-Opaque = 0
+Opaque = 1
-Premul = 1
+Premul = 2
-Unpremul = 2
+Unpremul = 3

public static SKBitmap Decode (SKStreamRewindable stream, SKColorType pref);
public static SKBitmap Decode (byte[] buffer, SKColorType pref);
public static SKBitmap Decode (string filename, SKColorType pref);
public static SKImageInfo DecodeBounds (SKStreamRewindable stream, SKColorType pref);
public static SKImageInfo DecodeBounds (byte[] buffer, SKColorType pref);
public static SKImageInfo DecodeBounds (string filename, SKColorType pref);

public void ClipPath (SKPath path);
public void ClipRect (SKRect rect);
public void Save ();
public void SaveLayer (SKPaint paint);
public void SaveLayer (SKRect limit, SKPaint paint);

Alpha_8 = 3,
Bgra_8888 = 2,
N_32 = 5,
Rgb_565 = 4,
Rgba_8888 = 1,

public static SKImageFilter CreateDownSample (float scale, SKImageFilter input);

public SKPictureRecorder (IntPtr handle);

public SKPixelGeometry PixelGeometry { get; set; }