real-time GPS integration, streaming from cloud storage, background tile generation

Contributing

Contributions are welcome! Please see CONTRIBUTING.md.

License

Licensed under Apache License 2.0. See LICENSE for details.

Authors

Copyright (c) 2026 COOLJAPAN OU (Team Kitasan)

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