/// <summary>
/// Draws the specified <see cref="CatalogManager.Catalog"/> tile to the <see
/// cref="PaintBuffer"/>, with alpha blending and color substitution.</summary>
/// <param name="dest">
/// The location within the <see cref="PaintBuffer"/> where to draw.</param>
/// <param name="region">
/// The bitmap region within the <see cref="CatalogManager.Catalog"/> to copy, relative to
/// the tile with the specified <paramref name="index"/>.</param>
/// <param name="index">
/// The <see cref="CatalogManager.Catalog"/> index of the tile to draw.</param>
/// <param name="color">
/// The <see cref="Color"/> whose color channels are substituted for those of all <see
/// cref="CatalogManager.Catalog"/> pixels, retaining only their alpha channel.</param>
private void DrawTile(PointI dest, RectI region, int index, Color color)
{
// add upper-left corner of catalog tile
region = region.Offset(MapView.GetTileLocation(index));
// copy visible part of catalog tile to buffer
PaintBuffer.Overlay(dest.X, dest.Y, MapView.Catalog, region, color);
}
public void Offset()
{
Assert.AreEqual(new RectD(4, 6, 4, 5), rectD.Offset(new PointD(3, 4)));
Assert.AreEqual(new RectF(4, 6, 4, 5), rectF.Offset(new PointF(3, 4)));
Assert.AreEqual(new RectI(4, 6, 4, 5), rectI.Offset(new PointI(3, 4)));
}