render method

void render({ required Mappoint leftUpper, required int tileSize, required HgtTileRenderer tileRenderer, required Uint8List pixels, })

Implementation

void render({required Mappoint leftUpper, required int tileSize, required HgtTileRenderer tileRenderer, required Uint8List pixels}) {
  _ElevationGrid? elevationGrid = _calculateGrid(leftUpper: leftUpper, tileSize: tileSize);
  //print("elevationGrid: $elevationGrid");
  if (elevationGrid == null) {
    return;
  }

  ILatLong leftUpperLL = projection.pixelToLatLong(leftUpper.x, leftUpper.y);

  int row = 0;
  int maxY = 0;
  for (int y = 0; y < tileSize; ++y) {
    int column = 0;
    if (y > maxY) {
      ++row;
      // not enough rows available, out of boundary of the file(s), nothing to render
      if (row + 1 == elevationGrid.rows) break;
    }
    _ElevationPoint leftTop = elevationGrid.get(column, row);
    _ElevationPoint rightTop = elevationGrid.get(column + 1, row);
    _ElevationPoint leftBottom = elevationGrid.get(column, row + 1);
    _ElevationPoint rightBottom = elevationGrid.get(column + 1, row + 1);
    _ElevationArea area = _ElevationArea(leftTop: leftTop, rightTop: rightTop, leftBottom: leftBottom, rightBottom: rightBottom);
    maxY = leftBottom != const _ElevationPoint.invalid()
        ? leftBottom.y
        : rightBottom != const _ElevationPoint.invalid()
        ? rightBottom.y
        : maxY;
    for (int x = 0; x < tileSize; ++x) {
      int elevation = _interpolatedElevation(area, x, y);
      tileRenderer.render(pixels, tileSize, x, y, projection, leftUpperLL.latitude, leftUpperLL.longitude, elevation);
      if (x > rightTop.x) {
        if (column + 2 == elevationGrid.columns) break;
        ++column;
        leftTop = elevationGrid.get(column, row);
        rightTop = elevationGrid.get(column + 1, row);
        leftBottom = elevationGrid.get(column, row + 1);
        rightBottom = elevationGrid.get(column + 1, row + 1);
        area = _ElevationArea(leftTop: leftTop, rightTop: rightTop, leftBottom: leftBottom, rightBottom: rightBottom);
        maxY = leftBottom != const _ElevationPoint.invalid()
            ? leftBottom.y
            : rightBottom != const _ElevationPoint.invalid()
            ? rightBottom.y
            : maxY;
      }
    }
  }

  // for (int x = tileSize - 10; x < tileSize; ++x) {
  //   for (int y = tileSize - 10; y < tileSize; ++y) {
  //     int idx = y * tileSize + x;
  //     pixels.buffer.asUint32List()[idx] = 0xff00ff00;
  //   }
  // }
}