pixelToWorld method

Projected pixelToWorld(Scalable2i pixel)

Transforms pixel coordinates to world coordinates.

Coordinate value ranges:

• pixel x (int): 0 .. mapWidth(zoom) - 1
• pixel y (int): 0 .. mapHeight(zoom) - 1
• world x (double): 0.0 .. mapWidth(0)
• world y (double): 0.0 .. mapHeight(0)

Implementation

Projected pixelToWorld(Scalable2i pixel) {
  // convert pixel coordinates to world coordinates
  // - pixel range is: 0 .. size-1 (integer)
  // - this is first approximated to: 0.5 .. size-0.5
  // (where size is either map width or map height)
  // - then mapped to world coordinates (double values at zoom 0)
  final x = (pixel.x + 0.5) / (1 << pixel.zoom);
  final y = (pixel.y + 0.5) / (1 << pixel.zoom);

  // world coordinates size: number of pixels for x and y at the zoom level 0
  final width = mapWidth(0);
  final height = mapHeight(0);

  return Projected(
    // x and y coordinates projected to world coordinates
    x: x.clamp(0.0, width).toDouble(),
    y: y.clamp(0.0, height).toDouble(),
  );
}